"use strict";

// --- state -----------------------------------------------------------------
const PAGE_SIZE = 1000;         // PPS API caps a single search at 1000 rows
let CONFIG = null;
let messages = [];              // cached messages for the current folder (the display source)
const selected = new Set();     // selected localguids
let jobPollTimer = null;
let sortField = "subject";      // subject | date | from | rcpt
let sortDir = 1;                // 1 = ascending, -1 = descending
let syncing = false;            // a full folder load is in progress
let syncCancelled = false;      // set by the Cancel button to stop paging early

// --- element refs ----------------------------------------------------------
const $ = (id) => document.getElementById(id);
const folderSelect = $("folder-select");
const limitInput = $("limit-input");
const msgBody = $("msg-body");
const selectAll = $("select-all");
const emptyNote = $("empty-note");
const statusBar = $("status-bar");
const moveBtn = $("move-btn");
const moveMenu = $("move-menu");
const overlay = $("overlay");

// --- init ------------------------------------------------------------------
async function init() {
  CONFIG = await fetchJSON("/api/config");
  const prefs = CONFIG.prefs || {};
  for (const f of CONFIG.folders) {
    folderSelect.append(new Option(f, f));
  }
  folderSelect.value = prefs.default_folder || CONFIG.folders[0];
  limitInput.value = prefs.default_limit ?? 200;
  sortField = prefs.sort_field || "subject";
  sortDir = prefs.sort_dir === "desc" ? -1 : 1;
  $("sort-field").value = sortField;
  $("sort-dir").textContent = sortDir === 1 ? "▲" : "▼";

  // Move dropdown targets
  moveMenu.innerHTML = "";
  for (const f of CONFIG.folders) {
    const item = document.createElement("button");
    item.className = "move-item";
    item.textContent = f;
    item.onclick = () => { hideMoveMenu(); runAction("move", f); };
    moveMenu.append(item);
  }

  wireEvents();
  await fullSync();           // cache the whole default folder on login
  startJobPolling();
}

function wireEvents() {
  // Refresh only re-renders from the cache; Reload re-fetches the folder.
  $("refresh-btn").onclick = () => renderRows();
  $("reload-btn").onclick = () => fullSync();
  $("cancel-sync-btn").onclick = () => {
    syncCancelled = true;
    const btn = $("cancel-sync-btn");
    btn.textContent = "Cancelling…";
    btn.disabled = true;
  };
  limitInput.onchange = () => { renderRows(); savePref("default_limit", +limitInput.value); };
  folderSelect.onchange = () => { savePref("default_folder", folderSelect.value); fullSync(); };
  selectAll.onchange = () => toggleSelectAll(selectAll.checked);

  $("sort-field").onchange = (e) => {
    sortField = e.target.value; renderRows(); savePref("sort_field", sortField);
  };
  $("sort-dir").onclick = () => {
    sortDir = -sortDir;
    $("sort-dir").textContent = sortDir === 1 ? "▲" : "▼";
    renderRows();
    savePref("sort_dir", sortDir === 1 ? "asc" : "desc");
  };

  document.querySelectorAll(".btn.action[data-action]").forEach((btn) => {
    btn.onclick = () => runAction(btn.dataset.action);
  });

  moveBtn.onclick = (e) => {
    e.stopPropagation();
    moveMenu.classList.toggle("hidden");
  };
  document.addEventListener("click", hideMoveMenu);

  $("overlay-close").onclick = closeOverlay;
  overlay.onclick = (e) => { if (e.target === overlay) closeOverlay(); };
  $("ov-toggle").onclick = () => setView(overlayView === "html" ? "text" : "html");
  $("ov-raw-toggle").onclick = () => setView(overlayView === "raw" ? "text" : "raw");
}

// --- full folder load (paged) ----------------------------------------------
// Page backwards through the folder by date until a page returns < PAGE_SIZE rows,
// caching everything client-side. The PPS API has no offset paging, so the cursor
// is the oldest date seen so far (passed as `before`).
async function fullSync() {
  if (syncing) return;
  syncing = true;
  syncCancelled = false;
  clearSelection();
  const folder = folderSelect.value;
  showProgress(`Loading messages from “${folder}”…`);
  msgBody.innerHTML = `<tr><td colspan="5" class="loading">Loading…</td></tr>`;

  const seen = new Set();
  const acc = [];
  let cursor = null;
  let cancelled = false;
  try {
    while (true) {
      const url = `/api/messages?folder=${encodeURIComponent(folder)}&limit=${PAGE_SIZE}` +
        (cursor ? `&before=${encodeURIComponent(cursor)}` : "");
      const data = await fetchJSON(url);

      let added = 0;
      for (const m of data.messages) {
        if (!seen.has(m.localguid)) { seen.add(m.localguid); acc.push(m); added++; }
      }
      updateProgress(acc.length);

      // Cancel takes effect after the in-flight page finishes; that page's messages
      // are kept, and we stop paging (the folder may still hold more).
      if (syncCancelled) { cancelled = true; break; }

      const page = data.page || {};
      // Stop when the folder is exhausted, or the cursor can't advance (guards
      // against a boundary where >PAGE_SIZE messages share the same timestamp).
      if (!page.has_more || !page.oldest) break;
      if (page.oldest === cursor && added === 0) break;
      cursor = page.oldest;
    }
    messages = acc;
    renderRows();
    if (cancelled) {
      flashStatus(
        `Loading cancelled — showing ${acc.length.toLocaleString()} loaded message(s). ` +
        `The folder may contain more; use “Reload from server” for the full list.`,
        false,
      );
    }
  } catch (err) {
    if (acc.length) {
      // Keep whatever we managed to page in; surface the error non-fatally.
      messages = acc;
      renderRows();
      flashStatus(`Partial load: ${err.message}`, true);
    } else {
      msgBody.innerHTML = `<tr><td colspan="5" class="error">${escapeHTML(err.message)}</td></tr>`;
    }
  } finally {
    hideProgress();
    syncing = false;
  }
}

// --- progress window -------------------------------------------------------
function showProgress(title) {
  $("progress-title").textContent = title;
  $("progress-count").textContent = "0 messages loaded";
  const btn = $("cancel-sync-btn");
  btn.textContent = "Cancel";
  btn.disabled = false;
  $("progress").classList.remove("hidden");
}
function updateProgress(n) {
  $("progress-count").textContent = `${n.toLocaleString()} messages loaded`;
}
function hideProgress() { $("progress").classList.add("hidden"); }

function sortValue(m) {
  if (sortField === "rcpt") return (m.rcpts || []).join(", ");
  return m[sortField] || "";  // subject | date | from
}

function sortMessages() {
  messages.sort((a, b) => {
    const va = String(sortValue(a)).trim();
    const vb = String(sortValue(b)).trim();
    // Empty values always sort to the bottom, regardless of direction.
    if (!va && vb) return 1;
    if (va && !vb) return -1;
    if (!va && !vb) return 0;
    return va.localeCompare(vb, undefined, { sensitivity: "base", numeric: true }) * sortDir;
  });
}

function displayLimit() {
  const v = parseInt(limitInput.value, 10);
  return Number.isFinite(v) && v > 0 ? v : Infinity;  // blank/invalid = show all
}

function renderRows() {
  sortMessages();
  clearSelection();
  msgBody.innerHTML = "";

  // The whole folder stays cached in `messages`; the Show box only caps how many
  // rows we render, to keep large folders manageable for a human.
  const visible = messages.slice(0, displayLimit());
  emptyNote.classList.toggle("hidden", messages.length > 0);
  $("cache-info").textContent =
    visible.length < messages.length
      ? `showing ${visible.length.toLocaleString()} of ${messages.length.toLocaleString()} cached`
      : `${messages.length.toLocaleString()} cached`;

  for (const m of visible) {
    const tr = document.createElement("tr");
    tr.dataset.localguid = m.localguid;

    const check = document.createElement("input");
    check.type = "checkbox";
    check.onchange = () => toggleRow(m.localguid, check.checked, tr);

    const tdCheck = document.createElement("td");
    tdCheck.className = "col-check";
    tdCheck.append(check);
    // The whole checkbox cell is a click target (bigger than the box itself).
    tdCheck.onclick = (e) => {
      e.stopPropagation();               // don't open the message overlay
      if (e.target !== check) {          // clicks on the box are handled natively
        check.checked = !check.checked;
        toggleRow(m.localguid, check.checked, tr);
      }
    };

    tr.append(tdCheck);
    tr.append(cell(formatDate(m.date), "col-date"));
    tr.append(cell(m.from || "", "col-from"));
    tr.append(cell((m.rcpts || []).join(", "), "col-rcpt"));
    tr.append(cell(m.subject || "(no subject)", "col-subj"));

    tr.onclick = () => openOverlay(m);
    msgBody.append(tr);
  }
  updateActionButtons();
}

function cell(text, cls) {
  const td = document.createElement("td");
  td.className = cls;
  td.textContent = text;
  td.title = text;
  return td;
}

// --- selection -------------------------------------------------------------
function toggleRow(localguid, on, tr) {
  if (on) selected.add(localguid); else selected.delete(localguid);
  tr.classList.toggle("selected", on);
  updateActionButtons();
}

function toggleSelectAll(on) {
  msgBody.querySelectorAll("tr").forEach((tr) => {
    const cb = tr.querySelector('input[type="checkbox"]');
    if (cb) { cb.checked = on; toggleRow(tr.dataset.localguid, on, tr); }
  });
}

function clearSelection() {
  selected.clear();
  selectAll.checked = false;
  updateActionButtons();
}

function updateActionButtons() {
  const has = selected.size > 0;
  document.querySelectorAll(".btn.action").forEach((b) => { b.disabled = !has; });
}

// --- actions ---------------------------------------------------------------
async function runAction(action, targetfolder) {
  const chosen = messages.filter((m) => selected.has(m.localguid));
  if (chosen.length === 0) return;
  if (action === "delete" &&
      !confirm(`Delete ${chosen.length} message(s)? They move to "${CONFIG.deleted_folder}".`)) {
    return;
  }

  const payload = {
    action,
    folder: folderSelect.value,
    messages: chosen.map((m) => ({
      localguid: m.localguid,
      guid: m.guid,
      subject: m.subject,
      sender: m.from,
      recipient: (m.rcpts || []).join(", "),
    })),
  };
  if (action === "move") payload.targetfolder = targetfolder;

  try {
    await fetchJSON("/api/actions", { method: "POST", body: JSON.stringify(payload) });
  } catch (err) {
    alert("Action failed to queue: " + err.message);
    return;
  }

  // Optimistic: remove acted-on rows immediately.
  const gone = new Set(chosen.map((m) => m.localguid));
  messages = messages.filter((m) => !gone.has(m.localguid));
  renderRows();
  pollJobs();
}

// --- overlay ---------------------------------------------------------------
let overlayView = "text";   // text | html | raw

async function openOverlay(m) {
  $("ov-subject").textContent = m.subject || "(no subject)";
  $("ov-meta").innerHTML = "";
  $("ov-attach").classList.add("hidden");
  $("ov-attach").innerHTML = "";
  $("ov-raw").textContent = "";
  $("ov-text").textContent = "Loading…";
  $("ov-toggle").classList.add("hidden");
  setView("text");
  overlay.classList.remove("hidden");

  try {
    const data = await fetchJSON(`/api/message/${encodeURIComponent(m.guid)}`);
    renderOverlay(data);
  } catch (err) {
    $("ov-text").textContent = "Failed to load message: " + err.message;
  }
}

function renderOverlay(data) {
  const h = data.headers || {};
  const meta = [
    ["From", h.from], ["To", h.to], ["Cc", h.cc], ["Date", h.date],
  ].filter(([, v]) => v);
  $("ov-meta").innerHTML = meta
    .map(([k, v]) => `<div><span class="mk">${k}:</span> ${escapeHTML(v)}</div>`)
    .join("");

  renderAttachments(data.attachments || []);

  const text = data.text || "";
  const html = data.html || "";
  $("ov-text").textContent = text || (html ? "(HTML message — use “Show HTML”.)" : "(empty body)");
  $("ov-raw").textContent = data.raw_headers || "(no headers)";
  overlay.dataset.html = html;

  $("ov-toggle").classList.toggle("hidden", !html);  // only offer HTML if present
  setView("text");
}

function renderAttachments(list) {
  const bar = $("ov-attach");
  if (!list.length) { bar.classList.add("hidden"); bar.innerHTML = ""; return; }
  bar.innerHTML =
    `<span class="attach-label">📎 ${list.length} attachment${list.length > 1 ? "s" : ""}:</span>` +
    list.map((a) =>
      `<span class="attach-chip" title="${escapeHTML(a.content_type || "")}">` +
      `${escapeHTML(a.filename)}` +
      (a.size != null ? `<span class="attach-size">${formatBytes(a.size)}</span>` : "") +
      `</span>`
    ).join("");
  bar.classList.remove("hidden");
}

// Switch among the body views: plain text, sandboxed HTML, raw headers.
function setView(view) {
  overlayView = view;
  $("ov-text").classList.toggle("hidden", view !== "text");
  $("ov-html").classList.toggle("hidden", view !== "html");
  $("ov-raw").classList.toggle("hidden", view !== "raw");
  // srcdoc + sandbox keeps scripts and remote loads from running.
  $("ov-html").srcdoc = view === "html" ? (overlay.dataset.html || "") : "";
  $("ov-toggle").textContent = view === "html" ? "Show text" : "Show HTML";
  $("ov-raw-toggle").textContent = view === "raw" ? "Show text" : "Show raw headers";
}

function closeOverlay() {
  overlay.classList.add("hidden");
  $("ov-html").srcdoc = "";
}

function formatBytes(n) {
  if (n < 1024) return `${n} B`;
  if (n < 1024 * 1024) return `${(n / 1024).toFixed(1)} KB`;
  return `${(n / 1024 / 1024).toFixed(1)} MB`;
}

// --- job status polling ----------------------------------------------------
function startJobPolling() { pollJobs(); }

async function pollJobs() {
  let data;
  try {
    data = await fetchJSON("/api/jobs");
  } catch {
    return;
  }
  const jobs = data.jobs || [];
  const active = jobs.filter((j) => j.status === "pending" || j.status === "running");
  renderStatus(jobs, active);

  clearTimeout(jobPollTimer);
  if (active.length > 0) {
    jobPollTimer = setTimeout(pollJobs, 3000);
  }
}

function renderStatus(jobs, active) {
  if (active.length === 0) {
    // Show the most recent finished job briefly, else hide.
    const last = jobs[0];
    if (last && (last.status === "failed")) {
      statusBar.className = "status-bar error";
      statusBar.textContent = `Job #${last.id} (${labelFor(last.action)}) failed: ${last.error || ""}`;
      statusBar.classList.remove("hidden");
    } else {
      statusBar.classList.add("hidden");
    }
    return;
  }
  statusBar.className = "status-bar";
  statusBar.textContent = active
    .map((j) => `${labelFor(j.action)}: ${j.processed}/${j.total} (${j.status})`)
    .join("   •   ");
  statusBar.classList.remove("hidden");
}

// --- misc helpers ----------------------------------------------------------
function hideMoveMenu() { moveMenu.classList.add("hidden"); }

function flashStatus(text, isError) {
  statusBar.className = isError ? "status-bar error" : "status-bar";
  statusBar.textContent = text;
  statusBar.classList.remove("hidden");
}

function labelFor(action) {
  return {
    release: "Release",
    report_release: "Report & Release",
    delete: "Delete",
    move: "Move",
  }[action] || action;
}

function formatDate(d) {
  if (!d) return "";
  return d.replace("T", " ").slice(0, 19);
}

async function fetchJSON(url, opts = {}) {
  const headers = { "Content-Type": "application/json", ...(opts.headers || {}) };
  // CSRF token on state-changing requests (the server requires it on non-GET /api/*).
  const method = (opts.method || "GET").toUpperCase();
  if (method !== "GET" && CONFIG && CONFIG.csrf_token) headers["X-CSRF-Token"] = CONFIG.csrf_token;
  const res = await fetch(url, { ...opts, headers });
  if (res.status === 401) { window.location = "/login"; throw new Error("Not signed in"); }
  const data = await res.json().catch(() => ({}));
  if (!res.ok) throw new Error(data.error || data.detail || `HTTP ${res.status}`);
  return data;
}

// Persist a single user preference, debounced and fire-and-forget: a failed pref save
// must never block the UI.
const _prefTimers = {};
function savePref(key, value) {
  clearTimeout(_prefTimers[key]);
  _prefTimers[key] = setTimeout(() => {
    fetchJSON("/api/prefs", { method: "PUT", body: JSON.stringify({ [key]: value }) })
      .catch(() => { /* ignore */ });
  }, 500);
}

function escapeHTML(s) {
  return String(s).replace(/[&<>"']/g, (c) =>
    ({ "&": "&amp;", "<": "&lt;", ">": "&gt;", '"': "&quot;", "'": "&#39;" }[c]));
}

init();