import { spawn } from 'node:child_process'
import path from 'node:path'
import { fileURLToPath } from 'node:url'

const serverDir = path.dirname(fileURLToPath(import.meta.url))

export function startQuicServer({ onEvent } = {}) {
  if (process.env.QUIC_ENABLED === 'false') return null

  const script = path.join(serverDir, 'quic', 'server.py')
  const python = process.env.QUIC_PYTHON || (process.platform === 'win32' ? 'py' : 'python3')
  const args = process.platform === 'win32' && !process.env.QUIC_PYTHON
    ? ['-3', script]
    : [script]

  const child = spawn(python, args, {
    cwd: path.resolve(serverDir, '..'),
    env: {
      ...process.env,
      QUIC_HOST: process.env.QUIC_HOST || '0.0.0.0',
      QUIC_PORT: process.env.QUIC_PORT || '5175',
      QUIC_CERT_FILE: process.env.QUIC_CERT_FILE || path.join(serverDir, 'certs', 'quic-gateway.crt'),
      QUIC_KEY_FILE: process.env.QUIC_KEY_FILE || path.join(serverDir, 'certs', 'quic-gateway.key')
    },
    stdio: ['ignore', 'pipe', 'pipe']
  })

  child.stdout.setEncoding('utf8')
  child.stderr.setEncoding('utf8')
  let stdoutBuffer = ''
  child.stdout.on('data', data => {
    stdoutBuffer += data
    const lines = stdoutBuffer.split(/\r?\n/)
    stdoutBuffer = lines.pop() || ''
    for (const line of lines) {
      if (!line) continue
      console.log(line)
      try {
        onEvent?.(JSON.parse(line))
      } catch {
        // Keep non-JSON Python diagnostics visible without feeding the registry.
      }
    }
  })
  child.stderr.on('data', data => process.stderr.write(data))
  child.on('error', error => console.error('[quic] 无法启动 Python 服务:', error.message))
  child.on('exit', (code, signal) => {
    if (code !== 0 && signal !== 'SIGTERM') {
      console.error(`[quic] 服务异常退出 (code=${code}, signal=${signal || 'none'})`)
    }
  })

  const stop = () => {
    if (!child.killed) child.kill()
  }
  process.once('SIGINT', stop)
  process.once('SIGTERM', stop)
  process.once('exit', stop)
  return child
}