// Side Notes — Notes List Page
//
// A dedicated extension page that lists all notes grouped by day and sorted
// by recency.  Clicking an entry either focuses an already-open tab (if one
// exists for that note's URL key) or navigates the current tab to it.
// The side panel is then opened on the target tab.

import { buildNoteKey } from '../shared/key-builder.js';
import { listNotes } from '../shared/storage.js';

// ---------------------------------------------------------------------------
// DOM
// ---------------------------------------------------------------------------
const listEl = document.getElementById('note-list');
const emptyMsg = document.getElementById('empty-message');

// ---------------------------------------------------------------------------
// Group notes by day
// ---------------------------------------------------------------------------

/**
 * Return a human-readable day label for a date.
 * Today → "Today", Yesterday → "Yesterday", otherwise the locale date.
 */
function dayLabel(date) {
  const now = new Date();
  const today = new Date(now.getFullYear(), now.getMonth(), now.getDate());
  const target = new Date(date.getFullYear(), date.getMonth(), date.getDate());
  const diffDays = Math.round((today - target) / (1000 * 60 * 60 * 24));

  if (diffDays === 0) return 'Today';
  if (diffDays === 1) return 'Yesterday';
  return target.toLocaleDateString(undefined, {
    weekday: 'long',
    year: 'numeric',
    month: 'long',
    day: 'numeric',
  });
}

/**
 * Format a time string from an ISO timestamp.
 */
function formatTime(isoString) {
  const d = new Date(isoString);
  return d.toLocaleTimeString(undefined, { hour: '2-digit', minute: '2-digit' });
}

function groupByDay(notes) {
  const groups = new Map();
  for (const note of notes) {
    const d = new Date(note.updatedAt);
    const key = dayLabel(d);
    if (!groups.has(key)) groups.set(key, []);
    groups.get(key).push(note);
  }
  return groups;
}

// ---------------------------------------------------------------------------
// Render
// ---------------------------------------------------------------------------
async function render() {
  const notes = await listNotes();

  if (notes.length === 0) {
    listEl.innerHTML = '';
    listEl.appendChild(emptyMsg);
    return;
  }

  emptyMsg.remove();
  listEl.innerHTML = '';

  const groups = groupByDay(notes);
  for (const [label, groupNotes] of groups) {
    const section = document.createElement('div');
    section.className = 'day-section';

    const labelEl = document.createElement('div');
    labelEl.className = 'day-label';
    labelEl.textContent = label;
    section.appendChild(labelEl);

    for (const note of groupNotes) {
      section.appendChild(buildEntry(note));
    }

    listEl.appendChild(section);
  }
}

function buildEntry(note) {
  const entry = document.createElement('div');
  entry.className = 'note-entry';
  entry.dataset.noteId = note.id;
  entry.dataset.key = note.key;
  entry.dataset.url = note.url || note.key; // fallback: reconstruct from key

  // Favicon
  const img = document.createElement('img');
  img.src = note.favIconUrl || '';
  img.alt = '';
  img.width = 16;
  img.height = 16;
  img.onerror = () => { img.style.visibility = 'hidden'; };
  entry.appendChild(img);

  // Text block
  const textBlock = document.createElement('div');
  textBlock.className = 'entry-text';

  const title = document.createElement('div');
  title.className = 'entry-title';
  title.textContent = note.pageTitle || note.key || 'Untitled';

  const url = document.createElement('div');
  url.className = 'entry-url';
  url.textContent = note.key || '';

  textBlock.appendChild(title);
  textBlock.appendChild(url);
  entry.appendChild(textBlock);

  // Time
  const time = document.createElement('div');
  time.className = 'entry-time';
  time.textContent = formatTime(note.updatedAt);
  entry.appendChild(time);

  // Click handler — see handleEntryClick below
  entry.addEventListener('click', () => handleEntryClick(note));

  return entry;
}

// Our own tab ID — resolved at init time so we can call sidePanel.open()
// synchronously in the click handler (required for user-gesture propagation).
let ownTabId = null;

// ---------------------------------------------------------------------------
// Click handling — focus existing tab or navigate current
// ---------------------------------------------------------------------------

/**
 * Handle a click on a notes-list entry.
 *
 * IMPORTANT: `chrome.sidePanel.open()` requires a live user gesture and MUST
 * be called synchronously (no preceding await) in the click handler.  We call
 * it first on our own tab as a fallback, then do the async matching work.  If
 * a matching tab is found we call sidePanel.open() again on the matched tab.
 */
async function handleEntryClick(note) {
  const noteKey = note.key;

  // Step 1 (SYNCHRONOUS): open the side panel on our own tab to satisfy the
  // user-gesture requirement.  This will be superseded if a matching tab is
  // found below, or if we navigate away.
  if (ownTabId != null) {
    chrome.sidePanel.open({ tabId: ownTabId });
  }

  // Step 2: query all tabs and check for a match.
  let allTabs;
  try {
    allTabs = await chrome.tabs.query({});
  } catch {
    return;
  }

  let matchTab = null;
  for (const tab of allTabs) {
    if (!tab.url) continue;
    try {
      const tabKey = buildNoteKey(tab.url);
      if (tabKey === noteKey) {
        matchTab = tab;
        break;
      }
    } catch {
      // URL parsing may fail for special URLs (chrome://, etc.) — skip.
    }
  }

  if (matchTab) {
    // A tab is already open at this note's URL → focus it and open its panel.
    chrome.windows.update(matchTab.windowId, { focused: true });
    chrome.tabs.update(matchTab.id, { active: true });
    chrome.sidePanel.open({ tabId: matchTab.id });
  } else if (ownTabId != null) {
    // No match → navigate our own tab to the note's URL.
    // The key is the normalized URL (scheme://host/path?search), sufficient
    // for navigation even though the hash was stripped.
    chrome.tabs.update(ownTabId, { url: noteKey });
    chrome.sidePanel.open({ tabId: ownTabId });
  } else {
    // Fallback (shouldn't normally happen): create a new tab.
    try {
      const tab = await chrome.tabs.create({ url: noteKey });
      chrome.sidePanel.open({ tabId: tab.id });
    } catch { /* last resort — do nothing */ }
  }
}

// ---------------------------------------------------------------------------
// Init
// ---------------------------------------------------------------------------
(async function init() {
  // Resolve our own tab ID so click handlers can use it synchronously.
  try {
    const tab = await chrome.tabs.getCurrent();
    if (tab) ownTabId = tab.id;
  } catch { /* not opened as a tab — ownTabId stays null */ }

  render();
})();