evening_detective_screen/electron/main.ts

import { app, BrowserWindow, ipcMain, protocol, screen, session } from 'electron'
import { createReadStream } from 'node:fs'
import { stat } from 'node:fs/promises'
import { join } from 'node:path'
import { Readable } from 'node:stream'
import { Controller } from './controller.js'
import { parseRange } from './range.js'
import type { HostInfo } from '../src/types/screen.js'

app.commandLine.appendSwitch('autoplay-policy', 'no-user-gesture-required')
protocol.registerSchemesAsPrivileged([
  {
    scheme: 'screen-app',
    privileges: { standard: true, secure: true, stream: true, supportFetchAPI: true },
  },
])
let control: BrowserWindow | null = null
let output: BrowserWindow | null = null
let selectedDisplay: number | null = null
const controller = new Controller((state) => {
  for (const window of [control, output])
    if (window && !window.isDestroyed()) window.webContents.send('state', state)
})
const rendererRoot = () => join(app.getAppPath(), 'dist')
function host(): HostInfo {
  const primary = screen.getPrimaryDisplay().id
  return {
    displays: screen
      .getAllDisplays()
      .filter((d) => d.id !== primary)
      .map((d) => ({
        id: d.id,
        label: `${d.label || 'Дисплей'} — ${d.size.width}×${d.size.height}`,
      })),
  }
}
function windowOptions() {
  return {
    backgroundColor: '#111111',
    webPreferences: {
      preload: join(__dirname, 'preload.js'),
      nodeIntegration: false,
      contextIsolation: true,
      sandbox: true,
    },
  }
}
function secure(window: BrowserWindow) {
  window.webContents.setWindowOpenHandler(() => ({ action: 'deny' }))
  window.webContents.on('will-navigate', (event) => event.preventDefault())
}
function requireControl(event: Electron.IpcMainInvokeEvent) {
  if (
    !control ||
    event.sender !== control.webContents ||
    event.senderFrame !== control.webContents.mainFrame
  )
    throw new Error('Недоступно')
}
function show(displayId: number) {
  const display = screen.getAllDisplays().find((d) => d.id === displayId)
  if (!display || display.id === screen.getPrimaryDisplay().id)
    throw new Error('Выберите внешний дисплей; включите расширенный рабочий стол')
  if (output) output.destroy()
  selectedDisplay = display.id
  output = new BrowserWindow({ ...windowOptions(), ...display.bounds, show: false })
  secure(output)
  const window = output
  output.on('closed', () => {
    if (output !== window) return
    output = null
    selectedDisplay = null
    controller.report({
      id: controller.state.command?.id ?? '',
      status: 'error',
      error: 'Окно показа закрыто',
    })
  })
  output.once('ready-to-show', () => {
    if (!window.isDestroyed()) {
      window.show()
      window.setFullScreen(true)
    }
  })
  void output.loadURL('screen-app://app/index.html?output=1')
}
app
  .whenReady()
  .then(async () => {
    session.defaultSession.setPermissionRequestHandler((_contents, _permission, callback) =>
      callback(false),
    )
    session.defaultSession.setPermissionCheckHandler(() => false)
    protocol.handle('screen-app', async (request) => {
      const url = new URL(request.url)
      const headers = {
        'Content-Security-Policy':
          "default-src 'self' screen-app:; script-src 'self'; style-src 'self' 'unsafe-inline'; media-src screen-app:; connect-src 'self'; frame-ancestors 'none'",
        'X-Content-Type-Options': 'nosniff',
      }
      if (url.host !== 'app' || request.method !== 'GET') return new Response(null, { status: 404 })
      if (url.pathname.startsWith('/media/')) {
        const media =
          url.pathname === '/media/audio'
            ? ['audio.wav', 'audio/wav']
            : url.pathname === '/media/video'
              ? ['video.mp4', 'video/mp4']
              : null
        if (!media) return new Response(null, { status: 404 })
        const filename = join(
          app.isPackaged ? process.resourcesPath : app.getAppPath(),
          'fixtures',
          media[0],
        )
        try {
          const info = await stat(filename)
          const rangeHeader = request.headers.get('range')
          const range = parseRange(rangeHeader, info.size)
          if (!range)
            return new Response(null, {
              status: 416,
              headers: { 'Content-Range': `bytes */${info.size}` },
            })
          const stream = createReadStream(filename, range)
          request.signal.addEventListener('abort', () => stream.destroy(), { once: true })
          const responseHeaders: Record<string, string> = {
            ...headers,
            'Content-Type': media[1],
            'Accept-Ranges': 'bytes',
            'Content-Length': String(range.end - range.start + 1),
          }
          if (rangeHeader)
            responseHeaders['Content-Range'] = `bytes ${range.start}-${range.end}/${info.size}`
          return new Response(Readable.toWeb(stream) as ReadableStream<Uint8Array>, {
            status: rangeHeader ? 206 : 200,
            headers: responseHeaders,
          })
        } catch {
          return new Response('Сначала выполните npm run media:generate', { status: 404 })
        }
      }
      const path = url.pathname
      if (path !== '/index.html' && !/^\/assets\/[a-zA-Z0-9_.-]+$/.test(path))
        return new Response(null, { status: 404 })
      try {
        const { readFile } = await import('node:fs/promises')
        const content = await readFile(join(rendererRoot(), path.slice(1)))
        const type = path.endsWith('.js')
          ? 'text/javascript'
          : path.endsWith('.css')
            ? 'text/css'
            : 'text/html; charset=utf-8'
        return new Response(content, { headers: { ...headers, 'Content-Type': type } })
      } catch {
        return new Response(null, { status: 404 })
      }
    })
    control = new BrowserWindow({ ...windowOptions(), width: 1000, height: 800 })
    secure(control)
    ipcMain.handle('state', (event) => {
      if (
        ![control?.webContents, output?.webContents].includes(event.sender) ||
        event.senderFrame !== event.sender.mainFrame
      )
        throw new Error('Недоступно')
      return controller.state
    })
    ipcMain.handle('host', (event) => {
      requireControl(event)
      return host()
    })
    ipcMain.handle('show', (event, id: unknown) => {
      requireControl(event)
      if (typeof id !== 'number') throw new Error('Некорректный дисплей')
      show(id)
    })
    ipcMain.handle('command', (event, command: unknown) => {
      requireControl(event)
      if (!output) throw new Error('Сначала откройте окно показа')
      controller.command(command)
    })
    ipcMain.on('report', (event, report: unknown) => {
      if (
        event.sender !== output?.webContents ||
        event.senderFrame !== output.webContents.mainFrame
      )
        return
      try {
        controller.report(report)
      } catch (error) {
        console.error('Ошибка отчёта проигрывателя', error)
      }
    })
    screen.on('display-removed', (_event, display) => {
      if (display.id === selectedDisplay) output?.close()
    })
    control.on('closed', () => {
      app.quit()
    })
    await control.loadURL('screen-app://app/index.html')
  })
  .catch((error) => {
    console.error(error)
    app.quit()
  })
app.on('window-all-closed', () => app.quit())