import 'dart:collection';
import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:preferences/preferences.dart';
import 'package:localstorage/localstorage.dart';
import 'package:yaml/yaml.dart';
import 'package:toolheim/data/warband_roster.dart';

class GitHubAdapter extends ChangeNotifier {
  final LocalStorage storage = new LocalStorage('rosters');

  List<String> _syncErrors = new List<String>();
  DateTime _lastSync;

  List<WarbandRoster> _rosters = [];
  String _activePlayerName;

  String get repository => PrefService.getString('repository');
  String get path => PrefService.getString('path');

  bool _syncinProgress = false;
  bool get isSyncInProgress => _syncinProgress;

  DateTime get lastSync => _lastSync;
  List<String> get syncErrors => _syncErrors;

  UnmodifiableListView<WarbandRoster> get rosters =>
      UnmodifiableListView(_rosters);

  WarbandRoster activeRoster() {
    if (_activePlayerName == null || _rosters.length == 0) {
      return null;
    }

    return _rosters.firstWhere((roster) {
      return roster.playerName == _activePlayerName;
    }, orElse: () => null);
  }

  void changeActiveRoster(String playerName) {
    _activePlayerName = playerName;
    notifyListeners();
  }

  // TODO: Add persistence layer here

  /// 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.
  void search() async {
    _syncErrors.clear();
    _syncinProgress = true;

    Stream<Map<String, String>> rosterStream() 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 roster 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']
          };
        }
      }
    }

    _rosters.clear();
    notifyListeners();

    if (_syncErrors.length == 0) {
      await for (Map<String, String> player in rosterStream()) {
        http.Response response;
        try {
          response = await http.get("https://raw.githubusercontent.com/" +
              repository +
              '/master/' +
              player['filePath']);
        } catch (e) {
          // TODO: Ignore this error, we catch it elsewhere.
        }

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

            roster.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.
            roster.lastSyncVersion = roster.currentVersion;

            _rosters.add(roster);
            //https://github.com/lesnitsky/flutter_localstorage/blob/master/example/lib/main.dart
            // FIXME: store it correctly
            //storage.setItem(player['player'], roster);
            notifyListeners();
          }
        } catch (e) {
          _syncErrors.add(e.toString());
        }
      }
    }

    // Sort by CP
    _rosters.sort((a, b) => b.campaignPoints.compareTo(a.campaignPoints));

    // Select first as active player if no active player is selected
    if (_rosters.length > 0) {
      _activePlayerName = _rosters.first.playerName;
    }

    _lastSync = DateTime.now();
    _syncinProgress = false;
    storage.setItem('lastSync', _lastSync.toIso8601String());
    notifyListeners();
  }

  void update() async {
    _syncinProgress = true;
    // 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();
    _syncinProgress = false;
    notifyListeners();
  }
}