import 'package:comunic/enums/post_target.dart';
import 'package:comunic/helpers/posts_helper.dart';
import 'package:comunic/models/advanced_group_info.dart';
import 'package:comunic/ui/routes/main_route/main_route.dart';
import 'package:comunic/ui/screens/group_members_screen.dart';
import 'package:comunic/ui/screens/group_settings_screen.dart';
import 'package:comunic/ui/widgets/group_following_widget.dart';
import 'package:comunic/ui/widgets/group_icon_widget.dart';
import 'package:comunic/ui/widgets/group_membership_widget.dart';
import 'package:comunic/ui/widgets/like_widget.dart';
import 'package:comunic/ui/widgets/post_create_form_widget.dart';
import 'package:comunic/ui/widgets/posts_list_widget.dart';
import 'package:comunic/ui/widgets/scroll_watcher.dart';
import 'package:comunic/utils/intl_utils.dart';
import 'package:flutter/material.dart';

/// Authorized group page screen
///
/// This screen is shown when the user is allowed to access to a group's page
///
/// @author Pierre Hubert

enum _MenuItems { OPEN_MEMBERS, OPEN_SETTINGS }

class AuthorizedGroupPageScreen extends StatefulWidget {
  final AdvancedGroupInfo advancedGroupInfo;
  final Function() needRefresh;

  const AuthorizedGroupPageScreen({
    Key key,
    @required this.advancedGroupInfo,
    @required this.needRefresh,
  })  : assert(advancedGroupInfo != null),
        assert(needRefresh != null),
        super(key: key);

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

class _AuthorizedGroupPageScreenState extends State<AuthorizedGroupPageScreen> {
  AdvancedGroupInfo get _group => widget.advancedGroupInfo;

  // Allows load older posts when we reach the bottom of the page
  final _postsKey = GlobalKey<PostsListWidgetState>();
  ScrollWatcher _postsController;

  @override
  void initState() {
    _postsController = ScrollWatcher(
        onReachBottom: () => _postsKey.currentState.reachedPostsBottom());
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return RefreshIndicator(
      onRefresh: () => widget.needRefresh(),
      child: ListView(
        physics: AlwaysScrollableScrollPhysics(),
        controller: _postsController,
        children: <Widget>[
          _buildGroupPageHeader(),
          _buildPostCreationArea(),
          _buildGroupPagePostsList()
        ],
      ),
    );
  }

  /// Build group page header
  Widget _buildGroupPageHeader() {
    return Container(
      color: Colors.black26,
      child: Padding(
        padding: const EdgeInsets.all(8.0),
        child: Row(
          children: <Widget>[
            GroupIcon(
              group: _group,
            ),
            Text(
              " ${_group.displayName}",
              style: TextStyle(fontSize: 20),
            ),
            Spacer(),
            Column(
              children: <Widget>[
                GroupMembershipWidget(
                  group: _group,
                  onUpdated: () => widget.needRefresh(),
                ),
                Container(
                  height: 4,
                ),
                GroupFollowingWidget(
                  group: _group,
                  onUpdated: () => widget.needRefresh(),
                ),
                Container(
                  height: 2,
                ),
                LikeWidget(
                  likeElement: _group,
                ),
              ],
            ),
            PopupMenuButton<_MenuItems>(
              itemBuilder: (c) => [
                PopupMenuItem(
                  child: Text(tr("Group members")),
                  value: _MenuItems.OPEN_MEMBERS,
                  enabled: _group.isAtLeastModerator,
                ),
                PopupMenuItem(
                  child: Text(tr("Group settings")),
                  value: _MenuItems.OPEN_SETTINGS,
                  enabled: _group.isAdmin,
                ),
              ],
              onSelected: _handleMenuSelection,
            ),
          ],
        ),
      ),
    );
  }

  /// Add create post target
  Widget _buildPostCreationArea() {
    if (!_group.canCreatePost) return Container();

    return PostCreateFormWidget(
        postTarget: PostTarget.GROUP_PAGE,
        targetID: _group.id,
        onCreated: () => _postsKey.currentState.loadPostsList(getOlder: false));
  }

  /// Build the list of posts of the group
  Widget _buildGroupPagePostsList() {
    return PostsListWidget(
      key: _postsKey,
      getPostsList: () => PostsHelper().getGroupPosts(_group.id),
      showPostsTarget: false,
      userNamesClickable: true,
      getOlder: (from) => PostsHelper().getGroupPosts(_group.id, from: from),
      buildListView: false,
    );
  }

  /// Handles menu selection
  void _handleMenuSelection(_MenuItems item) {
    switch (item) {
      case _MenuItems.OPEN_MEMBERS:
        MainController.of(context).push(GroupMembersScreen(groupID: _group.id));
        break;

      case _MenuItems.OPEN_SETTINGS:
        MainController.of(context)
            .push(GroupSettingsScreen(groupID: _group.id));
        break;
    }
  }
}