downkyi/DownKyi/ViewModels/Friends/ViewFollowingViewModel.cs

using DownKyi.Core.BiliApi.Users;
using DownKyi.Core.BiliApi.Users.Models;
using DownKyi.Core.Settings;
using DownKyi.Core.Settings.Models;
using DownKyi.Core.Storage;
using DownKyi.CustomControl;
using DownKyi.Utils;
using DownKyi.ViewModels.PageViewModels;
using Prism.Commands;
using Prism.Events;
using Prism.Regions;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Media.Imaging;

namespace DownKyi.ViewModels.Friends
{
    public class ViewFollowingViewModel : BaseViewModel
    {
        public const string Tag = "PageFriendsFollowing";

        // mid
        private long mid = -1;

        // 每页数量，暂时在此写死，以后在设置中增加选项
        private readonly int NumberInPage = 20;

        #region 页面属性申明

        private string pageName = ViewFriendsViewModel.Tag;
        public string PageName
        {
            get => pageName;
            set => SetProperty(ref pageName, value);
        }

        private Visibility contentVisibility;
        public Visibility ContentVisibility
        {
            get => contentVisibility;
            set => SetProperty(ref contentVisibility, value);
        }

        private Visibility innerContentVisibility;
        public Visibility InnerContentVisibility
        {
            get => innerContentVisibility;
            set => SetProperty(ref innerContentVisibility, value);
        }

        private GifImage loading;
        public GifImage Loading
        {
            get => loading;
            set => SetProperty(ref loading, value);
        }

        private Visibility loadingVisibility;
        public Visibility LoadingVisibility
        {
            get => loadingVisibility;
            set => SetProperty(ref loadingVisibility, value);
        }

        private Visibility noDataVisibility;
        public Visibility NoDataVisibility
        {
            get => noDataVisibility;
            set => SetProperty(ref noDataVisibility, value);
        }

        private GifImage contentLoading;
        public GifImage ContentLoading
        {
            get => contentLoading;
            set => SetProperty(ref contentLoading, value);
        }

        private Visibility contentLoadingVisibility;
        public Visibility ContentLoadingVisibility
        {
            get => contentLoadingVisibility;
            set => SetProperty(ref contentLoadingVisibility, value);
        }

        private Visibility contentNoDataVisibility;
        public Visibility ContentNoDataVisibility
        {
            get => contentNoDataVisibility;
            set => SetProperty(ref contentNoDataVisibility, value);
        }

        private ObservableCollection<TabHeader> tabHeaders;
        public ObservableCollection<TabHeader> TabHeaders
        {
            get => tabHeaders;
            set => SetProperty(ref tabHeaders, value);
        }

        private int selectTabId;
        public int SelectTabId
        {
            get => selectTabId;
            set => SetProperty(ref selectTabId, value);
        }

        private bool isEnabled = true;
        public bool IsEnabled
        {
            get => isEnabled;
            set => SetProperty(ref isEnabled, value);
        }

        private CustomPagerViewModel pager;
        public CustomPagerViewModel Pager
        {
            get => pager;
            set => SetProperty(ref pager, value);
        }

        private ObservableCollection<FriendInfo> contents;
        public ObservableCollection<FriendInfo> Contents
        {
            get => contents;
            set => SetProperty(ref contents, value);
        }

        #endregion

        public ViewFollowingViewModel(IEventAggregator eventAggregator) : base(eventAggregator)
        {
            #region 属性初始化

            // 初始化loading gif
            Loading = new GifImage(Properties.Resources.loading);
            Loading.StartAnimate();
            LoadingVisibility = Visibility.Collapsed;
            NoDataVisibility = Visibility.Collapsed;

            ContentLoading = new GifImage(Properties.Resources.loading);
            ContentLoading.StartAnimate();
            ContentLoadingVisibility = Visibility.Collapsed;
            ContentNoDataVisibility = Visibility.Collapsed;

            TabHeaders = new ObservableCollection<TabHeader>();
            Contents = new ObservableCollection<FriendInfo>();

            #endregion
        }

        #region 命令申明

        // 左侧tab点击事件
        private DelegateCommand<object> leftTabHeadersCommand;
        public DelegateCommand<object> LeftTabHeadersCommand => leftTabHeadersCommand ?? (leftTabHeadersCommand = new DelegateCommand<object>(ExecuteLeftTabHeadersCommand, CanExecuteLeftTabHeadersCommand));

        /// <summary>
        /// 左侧tab点击事件
        /// </summary>
        /// <param name="parameter"></param>
        private void ExecuteLeftTabHeadersCommand(object parameter)
        {
            if (!(parameter is TabHeader tabHeader)) { return; }

            // 页面选择
            Pager = new CustomPagerViewModel(1, (int)Math.Ceiling(double.Parse(tabHeader.SubTitle) / NumberInPage));
            Pager.CurrentChanged += OnCurrentChanged_Pager;
            Pager.CountChanged += OnCountChanged_Pager;
            Pager.Current = 1;
        }

        /// <summary>
        /// 左侧tab点击事件是否允许执行
        /// </summary>
        /// <param name="parameter"></param>
        /// <returns></returns>
        private bool CanExecuteLeftTabHeadersCommand(object parameter)
        {
            return IsEnabled;
        }

        #endregion

        /// <summary>
        /// 初始化页面数据
        /// </summary>
        private void InitView()
        {
            ContentVisibility = Visibility.Collapsed;
            InnerContentVisibility = Visibility.Collapsed;
            LoadingVisibility = Visibility.Visible;
            NoDataVisibility = Visibility.Collapsed;
            ContentLoadingVisibility = Visibility.Collapsed;
            ContentNoDataVisibility = Visibility.Collapsed;

            TabHeaders.Clear();
            Contents.Clear();
            SelectTabId = -1;
        }

        /// <summary>
        /// 初始化左侧列表
        /// </summary>
        private async void InitLeftTable()
        {
            TabHeaders.Clear();

            UserInfoSettings userInfo = SettingsManager.GetInstance().GetUserInfo();
            if (userInfo != null && userInfo.Mid == mid)
            {
                // 用户的关系状态数
                UserRelationStat relationStat = null;
                await Task.Run(() =>
                {
                    relationStat = UserStatus.GetUserRelationStat(mid);
                });
                if (relationStat != null)
                {
                    TabHeaders.Add(new TabHeader { Id = -1, Title = DictionaryResource.GetString("AllFollowing"), SubTitle = relationStat.Following.ToString() });
                    TabHeaders.Add(new TabHeader { Id = -2, Title = DictionaryResource.GetString("WhisperFollowing"), SubTitle = relationStat.Whisper.ToString() });
                }

                // 用户的关注分组
                List<FollowingGroup> followingGroup = null;
                await Task.Run(() =>
                {
                    followingGroup = UserRelation.GetFollowingGroup();
                });
                if (followingGroup != null)
                {
                    foreach (FollowingGroup tag in followingGroup)
                    {
                        TabHeaders.Add(new TabHeader { Id = tag.TagId, Title = tag.Name, SubTitle = tag.Count.ToString() });
                    }
                }
            }
            else
            {
                // 用户的关系状态数
                UserRelationStat relationStat = null;
                await Task.Run(() =>
                {
                    relationStat = UserStatus.GetUserRelationStat(mid);
                });
                if (relationStat != null)
                {
                    TabHeaders.Add(new TabHeader { Id = -1, Title = DictionaryResource.GetString("AllFollowing"), SubTitle = relationStat.Following.ToString() });
                }
            }

            ContentVisibility = Visibility.Visible;
            LoadingVisibility = Visibility.Collapsed;
        }

        private void LoadContent(List<RelationFollowInfo> contents)
        {
            InnerContentVisibility = Visibility.Visible;
            ContentLoadingVisibility = Visibility.Collapsed;
            ContentNoDataVisibility = Visibility.Collapsed;
            foreach (var item in contents)
            {
                StorageHeader storageHeader = new StorageHeader();
                BitmapImage header = storageHeader.GetHeaderThumbnail(item.Mid, item.Name, item.Face, 64, 64);
                App.PropertyChangeAsync(new Action(() =>
                {
                    Contents.Add(new FriendInfo(eventAggregator) { Mid = item.Mid, Header = header, Name = item.Name, Sign = item.Sign });
                }));
            }
        }

        private async Task<bool> LoadAllFollowings(int pn, int ps)
        {
            List<RelationFollowInfo> contents = null;
            await Task.Run(() =>
            {
                RelationFollow data = UserRelation.GetFollowings(mid, pn, ps);
                if (data != null && data.List != null && data.List.Count > 0)
                {
                    contents = data.List;
                }
                if (contents == null) { return; }

                LoadContent(contents);
            });

            if (contents == null) { return false; }
            return true;
        }

        private async Task<bool> LoadWhispers(int pn, int ps)
        {
            List<RelationFollowInfo> contents = null;
            await Task.Run(() =>
            {
                contents = UserRelation.GetWhispers(pn, ps);
                if (contents == null) { return; }

                LoadContent(contents);
            });

            if (contents == null) { return false; }
            return true;
        }

        private async Task<bool> LoadFollowingGroupContent(int tagId, int pn, int ps)
        {
            List<RelationFollowInfo> contents = null;
            await Task.Run(() =>
            {
                contents = UserRelation.GetFollowingGroupContent(tagId, pn, ps);
                if (contents == null) { return; }

                LoadContent(contents);
            });

            if (contents == null) { return false; }
            return true;
        }

        private async void UpdateContent(int current)
        {
            // 是否正在获取数据
            // 在所有的退出分支中都需要设为true
            IsEnabled = false;

            Contents.Clear();
            InnerContentVisibility = Visibility.Collapsed;
            ContentLoadingVisibility = Visibility.Visible;
            ContentNoDataVisibility = Visibility.Collapsed;

            TabHeader tab = TabHeaders[SelectTabId];

            bool isSucceed;
            switch (tab.Id)
            {
                case -1:
                    isSucceed = await LoadAllFollowings(current, NumberInPage);
                    break;
                case -2:
                    isSucceed = await LoadWhispers(current, NumberInPage);
                    break;
                default:
                    isSucceed = await LoadFollowingGroupContent(tab.Id, current, NumberInPage);
                    break;
            }

            if (isSucceed)
            {
                InnerContentVisibility = Visibility.Visible;
                ContentLoadingVisibility = Visibility.Collapsed;
                ContentNoDataVisibility = Visibility.Collapsed;
            }
            else
            {
                InnerContentVisibility = Visibility.Collapsed;
                ContentLoadingVisibility = Visibility.Collapsed;
                ContentNoDataVisibility = Visibility.Visible;
            }

            IsEnabled = true;
        }

        private void OnCountChanged_Pager(int count) { }

        private bool OnCurrentChanged_Pager(int old, int current)
        {
            if (!IsEnabled)
            {
                //Pager.Current = old;
                return false;
            }

            UpdateContent(current);

            return true;
        }

        /// <summary>
        /// 导航到页面时执行
        /// </summary>
        /// <param name="navigationContext"></param>
        public override void OnNavigatedTo(NavigationContext navigationContext)
        {
            base.OnNavigatedTo(navigationContext);

            // 传入mid
            long parameter = navigationContext.Parameters.GetValue<long>("mid");
            if (parameter == 0)
            {
                return;
            }
            mid = parameter;

            // 是否是从PageFriends的headerTable的item点击进入的
            // true表示加载PageFriends后第一次进入此页面
            // false表示从headerTable的item点击进入的
            bool isFirst = navigationContext.Parameters.GetValue<bool>("isFirst");
            if (isFirst)
            {
                InitView();

                // 初始化左侧列表
                InitLeftTable();

                // 进入页面时显示的设置项
                SelectTabId = 0;

            }
        }

    }
}