import 'dart:convert';

import 'package:http/http.dart' as http;
import 'package:toolheim/warband_roaster.dart';
import 'package:yaml/yaml.dart';

enum SyncState {
  unknown,
  running,
  success,
  error,
}

class GitHubAdapter {
  // TODO: Store this in the SharedPreferences
  final String repository;
  final String path;

  static SyncState syncState = SyncState.unknown;
  List<String> syncErrors = new List<String>();
  static DateTime lastSync;

  GitHubAdapter(this.repository, this.path);

  /// Search for warband files in the GitHub repository
  ///
  /// This method will search for matching files and check their content in a
  /// subfolder (see fields [repository] and [path]). If the file
  /// contain errors or can't read, a sync error message will be written into
  /// the [syncErrors] list.
  Future<List<WarbandRoaster>> search() async {
    syncErrors.clear();

    Stream<Map<String, String>> roasterStream() async* {
      // Get all files which could be potential warband files (end with
      // mordheim.yml and contain the word "heros").
      http.Response response = await http.get(
          "https://api.github.com/search/code?q=heros+repo:" +
              repository +
              "+filename:mordheim.yml+path:\"" +
              path +
              "\"");

      // GitHub is not reachable
      if (response.statusCode != 200) {
        syncErrors.add('Could not find any warband roaster files');
        yield {};
        return;
      }

      // No valid response from GitHub
      dynamic searchResults;
      try {
        searchResults = jsonDecode(response.body);
      } on FormatException catch (e) {
        syncErrors.add('Could not parse GitHub response.' + e.toString());
        yield {};
        return;
      }

      // Find suitable files for examination
      RegExp fileRegex = new RegExp(r"[a-zA-Z]+\.mordheim\.ya?ml");
      for (dynamic searchResult in searchResults['items']) {
        if (fileRegex.hasMatch(searchResult['name'])) {
          // We try to get the name of the player from the name of the folder
          // in which the file resists
          String completePath = searchResult['path'];
          List<String> pathParts =
              completePath.substring(path.length + 1).split('/');

          String playerName;
          if (pathParts.length >= 2) {
            playerName = pathParts.first;
          }

          // Fetch last change and some metainformation of the file
          http.Response response = await http.get(
              "https://api.github.com/repos/" +
                  repository +
                  "/commits?path=" +
                  completePath);

          if (response.statusCode != 200) {
            syncErrors.add('Could not load the warband metadata from GitHub.');
            continue;
          }

          // No valid response from GitHub
          dynamic commits;
          try {
            commits = jsonDecode(response.body);
          } on FormatException catch (e) {
            syncErrors.add('Could not parse GitHub response.' + e.toString());
            continue;
          }

          // No commits available
          if (commits.length == 0) {
            continue;
          }

          dynamic latestCommit = commits.first;
          yield {
            'filePath': completePath.toString(),
            'shaHash': latestCommit['sha'],
            'player': playerName.toString(),
            'author': latestCommit['commit']['author']['name'],
            'date': latestCommit['commit']['committer']['date'],
            'message': latestCommit['commit']['message']
          };
        }
      }
    }

    List<WarbandRoaster> roasters = new List<WarbandRoaster>();
    // TODO: Read params from share preferences
    await for (Map<String, String> player in roasterStream()) {
      http.Response response = await http.get(
          "https://raw.githubusercontent.com/" +
              repository +
              '/master/' +
              player['filePath']);

      try {
        YamlMap yamlObject = loadYaml(response.body);
        WarbandRoaster roaster = WarbandRoaster.fromJson(yamlObject);
        if (player['player'] != '') {
          roaster.playerName = player['player'];
        }

        roaster.currentVersion = new Version(player['shaHash'], player['date'],
            player['author'], player['message']);

        // On a search, we drop all previous information about the warbands,
        // Sp, lastSyncVersion is equal to the currentVersion.
        roaster.lastSyncVersion = roaster.currentVersion;

        roasters.add(roaster);
      } catch (e) {
        syncErrors.add(e.toString());
      }
    }

    return roasters;
  }

  Future<SyncState> update() async {
    // TODO: Search for warband yml files
    // TODO: Check if it is in the right format
    // TODO: Store it into the database if valid
    lastSync = DateTime.now();

    return SyncState.success;
  }
}