/* ═══════════════════════════════════════════════
   BREATHE — Front-end Application
   ═══════════════════════════════════════════════ */

const API = "";   // same-origin; change to http://localhost:5000 if running separately

const ADVICE = {
  Minimal:  "Great job! Your stress levels are minimal. Keep up your healthy routines and sleep schedule.",
  Mild:     "Your stress is mild. Consider a short walk or 5-minute breathing exercise today.",
  Moderate: "Moderate stress detected. Try to schedule a proper break, reduce screen time and stay hydrated.",
  Severe:   "High stress detected. Please prioritise rest, reach out to someone you trust, and consider reducing workload.",
  Critical: "Critical stress indicators found. We strongly recommend speaking with a mental health professional. You are not alone.",
};

const LEVEL_COLOURS = {
  Minimal:  "#4ade80",
  Mild:     "#86efac",
  Moderate: "#fbbf24",
  Severe:   "#fb923c",
  Critical: "#f87171",
};

/* ─── Helpers ─────────────────────────────────────────────── */
const $  = (s, el = document) => el.querySelector(s);
const $$ = (s, el = document) => el.querySelectorAll(s);

function setClass(el, cls, on) {
  el && (on ? el.classList.add(cls) : el.classList.remove(cls));
}

function formatDate(iso) {
  const d = new Date(iso);
  return d.toLocaleString(undefined, {
    year: "numeric", month: "short", day: "numeric",
    hour: "2-digit", minute: "2-digit",
  });
}

async function apiFetch(path, options = {}) {
  const res = await fetch(API + path, {
    credentials: "include",
    headers: { "Content-Type": "application/json", ...(options.headers || {}) },
    ...options,
  });
  const json = await res.json().catch(() => ({}));
  if (!res.ok) throw new Error(json.error || `HTTP ${res.status}`);
  return json;
}

/* ─── App State ───────────────────────────────────────────── */
const state = {
  user:          null,
  timelineChart: null,
  distChart:     null,
  historyPage:   1,
};

/* ═══════════════════════════════════════════════
   AUTH
═══════════════════════════════════════════════ */

function showAuth()    { setClass($("#auth-screen"), "active", true);  setClass($("#app-screen"), "active", false); }
function showApp()     { setClass($("#auth-screen"), "active", false); setClass($("#app-screen"), "active", true);  }

// Tab switching
$$(".tab").forEach(btn => {
  btn.addEventListener("click", () => {
    $$(".tab").forEach(t => t.classList.remove("active"));
    btn.classList.add("active");
    $$(".auth-form").forEach(f => f.classList.remove("active"));
    $(`#${btn.dataset.tab}-form`).classList.add("active");
  });
});

// Login
$("#login-form").addEventListener("submit", async e => {
  e.preventDefault();
  const errEl = $("#login-error");
  errEl.classList.add("hidden");
  try {
    const data = await apiFetch("/api/auth/login", {
      method: "POST",
      body: JSON.stringify({
        email:    $("#login-identity").value,
        username: $("#login-identity").value,
        password: $("#login-password").value,
      }),
    });
    state.user = data.user;
    onLogin();
  } catch (err) {
    errEl.textContent = err.message;
    errEl.classList.remove("hidden");
  }
});

// Signup
$("#signup-form").addEventListener("submit", async e => {
  e.preventDefault();
  const errEl = $("#signup-error");
  errEl.classList.add("hidden");
  try {
    const data = await apiFetch("/api/auth/signup", {
      method: "POST",
      body: JSON.stringify({
        username: $("#signup-username").value,
        email:    $("#signup-email").value,
        password: $("#signup-password").value,
      }),
    });
    state.user = data.user;
    onLogin();
  } catch (err) {
    errEl.textContent = err.message;
    errEl.classList.remove("hidden");
  }
});

// Logout
$("#logout-btn").addEventListener("click", async () => {
  await apiFetch("/api/auth/logout", { method: "POST" }).catch(() => {});
  state.user = null;
  showAuth();
});

async function onLogin() {
  showApp();
  $("#sidebar-username").textContent = state.user.username;
  $("#dash-greeting").textContent = `Welcome back, ${state.user.username}!`;
  await loadDashboard();
  goToView("dashboard");
}

/* ─── Check existing session on load ─────────────── */
(async () => {
  try {
    const data = await apiFetch("/api/auth/me");
    state.user = data.user;
    onLogin();
  } catch {
    showAuth();
  }
})();

/* ═══════════════════════════════════════════════
   NAVIGATION
═══════════════════════════════════════════════ */

function goToView(name) {
  $$(".view").forEach(v => v.classList.remove("active"));
  $(`#view-${name}`).classList.add("active");
  $$(".nav-item").forEach(b => {
    b.classList.toggle("active", b.dataset.view === name);
  });
  if (name === "history") loadHistory(1);
  if (name === "dashboard") loadDashboard();
}

$$(".nav-item").forEach(btn => {
  btn.addEventListener("click", () => goToView(btn.dataset.view));
});

/* ═══════════════════════════════════════════════
   DASHBOARD
═══════════════════════════════════════════════ */

async function loadDashboard() {
  try {
    const data  = await apiFetch("/api/assessments/summary");
    const s     = data.summary;
    const tl    = data.timeline;

    if (!s || !Object.keys(s).length) {
      // No data yet
      return;
    }

    // Stats
    $("#stat-total .stat-value").textContent  = s.total_assessments;
    $("#stat-latest .stat-value").textContent = stressIcon(s.latest_label) + " " + (s.latest_label || "—");
    $("#stat-latest .stat-value").style.fontSize = "1.2rem";
    $("#stat-avg .stat-value").textContent    = s.avg_score ? (s.avg_score * 100).toFixed(1) + "%" : "—";

    // Trend
    if (tl.length >= 2) {
      const diff = tl[tl.length-1].fused_score - tl[tl.length-2].fused_score;
      const el   = $("#stat-trend .stat-value");
      el.textContent = diff > 0.01 ? "▲ Up" : diff < -0.01 ? "▼ Down" : "→ Stable";
      el.style.color = diff > 0.01 ? "var(--danger)" : diff < -0.01 ? "var(--success)" : "var(--text-muted)";
      el.style.fontSize = "1rem";
    }

    // Timeline chart
    buildTimelineChart(tl);

    // Distribution chart
    buildDistChart(s.label_distribution);

    // Recent list (last 5)
    const recent = [...tl].reverse().slice(0, 5);
    const listEl = $("#recent-list");
    listEl.innerHTML = recent.length
      ? recent.map(r => assessmentItemHTML(r)).join("")
      : `<p class="empty-state">No assessments yet.</p>`;
    listEl.querySelectorAll(".assessment-item").forEach(el => {
      el.addEventListener("click", () => openDetailModal(el.dataset.id));
    });
  } catch (err) {
    console.error("Dashboard load error:", err);
  }
}

function buildTimelineChart(tl) {
  const ctx = $("#timeline-chart").getContext("2d");
  if (state.timelineChart) state.timelineChart.destroy();

  state.timelineChart = new Chart(ctx, {
    type: "line",
    data: {
      labels:   tl.map(r => r.date),
      datasets: [{
        label: "Stress Score",
        data:  tl.map(r => +(r.fused_score * 100).toFixed(1)),
        borderColor: "#4f8ef7",
        backgroundColor: "rgba(79,142,247,.08)",
        fill: true,
        tension: 0.4,
        pointRadius: 4,
        pointBackgroundColor: tl.map(r => LEVEL_COLOURS[r.fused_label] || "#4f8ef7"),
      }],
    },
    options: {
      responsive: true,
      maintainAspectRatio: false,
      plugins: { legend: { display: false } },
      scales: {
        x: {
          ticks: { color: "#7a8aa0", maxTicksLimit: 8 },
          grid:  { color: "#2a3348" },
        },
        y: {
          min: 0,
          max: 100,
          ticks: { color: "#7a8aa0", callback: v => v + "%" },
          grid:  { color: "#2a3348" },
        },
      },
    },
  });
}

function buildDistChart(dist) {
  const ctx = $("#distribution-chart").getContext("2d");
  if (state.distChart) state.distChart.destroy();

  const labels = Object.keys(dist);
  const values = Object.values(dist);
  const colours = labels.map(l => LEVEL_COLOURS[l] || "#4f8ef7");

  state.distChart = new Chart(ctx, {
    type: "doughnut",
    data: {
      labels,
      datasets: [{ data: values, backgroundColor: colours, borderWidth: 2, borderColor: "#161b27" }],
    },
    options: {
      responsive: true,
      maintainAspectRatio: false,
      plugins: {
        legend: { labels: { color: "#e2e8f0", font: { size: 12 } } },
      },
      cutout: "60%",
    },
  });
}

/* ═══════════════════════════════════════════════
   NEW ASSESSMENT
═══════════════════════════════════════════════ */

$("#assess-form").addEventListener("submit", async e => {
  e.preventDefault();
  const btn    = $("#assess-submit");
  const errEl  = $("#assess-error");
  errEl.classList.add("hidden");
  btn.disabled = true;
  btn.textContent = "Analysing…";

  try {
    // Build psychometric payload
    const psycho = {};
    const numFields = [
      "Sleep_Duration","Sleep_Quality","Work_Hours","Physical_Activity",
      "Screen_Time","Travel_Time","Social_Interactions","Caffeine_Intake",
      "Alcohol_Intake","Blood_Pressure","Cholesterol_Level","Blood_Sugar_Level",
    ];
    const catFields = ["Gender","Occupation","Smoking_Status","Diet_Quality"];

    let hasPsycho = false;
    numFields.forEach(f => {
      const el = $(`[name="${f}"]`, $("#assess-form"));
      if (el && el.value !== "") { psycho[f] = parseFloat(el.value); hasPsycho = true; }
    });
    catFields.forEach(f => {
      const el = $(`[name="${f}"]`, $("#assess-form"));
      if (el && el.value !== "") { psycho[f] = el.value; hasPsycho = true; }
    });

    const textNote = $("#text-note").value.trim();

    if (!hasPsycho && !textNote) {
      throw new Error("Please fill in at least one section.");
    }

    const body = {
      psychometric: hasPsycho ? psycho : null,
      text_note:    textNote || null,
    };

    const data = await apiFetch("/api/assessments", {
      method: "POST",
      body: JSON.stringify(body),
    });

    showResult(data.prediction, data.assessment);
  } catch (err) {
    errEl.textContent = err.message;
    errEl.classList.remove("hidden");
  } finally {
    btn.disabled = false;
    btn.textContent = "Analyse My Stress →";
  }
});

function showResult(pred, assessment) {
  const panel = $("#result-panel");
  panel.classList.remove("hidden");
  panel.scrollIntoView({ behavior: "smooth", block: "start" });

  const score = pred.fused_score;
  const label = pred.fused_label;
  const colour = LEVEL_COLOURS[label] || "#4f8ef7";
  const perc  = (score * 100).toFixed(1);

  // Gauge
  const circumference = 2 * Math.PI * 50; // r=50
  const filled = (score * circumference).toFixed(1);
  const arc = $("#gauge-arc");
  arc.style.strokeDasharray  = `${filled} ${circumference}`;
  arc.style.stroke           = colour;

  $("#gauge-score").textContent = perc + "%";
  $("#gauge-label").textContent = label;
  $("#gauge-label").style.color = colour;

  // Details
  $("#res-psycho-val").textContent = pred.psycho_label
    ? `${pred.psycho_label}  (${(pred.psycho_score * 100).toFixed(1)}%)`
    : "—";
  $("#res-text-val").textContent = pred.text_label
    ? `${pred.text_label}  (${(pred.text_score * 100).toFixed(1)}%)`
    : "—";
  $("#res-modality").textContent = pred.modality_used || "—";
  $("#res-time").textContent = assessment ? formatDate(assessment.created_at) : new Date().toLocaleString();

  // Advice
  $("#result-advice").textContent = ADVICE[label] || "";
}

/* ═══════════════════════════════════════════════
   HISTORY
═══════════════════════════════════════════════ */

async function loadHistory(page = 1) {
  state.historyPage = page;
  const listEl = $("#history-list");
  const pagEl  = $("#history-pagination");
  listEl.innerHTML = `<p class="empty-state">Loading…</p>`;
  pagEl.innerHTML  = "";

  try {
    const data = await apiFetch(`/api/assessments?page=${page}&per_page=15`);
    if (!data.assessments.length) {
      listEl.innerHTML = `<p class="empty-state">No assessments yet. Take your first one!</p>`;
      return;
    }

    listEl.innerHTML = data.assessments.map(a => assessmentItemHTML({
      id:          a.id,
      date:        formatDate(a.created_at),
      fused_score: a.fused_score,
      fused_label: a.fused_label,
      modality:    a.modality_used,
    })).join("");

    listEl.querySelectorAll(".assessment-item").forEach(el => {
      el.addEventListener("click", () => openDetailModal(el.dataset.id));
    });

    // Pagination
    if (data.pages > 1) {
      for (let p = 1; p <= data.pages; p++) {
        const btn = document.createElement("button");
        btn.className = `page-btn${p === page ? " active" : ""}`;
        btn.textContent = p;
        btn.addEventListener("click", () => loadHistory(p));
        pagEl.appendChild(btn);
      }
    }
  } catch (err) {
    listEl.innerHTML = `<p class="empty-state" style="color:var(--danger)">${err.message}</p>`;
  }
}

function assessmentItemHTML({ id, date, fused_score, fused_label, modality }) {
  const levelKey = (fused_label || "").toLowerCase();
  const scoreStr = fused_score != null ? (fused_score * 100).toFixed(1) + "%" : "—";
  return `
    <div class="assessment-item" data-id="${id}">
      <span class="assess-badge level-bg-${levelKey}">${stressIcon(fused_label)} ${fused_label || "—"}</span>
      <span class="assess-date">${date || ""}</span>
      <span class="assess-score">${scoreStr}</span>
      ${modality ? `<span class="assess-modality">${modality}</span>` : ""}
    </div>`;
}

function stressIcon(label) {
  const icons = { Minimal: "🟢", Mild: "🟡", Moderate: "🟠", Severe: "🔴", Critical: "🚨" };
  return icons[label] || "⚪";
}

/* ═══════════════════════════════════════════════
   DETAIL MODAL
═══════════════════════════════════════════════ */

async function openDetailModal(id) {
  const modal   = $("#detail-modal");
  const bodyEl  = $("#modal-body");
  bodyEl.innerHTML = "<p style='color:var(--text-muted)'>Loading…</p>";
  modal.classList.remove("hidden");

  try {
    const data = await apiFetch(`/api/assessments/${id}`);
    const a    = data.assessment;

    const psycho = a.psychometric_data
      ? Object.entries(a.psychometric_data)
          .map(([k,v]) => `<div class="modal-kv-item"><div class="modal-kv-key">${k.replace(/_/g," ")}</div><div class="modal-kv-val">${v}</div></div>`)
          .join("")
      : "<p style='color:var(--text-muted);font-size:.85rem'>Not provided</p>";

    bodyEl.innerHTML = `
      <div class="result-item" style="margin-bottom:8px">
        <span class="result-key">Fused Stress Level</span>
        <span class="result-val level-${(a.fused_label||"").toLowerCase()}">${stressIcon(a.fused_label)} ${a.fused_label} (${a.fused_score != null ? (a.fused_score*100).toFixed(1)+"%" : "—"})</span>
      </div>
      <div class="result-item" style="margin-bottom:8px">
        <span class="result-key">Psychometric</span>
        <span class="result-val">${a.psycho_label || "—"}${a.psycho_score != null ? "  (" + (a.psycho_score*100).toFixed(1)+"%)" : ""}</span>
      </div>
      <div class="result-item" style="margin-bottom:8px">
        <span class="result-key">Text Sentiment</span>
        <span class="result-val">${a.text_label || "—"}${a.text_score != null ? "  (" + (a.text_score*100).toFixed(1)+"%)" : ""}</span>
      </div>
      <div class="result-item" style="margin-bottom:16px">
        <span class="result-key">Date &amp; Time</span>
        <span class="result-val">${formatDate(a.created_at)}</span>
      </div>

      ${a.text_note ? `
      <h4 style="color:var(--text-muted);font-size:.78rem;text-transform:uppercase;letter-spacing:.05em;margin-bottom:8px">Text Note</h4>
      <div style="background:var(--surface2);padding:12px 14px;border-radius:8px;font-size:.9rem;margin-bottom:16px;line-height:1.6">${escapeHtml(a.text_note)}</div>
      ` : ""}

      <h4 style="color:var(--text-muted);font-size:.78rem;text-transform:uppercase;letter-spacing:.05em;margin-bottom:8px">Psychometric Data</h4>
      <div class="modal-kv">${psycho}</div>

      <div style="margin-top:14px;padding:12px 14px;border-radius:8px;border-left:4px solid var(--accent);background:rgba(79,142,247,.07);font-size:.88rem;line-height:1.6">
        ${ADVICE[a.fused_label] || ""}
      </div>
    `;
  } catch (err) {
    bodyEl.innerHTML = `<p style="color:var(--danger)">${err.message}</p>`;
  }
}

function closeModal() { $("#detail-modal").classList.add("hidden"); }

function escapeHtml(str) {
  return str.replace(/&/g,"&amp;").replace(/</g,"&lt;").replace(/>/g,"&gt;");
}

/* ── Expose globals used by inline onclick handlers ── */
const app = { goToView, closeModal };