import 'dart:convert';

import 'package:http/http.dart' as http;

import 'android_setup.dart';

/// [fetchLatestAppRemoteReleaseAssetDownloadUrl] fetches the latest release of the
/// Spotify Android SDK from GitHub API and returns the name and download url of
/// the spotify-app-remote-release-*.aar asset.
/// Throws an exception if the request fails.
class GitHubApi {
  static const String apiUrl = 'https://api.github.com/repos';
  static const String spotifyAndroidSdkRepo = '/spotify/android-sdk';
  static const String latestRelease = '/releases/latest';
  static const String allReleases = '/releases';

  static Future<(String, Uri)>
      fetchLatestAppRemoteReleaseAssetDownloadUrl() async {
    // fetch the github api to get the latest release
    Uri uri = Uri.parse(apiUrl + spotifyAndroidSdkRepo + latestRelease);
    try {
      final response = await http.get(uri);
      if (response.statusCode == 200) {
        final data = jsonDecode(response.body);
        return _findAsset(data);
      } else {
        logger.e('Failed to fetch data from the API.');
      }
    } catch (e) {
      logger.e('An error occurred: $e');
    }
    throw Exception();
  }

  static Future<(String, Uri)> fetchVersionedAppRemoteReleaseAssetDownloadUrl(
      String sdkVersion) async {
    if (sdkVersion.startsWith('--sdk-version=')) {
      sdkVersion = sdkVersion.substring(14);
    }
    if (sdkVersion.startsWith('v')) {
      sdkVersion = sdkVersion.substring(1);
    }

    // fetch the github api to get all releases
    Uri uri = Uri.parse(apiUrl + spotifyAndroidSdkRepo + allReleases);
    try {
      final response = await http.get(uri);
      if (response.statusCode == 200) {
        final data = jsonDecode(response.body) as List<dynamic>;

        logger.t(
            'Found ${data.length} releases of the Spotify Android SDK on GitHub.');
        final releaseData = data.firstWhere(
          (element) {
            final tagName = element['tag_name'] as String;
            return tagName.contains('v$sdkVersion');
          },
          orElse: () {
            logger.e('Failed to find a release with version "$sdkVersion".');
            throw Exception();
          },
        );

        return _findAsset(releaseData);
      }
    } catch (e) {
      logger.e('An error occurred: $e');
    }
    throw Exception();
  }

  static (String, Uri) _findAsset(Map<String, dynamic> data) {
    final assets = data['assets'] as List<dynamic>;

    final assetMap = <int, (String, String)>{};
    for (var asset in assets) {
      final id = asset['id'] as int;
      final name = asset['name'] as String;
      final url = asset['browser_download_url'] as String;
      assetMap[id] = (name, url);
    }

    // find the spotify-app-remote-release-*.aar asset
    final assetId = assetMap.keys.firstWhere(
      (id) =>
          assetMap[id]?.$1.startsWith('spotify-app-remote-release-') ?? false,
      orElse: () => -1,
    );

    if (assetId == -1) {
      logger.e('Failed to find the Spotify Android SDK asset.');
      throw Exception();
    }

    // return the download url of the spotify-app-remote-release-*.aar asset
    logger.i('Found the Spotify Android SDK asset: '
        '${assetMap[assetId]!.$1}');
    return (assetMap[assetId]!.$1, Uri.parse(assetMap[assetId]!.$2));
  }
}