/* =====================================================================
   MSG MOTOC — client PWA
   Vanilla JS, aucun build. Sections : état, API, auth, WebSocket,
   groupes, conversation, images P2P (WebRTC), réglages, administration.
   ===================================================================== */

(() => {
  'use strict';

  /* ------------------------------------------------------------------ */
  /* État                                                                */
  /* ------------------------------------------------------------------ */

  const state = {
    token: localStorage.getItem('motoc_token') || '',
    me: null,
    groups: [],
    groupsById: new Map(),
    currentGroup: null,
    messages: [],
    oldestId: null,
    hasMore: false,
    replyTo: null,
    ws: null,
    wsRetry: 0,
    typing: new Map(), // group_id -> Map(phone -> timestamp)
    pins: [],
    receipts: [], // état de lecture des membres du groupe ouvert
    pendingPhone: '',
    loginRole: 'benevole',
    loadingHistory: false,
  };

  const $ = (sel) => document.querySelector(sel);
  const $$ = (sel) => Array.from(document.querySelectorAll(sel));

  /* ------------------------------------------------------------------ */
  /* Utilitaires                                                         */
  /* ------------------------------------------------------------------ */

  function escapeHtml(s) {
    return String(s ?? '')
      .replace(/&/g, '&')
      .replace(/</g, '&lt;')
      .replace(/>/g, '&gt;')
      .replace(/"/g, '&quot;')
      .replace(/'/g, '&#39;');
  }

  // Applique les liens et les mentions sur du texte DÉJÀ échappé.
  function enrich(escaped) {
    return escaped
      .replace(
        /(https?:\/\/[^\s<]+)/g,
        (m) => `<a href="${m}" target="_blank" rel="noopener noreferrer">${m}</a>`,
      )
      .replace(/(^|\s)(@[\wÀ-ÿ'-]+)/gu, '$1<span class="mention">$2</span>');
  }

  function initials(name) {
    // Les comptes du bac à sable sont tous préfixés « test_ » : sans cette
    // coupe, les vingt avatars afficheraient le même « TE ».
    const raw = String(name || '')
      .trim()
      .replace(/\btest_/gi, '');
    // Un compte pas encore activé n'a que son numéro : « 06 11 22 » ne fait
    // pas des initiales lisibles, on retombe sur un neutre.
    if (!raw || /^[\d\s+.-]+$/.test(raw)) return '?';
    const parts = raw.split(/\s+/).filter(Boolean);
    if (!parts.length) return '?';
    if (parts.length === 1) return parts[0].slice(0, 2).toUpperCase();
    return (parts[0][0] + parts[1][0]).toUpperCase();
  }

  // Couleur d'avatar dérivée du numéro : stable, et alternée cyan/braise.
  function avatarClass(phone) {
    let h = 0;
    for (const c of String(phone || '')) h = (h * 31 + c.charCodeAt(0)) >>> 0;
    return h % 2 === 0 ? '' : 'ember';
  }

  function fmtTime(ms) {
    return new Date(ms).toLocaleTimeString('fr-FR', { hour: '2-digit', minute: '2-digit' });
  }

  function fmtDay(ms) {
    const d = new Date(ms);
    const today = new Date();
    const yest = new Date();
    yest.setDate(today.getDate() - 1);
    const same = (a, b) => a.toDateString() === b.toDateString();
    if (same(d, today)) return "Aujourd'hui";
    if (same(d, yest)) return 'Hier';
    return d.toLocaleDateString('fr-FR', { weekday: 'long', day: 'numeric', month: 'long' });
  }

  function fmtRelative(ms) {
    if (!ms) return '';
    const diff = Date.now() - ms;
    if (diff < 60000) return "à l'instant";
    if (diff < 3600000) return `${Math.floor(diff / 60000)} min`;
    if (diff < 86400000) return fmtTime(ms);
    const d = new Date(ms);
    return d.toLocaleDateString('fr-FR', { day: '2-digit', month: '2-digit' });
  }

  function fmtBytes(n) {
    if (n === null || n === undefined) return '—';
    if (n < 1024) return `${Math.round(n)} o`;
    if (n < 1048576) return `${(n / 1024).toFixed(0)} Ko`;
    if (n < 1073741824) return `${(n / 1048576).toFixed(1)} Mo`;
    return `${(n / 1073741824).toFixed(2)} Go`;
  }

  function fmtDateTime(ms) {
    return new Date(ms).toLocaleString('fr-FR', {
      day: '2-digit',
      month: '2-digit',
      hour: '2-digit',
      minute: '2-digit',
    });
  }

  function toast(message, kind = '') {
    const el = document.createElement('div');
    el.className = `toast ${kind}`;
    el.textContent = message;
    $('#toasts').appendChild(el);
    setTimeout(() => {
      el.style.opacity = '0';
      el.style.transition = 'opacity .3s';
      setTimeout(() => el.remove(), 300);
    }, 3600);
  }

  function vibrate(pattern) {
    if (navigator.vibrate) {
      try {
        navigator.vibrate(pattern);
      } catch (e) {
        /* ignoré */
      }
    }
  }

  /* ------------------------------------------------------------------ */
  /* API                                                                 */
  /* ------------------------------------------------------------------ */

  async function api(path, options = {}) {
    // Un FormData part tel quel : le navigateur pose lui-même le Content-Type
    // avec la frontière multipart, qu'on ne peut pas écrire à la main.
    const isForm = options.body instanceof FormData;
    const headers = {
      ...(isForm ? {} : { 'Content-Type': 'application/json' }),
      ...(options.headers || {}),
    };
    if (state.token) headers.Authorization = `Bearer ${state.token}`;
    const res = await fetch(path, {
      ...options,
      headers,
      body: options.body ? (isForm ? options.body : JSON.stringify(options.body)) : undefined,
    });
    let data = null;
    try {
      data = await res.json();
    } catch (e) {
      data = null;
    }
    if (!res.ok) {
      if (res.status === 401 && state.token) {
        logout(true);
        throw new Error('Session expirée. Reconnectez-vous.');
      }
      throw new Error((data && data.detail) || `Erreur ${res.status}`);
    }
    return data;
  }

  /* ------------------------------------------------------------------ */
  /* Navigation entre écrans                                             */
  /* ------------------------------------------------------------------ */

  function showScreen(id) {
    $$('.screen').forEach((s) => s.classList.remove('active'));
    $(`#${id}`).classList.add('active');
  }

  function openOverlay(id) {
    $(`#${id}`).classList.add('active');
    history.pushState({ overlay: id }, '');
  }

  function closeOverlay(id) {
    $(`#${id}`).classList.remove('active');
    // Quitter le panneau d'administration arrête le sondage matériel et
    // rend à l'application son cadre étroit.
    if (id === 'screen-admin') {
      stopSystem();
      $('#app').classList.remove('desk');
    }
  }

  window.addEventListener('popstate', () => {
    // Le bouton « retour » ferme la vue superposée la plus haute.
    for (const id of ['screen-sandbox', 'screen-chat', 'screen-admin', 'screen-settings']) {
      const el = $(`#${id}`);
      if (el.classList.contains('active')) {
        if (id === 'screen-chat') leaveChat(false);
        else closeOverlay(id);
        return;
      }
    }
  });

  /* ------------------------------------------------------------------ */
  /* Authentification                                                    */
  /* ------------------------------------------------------------------ */

  function authError(message) {
    $('#auth-error').textContent = message || '';
  }

  function showAuthStep(step) {
    $$('.auth-step').forEach((el) => {
      el.hidden = el.id !== step;
    });
    authError('');
  }

  /* --- Choix du profil : Admin ou Bénévole ---------------------------- */
  // « Admin » signifie superadmin. La vérification est faite côté serveur
  // après le PIN : l'écran ne révèle jamais quels numéros sont admins.

  function setRole(role) {
    state.loginRole = role;
    const isAdmin = role === 'admin';
    $('#role-pill-slot').innerHTML = `<span class="role-pill ${isAdmin ? '' : 'benevole'}">
      ${isAdmin ? 'Espace admin' : 'Espace bénévole'}</span>`;
    showAuthStep('step-phone');
    setTimeout(() => $('#in-phone').focus(), 120);
  }

  $$('.role-card').forEach((card) =>
    card.addEventListener('click', () => setRole(card.dataset.role)),
  );

  $$('[data-back-to-role]').forEach((b) =>
    b.addEventListener('click', () => showAuthStep('step-role')),
  );

  // Saisie du téléphone : groupée par deux, chiffres uniquement.
  $('#in-phone').addEventListener('input', (e) => {
    const digits = e.target.value.replace(/\D/g, '').slice(0, 10);
    e.target.value = digits.replace(/(\d{2})(?=\d)/g, '$1 ').trim();
  });

  // Champs PIN : chiffres uniquement.
  $$('.input-pin').forEach((input) => {
    input.addEventListener('input', (e) => {
      e.target.value = e.target.value.replace(/\D/g, '').slice(0, 6);
    });
  });

  async function submitPhone() {
    const phone = $('#in-phone').value.replace(/\D/g, '');
    if (phone.length !== 10) return authError('Saisissez un numéro à 10 chiffres.');
    const btn = $('#btn-phone');
    btn.disabled = true;
    try {
      const res = await api('/api/auth/check', { method: 'POST', body: { phone } });
      state.pendingPhone = phone;
      if (res.state === 'register') {
        $('#reg-phone').textContent = res.phone_display;
        // Numéro jamais vu : on prévient que les groupes viendront plus tard,
        // sinon l'écran suivant paraît cassé (aucun groupe à l'arrivée).
        $('#reg-newcomer').hidden = !res.new_account;
        showAuthStep('step-register');
        setTimeout(() => $('#in-first').focus(), 120);
      } else if (res.state === 'login') {
        $('#login-name').textContent = res.display_name || 'Bienvenue';
        $('#login-phone').textContent = res.phone_display;
        showAuthStep('step-login');
        setTimeout(() => $('#in-pin').focus(), 120);
      } else {
        authError(res.message || 'Numéro non reconnu.');
      }
    } catch (err) {
      authError(err.message);
    } finally {
      btn.disabled = false;
    }
  }

  async function submitRegister() {
    const first = $('#in-first').value.trim();
    const last = $('#in-last').value.trim();
    const nick = $('#in-nick').value.trim();
    const pin1 = $('#in-pin1').value;
    const pin2 = $('#in-pin2').value;

    if (!first) return authError('Le prénom est obligatoire.');
    if (!last) return authError('Le nom est obligatoire.');
    if (pin1.length !== 6) return authError('Le code PIN doit contenir 6 chiffres.');
    if (pin1 !== pin2) return authError('Les deux codes PIN ne correspondent pas.');

    const btn = $('#btn-register');
    btn.disabled = true;
    try {
      const res = await api('/api/auth/register', {
        method: 'POST',
        body: {
          phone: state.pendingPhone,
          first_name: first,
          last_name: last,
          nickname: nick,
          pin: pin1,
          role: state.loginRole,
        },
      });
      onAuthenticated(res);
    } catch (err) {
      authError(err.message);
    } finally {
      btn.disabled = false;
    }
  }

  async function submitLogin() {
    const pin = $('#in-pin').value;
    if (pin.length !== 6) return authError('Le code PIN doit contenir 6 chiffres.');
    const btn = $('#btn-login');
    btn.disabled = true;
    try {
      const res = await api('/api/auth/login', {
        method: 'POST',
        body: { phone: state.pendingPhone, pin, role: state.loginRole },
      });
      onAuthenticated(res);
    } catch (err) {
      authError(err.message);
      $('#in-pin').value = '';
    } finally {
      btn.disabled = false;
    }
  }

  function onAuthenticated(res) {
    state.token = res.token;
    state.me = res.user;
    localStorage.setItem('motoc_token', res.token);
    $('#in-pin').value = $('#in-pin1').value = $('#in-pin2').value = '';
    enterApp();
  }

  function logout(silent) {
    state.token = '';
    state.me = null;
    localStorage.removeItem('motoc_token');
    if (state.ws) {
      try {
        state.ws.close();
      } catch (e) {
        /* ignoré */
      }
      state.ws = null;
    }
    $$('.screen.overlay').forEach((s) => s.classList.remove('active'));
    $('#app').classList.remove('shell', 'desk');
    showScreen('screen-auth');
    showAuthStep('step-role');
    if (!silent) toast('Vous êtes déconnecté.');
  }

  $('#btn-phone').addEventListener('click', submitPhone);
  $('#btn-register').addEventListener('click', submitRegister);
  $('#btn-login').addEventListener('click', submitLogin);
  $$('[data-back-to-phone]').forEach((b) =>
    b.addEventListener('click', () => showAuthStep('step-phone')),
  );
  $('#in-phone').addEventListener('keydown', (e) => e.key === 'Enter' && submitPhone());
  $('#in-pin').addEventListener('keydown', (e) => e.key === 'Enter' && submitLogin());
  $('#in-pin2').addEventListener('keydown', (e) => e.key === 'Enter' && submitRegister());

  /* ------------------------------------------------------------------ */
  /* Entrée dans l'application                                           */
  /* ------------------------------------------------------------------ */

  async function enterApp() {
    showScreen('screen-groups');
    // Passe l'application en disposition « poste de travail » : au-delà de
    // 1024 px, la liste des groupes et la conversation cohabitent.
    $('#app').classList.add('shell');
    $('#btn-admin').hidden = !state.me.is_superadmin;
    await loadGroups();
    connectWS();
    refreshPushSwitch();
    loadHelpRequests();

    // Ouverture directe d'un groupe depuis une notification.
    const target = new URLSearchParams(location.search).get('groupe');
    if (target) {
      history.replaceState(null, '', '/');
      const g = state.groupsById.get(Number(target));
      if (g) openChat(g.id);
    }
  }

  async function boot() {
    if (!state.token) {
      showScreen('screen-auth');
      return;
    }
    try {
      state.me = await api('/api/me');
      await enterApp();
    } catch (err) {
      logout(true);
    }
  }

  /* ------------------------------------------------------------------ */
  /* WebSocket                                                           */
  /* ------------------------------------------------------------------ */

  function setConnState(text, ok) {
    const el = $('#conn-state');
    el.textContent = text;
    el.style.color = ok ? 'var(--text-faint)' : 'var(--ember)';
  }

  function connectWS() {
    if (!state.token) return;
    if (state.ws && state.ws.readyState <= 1) return;

    const proto = location.protocol === 'https:' ? 'wss' : 'ws';
    const ws = new WebSocket(`${proto}://${location.host}/ws`);
    state.ws = ws;
    setConnState('Connexion…', false);

    ws.onopen = () => {
      // Le token part dans une frame, jamais dans l'URL : une query string
      // finit dans les logs de proxy et l'historique du navigateur.
      ws.send(JSON.stringify({ type: 'auth', token: state.token }));
      state.wsRetry = 0;
      setConnState('Authentification…', false);
      if (state.currentGroup) wsSend({ type: 'focus', group_id: state.currentGroup.id });
    };

    ws.onmessage = (event) => {
      let data;
      try {
        data = JSON.parse(event.data);
      } catch (e) {
        return;
      }
      handleWsMessage(data);
    };

    ws.onclose = (event) => {
      state.ws = null;
      if (event.code === 4001) {
        logout(true);
        return;
      }
      if (event.code === 4002) {
        setConnState('Trop d’appareils connectés', false);
        return;
      }
      setConnState('Hors ligne', false);
      // Reconnexion en exponential backoff, plafonnée à 15 s.
      state.wsRetry = Math.min(state.wsRetry + 1, 6);
      setTimeout(connectWS, Math.min(1000 * 2 ** state.wsRetry, 15000));
    };

    ws.onerror = () => {
      /* onclose prend le relais */
    };
  }

  function wsSend(payload) {
    if (state.ws && state.ws.readyState === 1) {
      state.ws.send(JSON.stringify(payload));
      return true;
    }
    return false;
  }

  function handleWsMessage(data) {
    switch (data.type) {
      case 'ready':
        setConnState('En ligne', true);
        break;

      case 'message':
        onIncomingMessage(data.message);
        break;

      case 'message_deleted':
        if (state.currentGroup && state.currentGroup.id === data.group_id) {
          state.messages = state.messages.filter((m) => m.id !== data.id);
          renderThread();
        }
        loadGroups();
        break;

      case 'typing':
        onTyping(data);
        break;

      case 'groups_changed':
        loadGroups();
        break;

      case 'help_request':
        toast(`${data.label} demande de l'aide pour se connecter.`);
        vibrate([40, 60, 40]);
        loadHelpRequests();
        break;

      case 'read_receipt': {
        // Fait avancer les coches sans recharger toute la conversation.
        if (!state.currentGroup || state.currentGroup.id !== data.group_id) break;
        const member = state.receipts.find((m) => m.phone === data.phone);
        if (member) {
          member.last_read_id = Math.max(member.last_read_id, data.last_read_id);
          member.online = true;
          renderThread();
        }
        break;
      }

      case 'moderation_alert':
        toast(
          `Signalement · ${data.alert.category_label} — ${data.alert.author} dans ${data.alert.group_name}`,
          'error',
        );
        vibrate([40, 60, 40]);
        if ($('#screen-admin').classList.contains('active')) loadModeration();
        break;

      case 'new_self_registration':
        // Le compte existe mais n'a aucun groupe : sans cette alerte, la
        // personne attendrait indéfiniment devant une liste vide.
        toast(`${data.label} vient de s'inscrire. À affecter à un groupe.`);
        vibrate([40, 60, 40]);
        loadAdminUsers();
        break;

      case 'message_pinned':
        if (state.currentGroup && state.currentGroup.id === data.group_id) {
          const existing = state.messages.find((m) => m.id === data.message.id);
          if (existing) existing.pinned_at = data.message.pinned_at;
          loadPins(data.group_id);
          renderThread();
        }
        break;

      case 'rtc-signal':
        handleRtcSignal(data);
        break;

      case 'image-request':
        handleImageRequest(data);
        break;
    }
  }

  function onIncomingMessage(msg) {
    const open = state.currentGroup && state.currentGroup.id === msg.group_id;
    if (open) {
      if (state.messages.some((m) => m.id === msg.id)) return;
      const atBottom = isThreadAtBottom();
      state.messages.push(msg);
      renderThread();
      if (atBottom) scrollThreadToBottom();
      markRead(msg.group_id, msg.id);
    } else if (msg.author_phone !== state.me.phone && msg.kind !== 'system') {
      showInAppNotif(msg);
      vibrate(40);
    }
    loadGroups();
  }

  function showInAppNotif(msg) {
    const group = state.groupsById.get(msg.group_id);
    const el = document.createElement('div');
    el.className = 'inapp-notif';
    const preview = msg.kind === 'image' ? '📷 Photo' : msg.body;
    el.innerHTML = `
      <div class="avatar sm ${avatarClass(msg.author_phone)}">${escapeHtml(initials(msg.author_label))}</div>
      <div style="flex:1;min-width:0">
        <div class="t">${escapeHtml(group ? group.name : 'Nouveau message')}</div>
        <div class="b">${escapeHtml(msg.author_label)} : ${escapeHtml(preview)}</div>
      </div>`;
    el.addEventListener('click', () => {
      el.remove();
      openChat(msg.group_id);
    });
    document.body.appendChild(el);
    setTimeout(() => el.remove(), 4500);
  }

  function onTyping(data) {
    if (!state.currentGroup || state.currentGroup.id !== data.group_id) return;
    if (data.phone === state.me.phone) return;
    let map = state.typing.get(data.group_id);
    if (!map) {
      map = new Map();
      state.typing.set(data.group_id, map);
    }
    map.set(data.phone, { name: data.name, at: Date.now() });
    renderTyping();
  }

  function renderTyping() {
    const line = $('#typing-line');
    if (!state.currentGroup) {
      line.textContent = '';
      return;
    }
    const map = state.typing.get(state.currentGroup.id);
    if (!map) {
      line.textContent = '';
      return;
    }
    const now = Date.now();
    for (const [phone, info] of map) if (now - info.at > 4000) map.delete(phone);
    const names = Array.from(map.values()).map((v) => v.name);
    if (!names.length) line.textContent = '';
    else if (names.length === 1) line.textContent = `${names[0]} écrit…`;
    else line.textContent = `${names.slice(0, 2).join(', ')} écrivent…`;
  }

  setInterval(renderTyping, 1500);

  /* ------------------------------------------------------------------ */
  /* Liste des groupes                                                   */
  /* ------------------------------------------------------------------ */

  async function loadGroups() {
    try {
      const res = await api('/api/groups');
      state.groups = res.groups;
      state.groupsById = new Map(res.groups.map((g) => [g.id, g]));
      renderGroups();
      updateBadge();
    } catch (err) {
      /* la reconnexion réessaiera */
    }
  }

  function updateBadge() {
    const total = state.groups.reduce((sum, g) => sum + g.unread, 0);
    if (navigator.setAppBadge) {
      try {
        total ? navigator.setAppBadge(total) : navigator.clearAppBadge();
      } catch (e) {
        /* ignoré */
      }
    }
    document.title = total ? `(${total}) MSG MOTOC` : 'MSG MOTOC';
  }

  function renderGroups() {
    const term = $('#in-search').value.trim().toLowerCase();
    const list = $('#groups-list');
    let groups = state.groups;
    if (term) groups = groups.filter((g) => g.name.toLowerCase().includes(term));

    if (!groups.length) {
      list.innerHTML = `
        <div class="empty">
          <svg><use href="#i-chat" /></svg>
          <h3>${term ? 'Aucun résultat' : 'Aucun groupe'}</h3>
          <p>${
            term
              ? 'Essayez un autre terme de recherche.'
              : "Vous n'appartenez encore à aucun groupe.<br />Un administrateur doit vous y ajouter."
          }</p>
        </div>`;
      return;
    }

    // Arborescence à deux niveaux : groupe principal puis sous-groupes.
    const ids = new Set(groups.map((g) => g.id));
    const roots = groups.filter((g) => !g.parent_id || !ids.has(g.parent_id));
    const children = new Map();
    for (const g of groups) {
      if (g.parent_id && ids.has(g.parent_id)) {
        if (!children.has(g.parent_id)) children.set(g.parent_id, []);
        children.get(g.parent_id).push(g);
      }
    }

    const html = roots
      .map((root) => {
        const kids = children.get(root.id) || [];
        return `<div class="group-section">
          ${groupRow(root, false)}
          ${kids.map((k) => groupRow(k, true)).join('')}
        </div>`;
      })
      .join('');
    list.innerHTML = html;

    list.querySelectorAll('.group-row').forEach((row) => {
      row.addEventListener('click', () => openChat(Number(row.dataset.id)));
    });
  }

  function groupRow(g, isChild) {
    const last = g.last_message;
    let preview = 'Aucun message';
    if (last) {
      if (last.kind === 'system') preview = last.body;
      else if (last.kind === 'image') preview = `${last.author_label} : 📷 Photo`;
      else preview = `${last.author_label} : ${last.body}`;
    }
    return `
      <button class="group-row ${isChild ? 'child' : ''}" data-id="${g.id}">
        <div class="avatar ${isChild ? 'ember' : ''}">${escapeHtml(initials(g.name))}</div>
        <div class="group-main">
          <div class="group-name">
            <span>${escapeHtml(g.name)}</span>
            ${g.role === 'admin' ? '<span class="tag admin">Admin</span>' : ''}
            ${g.notif_mode === 'mute' ? '<span class="tag muted">Muet</span>' : ''}
          </div>
          <div class="group-preview">${escapeHtml(preview)}</div>
        </div>
        <div class="group-meta">
          <span class="group-time">${last ? fmtRelative(last.created_at) : ''}</span>
          ${g.unread ? `<span class="badge">${g.unread > 99 ? '99+' : g.unread}</span>` : ''}
        </div>
      </button>`;
  }

  $('#in-search').addEventListener('input', renderGroups);

  /* ------------------------------------------------------------------ */
  /* Conversation                                                        */
  /* ------------------------------------------------------------------ */

  async function openChat(groupId) {
    const group = state.groupsById.get(groupId);
    if (!group) return;
    state.currentGroup = group;
    state.messages = [];
    state.replyTo = null;
    updateReplyBar();

    $('#chat-title').textContent = group.name;
    $('#chat-sub').textContent = `${group.member_count} membre${group.member_count > 1 ? 's' : ''}`;
    $('#thread').innerHTML =
      '<div class="empty"><svg class="spin"><use href="#i-loader" /></svg></div>';

    openOverlay('screen-chat');
    wsSend({ type: 'focus', group_id: groupId });
    loadPins(groupId);
    await loadReceipts(groupId);

    try {
      const res = await api(`/api/groups/${groupId}/messages`);
      state.messages = res.messages;
      state.hasMore = res.has_more;
      state.oldestId = res.messages.length ? res.messages[0].id : null;
      renderThread();
      scrollThreadToBottom();
      if (res.messages.length) {
        markRead(groupId, res.messages[res.messages.length - 1].id);
      }
    } catch (err) {
      toast(err.message, 'error');
    }
  }

  /* --- Accusés de réception ------------------------------------------- */
  // Un seul chargement par conversation : l'état de lecture de chaque membre.
  // Les coches de chaque message s'en déduisent par comparaison d'identifiant,
  // ce qui évite de stocker un accusé par message et par destinataire.

  async function loadReceipts(groupId) {
    try {
      const res = await api(`/api/groups/${groupId}/receipts`);
      state.receipts = res.members;
    } catch (err) {
      state.receipts = [];
    }
  }

  // Destinataires : tout le monde sauf soi.
  function others() {
    return state.receipts.filter((m) => m.phone !== state.me.phone);
  }

  function readersOf(messageId) {
    return others().filter((m) => m.last_read_id >= messageId);
  }

  // « Remis » : le destinataire s'est connecté après l'envoi, donc son
  // appareil a reçu le message. C'est une approximation assumée — le seul
  // moyen d'être exact serait un accusé par message et par appareil, dont le
  // coût de stockage est disproportionné ici.
  function deliveredTo(message) {
    return others().filter((m) => m.online || m.last_seen >= message.created_at);
  }

  function receiptState(message) {
    const total = others().length;
    if (!total) return { level: 'sent', label: 'Envoyé' };
    const read = readersOf(message.id).length;
    if (read >= total) return { level: 'read', label: 'Lu par tout le monde' };
    if (read > 0) return { level: 'read-partial', label: `Lu par ${read} sur ${total}` };
    const delivered = deliveredTo(message).length;
    if (delivered >= total) return { level: 'delivered', label: 'Remis à tout le monde' };
    if (delivered > 0) return { level: 'delivered', label: `Remis à ${delivered} sur ${total}` };
    return { level: 'sent', label: 'Envoyé' };
  }

  function receiptMark(message) {
    // Uniquement sur ses propres messages : ailleurs, l'information n'a pas de sens.
    if (message.author_phone !== state.me.phone || message.kind === 'system') return '';
    const { level, label } = receiptState(message);
    const icon = level === 'sent' ? 'i-check' : 'i-check2';
    return `<svg class="receipt ${level}" title="${escapeHtml(label)}"><use href="#${icon}"/></svg>`;
  }

  async function showReaders(message) {
    await loadReceipts(message.group_id);
    const read = readersOf(message.id);
    const delivered = deliveredTo(message).filter((m) => m.last_read_id < message.id);
    const pending = others().filter(
      (m) => m.last_read_id < message.id && !delivered.includes(m),
    );

    const block = (title, people, className) =>
      people.length
        ? `<div class="readers-block">
             <div class="readers-title ${className}">${escapeHtml(title)} · ${people.length}</div>
             ${people
               .map(
                 (m) => `<div class="readers-row">
                   <div class="avatar sm ${avatarClass(m.phone)}">${escapeHtml(initials(m.display_name))}</div>
                   <span>${escapeHtml(m.display_name)}</span>
                   ${m.online ? '<span class="dot online"></span>' : ''}
                 </div>`,
               )
               .join('')}
           </div>`
        : '';

    openSheet(`
      <h3>Accusés de lecture</h3>
      <p class="sheet-note">« ${escapeHtml(
        (message.kind === 'image' ? 'Photo' : message.body).slice(0, 90),
      )} »</p>
      ${block('Lu', read, 'read')}
      ${block('Remis, pas encore lu', delivered, 'delivered')}
      ${block('Pas encore remis', pending, 'pending')}
      ${
        !others().length
          ? '<p class="empty-note">Vous êtes seul dans ce groupe pour le moment.</p>'
          : ''
      }
    `);
  }

  /* --- Messages épinglés ---------------------------------------------- */
  // Bandeau permanent en haut du fil : les consignes de service doivent
  // rester visibles sans remonter l'historique.

  async function loadPins(groupId) {
    const bar = $('#pin-bar');
    try {
      const res = await api(`/api/groups/${groupId}/pins`);
      state.pins = res.messages;
      if (!res.messages.length) {
        bar.hidden = true;
        bar.innerHTML = '';
        return;
      }
      bar.hidden = false;
      bar.innerHTML = res.messages
        .map(
          (m) => `<div class="pin-item" data-pin="${m.id}">
            <svg><use href="#i-pin"/></svg>
            <div class="pin-text">
              <strong>${escapeHtml(m.author_label)}</strong>
              ${escapeHtml(m.kind === 'image' ? 'Photo épinglée' : m.body).slice(0, 160)}
            </div>
          </div>`,
        )
        .join('');
      bar.querySelectorAll('[data-pin]').forEach((item) =>
        item.addEventListener('click', () => {
          const target = document.getElementById(`msg-${item.dataset.pin}`);
          if (target) target.scrollIntoView({ behavior: 'smooth', block: 'center' });
          else toast("Ce message n'est pas dans la partie chargée du fil.");
        }),
      );
    } catch (err) {
      bar.hidden = true;
    }
  }

  function leaveChat(pop = true) {
    closeOverlay('screen-chat');
    state.currentGroup = null;
    wsSend({ type: 'focus', group_id: null });
    loadGroups();
    if (pop) history.back();
  }

  function markRead(groupId, lastId) {
    wsSend({ type: 'read', group_id: groupId, last_read_id: lastId });
    const g = state.groupsById.get(groupId);
    if (g && g.unread) {
      g.unread = 0;
      renderGroups();
      updateBadge();
    }
  }

  function isThreadAtBottom() {
    const t = $('#thread');
    return t.scrollHeight - t.scrollTop - t.clientHeight < 120;
  }

  function scrollThreadToBottom() {
    const t = $('#thread');
    requestAnimationFrame(() => {
      t.scrollTop = t.scrollHeight;
    });
  }

  function renderThread() {
    const thread = $('#thread');
    if (!state.messages.length) {
      thread.innerHTML = `
        <div class="empty">
          <svg><use href="#i-chat" /></svg>
          <h3>Conversation vide</h3>
          <p>Envoyez le premier message.</p>
        </div>`;
      return;
    }

    const parts = [];
    if (state.hasMore) {
      parts.push(
        '<button class="btn-link" id="btn-more" style="margin-bottom:8px">Charger les messages précédents</button>',
      );
    }

    let lastDay = '';
    let prev = null;
    for (const msg of state.messages) {
      const day = fmtDay(msg.created_at);
      if (day !== lastDay) {
        parts.push(`<div class="day-sep">${escapeHtml(day)}</div>`);
        lastDay = day;
        prev = null;
      }
      if (msg.kind === 'system') {
        parts.push(`<div class="sys-msg">${escapeHtml(msg.body)}</div>`);
        prev = null;
        continue;
      }
      // Regroupement : même auteur, à moins de 5 minutes d'écart.
      const grouped =
        prev &&
        prev.author_phone === msg.author_phone &&
        msg.created_at - prev.created_at < 300000;
      parts.push(renderMessage(msg, grouped));
      prev = msg;
    }
    thread.innerHTML = parts.join('');

    const more = $('#btn-more');
    if (more) more.addEventListener('click', loadOlder);
    attachMessageHandlers();
    hydrateImages();
  }

  function renderMessage(msg, grouped) {
    const mine = msg.author_phone === state.me.phone;
    const cls = `msg ${mine ? 'mine' : 'theirs'} ${grouped ? 'grouped' : ''}`;

    let quote = '';
    if (msg.reply_to) {
      const parent = state.messages.find((m) => m.id === msg.reply_to);
      quote = `<div class="reply-quote">
          <strong>${escapeHtml(parent ? parent.author_label : 'Message')}</strong>
          <span>${escapeHtml(parent ? (parent.kind === 'image' ? '📷 Photo' : parent.body) : 'Message supprimé')}</span>
        </div>`;
    }

    let body = '';
    if (msg.kind === 'image') {
      const meta = msg.meta || {};
      body = `<div class="p2p-image" data-transfer="${escapeHtml(meta.transfer_id || '')}"
                   data-owner="${escapeHtml(msg.author_phone || '')}"
                   data-group="${msg.group_id}">
                <div class="p2p-state">
                  <svg class="spin"><use href="#i-loader" /></svg>
                  <span>Photo · ${escapeHtml(fmtBytes(meta.size || 0))}</span>
                </div>
                <div class="p2p-bar"><span style="width:0%"></span></div>
              </div>`;
      if (msg.body) body += `<div class="msg-body">${enrich(escapeHtml(msg.body))}</div>`;
    } else {
      body = `<div class="msg-body">${enrich(escapeHtml(msg.body))}</div>`;
    }

    return `
      <div class="${cls}${msg.pinned_at ? ' pinned' : ''}" id="msg-${msg.id}" data-id="${msg.id}">
        ${
          mine
            ? ''
            : `<div class="msg-avatar avatar ${avatarClass(msg.author_phone)}">${escapeHtml(initials(msg.author_label))}</div>`
        }
        <div class="bubble">
          ${mine ? '' : `<div class="msg-author">${escapeHtml(msg.author_label)}</div>`}
          ${quote}
          ${body}
          <div class="msg-time">${
            msg.pinned_at ? '<svg class="pin-mark"><use href="#i-pin"/></svg> ' : ''
          }${fmtTime(msg.created_at)}${msg.edited_at ? ' · modifié' : ''}${receiptMark(msg)}</div>
        </div>
      </div>`;
  }

  async function loadOlder() {
    if (state.loadingHistory || !state.oldestId) return;
    state.loadingHistory = true;
    const thread = $('#thread');
    const prevHeight = thread.scrollHeight;
    try {
      const res = await api(
        `/api/groups/${state.currentGroup.id}/messages?before=${state.oldestId}`,
      );
      if (res.messages.length) {
        state.messages = res.messages.concat(state.messages);
        state.oldestId = res.messages[0].id;
      }
      state.hasMore = res.has_more;
      renderThread();
      // On conserve la position de lecture après insertion en tête.
      thread.scrollTop = thread.scrollHeight - prevHeight;
    } catch (err) {
      toast(err.message, 'error');
    } finally {
      state.loadingHistory = false;
    }
  }

  // Appui long (ou clic droit) : actions sur le message.
  function attachMessageHandlers() {
    $('#thread')
      .querySelectorAll('.msg')
      .forEach((el) => {
        let timer = null;
        const start = () => {
          timer = setTimeout(() => {
            vibrate(18);
            openMessageSheet(Number(el.dataset.id));
          }, 480);
        };
        const cancel = () => timer && clearTimeout(timer);
        el.addEventListener('pointerdown', start);
        el.addEventListener('pointerup', cancel);
        el.addEventListener('pointerleave', cancel);
        el.addEventListener('pointercancel', cancel);
        el.addEventListener('contextmenu', (e) => {
          e.preventDefault();
          openMessageSheet(Number(el.dataset.id));
        });
      });
  }

  /* --- Envoi ---------------------------------------------------------- */

  const input = $('#in-message');

  function autoGrow() {
    input.style.height = 'auto';
    input.style.height = `${Math.min(input.scrollHeight, 130)}px`;
    $('#btn-send').disabled = !input.value.trim();
  }

  input.addEventListener('input', () => {
    autoGrow();
    throttledTyping();
  });

  input.addEventListener('keydown', (e) => {
    // Entrée envoie sur ordinateur ; sur mobile le clavier insère un saut de ligne.
    if (e.key === 'Enter' && !e.shiftKey && window.matchMedia('(min-width: 720px)').matches) {
      e.preventDefault();
      sendMessage();
    }
  });

  let typingAt = 0;
  function throttledTyping() {
    const now = Date.now();
    if (now - typingAt > 2500 && state.currentGroup) {
      typingAt = now;
      wsSend({ type: 'typing', group_id: state.currentGroup.id });
    }
  }

  async function sendMessage() {
    const body = input.value.trim();
    if (!body || !state.currentGroup) return;
    const groupId = state.currentGroup.id;
    input.value = '';
    autoGrow();
    const replyTo = state.replyTo ? state.replyTo.id : null;
    state.replyTo = null;
    updateReplyBar();
    try {
      const res = await api(`/api/groups/${groupId}/messages`, {
        method: 'POST',
        body: { body, kind: 'text', reply_to: replyTo },
      });
      // Le message revient par le WebSocket : rien à insérer ici.
      // Terme surveillé : le message est bien parti, on le signale seulement.
      if (res.message && res.message.warning) toast(res.message.warning);
    } catch (err) {
      toast(err.message, 'error');
      input.value = body;
      autoGrow();
    }
  }

  $('#btn-send').addEventListener('click', sendMessage);
  $$('[data-close-chat]').forEach((b) => b.addEventListener('click', () => leaveChat()));
  $$('[data-close-overlay]').forEach((b) =>
    b.addEventListener('click', () => {
      closeOverlay(b.dataset.closeOverlay);
      history.back();
    }),
  );

  function updateReplyBar() {
    const bar = $('#reply-bar');
    if (!state.replyTo) {
      bar.classList.remove('show');
      return;
    }
    bar.classList.add('show');
    $('#reply-author').textContent = state.replyTo.author_label;
    $('#reply-text').textContent =
      state.replyTo.kind === 'image' ? '📷 Photo' : state.replyTo.body.slice(0, 80);
  }

  $('#btn-cancel-reply').addEventListener('click', () => {
    state.replyTo = null;
    updateReplyBar();
  });

  $('#thread').addEventListener('scroll', () => {
    if ($('#thread').scrollTop < 60 && state.hasMore && !state.loadingHistory) loadOlder();
  });

  /* ------------------------------------------------------------------ */
  /* Feuilles contextuelles                                              */
  /* ------------------------------------------------------------------ */

  function openSheet(html) {
    $('#sheet').innerHTML = `<div class="sheet-grip"></div>${html}`;
    $('#sheet-backdrop').classList.add('open');
  }

  function closeSheet() {
    $('#sheet-backdrop').classList.remove('open');
  }

  $('#sheet-backdrop').addEventListener('click', (e) => {
    if (e.target === $('#sheet-backdrop')) closeSheet();
  });

  function openMessageSheet(id) {
    const msg = state.messages.find((m) => m.id === id);
    if (!msg) return;
    const mine = msg.author_phone === state.me.phone;
    const isAdmin = state.currentGroup && state.currentGroup.role === 'admin';

    const mineAndSent = mine && msg.kind !== 'system';
    openSheet(`
      <h3>Message</h3>
      ${
        mineAndSent
          ? `<button class="sheet-action" data-act="readers">
              <svg><use href="#i-check2"/></svg> Voir qui a lu ce message</button>`
          : ''
      }
      <button class="sheet-action" data-act="reply"><svg><use href="#i-reply"/></svg> Répondre</button>
      ${
        msg.kind !== 'image'
          ? '<button class="sheet-action" data-act="copy"><svg><use href="#i-copy"/></svg> Copier le texte</button>'
          : ''
      }
      ${
        isAdmin
          ? `<button class="sheet-action" data-act="pin"><svg><use href="#i-pin"/></svg>
              ${msg.pinned_at ? 'Retirer des épingles' : 'Épingler dans le groupe'}</button>`
          : ''
      }
      ${
        mine || isAdmin
          ? '<button class="sheet-action danger" data-act="delete"><svg><use href="#i-trash"/></svg> Supprimer</button>'
          : ''
      }
    `);

    $('#sheet')
      .querySelectorAll('[data-act]')
      .forEach((btn) =>
        btn.addEventListener('click', async () => {
          const act = btn.dataset.act;
          closeSheet();
          if (act === 'readers') {
            showReaders(msg);
          } else if (act === 'reply') {
            state.replyTo = msg;
            updateReplyBar();
            input.focus();
          } else if (act === 'copy') {
            try {
              await navigator.clipboard.writeText(msg.body);
              toast('Texte copié.', 'ok');
            } catch (e) {
              toast('Copie impossible.', 'error');
            }
          } else if (act === 'pin') {
            try {
              const res = await api(`/api/messages/${msg.id}/pin`, {
                method: 'POST',
                body: { pinned: !msg.pinned_at },
              });
              msg.pinned_at = res.message.pinned_at;
              toast(msg.pinned_at ? 'Message épinglé.' : 'Épingle retirée.', 'ok');
              loadPins(msg.group_id);
              renderThread();
            } catch (err) {
              toast(err.message, 'error');
            }
          } else if (act === 'delete') {
            try {
              await api(`/api/messages/${msg.id}`, { method: 'DELETE' });
              state.messages = state.messages.filter((m) => m.id !== msg.id);
              renderThread();
            } catch (err) {
              toast(err.message, 'error');
            }
          }
        }),
      );
  }

  /* --- Fiche du groupe ------------------------------------------------ */

  $('#btn-group-info').addEventListener('click', async () => {
    if (!state.currentGroup) return;
    const gid = state.currentGroup.id;
    try {
      const info = await api(`/api/groups/${gid}`);
      const mode = state.currentGroup.notif_mode || 'all';
      const isAdmin = info.role === 'admin';

      openSheet(`
        <h3>${escapeHtml(info.name)}</h3>
        ${info.description ? `<p style="color:var(--text-dim);font-size:14px;margin:-6px 0 14px">${escapeHtml(info.description)}</p>` : ''}
        ${info.parent ? `<p style="color:var(--text-faint);font-size:12.5px;margin:-6px 0 14px">Sous-groupe de ${escapeHtml(info.parent.name)}</p>` : ''}

        <div style="font-size:11px;text-transform:uppercase;letter-spacing:.13em;color:var(--cyan-dim);font-weight:700;margin:6px 0 8px">Notifications</div>
        <div class="segmented" id="seg-notif">
          <button data-mode="all" class="${mode === 'all' ? 'active' : ''}">Tous</button>
          <button data-mode="mentions" class="${mode === 'mentions' ? 'active' : ''}">Mentions</button>
          <button data-mode="mute" class="${mode === 'mute' ? 'active' : ''}">Muet</button>
        </div>

        <div style="font-size:11px;text-transform:uppercase;letter-spacing:.13em;color:var(--cyan-dim);font-weight:700;margin:18px 0 4px">
          ${info.members.length} membre${info.members.length > 1 ? 's' : ''}
        </div>
        <div>
          ${info.members
            .map(
              (m) => `<div class="admin-row">
                <div class="avatar sm ${avatarClass(m.phone)}">${escapeHtml(initials(m.display_name))}</div>
                <div class="group-main">
                  <div class="group-name">${escapeHtml(m.display_name)}
                    ${m.role === 'admin' ? '<span class="tag admin">Admin</span>' : ''}</div>
                  <div class="group-preview">${escapeHtml(m.phone_display)}</div>
                </div>
                ${
                  isAdmin && m.phone !== state.me.phone
                    ? `<button class="btn btn-danger btn-sm" data-remove="${escapeHtml(m.phone)}">Retirer</button>`
                    : ''
                }
              </div>`,
            )
            .join('')}
        </div>

        ${
          isAdmin
            ? `<div style="margin-top:16px">
                 <div class="field">
                   <label for="add-member-phone">Ajouter un membre</label>
                   <input id="add-member-phone" class="input-phone" type="tel" inputmode="numeric" placeholder="06 12 34 56 78" maxlength="14"/>
                 </div>
                 <button class="btn btn-ember btn-sm" id="btn-add-member" style="width:100%">Ajouter au groupe</button>
               </div>`
            : ''
        }
      `);

      $('#seg-notif')
        .querySelectorAll('button')
        .forEach((b) =>
          b.addEventListener('click', async () => {
            try {
              await api(`/api/groups/${gid}/prefs`, {
                method: 'PATCH',
                body: { notif_mode: b.dataset.mode },
              });
              state.currentGroup.notif_mode = b.dataset.mode;
              $('#seg-notif')
                .querySelectorAll('button')
                .forEach((x) => x.classList.toggle('active', x === b));
              renderGroups();
            } catch (err) {
              toast(err.message, 'error');
            }
          }),
        );

      $('#sheet')
        .querySelectorAll('[data-remove]')
        .forEach((b) =>
          b.addEventListener('click', async () => {
            if (!confirm('Retirer cette personne du groupe ?')) return;
            try {
              await api(`/api/groups/${gid}/members/${b.dataset.remove}`, { method: 'DELETE' });
              closeSheet();
              toast('Membre retiré.', 'ok');
            } catch (err) {
              toast(err.message, 'error');
            }
          }),
        );

      const addBtn = $('#btn-add-member');
      if (addBtn) {
        const phoneInput = $('#add-member-phone');
        phoneInput.addEventListener('input', (e) => {
          const digits = e.target.value.replace(/\D/g, '').slice(0, 10);
          e.target.value = digits.replace(/(\d{2})(?=\d)/g, '$1 ').trim();
        });
        addBtn.addEventListener('click', async () => {
          try {
            await api(`/api/groups/${gid}/members`, {
              method: 'POST',
              body: { phone: phoneInput.value.replace(/\D/g, ''), role: 'member' },
            });
            closeSheet();
            toast('Membre ajouté.', 'ok');
          } catch (err) {
            toast(err.message, 'error');
          }
        });
      }
    } catch (err) {
      toast(err.message, 'error');
    }
  });

  /* ------------------------------------------------------------------ */
  /* Images en pair-à-pair (WebRTC)                                      */
  /* ------------------------------------------------------------------ */
  /* Le serveur ne relaie que la signalisation : les octets de l'image
     passent directement d'un appareil à l'autre. Chaque photo envoyée est
     conservée localement par l'expéditeur, qui la resservira aux pairs
     tant qu'il est en ligne. */

  const RTC_CONFIG = {
    iceServers: [{ urls: ['stun:stun.l.google.com:19302', 'stun:stun1.l.google.com:19302'] }],
  };
  const CHUNK = 16 * 1024;
  const peers = new Map(); // transfer_id + pair -> RTCPeerConnection
  const incoming = new Map(); // transfer_id -> { chunks, received, total }

  /* --- Cache local (IndexedDB) --------------------------------------- */

  let idbPromise = null;
  function idb() {
    if (idbPromise) return idbPromise;
    idbPromise = new Promise((resolve, reject) => {
      const req = indexedDB.open('motoc-images', 1);
      req.onupgradeneeded = () => {
        const db = req.result;
        if (!db.objectStoreNames.contains('img')) db.createObjectStore('img', { keyPath: 'id' });
      };
      req.onsuccess = () => resolve(req.result);
      req.onerror = () => reject(req.error);
    });
    return idbPromise;
  }

  async function idbPut(id, blob) {
    const db = await idb();
    return new Promise((resolve, reject) => {
      const tx = db.transaction('img', 'readwrite');
      tx.objectStore('img').put({ id, blob, ts: Date.now() });
      tx.oncomplete = resolve;
      tx.onerror = () => reject(tx.error);
    });
  }

  async function idbGet(id) {
    const db = await idb();
    return new Promise((resolve) => {
      const tx = db.transaction('img', 'readonly');
      const req = tx.objectStore('img').get(id);
      req.onsuccess = () => resolve(req.result ? req.result.blob : null);
      req.onerror = () => resolve(null);
    });
  }

  /* --- Envoi ---------------------------------------------------------- */

  // Réduction avant envoi : 1600 px max, JPEG qualité 0.82.
  async function downscale(file) {
    const bitmap = await createImageBitmap(file);
    const max = 1600;
    let { width, height } = bitmap;
    if (width > max || height > max) {
      const ratio = Math.min(max / width, max / height);
      width = Math.round(width * ratio);
      height = Math.round(height * ratio);
    }
    const canvas = document.createElement('canvas');
    canvas.width = width;
    canvas.height = height;
    canvas.getContext('2d').drawImage(bitmap, 0, 0, width, height);
    bitmap.close();
    const blob = await new Promise((r) => canvas.toBlob(r, 'image/jpeg', 0.82));
    return { blob, width, height };
  }

  $('#btn-image').addEventListener('click', () => $('#file-image').click());

  $('#file-image').addEventListener('change', async (e) => {
    const file = e.target.files[0];
    e.target.value = '';
    if (!file || !state.currentGroup) return;
    if (!file.type.startsWith('image/')) return toast('Ce fichier n’est pas une image.', 'error');

    try {
      toast('Préparation de la photo…');
      const { blob, width, height } = await downscale(file);
      const transferId = `${state.me.phone}-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`;
      await idbPut(transferId, blob);

      await api(`/api/groups/${state.currentGroup.id}/messages`, {
        method: 'POST',
        body: {
          body: '',
          kind: 'image',
          meta: {
            transfer_id: transferId,
            name: file.name,
            size: blob.size,
            width,
            height,
            type: 'image/jpeg',
          },
        },
      });
    } catch (err) {
      toast(err.message || 'Envoi de la photo impossible.', 'error');
    }
  });

  /* --- Affichage / récupération --------------------------------------- */

  async function hydrateImages() {
    const nodes = $('#thread').querySelectorAll('.p2p-image[data-transfer]');
    for (const node of nodes) {
      const id = node.dataset.transfer;
      if (!id) continue;
      const blob = await idbGet(id);
      if (blob) {
        showImage(node, blob);
      } else if (node.dataset.owner && node.dataset.owner !== state.me.phone) {
        requestImage(node);
      } else {
        setImageState(node, 'Photo indisponible sur cet appareil.', true);
      }
    }
  }

  function showImage(node, blob) {
    const url = URL.createObjectURL(blob);
    node.innerHTML = `<img src="${url}" alt="Photo" loading="lazy" />`;
    node.querySelector('img').addEventListener('click', () => window.open(url, '_blank'));
  }

  function setImageState(node, text, error, progress) {
    node.innerHTML = `
      <div class="p2p-state ${error ? 'error' : ''}">
        <svg class="${error ? '' : 'spin'}"><use href="#${error ? 'i-alert' : 'i-loader'}" /></svg>
        <span>${escapeHtml(text)}</span>
      </div>
      ${progress !== undefined ? `<div class="p2p-bar"><span style="width:${progress}%"></span></div>` : ''}`;
  }

  function requestImage(node) {
    const transferId = node.dataset.transfer;
    const owner = node.dataset.owner;
    setImageState(node, 'Réception en cours…', false, 0);
    const sent = wsSend({
      type: 'image-request',
      to: owner,
      transfer_id: transferId,
      group_id: Number(node.dataset.group),
    });
    if (!sent) {
      setImageState(node, 'Hors ligne : photo indisponible.', true);
      return;
    }
    // Sans réponse au bout de 20 s, l'expéditeur est probablement absent.
    setTimeout(() => {
      if (node.querySelector('.p2p-state') && !incoming.has(transferId)) {
        setImageState(node, "Photo indisponible (expéditeur hors ligne).", true);
      }
    }, 20000);
  }

  // Côté expéditeur : un pair réclame une photo qu'on possède.
  async function handleImageRequest(data) {
    const blob = await idbGet(data.transfer_id);
    if (!blob) return;

    const key = `${data.transfer_id}:${data.from}`;
    const pc = new RTCPeerConnection(RTC_CONFIG);
    peers.set(key, pc);

    pc.onicecandidate = (e) => {
      if (e.candidate) {
        wsSend({
          type: 'rtc-signal',
          to: data.from,
          transfer_id: data.transfer_id,
          signal: { candidate: e.candidate },
        });
      }
    };
    pc.onconnectionstatechange = () => {
      if (['failed', 'closed', 'disconnected'].includes(pc.connectionState)) {
        pc.close();
        peers.delete(key);
      }
    };

    const channel = pc.createDataChannel('img');
    channel.binaryType = 'arraybuffer';
    channel.onopen = async () => {
      const buffer = await blob.arrayBuffer();
      channel.send(JSON.stringify({ size: buffer.byteLength, type: blob.type }));
      let offset = 0;
      const pump = () => {
        while (offset < buffer.byteLength) {
          // Backpressure : on laisse le buffer se vider avant de continuer.
          if (channel.bufferedAmount > 4 * CHUNK) {
            channel.onbufferedamountlow = pump;
            channel.bufferedAmountLowThreshold = 2 * CHUNK;
            return;
          }
          channel.send(buffer.slice(offset, offset + CHUNK));
          offset += CHUNK;
        }
        channel.onbufferedamountlow = null;
      };
      pump();
    };

    const offer = await pc.createOffer();
    await pc.setLocalDescription(offer);
    wsSend({
      type: 'rtc-signal',
      to: data.from,
      transfer_id: data.transfer_id,
      signal: { sdp: pc.localDescription },
    });
  }

  // Réception de la signalisation (des deux côtés).
  async function handleRtcSignal(data) {
    const key = `${data.transfer_id}:${data.from}`;
    let pc = peers.get(key);
    const signal = data.signal || {};

    if (signal.sdp && signal.sdp.type === 'offer') {
      pc = new RTCPeerConnection(RTC_CONFIG);
      peers.set(key, pc);

      pc.onicecandidate = (e) => {
        if (e.candidate) {
          wsSend({
            type: 'rtc-signal',
            to: data.from,
            transfer_id: data.transfer_id,
            signal: { candidate: e.candidate },
          });
        }
      };
      pc.ondatachannel = (e) => setupReceiveChannel(e.channel, data.transfer_id, key);

      await pc.setRemoteDescription(signal.sdp);
      const answer = await pc.createAnswer();
      await pc.setLocalDescription(answer);
      wsSend({
        type: 'rtc-signal',
        to: data.from,
        transfer_id: data.transfer_id,
        signal: { sdp: pc.localDescription },
      });
    } else if (signal.sdp && signal.sdp.type === 'answer' && pc) {
      await pc.setRemoteDescription(signal.sdp);
    } else if (signal.candidate && pc) {
      try {
        await pc.addIceCandidate(signal.candidate);
      } catch (e) {
        /* candidat tardif : sans conséquence */
      }
    }
  }

  function setupReceiveChannel(channel, transferId, key) {
    channel.binaryType = 'arraybuffer';
    const node = () => $('#thread').querySelector(`.p2p-image[data-transfer="${CSS.escape(transferId)}"]`);

    channel.onmessage = async (event) => {
      const rec = incoming.get(transferId);

      // Premier message : l'en-tête JSON décrivant le transfert.
      if (!rec) {
        try {
          const header = JSON.parse(event.data);
          incoming.set(transferId, { chunks: [], received: 0, total: header.size, type: header.type });
        } catch (e) {
          /* en-tête illisible */
        }
        return;
      }

      rec.chunks.push(event.data);
      rec.received += event.data.byteLength;

      const el = node();
      if (el) {
        const pct = Math.round((rec.received / rec.total) * 100);
        setImageState(el, `Réception… ${pct} %`, false, pct);
      }

      if (rec.received >= rec.total) {
        const blob = new Blob(rec.chunks, { type: rec.type || 'image/jpeg' });
        incoming.delete(transferId);
        await idbPut(transferId, blob);
        const target = node();
        if (target) showImage(target, blob);
        channel.close();
        const pc = peers.get(key);
        if (pc) {
          pc.close();
          peers.delete(key);
        }
      }
    };
  }

  /* ------------------------------------------------------------------ */
  /* Réglages                                                            */
  /* ------------------------------------------------------------------ */

  $('#btn-settings').addEventListener('click', () => {
    $('#set-first').value = state.me.first_name || '';
    $('#set-last').value = state.me.last_name || '';
    $('#set-nick').value = state.me.nickname || '';
    $('#set-phone').value = state.me.phone_display || '';
    refreshPushSwitch();
    openOverlay('screen-settings');
  });

  $('#btn-save-profile').addEventListener('click', async () => {
    try {
      state.me = await api('/api/me', {
        method: 'PATCH',
        body: {
          first_name: $('#set-first').value.trim(),
          last_name: $('#set-last').value.trim(),
          nickname: $('#set-nick').value.trim(),
        },
      });
      toast('Profil enregistré.', 'ok');
    } catch (err) {
      toast(err.message, 'error');
    }
  });

  $('#btn-change-pin').addEventListener('click', async () => {
    const oldPin = $('#set-pin-old').value;
    const newPin = $('#set-pin-new').value;
    if (oldPin.length !== 6 || newPin.length !== 6) {
      return toast('Les deux codes doivent contenir 6 chiffres.', 'error');
    }
    try {
      const res = await api('/api/me/pin', {
        method: 'POST',
        body: { current_pin: oldPin, new_pin: newPin },
      });
      state.token = res.token;
      localStorage.setItem('motoc_token', res.token);
      $('#set-pin-old').value = $('#set-pin-new').value = '';
      toast('Code PIN modifié.', 'ok');
    } catch (err) {
      toast(err.message, 'error');
    }
  });

  $('#btn-logout').addEventListener('click', () => {
    if (confirm('Se déconnecter de cet appareil ?')) logout();
  });

  /* ------------------------------------------------------------------ */
  /* Notifications push                                                  */
  /* ------------------------------------------------------------------ */

  function b64ToUint8(base64) {
    const padded = (base64 + '='.repeat((4 - (base64.length % 4)) % 4))
      .replace(/-/g, '+')
      .replace(/_/g, '/');
    const raw = atob(padded);
    return Uint8Array.from(raw, (c) => c.charCodeAt(0));
  }

  const pushSupported = () =>
    'serviceWorker' in navigator && 'PushManager' in window && 'Notification' in window;

  async function currentSubscription() {
    if (!pushSupported()) return null;
    const reg = await navigator.serviceWorker.ready;
    return reg.pushManager.getSubscription();
  }

  async function refreshPushSwitch() {
    const sw = $('#sw-push');
    const desc = $('#push-desc');
    if (!pushSupported()) {
      sw.classList.remove('on');
      desc.textContent = "Non pris en charge par ce navigateur.";
      return;
    }
    if (Notification.permission === 'denied') {
      sw.classList.remove('on');
      desc.textContent = 'Bloquées dans les réglages du navigateur.';
      return;
    }
    const sub = await currentSubscription();
    sw.classList.toggle('on', !!sub);
    // Sur iOS, le push n'existe que si l'app est installée sur l'écran d'accueil.
    const standalone =
      window.matchMedia('(display-mode: standalone)').matches || navigator.standalone;
    const isIOS = /iPad|iPhone|iPod/.test(navigator.userAgent);
    if (isIOS && !standalone) {
      desc.textContent = 'Sur iPhone : « Partager » puis « Sur l’écran d’accueil ».';
    } else {
      desc.textContent = sub
        ? 'Activées sur cet appareil.'
        : 'Recevoir les messages même application fermée.';
    }
  }

  $('#sw-push').addEventListener('click', async () => {
    if (!pushSupported()) return toast('Notifications non prises en charge.', 'error');
    const sw = $('#sw-push');
    try {
      const existing = await currentSubscription();
      if (existing) {
        await api('/api/push/unsubscribe', {
          method: 'POST',
          body: { endpoint: existing.endpoint },
        });
        await existing.unsubscribe();
        toast('Notifications désactivées.');
      } else {
        const permission = await Notification.requestPermission();
        if (permission !== 'granted') {
          toast('Autorisation refusée.', 'error');
          return refreshPushSwitch();
        }
        const { public_key: key } = await api('/api/push/key');
        const reg = await navigator.serviceWorker.ready;
        const sub = await reg.pushManager.subscribe({
          userVisibleOnly: true,
          applicationServerKey: b64ToUint8(key),
        });
        await api('/api/push/subscribe', { method: 'POST', body: { subscription: sub.toJSON() } });
        toast('Notifications activées.', 'ok');
      }
    } catch (err) {
      toast(err.message || 'Activation impossible.', 'error');
    }
    refreshPushSwitch();
  });

  $('#btn-test-push').addEventListener('click', async () => {
    try {
      await api('/api/push/test', { method: 'POST' });
      toast('Notification test envoyée.', 'ok');
    } catch (err) {
      toast(err.message, 'error');
    }
  });

  /* ------------------------------------------------------------------ */
  /* Administration (superadmin)                                         */
  /* ------------------------------------------------------------------ */

  $('#btn-admin').addEventListener('click', () => {
    openOverlay('screen-admin');
    // Libère le cadre « téléphone » : le panneau superadmin est le seul
    // écran conçu pour être lu en grand.
    $('#app').classList.add('desk');
    // On rouvre toujours sur le tableau de bord, pas sur le dernier onglet vu.
    $$('.tabs button').forEach((b) => b.classList.toggle('active', b.dataset.tab === 'tab-dash'));
    $$('.tab-panel').forEach((p) => p.classList.toggle('active', p.id === 'tab-dash'));
    loadDashboard();
    loadHelpRequests();
    loadAdminGroups();
    loadAdminUsers();
    loadStats();
  });

  $$('.tabs button').forEach((btn) =>
    btn.addEventListener('click', () => {
      $$('.tabs button').forEach((b) => b.classList.toggle('active', b === btn));
      $$('.tab-panel').forEach((p) => p.classList.toggle('active', p.id === btn.dataset.tab));
      // Les données du bord vieillissent vite : on rafraîchit à chaque retour.
      const tab = btn.dataset.tab;
      // La supervision matérielle ne sonde que si son onglet est à l'écran.
      if (tab !== 'tab-system') stopSystem();
      if (tab === 'tab-dash') {
        loadDashboard();
        loadHelpRequests();
      } else if (tab === 'tab-stats') {
        loadStats();
      } else if (tab === 'tab-moderation') {
        loadModeration();
      } else if (tab === 'tab-system') {
        startSystem();
      } else if (tab === 'tab-playground') {
        loadPlayground();
      }
    }),
  );

  async function loadAdminGroups() {
    try {
      const res = await api('/api/admin/groups');
      const groups = res.groups;

      // Alimente le sélecteur de parent (uniquement les groupes racines).
      const select = $('#ng-parent');
      select.innerHTML =
        '<option value="">— Aucun (groupe principal) —</option>' +
        groups
          .filter((g) => !g.parent_id)
          .map((g) => `<option value="${g.id}">${escapeHtml(g.name)}</option>`)
          .join('');

      // Sélecteur de l'import : tous les groupes, sous-groupes compris.
      $('#in-import-group').innerHTML =
        '<option value="">Aucun groupe</option>' +
        groups
          .map(
            (g) =>
              `<option value="${g.id}">${g.parent_id ? '↳ ' : ''}${escapeHtml(g.name)}</option>`,
          )
          .join('');

      const byId = new Map(groups.map((g) => [g.id, g]));
      $('#admin-groups').innerHTML = groups.length
        ? groups
            .map((g) => {
              const parent = g.parent_id ? byId.get(g.parent_id) : null;
              return `<div class="admin-row">
                <div class="avatar sm ${g.parent_id ? 'ember' : ''}">${escapeHtml(initials(g.name))}</div>
                <div class="group-main">
                  <div class="group-name">${escapeHtml(g.name)}</div>
                  <div class="group-preview">
                    ${parent ? `↳ ${escapeHtml(parent.name)} · ` : ''}${g.member_count} membre(s) · ${g.message_count} message(s)
                  </div>
                </div>
                <button class="btn btn-danger btn-sm" data-del-group="${g.id}">Suppr.</button>
              </div>`;
            })
            .join('')
        : '<p style="color:var(--text-faint);font-size:14px">Aucun groupe pour le moment.</p>';

      $('#admin-groups')
        .querySelectorAll('[data-del-group]')
        .forEach((b) =>
          b.addEventListener('click', async () => {
            const g = byId.get(Number(b.dataset.delGroup));
            if (
              !confirm(
                `Supprimer « ${g.name} » ?\n\nLes messages et les sous-groupes seront définitivement effacés.`,
              )
            )
              return;
            try {
              await api(`/api/admin/groups/${g.id}`, { method: 'DELETE' });
              toast('Groupe supprimé.', 'ok');
              loadAdminGroups();
              loadGroups();
            } catch (err) {
              toast(err.message, 'error');
            }
          }),
        );
    } catch (err) {
      toast(err.message, 'error');
    }
  }

  $('#btn-create-group').addEventListener('click', async () => {
    const name = $('#ng-name').value.trim();
    if (!name) return toast('Donnez un nom au groupe.', 'error');
    try {
      await api('/api/admin/groups', {
        method: 'POST',
        body: {
          name,
          parent_id: $('#ng-parent').value ? Number($('#ng-parent').value) : null,
          description: $('#ng-desc').value.trim(),
        },
      });
      $('#ng-name').value = $('#ng-desc').value = '';
      toast('Groupe créé.', 'ok');
      loadAdminGroups();
      loadGroups();
    } catch (err) {
      toast(err.message, 'error');
    }
  });

  $('#btn-add-users').addEventListener('click', async () => {
    const phones = $('#nu-phones').value.trim();
    if (!phones) return toast('Saisissez au moins un numéro.', 'error');
    try {
      const res = await api('/api/admin/users/bulk', { method: 'POST', body: { phones } });
      $('#nu-phones').value = '';
      const bits = [`${res.added.length} ajouté(s)`];
      if (res.skipped.length) bits.push(`${res.skipped.length} déjà connu(s)`);
      if (res.invalid.length) bits.push(`${res.invalid.length} invalide(s)`);
      toast(bits.join(' · '), res.added.length ? 'ok' : 'error');
      loadAdminUsers();
      loadStats();
    } catch (err) {
      toast(err.message, 'error');
    }
  });

  /* --- Import d'un tableur de bénévoles ------------------------------- */
  // Deux temps : un aperçu qui montre les colonnes reconnues, puis l'import.
  // Le fichier est renvoyé au serveur à la confirmation — rien n'est gardé
  // entre les deux appels, ni ici ni côté serveur.

  let importFile = null;

  function importFormData(dryRun) {
    const form = new FormData();
    form.append('file', importFile);
    form.append('dry_run', dryRun ? 'true' : 'false');
    const group = $('#in-import-group').value;
    if (group) form.append('group_id', group);
    // Colonnes corrigées à la main depuis l'aperçu, s'il y en a.
    for (const [field, id] of [
      ['first_col', '#imp-first'],
      ['last_col', '#imp-last'],
      ['phone_col', '#imp-phone'],
    ]) {
      const select = $(id);
      if (select && select.value !== '' && select.dataset.dirty === '1') {
        form.append(field, select.value);
      }
    }
    return form;
  }

  function columnOptions(count, selected, headers) {
    let html = '';
    for (let i = 0; i < count; i += 1) {
      const label = headers[i] ? `${headers[i]}` : `Colonne ${i + 1}`;
      html += `<option value="${i}" ${i === selected ? 'selected' : ''}>${escapeHtml(label)}</option>`;
    }
    return html;
  }

  function renderImportPreview(res) {
    const box = $('#import-result');
    const map = res.mapping;
    const headers = res.preview.length ? [] : [];
    // Nombre de colonnes proposées : au moins celles repérées par le serveur.
    const width = Math.max(
      (map.phone_col ?? 0) + 1,
      (map.first_col ?? 0) + 1,
      (map.last_col ?? 0) + 1,
      (map.full_col ?? 0) + 1,
      3,
    );
    const labels = map.labels;
    const rows = res.preview
      .map(
        (p) => `<tr class="${p.known ? 'known' : ''}">
          <td>${escapeHtml(p.first_name || '—')}</td>
          <td>${escapeHtml(p.last_name || '—')}</td>
          <td>${escapeHtml(p.phone_display)}</td>
          <td>${p.known ? 'déjà connu' : 'nouveau'}</td>
        </tr>`,
      )
      .join('');

    box.hidden = false;
    box.innerHTML = `
      <div class="import-summary">
        <strong>${res.detected}</strong> contact(s) lus dans
        ${escapeHtml(res.filename || 'le fichier')} —
        <strong>${res.new}</strong> nouveau(x), ${res.existing} déjà connu(s)${
          res.rejected_count ? `, ${res.rejected_count} ligne(s) ignorée(s)` : ''
        }.
      </div>
      <div class="import-mapping">
        <div>Colonnes reconnues :
          <span class="tag">Prénom → ${escapeHtml(labels.first || labels.full || '—')}</span>
          <span class="tag">Nom → ${escapeHtml(labels.last || labels.full || '—')}</span>
          <span class="tag">Téléphone → ${escapeHtml(labels.phone || '—')}</span>
        </div>
        ${
          map.assumed_order
            ? `<p class="import-warn">Aucun en-tête dans ce fichier : l'ordre « prénom puis nom »
                 est une hypothèse. Vérifiez l'aperçu ci-dessous et corrigez si besoin.</p>`
            : ''
        }
      </div>
      <details class="import-fix">
        <summary>Corriger les colonnes</summary>
        <div class="field">
          <label for="imp-first">Prénom</label>
          <select id="imp-first">${columnOptions(width, map.first_col ?? map.full_col, headers)}</select>
        </div>
        <div class="field">
          <label for="imp-last">Nom</label>
          <select id="imp-last">${columnOptions(width, map.last_col, headers)}</select>
        </div>
        <div class="field">
          <label for="imp-phone">Téléphone</label>
          <select id="imp-phone">${columnOptions(width, map.phone_col, headers)}</select>
        </div>
        <button class="btn btn-ghost btn-sm" id="imp-recheck" style="width:100%">
          Relire avec ces colonnes
        </button>
      </details>
      <table class="import-preview">
        <thead><tr><th>Prénom</th><th>Nom</th><th>Téléphone</th><th></th></tr></thead>
        <tbody>${rows}</tbody>
      </table>
      ${
        res.rejected.length
          ? `<details class="import-fix"><summary>${res.rejected_count} ligne(s) ignorée(s)</summary>
              <ul class="import-rejected">${res.rejected
                .map((r) => `<li>Ligne ${r.row} — ${escapeHtml(r.reason)} : ${escapeHtml(r.value)}</li>`)
                .join('')}</ul></details>`
          : ''
      }
      <button class="btn btn-ember btn-sm" id="imp-confirm" style="width:100%;margin-top:10px">
        Importer ${res.new} nouveau(x) contact(s)
      </button>
      <button class="btn-link" id="imp-cancel" style="width:100%">Annuler</button>
    `;

    $$('#imp-first, #imp-last, #imp-phone').forEach((select) =>
      select.addEventListener('change', () => {
        select.dataset.dirty = '1';
      }),
    );
    $('#imp-recheck').addEventListener('click', () => runImport(true));
    $('#imp-cancel').addEventListener('click', resetImport);
    $('#imp-confirm').addEventListener('click', () => runImport(false));
  }

  function resetImport() {
    importFile = null;
    $('#in-import-file').value = '';
    $('#import-result').hidden = true;
    $('#import-result').innerHTML = '';
  }

  async function runImport(dryRun) {
    if (!importFile) return;
    const button = dryRun ? $('#btn-pick-file') : $('#imp-confirm');
    if (button) button.disabled = true;
    try {
      const res = await api('/api/admin/users/import', {
        method: 'POST',
        body: importFormData(dryRun),
      });
      if (dryRun) {
        renderImportPreview(res);
      } else {
        const bits = [`${res.added} compte(s) créé(s)`];
        if (res.updated) bits.push(`${res.updated} mis à jour`);
        if (res.joined) bits.push(`${res.joined} ajouté(s) au groupe`);
        toast(bits.join(' · '), 'ok');
        resetImport();
        loadAdminUsers();
        loadAdminGroups();
        loadStats();
      }
    } catch (err) {
      toast(err.message, 'error');
    } finally {
      if (button) button.disabled = false;
    }
  }

  $('#btn-pick-file').addEventListener('click', () => $('#in-import-file').click());
  $('#in-import-file').addEventListener('change', (e) => {
    importFile = e.target.files[0] || null;
    if (importFile) runImport(true);
  });

  /* ------------------------------------------------------------------ */
  /* Modération                                                          */
  /* ------------------------------------------------------------------ */

  let moderationStatus = 'pending';

  async function loadModeration() {
    try {
      const res = await api(
        `/api/admin/moderation?status=${encodeURIComponent(moderationStatus)}&limit=100`,
      );
      const badge = $('#moderation-badge');
      badge.hidden = !res.pending;
      badge.textContent = res.pending;

      $('#moderation-list').innerHTML = res.alerts.length
        ? res.alerts
            .map(
              (a) => `<div class="alert-row ${a.status === 'pending' ? 'pending' : ''}">
                <div class="alert-head">
                  <span class="tag flagged">${escapeHtml(a.category_label)}</span>
                  <span class="alert-time">${fmtDateTime(a.created_at)}</span>
                </div>
                <div class="alert-body">« ${escapeHtml(a.excerpt)} »</div>
                <div class="alert-meta">
                  ${escapeHtml(a.author || 'inconnu')} · terme
                  <strong>${escapeHtml(a.term)}</strong>
                  ${a.matched && a.matched !== a.term ? `(écrit « ${escapeHtml(a.matched)} »)` : ''}
                </div>
                ${
                  a.status === 'pending'
                    ? `<button class="btn btn-ghost btn-sm" data-review="${a.id}">Marquer traité</button>`
                    : ''
                }
              </div>`,
            )
            .join('')
        : '<p class="empty-note">Aucun signalement.</p>';

      $('#moderation-list')
        .querySelectorAll('[data-review]')
        .forEach((b) =>
          b.addEventListener('click', async () => {
            try {
              await api(`/api/admin/moderation/${b.dataset.review}/review`, { method: 'POST' });
              loadModeration();
            } catch (err) {
              toast(err.message, 'error');
            }
          }),
        );

      // Éditeur de la liste surveillée : un textarea par catégorie.
      $('#terms-editor').innerHTML = Object.entries(res.categories)
        .map(
          ([key, label]) => `<div class="field">
            <label for="terms-${key}">${escapeHtml(label)}</label>
            <textarea id="terms-${key}" data-terms="${key}" rows="5">${escapeHtml(
              (res.terms[key] || []).join('\n'),
            )}</textarea>
          </div>`,
        )
        .join('');
    } catch (err) {
      toast(err.message, 'error');
    }
  }

  $('#seg-moderation')
    .querySelectorAll('button')
    .forEach((b) =>
      b.addEventListener('click', () => {
        moderationStatus = b.dataset.status;
        $('#seg-moderation')
          .querySelectorAll('button')
          .forEach((x) => x.classList.toggle('active', x === b));
        loadModeration();
      }),
    );

  $('#btn-save-terms').addEventListener('click', async () => {
    const terms = {};
    $$('[data-terms]').forEach((area) => {
      terms[area.dataset.terms] = area.value
        .split('\n')
        .map((line) => line.trim())
        .filter(Boolean);
    });
    try {
      await api('/api/admin/moderation/terms', { method: 'PUT', body: { terms } });
      toast('Liste enregistrée.', 'ok');
      loadModeration();
    } catch (err) {
      toast(err.message, 'error');
    }
  });

  /* ------------------------------------------------------------------ */
  /* Supervision machine et réseau                                       */
  /* ------------------------------------------------------------------ */
  // Sondage toutes les 3 s tant que l'onglet est ouvert ET la page visible :
  // inutile de mesurer une machine que personne ne regarde.

  const SPARK_POINTS = 40;
  // Surtout pas `history` : le nom masquerait `window.history` dans toute la
  // portée du module, et la navigation entre écrans cesserait de fonctionner.
  const samples = { cpu: [], rx: [], tx: [] };
  let systemTimer = null;
  let systemPaused = false;

  function pushSample(series, value) {
    series.push(Number.isFinite(value) ? value : 0);
    while (series.length > SPARK_POINTS) series.shift();
  }

  function drawSpark(id, series, max) {
    const svg = $(id);
    if (!svg) return;
    const line = svg.querySelector('polyline');
    const box = svg.viewBox.baseVal;
    const ceiling = Math.max(max || 0, ...series, 1);
    const step = series.length > 1 ? box.width / (series.length - 1) : box.width;
    line.setAttribute(
      'points',
      series
        .map((v, i) => `${(i * step).toFixed(1)},${(box.height - (v / ceiling) * box.height).toFixed(1)}`)
        .join(' '),
    );
  }

  function gauge(label, value, percent, hint) {
    const level = percent >= 90 ? 'danger' : percent >= 70 ? 'warn' : '';
    return `<div class="sys-card">
      <div class="sys-label">${escapeHtml(label)}</div>
      <div class="sys-value ${level}">${escapeHtml(value)}</div>
      ${
        percent === null || percent === undefined
          ? ''
          : `<div class="meter"><span class="${level}" style="width:${Math.min(100, percent)}%"></span></div>`
      }
      ${hint ? `<div class="sys-hint">${escapeHtml(hint)}</div>` : ''}
    </div>`;
  }

  function renderSystem(s) {
    const na = 'indisponible';
    const cpu = s.cpu || {};
    const mem = s.memory || {};
    const disk = s.disk || {};
    const net = s.network || {};
    const proc = s.process || {};

    pushSample(samples.cpu, cpu.percent || 0);
    pushSample(samples.rx, net.rx_rate || 0);
    pushSample(samples.tx, net.tx_rate || 0);

    // `has` et non la simple véracité : une valeur nulle est une mesure
    // légitime (un disque vide, un process qui n'a rien écrit), pas une
    // absence de mesure. La confondre affichait « indisponible » sur un
    // disque parfaitement lisible mais encore vide.
    const has = (v) => v !== null && v !== undefined;

    $('#sys-grid').innerHTML = [
      gauge(
        'Processeur',
        has(cpu.percent) ? `${cpu.percent} %` : na,
        cpu.percent,
        cpu.scope === 'machine'
          ? `machine entière · ${cpu.cores || '?'} cœur(s)`
          : `${cpu.allocated_cores || cpu.cores || '?'} cœur(s) alloué(s)`,
      ),
      gauge(
        'Mémoire',
        has(mem.used) ? `${fmtBytes(mem.used)} / ${fmtBytes(mem.total)}` : na,
        mem.percent,
        mem.limited_by_cgroup ? 'limite du conteneur' : 'mémoire de la machine',
      ),
      gauge(
        'Disque persistant',
        has(disk.used)
          ? disk.dedicated
            ? `${fmtBytes(disk.used)} / ${fmtBytes(disk.total)}`
            : fmtBytes(disk.used)
          : na,
        disk.percent,
        disk.dedicated
          ? disk.path
          : `${disk.path} · volume non dédié, place restante inconnue`,
      ),
      gauge(
        'Base de données',
        s.database ? fmtBytes(s.database.size) : na,
        s.database ? (s.database.size / s.database.hard_limit) * 100 : null,
        s.database ? `purge agressive au-delà de ${fmtBytes(s.database.soft_limit)}` : '',
      ),
      // La charge est celle de la machine hôte, partagée avec les autres
      // Spaces : elle ne dit rien de la santé de celui-ci, et l'afficher en
      // rouge ferait sonner une alarme sur laquelle personne ne peut agir.
      gauge(
        'Charge de l’hôte',
        cpu.load ? cpu.load.map((v) => v.toFixed(2)).join(' · ') : na,
        null,
        'machine partagée · 1 / 5 / 15 min',
      ),
      gauge(
        'Temps réel',
        s.realtime ? `${s.realtime.connections} connexion(s)` : na,
        null,
        s.realtime ? `${s.realtime.online_users} utilisateur(s) en ligne` : '',
      ),
      gauge(
        'Process',
        has(proc.rss) ? fmtBytes(proc.rss) : na,
        null,
        `${proc.threads || '?'} fils · ${proc.open_files || '?'} fichiers ouverts`,
      ),
      gauge('En service depuis', fmtDuration(s.app_uptime), null, 'redémarrage du serveur'),
    ].join('');

    $('#net-rx').textContent = net.rx_rate === null || net.rx_rate === undefined ? '—' : `${fmtBytes(net.rx_rate)}/s`;
    $('#net-tx').textContent = net.tx_rate === null || net.tx_rate === undefined ? '—' : `${fmtBytes(net.tx_rate)}/s`;
    drawSpark('#spark-rx', samples.rx);
    drawSpark('#spark-tx', samples.tx);
    drawSpark('#spark-cpu', samples.cpu, 100);

    const span = samples.cpu.length * 3;
    $('#cpu-detail').textContent = s.available
      ? `Échelle 0–100 %. ${samples.cpu.length} mesure(s) sur ${
          span < 60 ? `${span} secondes` : `${Math.round(span / 60)} minutes`
        }.`
      : "Ce système n'expose pas /proc : les mesures matérielles ne sont pas disponibles ici. Elles le seront dans le conteneur.";

    $('#sys-dot').className = `sys-dot ${s.available ? 'live' : 'off'}`;
    $('#sys-status').textContent = s.available
      ? `Mesure en direct · ${new Date(s.at).toLocaleTimeString('fr-FR')}`
      : 'Mesures matérielles indisponibles sur ce système';
  }

  async function pollSystem() {
    if (systemPaused || document.hidden) return;
    try {
      renderSystem(await api('/api/admin/system'));
    } catch (err) {
      $('#sys-status').textContent = err.message;
    }
  }

  function startSystem() {
    stopSystem();
    pollSystem();
    systemTimer = setInterval(pollSystem, 3000);
  }

  function stopSystem() {
    if (systemTimer) clearInterval(systemTimer);
    systemTimer = null;
  }

  $('#btn-sys-toggle').addEventListener('click', () => {
    systemPaused = !systemPaused;
    $('#btn-sys-toggle').textContent = systemPaused ? 'Reprendre' : 'Suspendre';
    if (!systemPaused) pollSystem();
  });

  /* ------------------------------------------------------------------ */
  /* Bac à sable                                                         */
  /* ------------------------------------------------------------------ */

  const sandbox = { groups: [], users: [], current: null };

  async function loadPlayground() {
    try {
      const res = await api('/api/admin/playground');
      sandbox.groups = res.groups;
      sandbox.users = res.users;

      $('#playground-groups').innerHTML = res.groups.length
        ? res.groups
            .map(
              (g) => `<div class="admin-row" data-sandbox-group="${g.id}">
                <div class="avatar sm ${g.parent_id ? 'ember' : ''}">${escapeHtml(initials(g.name))}</div>
                <div class="group-main">
                  <div class="group-name">${escapeHtml(g.name)}</div>
                  <div class="group-preview">${g.member_count} membre(s) · ${g.message_count} message(s)</div>
                </div>
                <button class="btn btn-ghost btn-sm">Ouvrir</button>
              </div>`,
            )
            .join('')
        : `<p class="empty-note">Bac à sable vide. Il est créé au démarrage du conteneur
             quand <code>SEED_DEMO=1</code>.</p>`;

      $('#playground-users').innerHTML = res.users.length
        ? res.users
            .map(
              (u) => `<div class="admin-row">
                <div class="avatar sm ${avatarClass(u.phone)}">${escapeHtml(initials(u.display_name))}</div>
                <div class="group-main">
                  <div class="group-name">${escapeHtml(u.display_name)}
                    ${u.is_group_admin ? '<span class="tag admin">Admin</span>' : ''}</div>
                  <div class="group-preview">${escapeHtml(u.phone_display)} · ${u.groups.length} groupe(s)</div>
                </div>
              </div>`,
            )
            .join('')
        : '<p class="empty-note">Aucun compte fictif.</p>';

      $('#playground-groups')
        .querySelectorAll('[data-sandbox-group]')
        .forEach((row) =>
          row.addEventListener('click', () => openSandbox(Number(row.dataset.sandboxGroup))),
        );
    } catch (err) {
      toast(err.message, 'error');
    }
  }

  async function openSandbox(groupId) {
    const group = sandbox.groups.find((g) => g.id === groupId);
    if (!group) return;
    sandbox.current = group;
    $('#sandbox-title').textContent = group.name;
    $('#sandbox-sub').textContent = `${group.member_count} membre(s) fictif(s)`;

    // Le sélecteur d'auteur : soi-même, ou n'importe quel compte fictif du groupe.
    const members = sandbox.users.filter((u) => u.groups.some((g) => g.group_id === groupId));
    $('#sandbox-as').innerHTML =
      `<option value="">Moi (${escapeHtml(state.me.display_name)})</option>` +
      members
        .map((u) => `<option value="${escapeHtml(u.phone)}">${escapeHtml(u.display_name)}</option>`)
        .join('');

    openOverlay('screen-sandbox');
    await loadSandboxThread();
  }

  async function loadSandboxThread() {
    if (!sandbox.current) return;
    try {
      const res = await api(`/api/admin/playground/groups/${sandbox.current.id}/messages`);
      const thread = $('#sandbox-thread');
      thread.innerHTML = res.messages.length
        ? res.messages
            .map(
              (m) => `<div class="msg theirs">
                <div class="msg-avatar avatar ${avatarClass(m.author_phone)}">${escapeHtml(
                  initials(m.author_label),
                )}</div>
                <div class="bubble">
                  <div class="msg-author">${escapeHtml(m.author_label)}</div>
                  <div class="msg-body">${enrich(escapeHtml(m.body))}</div>
                  <div class="msg-time">${fmtTime(m.created_at)}</div>
                </div>
              </div>`,
            )
            .join('')
        : `<div class="empty"><svg><use href="#i-chat"/></svg><h3>Conversation vide</h3>
             <p>Écrivez un message, en changeant d'auteur pour simuler un échange.</p></div>`;
      thread.scrollTop = thread.scrollHeight;
    } catch (err) {
      toast(err.message, 'error');
    }
  }

  $('#btn-sandbox-send').addEventListener('click', async () => {
    const input = $('#sandbox-message');
    const body = input.value.trim();
    if (!body || !sandbox.current) return;
    try {
      const res = await api('/api/admin/playground/messages', {
        method: 'POST',
        body: { group_id: sandbox.current.id, phone: $('#sandbox-as').value, body },
      });
      input.value = '';
      if (res.message.warning) toast(res.message.warning);
      loadSandboxThread();
      loadModeration();
    } catch (err) {
      toast(err.message, 'error');
    }
  });

  $('#sandbox-message').addEventListener('keydown', (e) => {
    if (e.key === 'Enter' && !e.shiftKey) {
      e.preventDefault();
      $('#btn-sandbox-send').click();
    }
  });

  $('#btn-sandbox-menu').addEventListener('click', () => {
    if (!sandbox.current) return;
    openSheet(`
      <h3>${escapeHtml(sandbox.current.name)}</h3>
      <button class="sheet-action" id="sb-read">
        <svg><use href="#i-check"/></svg> Simuler la lecture par tous
      </button>
      <button class="sheet-action danger" id="sb-clear">
        <svg><use href="#i-trash"/></svg> Vider la conversation
      </button>
    `);
    $('#sb-read').addEventListener('click', async () => {
      try {
        const res = await api(`/api/admin/playground/groups/${sandbox.current.id}/read`, {
          method: 'POST',
        });
        closeSheet();
        toast(`${res.readers} compte(s) ont lu la conversation.`, 'ok');
      } catch (err) {
        toast(err.message, 'error');
      }
    });
    $('#sb-clear').addEventListener('click', async () => {
      try {
        await api(`/api/admin/playground/groups/${sandbox.current.id}/clear`, { method: 'POST' });
        closeSheet();
        loadSandboxThread();
        loadPlayground();
      } catch (err) {
        toast(err.message, 'error');
      }
    });
  });

  let userSearchTimer = null;
  $('#in-user-search').addEventListener('input', () => {
    clearTimeout(userSearchTimer);
    userSearchTimer = setTimeout(loadAdminUsers, 260);
  });

  async function loadAdminUsers() {
    try {
      const term = encodeURIComponent($('#in-user-search').value.trim());
      const res = await api(`/api/admin/users?search=${term}&limit=200`);
      $('#admin-users').innerHTML = res.users.length
        ? res.users
            .map(
              (u) => `<div class="admin-row">
                <span class="dot ${u.online ? 'online' : u.status === 'invited' ? 'invited' : u.status === 'blocked' ? 'blocked' : ''}"></span>
                <div class="avatar sm ${avatarClass(u.phone)}">${escapeHtml(initials(u.display_name))}</div>
                <div class="group-main">
                  <div class="group-name">${escapeHtml(u.display_name)}
                    ${u.is_superadmin ? '<span class="tag admin">Super</span>' : ''}
                    ${u.flagged ? '<span class="tag flagged">Signalé</span>' : ''}
                    ${
                      u.self_registered && !u.group_count
                        ? '<span class="tag muted">à affecter</span>'
                        : ''
                    }</div>
                  <div class="group-preview">${escapeHtml(u.phone_display)} · ${u.group_count} groupe(s)${
                    u.status === 'invited' ? ' · en attente' : u.status === 'blocked' ? ' · bloqué' : ''
                  }${u.flagged && u.flag_reason ? ` · ${escapeHtml(u.flag_reason)}` : ''}</div>
                </div>
                <button class="btn btn-ghost btn-sm" data-user="${escapeHtml(u.phone)}">Gérer</button>
              </div>`,
            )
            .join('')
        : '<p style="color:var(--text-faint);font-size:14px">Aucun compte.</p>';

      $('#admin-users')
        .querySelectorAll('[data-user]')
        .forEach((b) =>
          b.addEventListener('click', () =>
            openUserSheet(res.users.find((u) => u.phone === b.dataset.user)),
          ),
        );
    } catch (err) {
      toast(err.message, 'error');
    }
  }

  async function openUserSheet(user) {
    if (!user) return;
    const [allGroups, mine] = await Promise.all([
      api('/api/admin/groups').then((r) => r.groups),
      api(`/api/admin/users/${user.phone}/groups`).then((r) => r.groups),
    ]);
    const mineById = new Map(mine.map((g) => [g.id, g]));
    // Les sous-groupes s'affichent sous leur parent pour rester lisibles.
    const ordered = [];
    for (const g of allGroups.filter((x) => !x.parent_id)) {
      ordered.push(g);
      ordered.push(...allGroups.filter((x) => x.parent_id === g.id));
    }
    ordered.push(...allGroups.filter((x) => x.parent_id && !allGroups.some((p) => p.id === x.parent_id)));

    openSheet(`
      <h3>${escapeHtml(user.display_name)}</h3>
      <p style="color:var(--text-faint);font-size:13px;margin:-8px 0 14px">
        ${escapeHtml(user.phone_display)} · ${
          user.status === 'active' ? 'compte actif' : user.status === 'invited' ? 'en attente d’activation' : 'bloqué'
        }
      </p>

      <div style="font-size:11px;text-transform:uppercase;letter-spacing:.13em;color:var(--cyan-dim);font-weight:700;margin:6px 0 8px">
        Groupes actuels (${mine.length})
      </div>
      <div id="us-current" style="margin-bottom:14px">
        ${
          mine.length
            ? mine
                .map(
                  (g) => `<span class="chip ${g.role === 'admin' ? 'admin' : ''}">
                    ${escapeHtml(g.name)}${g.role === 'admin' ? ' · admin' : ''}
                    <button data-unassign="${g.id}" title="Retirer">×</button>
                  </span>`,
                )
                .join('')
            : '<span style="color:var(--text-faint);font-size:13px">Aucun groupe.</span>'
        }
      </div>

      <div style="font-size:11px;text-transform:uppercase;letter-spacing:.13em;color:var(--cyan-dim);font-weight:700;margin:6px 0 8px">
        Affecter à plusieurs groupes
      </div>
      <div class="group-picker" id="us-picker">
        ${
          ordered.length
            ? ordered
                .map(
                  (g) => `<div class="pick-row ${g.parent_id ? 'child' : ''} ${
                    mineById.has(g.id) ? 'member-of' : ''
                  }" data-gid="${g.id}">
                    <span class="pick-box"></span>
                    <span style="flex:1;min-width:0">${escapeHtml(g.name)}</span>
                    ${mineById.has(g.id) ? '<span class="tag muted">déjà membre</span>' : ''}
                  </div>`,
                )
                .join('')
            : '<div class="chart-empty">Aucun groupe à proposer.</div>'
        }
      </div>
      <div class="segmented" id="us-role" style="margin:10px 0">
        <button data-role="member" class="active">Membre</button>
        <button data-role="admin">Administrateur</button>
      </div>
      <button class="btn btn-ember btn-sm" id="us-assign" style="width:100%">
        Ajouter aux groupes sélectionnés
      </button>

      <div style="height:18px"></div>
      <button class="sheet-action" id="us-super">
        <svg><use href="#i-shield"/></svg>
        ${user.is_superadmin ? 'Retirer le rôle de superadmin' : 'Promouvoir superadmin'}
      </button>
      <button class="sheet-action" id="us-reset">
        <svg><use href="#i-key"/></svg> Réinitialiser le code PIN
      </button>
      <button class="sheet-action" id="us-flag">
        <svg><use href="#i-alert"/></svg>
        ${user.flagged ? 'Lever le signalement' : 'Signaler ce compte'}
      </button>
      <button class="sheet-action" id="us-block">
        <svg><use href="#i-alert"/></svg>
        ${user.status === 'blocked' ? 'Débloquer le compte' : 'Bloquer le compte'}
      </button>
      <button class="sheet-action danger" id="us-delete">
        <svg><use href="#i-trash"/></svg> Supprimer le compte
      </button>
    `);

    let role = 'member';
    $('#us-role')
      .querySelectorAll('button')
      .forEach((b) =>
        b.addEventListener('click', () => {
          role = b.dataset.role;
          $('#us-role')
            .querySelectorAll('button')
            .forEach((x) => x.classList.toggle('active', x === b));
        }),
      );

    const patch = async (body, message) => {
      try {
        await api(`/api/admin/users/${user.phone}`, { method: 'PATCH', body });
        closeSheet();
        toast(message, 'ok');
        loadAdminUsers();
      } catch (err) {
        toast(err.message, 'error');
      }
    };

    // Sélection multiple : un numéro peut appartenir à autant de groupes qu'on veut.
    $('#us-picker')
      .querySelectorAll('.pick-row')
      .forEach((row) => row.addEventListener('click', () => row.classList.toggle('on')));

    $('#us-current')
      .querySelectorAll('[data-unassign]')
      .forEach((b) =>
        b.addEventListener('click', async () => {
          try {
            await api(`/api/admin/users/${user.phone}/groups/${b.dataset.unassign}`, {
              method: 'DELETE',
            });
            closeSheet();
            toast('Retiré du groupe.', 'ok');
            loadAdminUsers();
            loadAdminGroups();
          } catch (err) {
            toast(err.message, 'error');
          }
        }),
      );

    $('#us-assign').addEventListener('click', async () => {
      const ids = Array.from($('#us-picker').querySelectorAll('.pick-row.on')).map((r) =>
        Number(r.dataset.gid),
      );
      if (!ids.length) return toast('Sélectionnez au moins un groupe.', 'error');
      try {
        const res = await api(`/api/admin/users/${user.phone}/groups`, {
          method: 'POST',
          body: { group_ids: ids, role },
        });
        closeSheet();
        toast(`Ajouté à ${res.added.length} groupe(s).`, 'ok');
        loadAdminGroups();
        loadAdminUsers();
        loadGroups();
      } catch (err) {
        toast(err.message, 'error');
      }
    });

    $('#us-super').addEventListener('click', () =>
      patch(
        { is_superadmin: !user.is_superadmin },
        user.is_superadmin ? 'Rôle superadmin retiré.' : 'Superadmin promu.',
      ),
    );

    // Signaler ne coupe pas l'accès : le compte remonte simplement en tête
    // d'annuaire avec son motif, en attendant qu'on tranche.
    $('#us-flag').addEventListener('click', async () => {
      let reason = '';
      if (!user.flagged) {
        reason = prompt('Motif du signalement (visible par les superadmins) :', '') || '';
        if (reason === null) return;
      }
      try {
        await api(`/api/admin/users/${user.phone}/flag`, {
          method: 'POST',
          body: { flagged: !user.flagged, reason },
        });
        closeSheet();
        toast(user.flagged ? 'Signalement levé.' : 'Compte signalé.', 'ok');
        loadAdminUsers();
      } catch (err) {
        toast(err.message, 'error');
      }
    });

    $('#us-block').addEventListener('click', () =>
      patch(
        { status: user.status === 'blocked' ? 'active' : 'blocked' },
        user.status === 'blocked' ? 'Compte débloqué.' : 'Compte bloqué.',
      ),
    );

    $('#us-reset').addEventListener('click', async () => {
      if (!confirm('Réinitialiser le code PIN ? La personne devra en choisir un nouveau.')) return;
      try {
        const res = await api(`/api/admin/users/${user.phone}/reset-pin`, { method: 'POST' });
        closeSheet();
        toast(res.message, 'ok');
        loadAdminUsers();
      } catch (err) {
        toast(err.message, 'error');
      }
    });

    $('#us-delete').addEventListener('click', async () => {
      if (!confirm(`Supprimer définitivement le compte ${user.phone_display} ?`)) return;
      try {
        await api(`/api/admin/users/${user.phone}`, { method: 'DELETE' });
        closeSheet();
        toast('Compte supprimé.', 'ok');
        loadAdminUsers();
        loadStats();
      } catch (err) {
        toast(err.message, 'error');
      }
    });
  }

  async function loadStats() {
    try {
      const s = await api('/api/admin/stats');
      $('#stat-grid').innerHTML = [
        ['Comptes', s.users.total],
        ['Actifs', s.users.active],
        ['En attente', s.users.invited],
        ['En ligne', s.users.online],
        ['Groupes', s.groups.total],
        ['Sous-groupes', s.groups.subgroups],
        ['Messages', s.messages.total],
        ['Dernières 24 h', s.messages.last_24h],
      ]
        .map(([k, v]) => `<div class="stat"><div class="v">${v}</div><div class="k">${k}</div></div>`)
        .join('');

      const st = s.storage;
      $('#storage-bar').style.width = `${Math.min(st.percent, 100)}%`;
      $('#storage-text').innerHTML = `
        <strong>${st.megabytes} Mo</strong> utilisés sur ${st.hard_limit_mb} Mo (${st.percent} %).<br />
        Rétention : les <strong>${st.keep_per_group} derniers messages</strong> par groupe,
        purgés au-delà de <strong>${st.retention_days} jours</strong>.`;
    } catch (err) {
      toast(err.message, 'error');
    }
  }

  $('#btn-purge').addEventListener('click', async () => {
    if (!confirm('Lancer la purge de rétention maintenant ?')) return;
    try {
      const r = await api('/api/admin/purge', { method: 'POST' });
      toast(
        `${r.deleted_age + r.deleted_overflow} message(s) supprimé(s) · ${(r.size_after / 1e6).toFixed(1)} Mo`,
        'ok',
      );
      loadStats();
    } catch (err) {
      toast(err.message, 'error');
    }
  });

  /* ------------------------------------------------------------------ */
  /* Tableau de bord — graphiques                                        */
  /* ------------------------------------------------------------------ */
  /* Toutes les séries sont mono-série (une magnitude dans le temps ou un
     classement) : une seule teinte, pas de légende, base à zéro. */

  const tip = document.createElement('div');
  tip.id = 'chart-tip';
  document.body.appendChild(tip);

  function showTip(event, label, value, unit) {
    tip.innerHTML = `${escapeHtml(label)} · <span class="tv">${value}</span> ${escapeHtml(unit)}`;
    tip.style.display = 'block';
    const rect = tip.getBoundingClientRect();
    let x = event.clientX - rect.width / 2;
    x = Math.max(8, Math.min(x, window.innerWidth - rect.width - 8));
    tip.style.left = `${x}px`;
    tip.style.top = `${Math.max(8, event.clientY - rect.height - 12)}px`;
  }

  function hideTip() {
    tip.style.display = 'none';
  }

  document.addEventListener('scroll', hideTip, true);

  // Barre à extrémité haute arrondie, ancrée sur la ligne de base.
  function barPath(x, y, w, h, r) {
    const rr = Math.max(0, Math.min(r, w / 2, h));
    return (
      `M${x},${y + h}` +
      `L${x},${y + rr}` +
      `Q${x},${y} ${x + rr},${y}` +
      `L${x + w - rr},${y}` +
      `Q${x + w},${y} ${x + w},${y + rr}` +
      `L${x + w},${y + h}Z`
    );
  }

  /**
   * Histogramme vertical mono-série.
   * @param {HTMLElement} host conteneur
   * @param {Array<{label:string,count:number}>} data
   */
  function barChart(host, data, { barW = 18, gap = 4, height = 120, labelEvery = 1, unit = 'messages' } = {}) {
    if (!data.length) {
      host.innerHTML = '<div class="chart-empty">Aucune donnée.</div>';
      return;
    }
    const padLeft = 26;
    const padBottom = 18;
    const padTop = 12;
    const plotW = data.length * (barW + gap) - gap;
    const width = padLeft + plotW + 6;
    const max = Math.max(1, ...data.map((d) => d.count));
    const scale = (v) => (v / max) * height;

    // Trois repères suffisent : 0, milieu, maximum.
    const ticks = [0, Math.round(max / 2), max].filter((v, i, a) => a.indexOf(v) === i);

    const parts = [`<svg width="${width}" height="${height + padTop + padBottom}" role="img">`];

    for (const t of ticks) {
      const y = padTop + height - scale(t);
      parts.push(
        `<line class="grid-line" x1="${padLeft}" y1="${y}" x2="${width - 4}" y2="${y}" />`,
        `<text class="axis-label" x="${padLeft - 5}" y="${y + 3}" text-anchor="end">${t}</text>`,
      );
    }

    const maxIndex = data.findIndex((d) => d.count === max);

    data.forEach((d, i) => {
      const x = padLeft + i * (barW + gap);
      const h = scale(d.count);
      const y = padTop + height - h;
      if (d.count > 0) {
        parts.push(`<path class="bar" d="${barPath(x, y, barW, h, 4)}" />`);
      }
      // Zone de survol pleine hauteur : plus facile à viser qu'une barre fine.
      parts.push(
        `<rect class="bar-hit" x="${x - gap / 2}" y="${padTop}" width="${barW + gap}" height="${height}" ` +
          `data-label="${escapeHtml(d.label)}" data-value="${d.count}" />`,
      );
      // Label direct sur le seul maximum, jamais sur chaque barre.
      if (i === maxIndex && max > 0) {
        parts.push(
          `<text class="value-label" x="${x + barW / 2}" y="${y - 4}" text-anchor="middle">${max}</text>`,
        );
      }
      if (i % labelEvery === 0) {
        parts.push(
          `<text class="axis-label" x="${x + barW / 2}" y="${padTop + height + 12}" text-anchor="middle">${escapeHtml(d.label)}</text>`,
        );
      }
    });

    parts.push('</svg>');
    host.className = 'chart';
    host.innerHTML = parts.join('');

    host.querySelectorAll('.bar-hit').forEach((hit) => {
      const show = (e) => showTip(e, hit.dataset.label, hit.dataset.value, unit);
      hit.addEventListener('pointerenter', show);
      hit.addEventListener('pointermove', show);
      hit.addEventListener('pointerdown', show);
      hit.addEventListener('pointerleave', hideTip);
    });
  }

  /** Classement en barres horizontales (lisible sur mobile, pas de rotation de texte). */
  function rankList(host, items, { unit = 'messages' } = {}) {
    if (!items.length) {
      host.innerHTML = '<div class="chart-empty">Aucune donnée sur la période.</div>';
      return;
    }
    const max = Math.max(1, ...items.map((i) => i.value));
    host.innerHTML = items
      .map(
        (i) => `<div class="rank-row ${i.sub ? 'sub' : ''}">
          <div class="rank-label">${i.dot ? `<span class="dot ${i.dot}"></span>` : ''}${escapeHtml(i.label)}</div>
          <div class="rank-value">${i.value} ${escapeHtml(unit)}</div>
          <div class="rank-track"><div class="rank-fill" style="width:${Math.round((i.value / max) * 100)}%"></div></div>
        </div>`,
      )
      .join('');
  }

  function fmtDuration(seconds) {
    const d = Math.floor(seconds / 86400);
    const h = Math.floor((seconds % 86400) / 3600);
    const m = Math.floor((seconds % 3600) / 60);
    if (d) return `${d} j ${h} h`;
    if (h) return `${h} h ${m} min`;
    return `${m} min`;
  }

  /* --- Journal d'audit ------------------------------------------------- */

  const AUDIT_LABELS = {
    login: 'Connexion',
    login_failed: 'Échec de connexion',
    account_locked: 'Compte verrouillé',
    account_activated: 'Compte activé',
    rate_limit: 'Rate limit atteint',
    ws_flood: 'Flood WebSocket',
    help_request: "Demande d'assistance",
    help_request_unknown: "Demande d'assistance (numéro inconnu)",
    help_unlock: 'Déverrouillage',
    help_reset_pin: 'PIN réinitialisé',
    help_dismiss: 'Demande classée',
    user_whitelisted: 'Numéro enregistré',
    users_bulk_import: 'Import de numéros',
    user_groups_assigned: 'Affectation de groupes',
    user_group_removed: 'Retrait de groupe',
    server_start: 'Démarrage du serveur',
  };

  const AUDIT_SEVERITY = {
    login_failed: 'sev-warn',
    account_locked: 'sev-bad',
    rate_limit: 'sev-warn',
    ws_flood: 'sev-bad',
    help_request: 'sev-warn',
    help_request_unknown: 'sev-warn',
    login: 'sev-ok',
    account_activated: 'sev-ok',
    help_unlock: 'sev-ok',
  };

  function renderAudit(host, entries) {
    if (!entries.length) {
      host.innerHTML = '<div class="chart-empty">Aucun événement.</div>';
      return;
    }
    host.innerHTML = entries
      .map((e) => {
        const bits = [];
        if (e.actor) bits.push(e.actor);
        if (e.target && e.target !== e.actor) bits.push(`→ ${e.target}`);
        if (e.detail) bits.push(e.detail);
        if (e.ip && e.ip !== 'inconnu') bits.push(e.ip);
        return `<div class="audit-row ${AUDIT_SEVERITY[e.action] || ''}">
            <div class="audit-time">${fmtRelative(e.at)}</div>
            <div class="audit-main">
              <div class="audit-action">${escapeHtml(AUDIT_LABELS[e.action] || e.action)}</div>
              <div class="audit-detail">${escapeHtml(bits.join(' · '))}</div>
            </div>
          </div>`;
      })
      .join('');
  }

  /* --- Chargement du tableau de bord ----------------------------------- */

  async function loadDashboard() {
    try {
      const d = await api('/api/admin/dashboard');
      const k = d.kpis;

      $('#dash-kpis').innerHTML = [
        { v: k.users_online, k: 'En ligne', cls: 'accent' },
        { v: k.weekly_active, k: 'Actifs 7 j', cls: 'accent' },
        { v: k.users_active, k: 'Comptes actifs' },
        { v: k.users_invited, k: 'En attente', cls: k.users_invited ? 'warn' : '' },
        { v: k.users_blocked, k: 'Bloqués', cls: k.users_blocked ? 'alert' : '' },
        { v: k.groups_total, k: 'Groupes' },
        { v: k.messages_24h, k: 'Msg 24 h' },
        { v: k.messages_7d, k: 'Msg 7 j' },
        { v: k.images_30d, k: 'Photos 30 j' },
        { v: `${k.activation_rate} %`, k: 'Activation' },
        { v: k.push_subscriptions, k: 'Abonnés push' },
        { v: fmtDuration(k.uptime_seconds), k: 'Uptime' },
      ]
        .map(
          (x) =>
            `<div class="kpi ${x.cls || ''}"><div class="v">${escapeHtml(String(x.v))}</div><div class="k">${x.k}</div></div>`,
        )
        .join('');

      const totalDaily = d.daily.reduce((s, x) => s + x.count, 0);
      $('#daily-note').textContent = `${d.daily.length} jours · ${totalDaily} au total`;
      barChart($('#chart-daily'), d.daily, { barW: 18, gap: 4, labelEvery: 2 });

      const totalHourly = d.hourly.reduce((s, x) => s + x.count, 0);
      $('#hourly-note').textContent = `${totalHourly} message(s)`;
      barChart($('#chart-hourly'), d.hourly, { barW: 11, gap: 3, height: 90, labelEvery: 3 });

      rankList(
        $('#chart-groups'),
        d.top_groups.map((g) => ({ label: g.name, value: g.messages, sub: g.is_subgroup })),
      );

      rankList(
        $('#chart-members'),
        d.top_members.map((m) => ({
          label: m.name,
          value: m.messages,
          dot: m.online ? 'online' : '',
        })),
      );

      renderAudit($('#audit-list'), d.audit.slice(0, 12));
    } catch (err) {
      toast(err.message, 'error');
    }
  }

  $('#btn-audit-all').addEventListener('click', async () => {
    try {
      const res = await api('/api/admin/audit?limit=200');
      openSheet('<h3>Journal d\'audit</h3><div id="audit-full"></div>');
      renderAudit($('#audit-full'), res.entries);
    } catch (err) {
      toast(err.message, 'error');
    }
  });

  /* ------------------------------------------------------------------ */
  /* Demandes d'assistance (comptes verrouillés)                         */
  /* ------------------------------------------------------------------ */

  const HELP_REASONS = {
    locked: 'Compte verrouillé',
    blocked: 'Compte bloqué',
    forgot_pin: 'Code PIN oublié',
    other: 'Autre demande',
  };

  async function loadHelpRequests() {
    // Deux points d'affichage : le tableau de bord (superadmin) et la liste
    // des groupes (tout admin de groupe).
    const hosts = [$('#help-requests-card'), $('#help-requests-inline')].filter(Boolean);
    if (!hosts.length) return;
    const host = { set innerHTML(v) { hosts.forEach((h) => (h.innerHTML = v)); },
                   querySelectorAll: (s) => hosts.flatMap((h) => Array.from(h.querySelectorAll(s))) };
    try {
      const res = await api('/api/help-requests');
      const pip = $('#btn-admin').querySelector('.pip');
      if (res.count) {
        if (pip) pip.textContent = res.count;
        else {
          const el = document.createElement('span');
          el.className = 'pip';
          el.textContent = res.count;
          $('#btn-admin').appendChild(el);
        }
      } else if (pip) {
        pip.remove();
      }

      if (!res.count) {
        host.innerHTML = '';
        return;
      }

      host.innerHTML = `<div class="help-card">
        <h4><svg style="width:16px;height:16px;stroke:currentColor;fill:none;stroke-width:2"><use href="#i-alert"/></svg>
          ${res.count} demande${res.count > 1 ? 's' : ''} d'assistance</h4>
        ${res.requests
          .map(
            (r) => `<div class="help-item" data-req="${r.id}">
              <div class="help-who">${escapeHtml(r.name)}</div>
              <div class="help-meta">${escapeHtml(r.phone_display)} · ${escapeHtml(
                HELP_REASONS[r.reason] || r.reason,
              )} · ${fmtRelative(r.created_at)}</div>
              ${r.message ? `<div class="help-msg">« ${escapeHtml(r.message)} »</div>` : ''}
              <div class="help-actions">
                <button class="btn btn-primary btn-sm" data-act="unlock" data-id="${r.id}">Déverrouiller</button>
                <button class="btn btn-ghost btn-sm" data-act="reset_pin" data-id="${r.id}">Réinit. PIN</button>
                <button class="btn btn-ghost btn-sm" data-act="dismiss" data-id="${r.id}">Ignorer</button>
              </div>
            </div>`,
          )
          .join('')}
      </div>`;

      host.querySelectorAll('[data-act]').forEach((b) =>
        b.addEventListener('click', async () => {
          const action = b.dataset.act;
          if (action === 'reset_pin' && !confirm('Réinitialiser le code PIN de cette personne ?')) {
            return;
          }
          try {
            const r = await api(`/api/help-requests/${b.dataset.id}/resolve`, {
              method: 'POST',
              body: { action },
            });
            toast(r.message, 'ok');
            loadHelpRequests();
            loadAdminUsers();
          } catch (err) {
            toast(err.message, 'error');
          }
        }),
      );
    } catch (err) {
      // Un membre sans rôle d'admin n'a rien à voir ici : échec silencieux.
      host.innerHTML = '';
    }
  }

  /* --- Côté utilisateur : demander de l'aide depuis l'écran d'accueil --- */

  $$('[data-open-help]').forEach((b) =>
    b.addEventListener('click', () => {
      showAuthStep('step-help');
      // Pré-sélectionne le motif le plus probable d'après le message d'erreur.
      const err = $('#auth-error').textContent;
      $('#in-help-reason').value = /bloqué/i.test(err)
        ? 'blocked'
        : /tentatives|verrouill/i.test(err)
          ? 'locked'
          : 'forgot_pin';
    }),
  );

  $('#btn-help-send').addEventListener('click', async () => {
    const btn = $('#btn-help-send');
    btn.disabled = true;
    try {
      const res = await api('/api/auth/help', {
        method: 'POST',
        body: {
          phone: state.pendingPhone,
          reason: $('#in-help-reason').value,
          message: $('#in-help-msg').value.trim(),
        },
      });
      $('#in-help-msg').value = '';
      showAuthStep('step-phone');
      authError('');
      toast(res.message, 'ok');
    } catch (err) {
      authError(err.message);
    } finally {
      btn.disabled = false;
    }
  });

  /* ------------------------------------------------------------------ */
  /* Service worker et cycle de vie                                      */
  /* ------------------------------------------------------------------ */

  if ('serviceWorker' in navigator) {
    window.addEventListener('load', () => {
      navigator.serviceWorker.register('/sw.js').catch(() => {
        /* hors ligne au premier chargement */
      });
    });
    navigator.serviceWorker.addEventListener('message', (event) => {
      if (event.data && event.data.type === 'open-group' && event.data.group_id) {
        openChat(Number(event.data.group_id));
      }
    });
  }

  document.addEventListener('visibilitychange', () => {
    if (document.visibilityState === 'visible') {
      connectWS();
      loadGroups();
      if (navigator.clearAppBadge) {
        try {
          navigator.clearAppBadge();
        } catch (e) {
          /* ignoré */
        }
      }
    }
  });

  boot();
})();