const { app, BrowserWindow, dialog, ipcMain, Menu } = require('electron')
const { spawn } = require('child_process')
const fs = require('fs')
const http = require('http')
const path = require('path')

const BACKEND_HOST = 'localhost'
const BACKEND_PORT = 9996
const BACKEND_URL = `http://${BACKEND_HOST}:${BACKEND_PORT}`
const STARTUP_TIMEOUT_MS = 30000

let mainWindow = null
let backendProcess = null
let startedBackend = false
const projectionWindows = new Set()

function getSharedWebPreferences() {
  return {
    contextIsolation: true,
    nodeIntegration: false,
    sandbox: true,
    preload: path.join(__dirname, 'preload.cjs'),
  }
}

function isProjectionUrl(url) {
  try {
    return new URL(url).searchParams.get('screen') === 'counter'
  } catch {
    return false
  }
}

function createProjectionWindow(url) {
  const projectionWindow = new BrowserWindow({
    width: 1280,
    height: 720,
    minWidth: 960,
    minHeight: 540,
    frame: false,
    fullscreen: false,
    movable: true,
    resizable: true,
    autoHideMenuBar: true,
    title: '投屏计数',
    backgroundColor: '#000000',
    thickFrame: false,
    webPreferences: getSharedWebPreferences(),
  })

  projectionWindows.add(projectionWindow)
  hideMenuBar(projectionWindow)
  projectionWindow.loadURL(url)

  projectionWindow.on('closed', () => {
    projectionWindows.delete(projectionWindow)
  })

  return projectionWindow
}

function hideMenuBar(win) {
  win.setMenuBarVisibility(false)
  win.removeMenu()
}

function attachWindowOpenHandler(win) {
  win.webContents.setWindowOpenHandler(({ url }) => {
    if (isProjectionUrl(url)) {
      createProjectionWindow(url)
      return { action: 'deny' }
    }

    return { action: 'allow' }
  })

  win.webContents.on('did-create-window', (childWindow) => {
    hideMenuBar(childWindow)
  })
}

function getBackendExecutablePath() {
  if (app.isPackaged) {
    return path.join(
      process.resourcesPath,
      'backend',
      process.platform === 'win32' ? 'YD_TrainingCompetition_Api.exe' : 'YD_TrainingCompetition_Api',
    )
  }

  return path.join(
    __dirname,
    '..',
    'build',
    'backend',
    process.platform === 'win32' ? 'YD_TrainingCompetition_Api.exe' : 'YD_TrainingCompetition_Api',
  )
}

function getFrontendIndexPath() {
  return path.join(__dirname, '..', 'frontend', 'index.html')
}

function probeBackend() {
  return new Promise((resolve) => {
    const request = http.get(BACKEND_URL, (response) => {
      response.resume()
      resolve(true)
    })

    request.on('error', () => resolve(false))
    request.setTimeout(1000, () => {
      request.destroy()
      resolve(false)
    })
  })
}

async function waitForBackend(timeoutMs = STARTUP_TIMEOUT_MS) {
  const startedAt = Date.now()

  while (Date.now() - startedAt < timeoutMs) {
    if (await probeBackend()) {
      return
    }

    await new Promise((resolve) => setTimeout(resolve, 300))
  }

  throw new Error(`后端服务启动超时：${BACKEND_URL}`)
}

async function startBackend() {
  if (await probeBackend()) {
    return
  }

  const backendPath = getBackendExecutablePath()
  if (!fs.existsSync(backendPath)) {
    throw new Error(`未找到后端程序：${backendPath}\n请先执行 npm run build:assets。`)
  }

  backendProcess = spawn(backendPath, [], {
    cwd: path.dirname(backendPath),
    env: {
      ...process.env,
      ASPNETCORE_ENVIRONMENT: 'Production',
      ASPNETCORE_URLS: BACKEND_URL,
    },
    stdio: ['ignore', 'pipe', 'pipe'],
    windowsHide: true,
  })
  startedBackend = true

  backendProcess.stdout.on('data', (data) => {
    console.log(`[backend] ${data.toString().trimEnd()}`)
  })
  backendProcess.stderr.on('data', (data) => {
    console.error(`[backend] ${data.toString().trimEnd()}`)
  })
  backendProcess.on('exit', (code, signal) => {
    console.log(`[backend] exited code=${code} signal=${signal}`)
    backendProcess = null
  })

  await waitForBackend()
}

function stopBackend() {
  if (!startedBackend || !backendProcess || backendProcess.killed) {
    return
  }

  if (process.platform === 'win32') {
    spawn('taskkill', ['/pid', String(backendProcess.pid), '/f', '/t'], {
      windowsHide: true,
      stdio: 'ignore',
    })
  } else {
    backendProcess.kill('SIGTERM')
  }

  backendProcess = null
}

async function createWindow() {
  mainWindow = new BrowserWindow({
    width: 1366,
    height: 900,
    minWidth: 1024,
    minHeight: 700,
    title: '赛事训练比赛系统',
    autoHideMenuBar: true,
    webPreferences: getSharedWebPreferences(),
  })

  hideMenuBar(mainWindow)
  attachWindowOpenHandler(mainWindow)

  const devServerUrl = process.env.ELECTRON_RENDERER_URL
  if (!app.isPackaged && devServerUrl) {
    await mainWindow.loadURL(devServerUrl)
    mainWindow.webContents.openDevTools({ mode: 'detach' })
    return
  }

  // 由后端通过 http 托管前端：绝对路径 /static、fetch、SignalR 与 API 均同源可用。
  await mainWindow.loadURL(BACKEND_URL)
}

ipcMain.handle('dialog:pickFolder', async () => {
  const targetWindow = mainWindow ?? BrowserWindow.getFocusedWindow()
  const result = await dialog.showOpenDialog(targetWindow, {
    title: '选择赛事文件夹',
    properties: ['openDirectory'],
  })

  if (result.canceled || result.filePaths.length === 0) {
    return null
  }

  return result.filePaths[0]
})

app.whenReady().then(async () => {
  if (app.isPackaged) {
    Menu.setApplicationMenu(null)
  }

  try {
    await startBackend()
    await createWindow()
  } catch (error) {
    dialog.showErrorBox('应用启动失败', error instanceof Error ? error.message : String(error))
    app.quit()
  }

  app.on('activate', () => {
    if (BrowserWindow.getAllWindows().length === 0) {
      createWindow()
    }
  })
})

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

app.on('before-quit', stopBackend)