// sessionStore.js — access_token + Supabase RLS, no service role key needed.
// Device sessions live in memory only (restart clears them).
import { createClient } from '@supabase/supabase-js';
import crypto from 'crypto';
import { saveEncryptedJson, loadEncryptedJson } from './cryptoUtils.js';
import path from 'path';

let _SUPABASE_URL, _SUPABASE_ANON_KEY;
export function initStoreConfig(url, key) { _SUPABASE_URL = url; _SUPABASE_ANON_KEY = key; }

const TEMP_TTL_MS     = 24 * 60 * 60 * 1000;
const TEMP_INACTIVITY = 12 * 60 * 60 * 1000;
const TEMP_MSG_LIMIT  = 10;

const userCache   = new Map(); // userId -> { sessions: Map, online: Set }
const tempStore   = new Map(); // tempId -> TempData
const devSessions = new Map(); // token  -> DeviceSession

const TEMP_STORE_FILE = '/data/temp_sessions.json';

async function loadTempStore() {
  const data = await loadEncryptedJson(TEMP_STORE_FILE);
  if (data) {
    for (const [id, d] of Object.entries(data)) {
      tempStore.set(id, {
        sessions: new Map(Object.entries(d.sessions || {})),
        msgCount: d.msgCount || 0,
        created: d.created || Date.now(),
        lastActive: d.lastActive || Date.now(),
      });
    }
  }
}

async function saveTempStore() {
  const data = {};
  for (const [id, d] of tempStore) {
    data[id] = {
      sessions: Object.fromEntries(d.sessions),
      msgCount: d.msgCount,
      created: d.created,
      lastActive: d.lastActive,
    };
  }
  await saveEncryptedJson(TEMP_STORE_FILE, data);
}

// Load temp store on init
loadTempStore().catch(err => console.error('Failed to load temp store:', err));

setInterval(async () => {
  const now = Date.now();
  for (const [id, d] of tempStore)
    if (now - d.created > TEMP_TTL_MS || now - d.lastActive > TEMP_INACTIVITY)
      tempStore.delete(id);
  // Save after cleanup
  await saveTempStore().catch(err => console.error('Failed to save temp store:', err));
}, 30 * 60 * 1000);

function userClient(accessToken) {
  return createClient(_SUPABASE_URL, _SUPABASE_ANON_KEY, {
    global: { headers: { Authorization: `Bearer ${accessToken}` } },
    auth: { persistSession: false },
  });
}

export const sessionStore = {
  // ── TEMP ────────────────────────────────────────────────────────────────
  initTemp(t) {
    if (!tempStore.has(t))
      tempStore.set(t, { sessions: new Map(), msgCount: 0, created: Date.now(), lastActive: Date.now() });
    return tempStore.get(t);
  },
  tempCanSend(t)  { const d = tempStore.get(t); return d ? d.msgCount < TEMP_MSG_LIMIT : false; },
  tempBump(t)     { const d = tempStore.get(t); if (d) { d.msgCount++; d.lastActive = Date.now(); } },
  getTempSessions(t) { return [...(tempStore.get(t)?.sessions.values() || [])]; },
  getTempSession(t, id) { return tempStore.get(t)?.sessions.get(id) || null; },
  createTempSession(t) {
    const d = this.initTemp(t);
    const s = { id: crypto.randomUUID(), name: 'New Chat', created: Date.now(), history: [] };
    d.sessions.set(s.id, s); d.lastActive = Date.now();
    saveTempStore().catch(err => console.error('Failed to save temp store:', err));
    return s;
  },
  updateTempSession(t, id, patch) {
    const d = tempStore.get(t); if (!d) return null;
    const s = d.sessions.get(id); if (!s) return null;
    Object.assign(s, patch); d.lastActive = Date.now();
    saveTempStore().catch(err => console.error('Failed to save temp store:', err));
    return s;
  },
  restoreTempSession(t, session) {
    const d = this.initTemp(t);
    const restored = JSON.parse(JSON.stringify(session));
    d.sessions.set(restored.id, restored);
    d.lastActive = Date.now();
    saveTempStore().catch(err => console.error('Failed to save temp store:', err));
    return restored;
  },
  deleteTempSession(t, id) { tempStore.get(t)?.sessions.delete(id); saveTempStore().catch(err => console.error('Failed to save temp store:', err)); },
  deleteTempAll(t)         { tempStore.get(t)?.sessions.clear(); saveTempStore().catch(err => console.error('Failed to save temp store:', err)); },
  deleteTempSessionEverywhere(id) {
    let changed = false;
    for (const temp of tempStore.values()) {
      if (temp.sessions.delete(id)) changed = true;
    }
    if (changed) saveTempStore().catch(err => console.error('Failed to save temp store:', err));
    return changed;
  },

  /**
   * Copy temp sessions into the user's account on login.
   * We intentionally do NOT delete from tempStore so the guest session
   * remains usable if the user logs out again (and so the WS client's
   * tempId still resolves while the tab is open).
   * Sessions that already exist in the user account (same id) are skipped
   * to avoid overwriting newer server data.
   */
  async transferTempToUser(tempId, userId, accessToken) {
    const d = tempStore.get(tempId);
    if (!d || !d.sessions.size) return;

    const uc   = userClient(accessToken);
    const user = this._ensureUser(userId);

    for (const s of d.sessions.values()) {
      // Skip sessions that are empty (never actually used)
      if (!s.history || s.history.length === 0) continue;

      // Skip if the user already has a session with the same id
      if (user.sessions.has(s.id)) continue;

      // Deep-clone so mutations to the user copy don't affect temp copy
      const copy = JSON.parse(JSON.stringify(s));
      user.sessions.set(copy.id, copy);
      await this._persist(uc, userId, copy).catch(err =>
        console.error('transferTempToUser persist error:', err.message));
    }
  },

  // ── USERS ────────────────────────────────────────────────────────────────
  _ensureUser(uid) {
    if (!userCache.has(uid)) userCache.set(uid, { sessions: new Map(), online: new Set() });
    return userCache.get(uid);
  },
  async loadUserSessions(userId, accessToken) {
    const uc = userClient(accessToken);
    const { data, error } = await uc.from('web_sessions').select('*')
      .eq('user_id', userId).order('updated_at', { ascending: false });
    if (error) { console.error('loadUserSessions', error.message); return []; }
    const user = this._ensureUser(userId);
    for (const row of data || [])
      user.sessions.set(row.id, { id: row.id, name: row.name,
        created: new Date(row.created_at).getTime(), history: row.history || [], model: row.model });
    return [...user.sessions.values()];
  },
  getUserSessions(uid)    { return [...(userCache.get(uid)?.sessions.values() || [])]; },
  getUserSession(uid, id) { return userCache.get(uid)?.sessions.get(id) || null; },
  async createUserSession(userId, accessToken) {
    const s = { id: crypto.randomUUID(), name: 'New Chat', created: Date.now(), history: [] };
    this._ensureUser(userId).sessions.set(s.id, s);
    await this._persist(userClient(accessToken), userId, s).catch(() => {});
    return s;
  },
  async restoreUserSession(userId, accessToken, session) {
    const restored = JSON.parse(JSON.stringify(session));
    this._ensureUser(userId).sessions.set(restored.id, restored);
    await this._persist(userClient(accessToken), userId, restored).catch(() => {});
    return restored;
  },
  async updateUserSession(userId, accessToken, sessionId, patch) {
    const user = userCache.get(userId); if (!user) { console.error("No user for " + userId); return null; }
    const s = user.sessions.get(sessionId); if (!s) { console.error ("No session found for " + sessionId); return null; }
    Object.assign(s, patch);
    await this._persist(userClient(accessToken), userId, s).catch(() => {});
    return s;
  },
  async deleteUserSession(userId, accessToken, id) {
    try {
      userCache.get(userId)?.sessions.delete(id);
      const { error } = await userClient(accessToken)
        .from('web_sessions')
        .delete()
        .eq('id', id)
        .eq('user_id', userId);
      if (error) console.error('Supabase delete error:', error.message);
    } catch (ex) {
      console.error('Unexpected deleteUserSession error:', ex);
    }
  },
  async deleteAllUserSessions(userId, accessToken) {
    const u = userCache.get(userId);
    if (u) {
      u.sessions.clear();
    } else {
      console.error('No user for ' + userId);
      return null;
    }
    try {
      const { error } = await userClient(accessToken)
        .from('web_sessions')
        .delete()
        .eq('user_id', userId);
      if (error) console.error('Supabase bulk delete error:', error.message);
    } catch (ex) {
      console.error('Unexpected deleteAllUserSessions error:', ex);
    }
  },
  async _persist(uc, userId, s) {
    await uc.from('web_sessions').upsert({
      id: s.id, user_id: userId, name: s.name, history: s.history || [],
      model: s.model || null, updated_at: new Date().toISOString(),
      created_at: new Date(s.created).toISOString(),
    });
  },
  markOnline(uid, ws)  { this._ensureUser(uid).online.add(ws); },
  markOffline(uid, ws) { userCache.get(uid)?.online.delete(ws); },
  // ── SHARE ────────────────────────────────────────────────────────────────
  async createShareToken(userId, accessToken, sessionId) {
    const s = this.getUserSession(userId, sessionId); if (!s) return null;
    const token = crypto.randomBytes(24).toString('base64url');
    const uc = userClient(accessToken);
    const { error } = await uc.from('shared_sessions').insert({
      token, owner_id: userId, session_snapshot: s, created_at: new Date().toISOString(),
    });
    return error ? null : token;
  },
  async resolveShareToken(token) {
    // shared_sessions SELECT is public via RLS
    const uc = createClient(_SUPABASE_URL, _SUPABASE_ANON_KEY, { auth: { persistSession: false } });
    const { data } = await uc.from('shared_sessions').select('*').eq('token', token).single();
    return data || null;
  },
  async importSharedSession(userId, accessToken, token) {
    const shared = await this.resolveShareToken(token); if (!shared) return null;
    const snap = shared.session_snapshot;
    const newSession = { ...snap, id: crypto.randomUUID(),
      name: `${snap.name} (shared)`, created: Date.now() };
    const uc = userClient(accessToken);
    this._ensureUser(userId).sessions.set(newSession.id, newSession);
    await this._persist(uc, userId, newSession).catch(() => {});
    return newSession;
  },
};

export const deviceSessionStore = {
  create(userId, ip, userAgent) {
    const token = crypto.randomBytes(32).toString('hex');
    devSessions.set(token, { token, userId, ip, userAgent,
      createdAt: new Date().toISOString(), lastSeen: new Date().toISOString(), active: true });
    return token;
  },
  getForUser(uid)  { return [...devSessions.values()].filter(s => s.userId === uid && s.active); },
  revoke(token)    { const s = devSessions.get(token); if (s) { s.active = false; return s; } return null; },
  revokeAllExcept(uid, except) {
    for (const [t, s] of devSessions) if (s.userId === uid && t !== except) s.active = false;
  },
  validate(token)  {
    const s = devSessions.get(token); if (!s || !s.active) return null;
    s.lastSeen = new Date().toISOString(); return s;
  },
};