from time import perf_counter
from urllib import error, request


LATENCY_WARNING_MS = 500
REQUEST_TIMEOUT_SECONDS = 3


def make_status(status, message, latency_ms=None):
  return {
    'status': status,
    'latencyMs': latency_ms,
    'message': message
  }


def probe_url(url):
  started_at = perf_counter()
  req = request.Request(
    url,
    headers={'User-Agent': 'MusicWorkshop/0.1'},
    method='GET'
  )

  try:
    with request.urlopen(req, timeout=REQUEST_TIMEOUT_SECONDS) as response:
      status_code = response.status
  except error.HTTPError as exc:
    status_code = exc.code
  except (error.URLError, ValueError):
    return make_status('offline', '无法连接')

  latency_ms = max(1, round((perf_counter() - started_at) * 1000))

  if 500 <= status_code:
    return make_status('offline', f'服务异常 (HTTP {status_code})')

  status = 'warning' if latency_ms >= LATENCY_WARNING_MS else 'online'
  message = (
    f'高延迟 (HTTP {status_code})'
    if status == 'warning'
    else f'可达 (HTTP {status_code})'
  )
  return make_status(status, message, latency_ms)


def probe_metadata_services(metadata_config):
  services = {
    'acoustid': {
      'url': metadata_config['acoustidUrl'],
      'required_credentials': [metadata_config['acoustidClientKey']]
    },
    'musicbrainz': {
      'url': metadata_config['musicbrainz']
    },
    'netease': {
      'url': metadata_config['netease']
    },
    'qq': {
      'url': metadata_config['qq']
    },
    'spotify': {
      'url': metadata_config['spotifyUrl'],
      'required_credentials': [
        metadata_config['spotifyClientId'],
        metadata_config['spotifySecret']
      ]
    },
    'discogs': {
      'url': metadata_config['discogsUrl'],
      'required_credentials': [metadata_config['discogsToken']]
    },
    'lastfm': {
      'url': metadata_config['lastfmUrl'],
      'required_credentials': [metadata_config['lastfmKey']]
    },
    'genius': {
      'url': metadata_config['geniusUrl'],
      'required_credentials': [metadata_config['geniusToken']]
    }
  }

  statuses = {}

  for service_name, service_config in services.items():
    credentials = service_config.get('required_credentials', [])
    if credentials and not all(value.strip() for value in credentials):
      statuses[service_name] = make_status('none', '缺失凭据，跳过测试')
      continue

    url = service_config['url'].strip()
    if not url:
      statuses[service_name] = make_status('none', '未配置地址，跳过测试')
      continue

    statuses[service_name] = probe_url(url)

  return statuses