const assert = require('node:assert/strict')
const { spawn } = require('node:child_process')
const { mkdtemp, readFile, rm } = require('node:fs/promises')
const net = require('node:net')
const os = require('node:os')
const path = require('node:path')
const { test } = require('node:test')

const HOST = '127.0.0.1'
const TOKEN = 'server-e2e-token'
const CHROME = process.env.PUPPETEER_EXECUTABLE_PATH || '/usr/bin/chromium'

test('render server produces a playable MP4 for a tiny scene', async (t) => {
  const ffmpeg = await commandPath('ffmpeg')
  const ffprobe = await commandPath('ffprobe')
  if (!ffmpeg || !ffprobe || !(await canAccess(CHROME))) {
    t.skip('requires ffmpeg, ffprobe, and Chromium')
    return
  }

  const port = await freePort()
  const tmp = await mkdtemp(path.join(os.tmpdir(), 'ruwio-render-e2e-'))
  const server = spawn(process.execPath, ['server.js'], {
    cwd: __dirname,
    env: {
      ...process.env,
      HOST,
      PORT: String(port),
      RENDER_TOKEN: TOKEN,
      RENDER_JOB_TTL_MS: '1000',
      RENDER_JOB_TIMEOUT_MS: '30000',
      PUPPETEER_EXECUTABLE_PATH: CHROME,
      CHROME_NO_SANDBOX: '1',
    },
    stdio: ['ignore', 'pipe', 'pipe'],
  })

  let output = ''
  server.stdout.on('data', (chunk) => {
    output += chunk.toString()
  })
  server.stderr.on('data', (chunk) => {
    output += chunk.toString()
  })

  t.after(async () => {
    if (server.exitCode === null) {
      server.kill('SIGTERM')
      await waitForExit(server)
    }
    await rm(tmp, { recursive: true, force: true })
  })

  await waitForServer(server, port, () => output)

  const base = `http://${HOST}:${port}`
  const start = await fetch(`${base}/render`, {
    method: 'POST',
    headers: {
      Authorization: `Bearer ${TOKEN}`,
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({ scene: tinyScene(), options: { fps: 2, crf: 28, preset: 'ultrafast' } }),
  })
  const startText = await start.text()
  assert.equal(start.status, 200, startText)
  const { jobId, accessToken } = JSON.parse(startText)
  assert.equal(typeof jobId, 'string')
  assert.equal(typeof accessToken, 'string')

  const done = await waitForDone(`${base}/render/${jobId}/events?token=${encodeURIComponent(accessToken)}`)
  assert.equal(done.done, true)
  assert.equal(done.error, null)
  assert.equal(done.progress, 1)
  assert.equal(done.url, `/render/${jobId}/file?token=${encodeURIComponent(accessToken)}`)

  const file = await fetch(`${base}${done.url}`)
  assert.equal(file.status, 200)
  const outPath = path.join(tmp, 'tiny.mp4')
  await require('node:fs/promises').writeFile(outPath, Buffer.from(await file.arrayBuffer()))

  const metadata = await ffprobeJson(outPath)
  const video = metadata.streams.find((stream) => stream.codec_type === 'video')
  assert.ok(video, 'expected a video stream')
  assert.equal(video.codec_name, 'h264')
  assert.equal(video.width, 64)
  assert.equal(video.height, 64)
})

test('render server pads odd canvas dimensions to an even MP4', async (t) => {
  const ffmpeg = await commandPath('ffmpeg')
  const ffprobe = await commandPath('ffprobe')
  if (!ffmpeg || !ffprobe || !(await canAccess(CHROME))) {
    t.skip('requires ffmpeg, ffprobe, and Chromium')
    return
  }

  const port = await freePort()
  const tmp = await mkdtemp(path.join(os.tmpdir(), 'ruwio-render-e2e-'))
  const server = spawn(process.execPath, ['server.js'], {
    cwd: __dirname,
    env: {
      ...process.env,
      HOST,
      PORT: String(port),
      RENDER_TOKEN: TOKEN,
      RENDER_JOB_TTL_MS: '1000',
      RENDER_JOB_TIMEOUT_MS: '30000',
      PUPPETEER_EXECUTABLE_PATH: CHROME,
      CHROME_NO_SANDBOX: '1',
    },
    stdio: ['ignore', 'pipe', 'pipe'],
  })

  let output = ''
  server.stdout.on('data', (chunk) => {
    output += chunk.toString()
  })
  server.stderr.on('data', (chunk) => {
    output += chunk.toString()
  })

  t.after(async () => {
    if (server.exitCode === null) {
      server.kill('SIGTERM')
      await waitForExit(server)
    }
    await rm(tmp, { recursive: true, force: true })
  })

  await waitForServer(server, port, () => output)

  const base = `http://${HOST}:${port}`
  const start = await fetch(`${base}/render`, {
    method: 'POST',
    headers: {
      Authorization: `Bearer ${TOKEN}`,
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({ scene: oddScene(), options: { fps: 2, crf: 28, preset: 'ultrafast' } }),
  })
  const startText = await start.text()
  assert.equal(start.status, 200, startText)
  const { jobId, accessToken } = JSON.parse(startText)

  const done = await waitForDone(`${base}/render/${jobId}/events?token=${encodeURIComponent(accessToken)}`)
  assert.equal(done.done, true)
  assert.equal(done.error, null)
  assert.equal(done.progress, 1)

  const file = await fetch(`${base}${done.url}`)
  assert.equal(file.status, 200)
  const outPath = path.join(tmp, 'odd.mp4')
  await require('node:fs/promises').writeFile(outPath, Buffer.from(await file.arrayBuffer()))

  const metadata = await ffprobeJson(outPath)
  const video = metadata.streams.find((stream) => stream.codec_type === 'video')
  assert.ok(video, 'expected a video stream')
  assert.equal(video.codec_name, 'h264')
  assert.equal(video.width, 102)
  assert.equal(video.height, 102)
})

function tinyScene() {
  return {
    canvas: { width: 64, height: 64, background: '#ffffff' },
    duration: 1,
    fps: 2,
    assets: [
      { id: 'asset-rect', kind: 'rect', name: 'Box', width: 24, height: 24, fill: '#22cc88' },
    ],
    layers: [
      {
        id: 'layer-rect',
        name: 'Box',
        assetId: 'asset-rect',
        visible: true,
        base: { x: 16, y: 32, scaleX: 1, scaleY: 1, rotation: 0, opacity: 1 },
        keyframes: [
          { id: 'kf-0', time: 0, easing: 'linear', props: { x: 16 } },
          { id: 'kf-1', time: 0.5, easing: 'linear', props: { x: 48 } },
        ],
      },
    ],
  }
}

function oddScene() {
  const s = tinyScene()
  s.canvas.width = 101
  s.canvas.height = 101
  s.layers[0].base.x = 50
  s.layers[0].base.y = 50
  s.layers[0].keyframes = [
    { id: 'kf-0', time: 0, easing: 'linear', props: { x: 42 } },
    { id: 'kf-1', time: 0.5, easing: 'linear', props: { x: 58 } },
  ]
  return s
}

async function waitForDone(url) {
  const res = await fetch(url)
  assert.equal(res.status, 200)
  const reader = res.body.getReader()
  const decoder = new TextDecoder()
  let buffer = ''
  const deadline = Date.now() + 30000

  while (Date.now() < deadline) {
    const { value, done } = await reader.read()
    if (done) break
    buffer += decoder.decode(value, { stream: true })
    const messages = buffer.split('\n\n')
    buffer = messages.pop() || ''
    for (const message of messages) {
      const line = message.split('\n').find((entry) => entry.startsWith('data: '))
      if (!line) continue
      const payload = JSON.parse(line.slice(6))
      if (payload.done) return payload
    }
  }

  throw new Error('render did not finish before timeout')
}

function ffprobeJson(file) {
  return new Promise((resolve, reject) => {
    const child = spawn('ffprobe', [
      '-v', 'error',
      '-show_streams',
      '-of', 'json',
      file,
    ])
    let stdout = ''
    let stderr = ''
    child.stdout.on('data', (chunk) => {
      stdout += chunk.toString()
    })
    child.stderr.on('data', (chunk) => {
      stderr += chunk.toString()
    })
    child.on('error', reject)
    child.on('exit', (code) => {
      if (code === 0) resolve(JSON.parse(stdout))
      else reject(new Error(`ffprobe exited with code ${code}: ${stderr}`))
    })
  })
}

function commandPath(command) {
  return new Promise((resolve) => {
    const probe = spawn(process.platform === 'win32' ? 'where' : 'which', [command])
    probe.on('error', () => resolve(''))
    probe.on('exit', (code) => resolve(code === 0 ? command : ''))
  })
}

async function canAccess(file) {
  try {
    await readFile(file)
    return true
  } catch {
    return false
  }
}

function freePort() {
  return new Promise((resolve, reject) => {
    const server = net.createServer()
    server.once('error', reject)
    server.listen(0, HOST, () => {
      const address = server.address()
      server.close(() => {
        if (!address || typeof address === 'string') reject(new Error('could not allocate test port'))
        else resolve(address.port)
      })
    })
  })
}

async function waitForServer(server, port, output) {
  const deadline = Date.now() + 5000
  while (Date.now() < deadline) {
    if (server.exitCode !== null) {
      throw new Error(`server exited early with code ${server.exitCode}\n${output()}`)
    }
    try {
      const res = await fetch(`http://${HOST}:${port}/health`)
      if (res.ok) return
    } catch {
      /* retry */
    }
    await delay(50)
  }
  throw new Error(`server did not start\n${output()}`)
}

function waitForExit(child) {
  return new Promise((resolve) => {
    child.once('exit', () => resolve())
    setTimeout(() => {
      if (child.exitCode === null) child.kill('SIGKILL')
      resolve()
    }, 1000).unref()
  })
}

function delay(ms) {
  return new Promise((resolve) => setTimeout(resolve, ms))
}