import 'package:comunic/helpers/posts_helper.dart';
import 'package:comunic/helpers/users_helper.dart';
import 'package:comunic/models/advanced_user_info.dart';
import 'package:comunic/ui/widgets/network_image_widget.dart';
import 'package:comunic/ui/widgets/posts_list_widget.dart';
import 'package:comunic/utils/intl_utils.dart';
import 'package:comunic/utils/ui_utils.dart';
import 'package:flutter/material.dart';

/// User page route
///
/// @author Pierre HUBERT

enum _PageStatus { LOADING, ERROR, READY }

class UserPageRoute extends StatefulWidget {
  final int userID;

  const UserPageRoute({Key key, @required this.userID})
      : assert(userID != null),
        super(key: key);

  @override
  _UserPageRouteState createState() => _UserPageRouteState();
}

class _UserPageRouteState extends State<UserPageRoute> {
  // Helpers
  final usersHelper = UsersHelper();
  final PostsHelper _postsHelper = PostsHelper();

  // Objects members
  final double _appBarHeight = 256.0;
  _PageStatus _status = _PageStatus.LOADING;
  AdvancedUserInfo _userInfo;

  _setStatus(_PageStatus s) => setState(() => _status = s);

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    _getUserInfo();
  }

  Future<void> _getUserInfo() async {
    _setStatus(_PageStatus.LOADING);

    try {
      final user = await usersHelper.getAdvancedInfo(widget.userID);

      setState(() {
        _userInfo = user;
      });

      _setStatus(_PageStatus.READY);
    } on GetUserAdvancedUserError {
      _setStatus(_PageStatus.ERROR);
    }
  }

  @override
  Widget build(BuildContext context) {
    if (_status == _PageStatus.LOADING) return buildLoadingPage();

    if (_status == _PageStatus.ERROR) return _buildError();

    return Scaffold(
      body: CustomScrollView(
        slivers: <Widget>[_buildHeader(), _buildBody()],
      ),
    );
  }

  /// Error card
  Widget _buildError() {
    return Scaffold(
      appBar: AppBar(
        title: Text(tr("Error")),
      ),
      body: Center(
          child:
              buildErrorCard(tr("Could not get user information!"), actions: [
        FlatButton(
          onPressed: _getUserInfo,
          child: Text(
            tr("Retry").toUpperCase(),
            style: TextStyle(color: Colors.white),
          ),
        )
      ])),
    );
  }

  Widget _buildHeader() {
    return SliverAppBar(
      expandedHeight: _appBarHeight,
      floating: false,
      pinned: true,
      snap: false,
      flexibleSpace: FlexibleSpaceBar(
        title: Text(_userInfo.displayName),
        background: Stack(
          fit: StackFit.expand,
          children: <Widget>[
            NetworkImageWidget(
              url: _userInfo.accountImageURL,
              height: _appBarHeight,
            ),
            // This gradient ensures that the toolbar icons are distinct
            // against the background image.
            const DecoratedBox(
              decoration: BoxDecoration(
                gradient: LinearGradient(
                  begin: Alignment(0.0, -1.0),
                  end: Alignment(0.0, -0.4),
                  colors: <Color>[Color(0x60000000), Color(0x00000000)],
                ),
              ),
            ),

            const DecoratedBox(
              decoration: BoxDecoration(
                gradient: LinearGradient(
                  begin: Alignment(0.0, 0.4),
                  end: Alignment(0.0, 0.9),
                  colors: <Color>[Color(0x00000000), Color(0x60000000)],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildBody() {
    return SliverList(
      delegate: SliverChildListDelegate(
        <Widget>[
          PostsListWidget(
            getPostsList: () => _postsHelper.getUserPosts(widget.userID),
            showPostsTarget: false,
            buildListView: false,
          ),
        ],
      ),
    );
  }
}