import { app, BrowserWindow, desktopCapturer, dialog, ipcMain, net, shell, session, systemPreferences, type WebContents } from 'electron';
import { promises as fs } from 'node:fs';
import os from 'node:os';
import path from 'node:path';
import { IdentityStore } from './identity-store.ts';
import { describeCert } from './certs.ts';
import * as tray from './tray.ts';
import { fetchLinkPreview } from './link-preview.ts';
import { fetchPublicListWith, pingServer } from './publist.ts';
import { openTls } from './tls-transport.ts';
import { udpChannel } from './udp-voice.ts';
import { ShareAudio, pipewireAvailable, VIRTUAL_MIC_LABEL, type AudioTarget } from './pipewire.ts';

const devUrl = process.env.VITE_DEV_SERVER_URL;

// Screen sharing connects mumh5 users directly. Chromium would hide this computer's addresses
// behind names that only resolve on the local network, so two people on IPv6 could not reach
// each other without a helper server. Only this app's own page runs here.
app.commandLine.appendSwitch('disable-features', 'WebRtcHideLocalIpsWithMdns');

let identityStore: IdentityStore | null = null;
const identities = () => (identityStore ??= new IdentityStore(app.getPath('userData')));

// ─── Mumble TLS connections, one per renderer request ─────────────────────────

type Conn = ReturnType<typeof openTls> & { owner: WebContents; udp?: ReturnType<typeof udpChannel> };
const conns = new Map<string, Conn>();

// ─── Identities (client certificates) ─────────────────────────────────────────

ipcMain.handle('identities:list', () => identities().list());
ipcMain.handle('identities:create', (_e, name: string, email: string) => identities().create(String(name), String(email ?? '')));
ipcMain.handle('identities:import', (_e, bytes: Uint8Array, password: string, name: string) =>
  identities().importP12(new Uint8Array(bytes), String(password ?? ''), String(name ?? '')));
ipcMain.handle('identities:findMumble', () => identities().findMumbleCertificate().then(f => f && { name: f.name }));
ipcMain.handle('identities:importMumble', (_e, name: string) => identities().importFromMumble(String(name ?? '')));
ipcMain.handle('identities:setDefault', (_e, id: string) => identities().setDefault(String(id)));
ipcMain.handle('identities:rename', (_e, id: string, name: string) => identities().rename(String(id), String(name)));
ipcMain.handle('identities:remove', (_e, id: string) => identities().remove(String(id)));
ipcMain.handle('identities:finishSetup', () => identities().finishSetup());

// Saves a password-protected .p12 backup where the user chooses; returns the path or null
ipcMain.handle('identities:export', async (e, id: string, password: string) => {
  const { bytes, name } = await identities().exportP12(String(id), String(password ?? ''));
  const win = BrowserWindow.fromWebContents(e.sender);
  const opts = {
    title: 'Save identity backup',
    defaultPath: path.join(app.getPath('documents'), `${name.replace(/[^\w.-]+/g, '_') || 'identity'}.p12`),
    filters: [{ name: 'PKCS#12 certificate', extensions: ['p12', 'pfx'] }]
  };
  const res = win ? await dialog.showSaveDialog(win, opts) : await dialog.showSaveDialog(opts);
  if (res.canceled || !res.filePath) return null;
  await fs.writeFile(res.filePath, bytes, { mode: 0o600 });
  return res.filePath;
});

// The renderer picks the connection id and subscribes before calling open, so no event can be missed
ipcMain.handle('mumble:open', async (e, connId: string, host: string, port: number, identityId?: string) => {
  if (typeof connId !== 'string' || conns.has(connId)) throw new Error('Invalid connection id');
  const id = await identities().get(identityId);
  const owner = e.sender;
  const emit = (channel: string, ...args: unknown[]) => { if (!owner.isDestroyed()) owner.send(channel, connId, ...args); };
  const conn = openTls(String(host), Number(port) || 64738, id.certPem, id.keyPem, {
    onSecure: info => {
      // Encrypted UDP voice to the address the TLS connection actually reached
      const udp = udpChannel(info.address, info.port);
      udp.onVoice = p => emit('mumble:udpVoice', p);
      udp.onState = (ok, rtt) => emit('mumble:udpState', ok, rtt);
      udp.onResync = () => emit('mumble:udpResync');
      const c = conns.get(connId);
      if (c) c.udp = udp;
      else udp.close();
      emit('mumble:secure', info);
    },
    onData: chunk => emit('mumble:data', chunk),
    onClose: reason => { conns.get(connId)?.udp?.close(); conns.delete(connId); emit('mumble:close', reason); }
  });
  conns.set(connId, Object.assign(conn, { owner }));
  owner.once('destroyed', () => conn.close());
});

ipcMain.on('mumble:send', (e, connId: string, bytes: Uint8Array) => {
  const conn = conns.get(connId);
  if (conn && conn.owner === e.sender) conn.send(bytes);
});

// UDP voice: keys from the server's CryptSetup, voice packets, nonce resync
const ownUdp = (e: Electron.IpcMainEvent | Electron.IpcMainInvokeEvent, connId: string) => {
  const conn = conns.get(connId);
  return conn && conn.owner === e.sender ? conn.udp : undefined;
};
ipcMain.on('mumble:udpSetup', (e, connId: string, key: Uint8Array, cn: Uint8Array, sn: Uint8Array, protobuf: boolean) =>
  ownUdp(e, connId)?.setup(new Uint8Array(key), new Uint8Array(cn), new Uint8Array(sn), !!protobuf));
ipcMain.on('mumble:udpNonce', (e, connId: string, sn: Uint8Array) => ownUdp(e, connId)?.setServerNonce(new Uint8Array(sn)));
ipcMain.on('mumble:udpSend', (e, connId: string, bytes: Uint8Array) => ownUdp(e, connId)?.send(new Uint8Array(bytes)));
ipcMain.handle('mumble:udpClientNonce', (e, connId: string) => ownUdp(e, connId)?.clientNonce() ?? null);

ipcMain.on('mumble:close', (e, connId: string) => {
  const conn = conns.get(connId);
  if (conn && conn.owner === e.sender) conn.close();
});

// Parses DER certificates (e.g. a user's chain from UserStats) for the viewer
ipcMain.handle('certs:describe', (_e, ders: Uint8Array[]) =>
  (Array.isArray(ders) ? ders.slice(0, 8) : []).flatMap(d => { try { return [describeCert(Buffer.from(d))]; } catch { return []; } }));

// Edit commands for the renderer's context menu (clipboard access goes through the browser engine)
ipcMain.on('edit:action', (e, action: string, arg?: unknown) => {
  const wc = e.sender;
  switch (action) {
    case 'undo': return wc.undo();
    case 'redo': return wc.redo();
    case 'cut': return wc.cut();
    case 'copy': return wc.copy();
    case 'paste': return wc.paste();
    case 'selectAll': return wc.selectAll();
    case 'replaceMisspelling': return wc.replaceMisspelling(String(arg));
    case 'addWord': return wc.session.addWordToSpellCheckerDictionary(String(arg));
    case 'copyImageAt': { const p = arg as { x: number; y: number }; return wc.copyImageAt(p.x, p.y); }
    case 'saveImage': return wc.downloadURL(String(arg));
  }
});

ipcMain.handle('publist:fetch', (_e, url: string) => fetchPublicListWith(u => net.fetch(u), String(url)));
ipcMain.handle('publist:ping', (_e, host: string, port: number) => pingServer(String(host), Number(port)));

ipcMain.handle('preview:fetch', (_e, url: string) => fetchLinkPreview(String(url).slice(0, 2048)));

// ─── Screen sharing ───────────────────────────────────────────────────────────
// The renderer lists the sources, the user picks one, and the next getDisplayMedia call gets it.
// On Wayland, listing already opens the system's picker and returns the one chosen source;
// `chosen` tells the renderer not to ask a second time.
let screenSources: Electron.DesktopCapturerSource[] = [];
let pickedSource: string | null = null;
const onWayland = () => process.platform === 'linux' && app.commandLine.getSwitchValue('ozone-platform') !== 'x11' &&
  (process.env.XDG_SESSION_TYPE === 'wayland' || !!process.env.WAYLAND_DISPLAY);

// Sound: PipeWire on Linux (one program or everything but this app), system loopback on Windows
const shareAudio = new ShareAudio(() => app.getAppMetrics().map(m => m.pid));
ipcMain.handle('share:info', async () => ({
  portal: onWayland(),
  audio: process.platform === 'win32' ? 'loopback' : (await pipewireAvailable()) ? 'pipewire' : 'none',
  micLabel: VIRTUAL_MIC_LABEL
}));
ipcMain.handle('share:audioApps', () => shareAudio.apps().catch(() => []));
ipcMain.handle('share:audioStart', (_e, target: AudioTarget) =>
  shareAudio.start(target?.kind === 'app' ? { kind: 'app', name: String(target.name) } : { kind: 'all' }));
ipcMain.handle('share:audioStop', () => shareAudio.stop());
// The virtual microphone outlives the process otherwise
app.on('will-quit', () => { shareAudio.stop(); });

// Names first (fast and dependable), thumbnails in a second call: grabbing the pictures can be
// slow and, under X11, can come back with nothing.
ipcMain.handle('share:sources', async (_e, thumbnails: boolean) => {
  const wayland = onWayland();
  const size = thumbnails ? { width: 320, height: 180 } : { width: 0, height: 0 };
  const list = () => desktopCapturer.getSources({ types: ['screen', 'window'], thumbnailSize: size });
  let found = await list();
  // Not on Wayland, where empty means the user cancelled the system's picker and asking again would reopen it
  for (let i = 0; i < 3 && !found.length && !wayland; i++) {
    await new Promise(r => setTimeout(r, 250));
    found = await list();
  }
  if (found.length || !thumbnails) screenSources = found;
  return {
    chosen: wayland && found.length === 1,
    sources: found.map(s => ({ id: s.id, name: s.name, thumbnail: s.thumbnail.isEmpty() ? '' : s.thumbnail.toDataURL() }))
  };
});
ipcMain.on('share:pick', (_e, id: string) => { pickedSource = String(id); });

ipcMain.on('tray:update', (_e, state: tray.TrayState) => tray.update(state));

ipcMain.handle('platform:info', () => ({ os: process.platform, osVersion: os.release() }));

// ─── Window ────────────────────────────────────────────────────────────────────

let mainWindow: BrowserWindow | null = null;

function createWindow() {
  const win = new BrowserWindow({
    width: 1280,
    height: 800,
    minWidth: 360,
    minHeight: 480,
    backgroundColor: '#111214',
    title: 'mumh5',
    // Window and taskbar icon on Linux (Windows and macOS take it from the package)
    icon: path.join(__dirname, '../dist/icon.png'),
    autoHideMenuBar: true,
    webPreferences: {
      preload: path.join(__dirname, 'preload.cjs'),
      contextIsolation: true,
      sandbox: true,
      nodeIntegration: false,
      // Voice must play without a click first
      autoplayPolicy: 'no-user-gesture-required',
      // Keep audio and timers running at full speed when the window is in the background
      backgroundThrottling: false
    }
  });

  // Links from chat open in the system browser, never inside the app
  win.webContents.setWindowOpenHandler(({ url }) => {
    if (/^https?:\/\//i.test(url)) shell.openExternal(url);
    return { action: 'deny' };
  });
  win.webContents.on('will-navigate', (e, url) => {
    if (devUrl && url.startsWith(devUrl)) return;
    e.preventDefault();
    if (/^https?:\/\//i.test(url)) shell.openExternal(url);
  });

  mainWindow = win;
  win.on('close', e => {
    if (tray.shouldHideOnClose()) {
      e.preventDefault();
      win.hide();
    }
  });
  // No default menu in Electron: report what was right-clicked, the renderer shows its own menu
  // (custom menus call preventDefault, which suppresses this event)
  win.webContents.on('context-menu', (_e, p) => {
    win.webContents.send('context-menu', {
      x: p.x, y: p.y, isEditable: p.isEditable, selectionText: p.selectionText, linkURL: p.linkURL,
      mediaType: p.mediaType, srcURL: p.srcURL, misspelledWord: p.misspelledWord,
      suggestions: p.dictionarySuggestions.slice(0, 5), editFlags: p.editFlags
    });
  });
  win.on('show', () => tray.onWindowVisibility());
  win.on('hide', () => tray.onWindowVisibility());
  win.on('closed', () => { if (mainWindow === win) mainWindow = null; });

  if (devUrl) win.loadURL(devUrl);
  else win.loadFile(path.join(__dirname, '../dist/index.html'));
}

app.whenReady().then(async () => {
  // macOS asks once per app for microphone access
  if (process.platform === 'darwin') await systemPreferences.askForMediaAccess('microphone').catch(() => false);
  // YouTube refuses embeds without a referrer (error 153); a file:// app sends none
  session.defaultSession.webRequest.onBeforeSendHeaders({ urls: ['https://www.youtube-nocookie.com/*'] }, (details, cb) => {
    if (!details.requestHeaders.Referer) details.requestHeaders.Referer = 'https://mumh5.app/';
    cb({ requestHeaders: details.requestHeaders });
  });

  session.defaultSession.setDisplayMediaRequestHandler((request, callback) => {
    const source = screenSources.find(s => s.id === pickedSource);
    pickedSource = null;
    // Without a picked source the request is refused
    try {
      if (!source) callback({});
      else if (request.audioRequested && process.platform === 'win32') callback({ video: source, audio: 'loopback' });
      else callback({ video: source });
    } catch { /* refused */ }
  });

  // Microphone, camera and screen capture for voice and video; nothing else
  session.defaultSession.setPermissionRequestHandler((_wc, permission, cb) => {
    cb(['media', 'display-capture', 'clipboard-sanitized-write', 'notifications'].includes(permission));
  });
  createWindow();
  await tray.setupTray(() => mainWindow, action => mainWindow?.webContents.send('tray:action', action));
  app.on('activate', () => { if (BrowserWindow.getAllWindows().length === 0) createWindow(); });
});

app.on('window-all-closed', () => {
  if (process.platform !== 'darwin') app.quit();
});