import {
  app,
  shell,
  BrowserWindow,
  ipcMain,
  dialog,
  clipboard,
  nativeTheme,
  Notification,
  Menu
} from 'electron'
import { join, resolve } from 'path'
import { existsSync } from 'fs'
import { electronApp, optimizer, is } from '@electron-toolkit/utils'
import {
  IpcChannels,
  type StartDownloadOptions,
  type Settings,
  type HistoryEntry,
  type CommandTemplate,
  type YtdlpUpdateChannel,
  type SystemThemeInfo,
  type TaskbarProgress
} from '@shared/ipc'
import { PAGE_BACKGROUND } from '@shared/theme'
import { getYtdlpVersion, updateYtdlp, runStartupYtdlpAutoUpdate } from './ytdlp'
import { getFfmpegVersions } from './ffmpeg'
import { checkForAppUpdate, downloadAppUpdate, runAppUpdate } from './updater'
import { probeMedia } from './probe'
import { getAppIconImage } from './binaries'
import {
  startDownload,
  cancelDownload,
  pauseDownload,
  previewCommand,
  hasActiveDownloads
} from './download'
import { runTerminal, cancelTerminal } from './terminal'
import {
  getSettings,
  setSettings,
  ensureMediaDirs,
  applyLaunchAtStartup,
  migrateSecretsAtRest
} from './settings'
import { listHistory, addHistory, removeHistory, removeManyHistory, clearHistory } from './history'
import { listTemplates, saveTemplate, removeTemplate } from './templates'
import { setupPortableData } from './portable'
import { safeOpenPath, safeShowInFolder } from './reveal'
import {
  openCookieLoginWindow,
  getCookiesStatus,
  clearCookies,
  migrateLegacyCookies
} from './cookies'
import { attachEditContextMenu } from './contextMenu'
import { listErrorLog, addErrorLog, clearErrorLog } from './errorlog'
import { flushAllStores } from './jsonStore'
import { exportBackup, importBackup } from './backup'
import { extractIncomingUrl, registerSendToShortcut, focusWindow } from './deeplink'
import {
  listSources,
  getSource,
  removeSource,
  listMediaItems,
  setMediaItemDownloaded,
  setSourceWatched
} from './sources'
import { indexSource } from './indexer'
import { syncWatchedSources } from './sync'
import { getScheduledSync, setScheduledSync, isSyncLaunch } from './schedule'
import { createTray, markQuitting, isQuitting } from './tray'
import { getActiveBadge, getErrorBadge } from './badge'
import { openPoTokenWindow } from './poToken'

// Only one instance ever runs. A second launch — e.g. the OS invoking us again
// for an aerofetch:// link or a "Send to AeroFetch" file — hands its argv to
// this instance via 'second-instance' below, instead of opening a duplicate window.
const isPrimaryInstance = app.requestSingleInstanceLock()
if (!isPrimaryInstance) app.quit()

// Force software compositing (GPU acceleration off). On this dev machine's old GeForce
// GT 625 — and plausibly on the old / locked-down public PCs this app targets —
// Chromium's GPU compositor renders blank: under hardware acceleration the WHOLE window
// paints white (popup overlays alone were blank earlier). Updating the NVIDIA driver to
// the last Fermi release did not fix it. Software compositing renders correctly and
// costs no meaningful performance for this lightweight UI, so it is the safe default for
// this app's target hardware. The only downside is a minor overlay-repaint flicker that
// appears on the most broken GPUs. The window backgroundColor is theme-matched (see
// createWindow); native window-occlusion tracking is disabled (a separate documented
// Windows blank/flicker cause). Must run before the app is ready.
app.disableHardwareAcceleration()
app.commandLine.appendSwitch('disable-features', 'CalculateNativeWinOcclusion')

// Redirect user data next to the exe when possible (portable, no-admin). Must run
// before the app is ready and before any user path is read.
setupPortableData()

// Register aerofetch:// so a browser/another app can hand AeroFetch a link
// (?url=<encoded>) the way Android's share sheet hands Seal one. The NSIS
// installer also declares this scheme (electron-builder.yml's `protocols`)
// so it's registered even before first launch; this call additionally covers
// the portable build and dev, which have no installer step to do it for us.
const devScript = process.argv[1]
if (is.dev && devScript) {
  app.setAsDefaultProtocolClient('aerofetch', process.execPath, [resolve(devScript)])
} else {
  app.setAsDefaultProtocolClient('aerofetch')
}

let mainWindow: BrowserWindow | null = null

// Resolve 'system' against the OS preference so callers always get a concrete color.
function resolveBackgroundMode(theme: Settings['theme']): 'light' | 'dark' {
  return theme === 'system' ? (nativeTheme.shouldUseDarkColors ? 'dark' : 'light') : theme
}

// Keep the OS-drawn title bar consistent with the in-app theme (W3). Setting
// themeSource to 'light'/'dark' forces the caption/chrome to match; 'system'
// restores OS control. Called at startup and on every theme change.
function applyNativeTheme(theme: Settings['theme']): void {
  nativeTheme.themeSource = theme
}

function getSystemThemeInfo(): SystemThemeInfo {
  return {
    shouldUseDarkColors: nativeTheme.shouldUseDarkColors,
    shouldUseHighContrastColors: nativeTheme.shouldUseHighContrastColors
  }
}

// Tell the user (once per run) that closing the window left AeroFetch running so
// an in-progress download could finish — shown only when they haven't already
// opted into tray mode, so a window that "won't close" doesn't read as a bug.
let notifiedBackground = false
function notifyBackgroundOnce(): void {
  if (notifiedBackground || !Notification.isSupported()) return
  notifiedBackground = true
  new Notification({
    title: 'AeroFetch is still running',
    body: 'Your download is finishing in the background. Use the tray icon to reopen or quit.',
    icon: getAppIconImage()
  }).show()
}

// Web permissions a download manager never needs. They're denied for the app
// window as defence-in-depth (audit T6): even if the renderer were compromised
// (e.g. XSS via remote video metadata) it can't open the camera/mic, read
// location, or reach USB/HID/serial/Bluetooth devices — none of which the IPC
// surface grants either. Clipboard (paste/copy) and everything else is left to
// the default so the app's own features keep working.
const DENIED_PERMISSIONS = new Set([
  'media', // camera + microphone
  'geolocation',
  'midi',
  'midiSysex',
  'hid',
  'serial',
  'usb',
  'bluetooth',
  'speaker-selection',
  'idle-detection'
])

function createWindow(): void {
  const win = new BrowserWindow({
    title: 'AeroFetch',
    width: 920,
    height: 700,
    // Below this the 212px sidebar + content layout breaks; pin a sensible
    // floor so the window can't be dragged down to unusable widths (W1).
    minWidth: 640,
    minHeight: 480,
    show: false,
    backgroundColor: PAGE_BACKGROUND[resolveBackgroundMode(getSettings().theme)],
    autoHideMenuBar: true,
    webPreferences: {
      preload: join(__dirname, '../preload/index.cjs'),
      sandbox: true,
      contextIsolation: true,
      nodeIntegration: false
    }
  })
  mainWindow = win

  // Standard Cut/Copy/Paste/Select All right-click menu on editable fields (W4).
  attachEditContextMenu(win.webContents)

  win.on('ready-to-show', () => {
    // A scheduled `--sync` launch starts unobtrusively (shown but not focused) so
    // the daily background sync doesn't steal focus; a normal launch shows + focuses.
    if (isSyncLaunch(process.argv)) win.showInactive()
    else win.show()
  })

  // Closing the window hides to the tray (instead of quitting) when either the
  // user opted into background mode, OR a download is in flight — quitting would
  // kill the spawned yt-dlp processes and lose the download. A real quit (tray
  // menu / before-quit) sets isQuitting() so this lets the close through.
  win.on('close', (e) => {
    if (isQuitting()) return
    const downloadsRunning = hasActiveDownloads()
    if (getSettings().minimizeToTray || downloadsRunning) {
      e.preventDefault()
      win.hide()
      // If we're only staying alive because a download is running (the user
      // didn't opt into tray mode), tell them once — otherwise a window that
      // won't close looks like a bug.
      if (downloadsRunning && !getSettings().minimizeToTray) notifyBackgroundOnce()
    }
  })

  win.on('closed', () => {
    if (mainWindow === win) mainWindow = null
  })

  // When the user re-opens the window (via tray, second-instance, or deeplink)
  // reset the background-notify latch so they're informed again if they close
  // while a download is still running (L68).
  win.on('show', () => {
    notifiedBackground = false
  })

  // The OS may have launched us with an aerofetch:// link or a "Send to" .url
  // file on the command line — hand it to DownloadBar's link-suggestion banner
  // once the page (and its IPC listener) is actually ready to receive it.
  const incomingUrl = extractIncomingUrl(process.argv)
  if (incomingUrl) {
    win.webContents.once('did-finish-load', () => {
      win.webContents.send(IpcChannels.externalUrl, incomingUrl)
    })
  }

  // Open external links in the OS browser, never in-app — and only http(s), so a
  // file:// or custom-protocol URL can't be used to launch a local handler.
  win.webContents.setWindowOpenHandler((details) => {
    try {
      const { protocol } = new URL(details.url)
      if (protocol === 'http:' || protocol === 'https:') shell.openExternal(details.url)
    } catch {
      /* unparseable URL — ignore */
    }
    return { action: 'deny' }
  })

  // The app shell is local and self-contained — never let the renderer navigate
  // away from it (defence in depth; HMR uses websockets, not navigation).
  win.webContents.on('will-navigate', (e) => e.preventDefault())

  // Deny the sensitive hardware/location web permissions the app never uses, so
  // a compromised renderer can't escalate to capabilities the IPC surface
  // doesn't grant. Both the async request and the sync check are covered. (audit T6)
  const ses = win.webContents.session
  ses.setPermissionRequestHandler((_wc, permission, callback) =>
    callback(!DENIED_PERMISSIONS.has(permission))
  )
  ses.setPermissionCheckHandler((_wc, permission) => !DENIED_PERMISSIONS.has(permission))

  if (is.dev && process.env['ELECTRON_RENDERER_URL']) {
    win.loadURL(process.env['ELECTRON_RENDERER_URL'])
  } else {
    win.loadFile(join(__dirname, '../renderer/index.html'))
  }
}

function registerIpcHandlers(): void {
  // M30: a broken contextBridge causes the renderer to silently run in preview/mock
  // mode. Catch it here and show a hard error so the failure is never invisible.
  ipcMain.once(IpcChannels.preloadBridgeFailure, (_e, detail: unknown) => {
    dialog.showErrorBox(
      'AeroFetch could not start',
      `The renderer bridge failed to initialize. Please reinstall the application.\n\n${String(detail)}`
    )
    app.quit()
  })

  ipcMain.handle(IpcChannels.appVersion, () => app.getVersion())

  ipcMain.handle(IpcChannels.appUpdateCheck, () => checkForAppUpdate())
  ipcMain.handle(IpcChannels.appUpdateDownload, (e, url: string) =>
    downloadAppUpdate(url, e.sender)
  )
  ipcMain.handle(IpcChannels.appUpdateRun, (_e, filePath: string) => runAppUpdate(filePath))

  ipcMain.handle(IpcChannels.ytdlpVersion, () => getYtdlpVersion())

  ipcMain.handle(IpcChannels.ffmpegVersion, () => getFfmpegVersions())

  ipcMain.handle(IpcChannels.probe, (_e, url: string) => probeMedia(url))

  ipcMain.handle(IpcChannels.downloadStart, (e, opts: StartDownloadOptions) => {
    const result = startDownload(e.sender, opts)
    // Pre-spawn failures (missing yt-dlp.exe, bad URL, duplicate id) never reach
    // download.ts's own close/error handlers, so log them here instead.
    if (!result.ok) {
      addErrorLog({
        id: opts.id,
        url: opts.url,
        kind: opts.kind,
        error: result.error ?? 'Unknown error',
        occurredAt: Date.now()
      })
    }
    return result
  })
  ipcMain.handle(IpcChannels.downloadCancel, (_e, id: string) => cancelDownload(id))
  ipcMain.handle(IpcChannels.downloadPause, (_e, id: string) => pauseDownload(id))
  ipcMain.handle(IpcChannels.terminalRun, (e, id: string, args: string) =>
    runTerminal(e.sender, id, args)
  )
  ipcMain.handle(IpcChannels.terminalCancel, (_e, id: string) => cancelTerminal(id))

  ipcMain.handle(IpcChannels.chooseFolder, async (e, current?: string) => {
    const win = BrowserWindow.fromWebContents(e.sender) ?? undefined
    // Seed the picker at the currently-configured folder so it opens where the
    // user already points, not a generic default (W5). 'createDirectory' is a
    // macOS-only property and a no-op on Windows, so it's dropped (L58).
    const defaultPath = current && existsSync(current) ? current : undefined
    // Use the parented overload only when we actually have a window — passing a
    // forced non-null window that's gone can throw (L53).
    const res = win
      ? await dialog.showOpenDialog(win, { properties: ['openDirectory'], defaultPath })
      : await dialog.showOpenDialog({ properties: ['openDirectory'], defaultPath })
    return res.canceled || !res.filePaths[0] ? null : res.filePaths[0]
  })

  ipcMain.handle(IpcChannels.openPath, (_e, p: string) => safeOpenPath(p))
  ipcMain.handle(IpcChannels.openUrl, (_e, url: string) => {
    try {
      const { protocol } = new URL(url)
      if (protocol === 'http:' || protocol === 'https:') void shell.openExternal(url)
    } catch {
      // Ignore malformed URLs.
    }
  })
  ipcMain.handle(IpcChannels.showInFolder, (_e, p: string) => safeShowInFolder(p))

  ipcMain.handle(IpcChannels.clipboardRead, () => clipboard.readText())

  ipcMain.handle(IpcChannels.settingsGet, () => getSettings())
  ipcMain.handle(IpcChannels.settingsSet, (e, partial: Partial<Settings>) => {
    const result = setSettings(partial)
    // Keep the window's native background and title bar in sync with the theme
    // so a compositor repaint never flashes a mismatched color, and the OS-drawn
    // caption always matches the in-app theme (W3). Use the validated result.
    if (partial.theme) {
      BrowserWindow.fromWebContents(e.sender)?.setBackgroundColor(
        PAGE_BACKGROUND[resolveBackgroundMode(result.theme)]
      )
      applyNativeTheme(result.theme)
    }
    return result
  })

  ipcMain.handle(IpcChannels.systemThemeGet, () => getSystemThemeInfo())

  ipcMain.handle(IpcChannels.openHighContrastSettings, () =>
    shell.openExternal('ms-settings:easeofaccess-highcontrast')
  )

  ipcMain.handle(IpcChannels.historyList, () => listHistory())
  ipcMain.handle(IpcChannels.historyAdd, (_e, entry: HistoryEntry) => addHistory(entry))
  ipcMain.handle(IpcChannels.historyRemove, (_e, id: string) => removeHistory(id))
  ipcMain.handle(IpcChannels.historyRemoveMany, (_e, ids: string[]) => removeManyHistory(ids))
  ipcMain.handle(IpcChannels.historyClear, () => clearHistory())

  ipcMain.handle(IpcChannels.cookiesLogin, (e, url: string) =>
    // Parent the sign-in window to the app window (W6) so it groups under
    // AeroFetch instead of spawning a second taskbar button.
    openCookieLoginWindow(url, BrowserWindow.fromWebContents(e.sender) ?? undefined)
  )
  ipcMain.handle(IpcChannels.cookiesStatus, () => getCookiesStatus())
  ipcMain.handle(IpcChannels.cookiesClear, () => clearCookies())

  ipcMain.handle(IpcChannels.templatesList, () => listTemplates())
  ipcMain.handle(IpcChannels.templatesSave, (_e, template: CommandTemplate) =>
    saveTemplate(template)
  )
  ipcMain.handle(IpcChannels.templatesRemove, (_e, id: string) => removeTemplate(id))

  ipcMain.handle(IpcChannels.commandPreview, (_e, opts: StartDownloadOptions) =>
    previewCommand(opts)
  )

  ipcMain.handle(IpcChannels.ytdlpUpdate, (_e, channel: YtdlpUpdateChannel) => updateYtdlp(channel))

  ipcMain.handle(IpcChannels.errorLogList, () => listErrorLog())
  ipcMain.handle(IpcChannels.errorLogClear, () => clearErrorLog())

  ipcMain.handle(IpcChannels.backupExport, (e) =>
    exportBackup(BrowserWindow.fromWebContents(e.sender) ?? undefined)
  )
  ipcMain.handle(IpcChannels.backupImport, async (e) => {
    const win = BrowserWindow.fromWebContents(e.sender) ?? undefined
    const result = await importBackup(win)
    // A restored backup may have changed the theme; keep the native window
    // background and title bar in sync the same way settingsSet does (W3).
    if (result.ok) {
      const theme = getSettings().theme
      win?.setBackgroundColor(PAGE_BACKGROUND[resolveBackgroundMode(theme)])
      applyNativeTheme(theme)
    }
    return result
  })

  // --- Media-manager sources (Pinchflat-style index; see ROADMAP-PINCHFLAT.md) ---
  ipcMain.handle(IpcChannels.sourcesList, () => listSources())
  ipcMain.handle(IpcChannels.sourceItems, (_e, sourceId: string) => listMediaItems(sourceId))
  ipcMain.handle(IpcChannels.sourceRemove, (_e, id: string) => removeSource(id))
  ipcMain.handle(IpcChannels.sourceItemDownloaded, (_e, id: string, filePath?: string) =>
    setMediaItemDownloaded(id, filePath)
  )
  // Indexing pushes live progress to the requesting renderer over `indexProgress`
  // and resolves with the final result.
  ipcMain.handle(IpcChannels.sourceIndex, (e, url: string) =>
    indexSource(url, (p) => {
      if (!e.sender.isDestroyed()) e.sender.send(IpcChannels.indexProgress, p)
    })
  )
  ipcMain.handle(IpcChannels.sourceReindex, (e, id: string) => {
    const src = getSource(id)
    if (!src) return { ok: false, error: 'Source not found.' }
    return indexSource(src.url, (p) => {
      if (!e.sender.isDestroyed()) e.sender.send(IpcChannels.indexProgress, p)
    })
  })
  ipcMain.handle(IpcChannels.sourceSetWatched, (_e, id: string, watched: boolean) =>
    setSourceWatched(id, watched)
  )
  ipcMain.handle(IpcChannels.sourcesSync, (e) =>
    syncWatchedSources((p) => {
      if (!e.sender.isDestroyed()) e.sender.send(IpcChannels.indexProgress, p)
    })
  )
  ipcMain.handle(IpcChannels.scheduledSyncGet, () => getScheduledSync())
  ipcMain.handle(IpcChannels.scheduledSyncSet, (_e, enabled: boolean) => setScheduledSync(enabled))

  // Reflect overall queue progress on the Windows taskbar.
  ipcMain.handle(IpcChannels.taskbarProgress, (_e, p: TaskbarProgress) => {
    if (!mainWindow || mainWindow.isDestroyed()) return
    if (p.mode === 'none') {
      mainWindow.setProgressBar(-1)
      mainWindow.setOverlayIcon(null, '')
    } else {
      mainWindow.setProgressBar(Math.max(0, Math.min(1, p.fraction)), { mode: p.mode })
      const badge = p.mode === 'error' ? getErrorBadge() : getActiveBadge()
      const n = p.badgeCount ?? 0
      const label =
        p.mode === 'error' ? 'Download error' : `${n} download${n !== 1 ? 's' : ''} active`
      mainWindow.setOverlayIcon(badge, label)
    }
  })

  // Open a YouTube WebView and extract a PO token for bot-check bypass (Phase P).
  ipcMain.handle(IpcChannels.youtubePoTokenMint, async () => {
    const token = await openPoTokenWindow()
    if (token) await setSettings({ youtubePoToken: token })
    return token
  })
}

// Push OS theme/contrast changes to every window, and keep the native
// background in sync for windows currently following 'system'.
function registerSystemThemeBridge(): void {
  nativeTheme.on('updated', () => {
    const info = getSystemThemeInfo()
    const bg = PAGE_BACKGROUND[resolveBackgroundMode(getSettings().theme)]
    for (const win of BrowserWindow.getAllWindows()) {
      win.webContents.send(IpcChannels.systemThemeUpdate, info)
      if (getSettings().theme === 'system') win.setBackgroundColor(bg)
    }
  })
}

if (isPrimaryInstance) {
  // A second launch arrives here as argv, not a real new process — extract any
  // link it carried and hand it to the window we already have.
  app.on('second-instance', (_e, argv) => {
    if (!mainWindow) return
    focusWindow(mainWindow)
    const incomingUrl = extractIncomingUrl(argv)
    if (incomingUrl) mainWindow.webContents.send(IpcChannels.externalUrl, incomingUrl)
  })

  app.whenReady().then(() => {
    electronApp.setAppUserModelId('com.aerofetch.app')

    // M31: suppress the default Electron menu (which exposes DevTools/Reload via
    // Alt) in production builds. In dev the menu is kept so DevTools are accessible.
    if (!is.dev) Menu.setApplicationMenu(null)

    // Create the default Documents\Video and Documents\Audio destinations so they
    // exist from first launch (downloads are routed into them by kind).
    ensureMediaDirs()

    // Encrypt any credential still stored as legacy plaintext (from before at-rest
    // encryption), once safeStorage is available post-ready.
    migrateSecretsAtRest()
    // Same for a pre-encryption plaintext cookies.txt — encrypt it and delete the
    // plaintext so a logged-in session no longer sits in the open (H7).
    migrateLegacyCookies()

    // Sync the Windows "run at sign-in" entry with the persisted setting, so it
    // reflects the user's choice even if they changed it on another install.
    applyLaunchAtStartup(getSettings().launchAtStartup)

    app.on('browser-window-created', (_, window) => {
      optimizer.watchWindowShortcuts(window)
    })

    registerIpcHandlers()
    registerSystemThemeBridge()
    registerSendToShortcut()
    // Apply the persisted theme to the OS title bar before the window opens (W3).
    applyNativeTheme(getSettings().theme)
    createWindow()
    createTray(() => mainWindow)

    // Taskbar right-click jump list: a quick "Open AeroFetch" task. Launching the
    // exe again is caught by the single-instance lock, which focuses this window.
    app.setUserTasks([
      {
        program: process.execPath,
        arguments: '',
        title: 'Open AeroFetch',
        description: 'Open the AeroFetch window',
        iconPath: process.execPath,
        iconIndex: 0
      }
    ])

    // Keep yt-dlp current on its own: seed the managed copy, then (throttled to
    // once a day) self-update it to the chosen channel so a stale binary can't
    // silently cause YouTube 403s. Best-effort and off the critical path — it
    // never blocks startup, and status is pushed to the window if it's listening.
    runStartupYtdlpAutoUpdate((status) => {
      if (mainWindow && !mainWindow.isDestroyed()) {
        mainWindow.webContents.send(IpcChannels.ytdlpAutoUpdateStatus, status)
      }
    }).catch((e) => console.error('[AeroFetch] yt-dlp auto-update failed:', e))
  })

  // Any real quit path (tray "Quit", OS shutdown, the updater's app.quit) must set
  // the quitting flag so the window's close handler exits instead of hiding to tray.
  // Also flush any debounced JSON-store writes synchronously so a quit mid-debounce
  // can't drop the last history/sources/template change (R3).
  app.on('before-quit', () => {
    markQuitting()
    flushAllStores()
  })

  // Windows-only app: closing the last window quits (the tray/in-flight-download
  // paths hide rather than close, so this only fires on a real exit). The former
  // macOS 'activate' handler and darwin guard were dead branches here (L147).
  app.on('window-all-closed', () => app.quit())
}