const { spawn, exec } = require('child_process')
const path = require('path')
const fs = require('fs')

let ffmpegPath = null

function getFfmpegPath() {
  if (ffmpegPath) return ffmpegPath

  const resourcesPath = process.resourcesPath || path.join(__dirname, '..')
  const candidates = [
    path.join(resourcesPath, 'ffmpeg-bin', process.platform === 'win32' ? 'ffmpeg.exe' : 'ffmpeg'),
    path.join(__dirname, '..', 'ffmpeg-bin', process.platform === 'win32' ? 'ffmpeg.exe' : 'ffmpeg'),
  ]

  for (const p of candidates) {
    if (fs.existsSync(p)) {
      ffmpegPath = p
      return p
    }
  }

  ffmpegPath = process.platform === 'win32' ? 'ffmpeg.exe' : 'ffmpeg'
  return ffmpegPath
}

function runCommand(cmd, args) {
  return new Promise((resolve) => {
    const proc = spawn(cmd, args, { stdio: ['pipe', 'pipe', 'pipe'] })
    let stdout = ''
    let stderr = ''
    proc.stdout.on('data', d => stdout += d)
    proc.stderr.on('data', d => stderr += d)
    proc.on('close', () => resolve({ stdout, stderr }))
    proc.on('error', () => resolve({ stdout: '', stderr: '' }))
    // Timeout
    setTimeout(() => { proc.kill(); resolve({ stdout, stderr }) }, 10000)
  })
}

async function getWindowsDevices() {
  const ffmpeg = getFfmpegPath()
  const { stderr } = await runCommand(ffmpeg, [
    '-list_devices', 'true',
    '-f', 'dshow',
    '-i', 'dummy'
  ])

  const video = []
  const audio = []

  const lines = stderr.split('\n')
  let section = null

  for (const line of lines) {
    if (line.includes('"') && line.includes('(video)')) {
      section = 'video'
      const match = line.match(/"([^"]+)"\s*\(video\)/)
      if (match) {
        video.push({ name: match[1], deviceName: match[1], type: 'device' })
      }
    } else if (line.includes('"') && line.includes('(audio)')) {
      section = 'audio'
      const match = line.match(/"([^"]+)"\s*\(audio\)/)
      if (match) {
        audio.push({ name: match[1], deviceName: match[1], type: 'device' })
      }
    }
  }

  // Add system audio loopback devices (WASAPI)
  // These appear as "virtual-audio-capturer" or similar dshow devices
  // Also detect via registry / wmic
  audio.push({
    name: 'System Audio (Loopback)',
    deviceName: 'virtual-audio-capturer',
    type: 'system',
    description: 'Capture all system audio output'
  })

  // Add screen capture options
  const screenDevices = [
    { name: 'Desktop (Full Screen)', type: 'desktop', deviceName: 'desktop' },
  ]

  // Try to enumerate monitors
  const monitors = await getWindowsMonitors()
  monitors.forEach((m, i) => {
    screenDevices.push({
      name: `Monitor ${i + 1}${m.label ? ': ' + m.label : ''}`,
      type: 'desktop',
      deviceName: `desktop`,
      monitorIndex: i
    })
  })

  return { video: [...screenDevices, ...video], audio }
}

async function getWindowsMonitors() {
  return new Promise((resolve) => {
    exec('wmic desktopmonitor get Name,ScreenHeight,ScreenWidth /format:list', (err, stdout) => {
      if (err) { resolve([]); return }
      const monitors = []
      const blocks = stdout.split('\r\n\r\n').filter(b => b.trim())
      for (const block of blocks) {
        const nameMatch = block.match(/Name=(.+)/)
        if (nameMatch) monitors.push({ label: nameMatch[1].trim() })
      }
      resolve(monitors)
    })
    setTimeout(() => resolve([]), 5000)
  })
}

async function getMacDevices() {
  const ffmpeg = getFfmpegPath()
  const { stderr } = await runCommand(ffmpeg, [
    '-f', 'avfoundation',
    '-list_devices', 'true',
    '-i', ''
  ])

  const video = []
  const audio = []

  const lines = stderr.split('\n')
  let section = null

  for (const line of lines) {
    if (line.includes('AVFoundation video devices')) {
      section = 'video'
      continue
    }
    if (line.includes('AVFoundation audio devices')) {
      section = 'audio'
      continue
    }

    const match = line.match(/\[(\d+)\]\s+(.+)/)
    if (match) {
      const index = match[1]
      const name = match[2].trim()
      if (section === 'video') {
        const isScreen = name.toLowerCase().includes('screen') || name.toLowerCase().includes('capture')
        video.push({
          name,
          deviceIndex: index,
          type: isScreen ? 'desktop' : 'device'
        })
      } else if (section === 'audio') {
        audio.push({
          name,
          deviceIndex: index,
          type: 'device'
        })
      }
    }
  }

  return { video, audio }
}

async function getLinuxDevices() {
  const video = []
  const audio = []

  // V4L2 devices
  try {
    const v4l2Devices = await new Promise((resolve) => {
      exec('ls /dev/video* 2>/dev/null', (err, stdout) => {
        if (err) { resolve([]); return }
        resolve(stdout.trim().split('\n').filter(Boolean))
      })
    })

    for (const dev of v4l2Devices) {
      const { stdout } = await runCommand('v4l2-ctl', ['--device', dev, '--info'])
      const nameMatch = stdout.match(/Card type\s*:\s*(.+)/)
      video.push({
        name: nameMatch ? nameMatch[1].trim() : dev,
        devicePath: dev,
        type: 'device'
      })
    }
  } catch (e) {}

  // Add screen capture
  const display = process.env.DISPLAY || ':0'
  video.unshift({ name: `Desktop (${display})`, type: 'desktop', devicePath: display })

  // PulseAudio devices
  try {
    const { stdout: paList } = await runCommand('pactl', ['list', 'short', 'sources'])
    const lines = paList.split('\n').filter(Boolean)
    for (const line of lines) {
      const parts = line.split('\t')
      if (parts.length >= 2) {
        const deviceName = parts[1]
        const isMonitor = deviceName.includes('.monitor')
        audio.push({
          name: deviceName,
          deviceName,
          type: isMonitor ? 'system' : 'device',
          description: isMonitor ? 'System audio (loopback)' : ''
        })
      }
    }
  } catch (e) {
    audio.push({ name: 'default', deviceName: 'default', type: 'device' })
  }

  return { video, audio }
}

async function getDevices() {
  let result

  if (process.platform === 'win32') {
    result = await getWindowsDevices()
  } else if (process.platform === 'darwin') {
    result = await getMacDevices()
  } else {
    result = await getLinuxDevices()
  }

  // Always add "None" options
  result.video.unshift({ name: '— No Video —', type: 'none', deviceName: 'none' })
  result.audio.unshift({ name: '— No Audio —', type: 'none', deviceName: 'none' })

  return result
}

async function getWindows() {
  if (process.platform === 'win32') {
    return getWindowsWindowsList()
  } else if (process.platform === 'darwin') {
    return getMacWindowsList()
  } else {
    return getLinuxWindowsList()
  }
}

function getWindowsWindowsList() {
  return new Promise((resolve) => {
    const script = `
      $windows = Get-Process | Where-Object {$_.MainWindowTitle -ne ""} | Select-Object ProcessName, MainWindowTitle
      $windows | ForEach-Object { Write-Output "$($_.MainWindowTitle)" }
    `
    exec(`powershell -Command "${script.replace(/\n/g, ' ')}"`, (err, stdout) => {
      if (err) { resolve([]); return }
      const windows = stdout.trim().split('\n')
        .map(w => w.trim())
        .filter(Boolean)
        .map(title => ({ title, type: 'window' }))
      resolve(windows)
    })
  })
}

function getMacWindowsList() {
  return new Promise((resolve) => {
    exec(`osascript -e 'tell application "System Events" to get name of every process whose has UI elements is true'`, (err, stdout) => {
      if (err) { resolve([]); return }
      const apps = stdout.trim().split(', ')
        .filter(Boolean)
        .map(title => ({ title, type: 'window' }))
      resolve(apps)
    })
  })
}

function getLinuxWindowsList() {
  return new Promise((resolve) => {
    exec('wmctrl -l 2>/dev/null', (err, stdout) => {
      if (err) { resolve([]); return }
      const windows = stdout.trim().split('\n')
        .map(line => {
          const parts = line.split(/\s+/)
          const title = parts.slice(3).join(' ')
          return { title, type: 'window' }
        })
        .filter(w => w.title)
      resolve(windows)
    })
  })
}

module.exports = { getDevices, getWindows }