import 'dart:io';
import 'dart:convert';
import 'dart:async';
import 'package:http/http.dart' as http;
import 'package:uni_links/uni_links.dart';
import 'package:nanoid/nanoid.dart';
import 'package:url_launcher/url_launcher.dart';
// import 'package:flutter/services.dart';
import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';
import 'package:shared_preferences/shared_preferences.dart';
// import '../utils/utils.dart';
import '../utils/constants.dart';
import '../utils/utils.dart';
import 'account.dart';

class PlatformType {
  static const github = 'github';
  static const gitlab = 'gitlab';
}

class AuthModel with ChangeNotifier {
  static const _apiPrefix = 'https://api.github.com';

  List<Account> _accounts;
  int activeAccountIndex;
  StreamSubscription<Uri> _sub;
  bool loading = false;

  List<Account> get accounts => _accounts;
  bool get ready => _accounts != null;
  Account get activeAccount {
    if (activeAccountIndex == null || _accounts == null) return null;
    return _accounts[activeAccountIndex];
  }

  String get token => activeAccount.token;

  _addAccount(Account account) async {
    // Remove previous if duplicated
    List<Account> newAccounts = [];
    for (var a in _accounts) {
      if (!account.equals(a)) {
        newAccounts.add(a);
      }
    }
    newAccounts.add(account);

    _accounts = newAccounts;

    // Save
    final prefs = await SharedPreferences.getInstance();
    await prefs.setString(StorageKeys.accounts, json.encode(_accounts));
  }

  // https://developer.github.com/apps/building-oauth-apps/authorizing-oauth-apps/#web-application-flow
  Future<void> _onSchemeDetected(Uri uri) async {
    await closeWebView();

    loading = true;
    notifyListeners();

    // Get token by code
    final res = await http.post(
      'https://github.com/login/oauth/access_token',
      headers: {
        HttpHeaders.acceptHeader: 'application/json',
        HttpHeaders.contentTypeHeader: 'application/json',
      },
      body: json.encode({
        'client_id': clientId,
        'client_secret': clientSecret,
        'code': uri.queryParameters['code'],
        'state': _oauthState,
      }),
    );
    final token = json.decode(res.body)['access_token'] as String;
    await loginWithToken(token);
  }

  Future<void> loginWithToken(String token) async {
    // Get login and avatar url
    final queryData = await query('''
{
  viewer {
    login
    avatarUrl
  }
}
''', token);

    await _addAccount(Account(
      platform: PlatformType.github,
      domain: 'https://github.com',
      token: token,
      login: queryData['viewer']['login'] as String,
      avatarUrl: queryData['viewer']['avatarUrl'] as String,
    ));

    loading = false;
    notifyListeners();
  }

  Future<void> loginToGitlab(String domain, String token) async {
    try {
      loading = true;
      notifyListeners();

      final res = await http
          .get('$domain/api/v4/user', headers: {'Private-Token': token});
      final info = json.decode(res.body);

      if (info['message'] != null) {
        throw info['message'];
      }

      await _addAccount(Account(
        platform: PlatformType.gitlab,
        domain: domain,
        token: token,
        login: info['username'] as String,
        avatarUrl: info['avatar_url'] as String,
      ));
    } catch (err) {
      print(err);
      // TODO: show errors
    } finally {
      loading = false;
      notifyListeners();
    }
  }

  void init() async {
    // Listen scheme
    _sub = getUriLinksStream().listen(_onSchemeDetected, onError: (err) {
      print(err);
    });

    var prefs = await SharedPreferences.getInstance();

    // Read accounts
    try {
      String str = prefs.getString(StorageKeys.accounts);
      print('read accounts: $str');
      _accounts = (json.decode(str ?? '[]') as List)
          .map((item) => Account.fromJson(item))
          .toList();
    } catch (err) {
      print(err);
      _accounts = [];
    }

    notifyListeners();
  }

  @override
  void dispose() {
    _sub.cancel();
    super.dispose();
  }

  void setActiveAccountIndex(int index) {
    activeAccountIndex = index;
    notifyListeners();
  }

  Map<String, String> get _headers =>
      {HttpHeaders.authorizationHeader: 'token $token'};

  // http timeout
  var _timeoutDuration = Duration(seconds: 10);
  // var _timeoutDuration = Duration(seconds: 1);

  Future<dynamic> query(String query, [String _token]) async {
    if (_token == null) {
      _token = token;
    }
    if (_token == null) {
      throw 'token is null';
    }

    final res = await http
        .post(_apiPrefix + '/graphql',
            headers: {
              HttpHeaders.authorizationHeader: 'token $_token',
              HttpHeaders.contentTypeHeader: 'application/json'
            },
            body: json.encode({'query': query}))
        .timeout(_timeoutDuration);

    // print(res.body);
    final data = json.decode(res.body);

    if (data['errors'] != null) {
      throw data['errors'][0]['message'];
    }

    return data['data'];
  }

  Future<dynamic> getWithCredentials(String url, {String contentType}) async {
    var headers = _headers;
    if (contentType != null) {
      // https://developer.github.com/v3/repos/contents/#custom-media-types
      headers[HttpHeaders.contentTypeHeader] = contentType;
    }
    final res = await http
        .get(_apiPrefix + url, headers: headers)
        .timeout(_timeoutDuration);
    // print(res.body);
    final data = json.decode(res.body);
    return data;
  }

  Future<void> patchWithCredentials(String url) async {
    await http
        .patch(_apiPrefix + url, headers: _headers)
        .timeout(_timeoutDuration);
  }

  Future<http.Response> putWithCredentials(
    String url, {
    String contentType = 'application/json',
    Map<String, dynamic> body = const {},
  }) async {
    return http
        .put(
          _apiPrefix + url,
          headers: {..._headers, HttpHeaders.contentTypeHeader: contentType},
          body: json.encode(body),
        )
        .timeout(_timeoutDuration);
  }

  Future<http.Response> postWithCredentials(
    String url, {
    String contentType = 'application/json',
    Map<String, dynamic> body = const {},
  }) async {
    return http
        .post(
          _apiPrefix + url,
          headers: {..._headers, HttpHeaders.contentTypeHeader: contentType},
          body: json.encode(body),
        )
        .timeout(_timeoutDuration);
  }

  Future<void> deleteWithCredentials(String url) async {
    await http
        .delete(_apiPrefix + url, headers: _headers)
        .timeout(_timeoutDuration);
  }

  String _oauthState;
  void redirectToGithubOauth() {
    _oauthState = nanoid();
    var scope = Uri.encodeComponent('user,repo,read:org');
    launchUrl(
      'https://github.com/login/oauth/authorize?client_id=$clientId&redirect_uri=gittouch://login&scope=$scope&state=$_oauthState',
    );
  }
}