using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Avalonia.Media.Imaging;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using CRD.Downloader;
using CRD.Downloader.Crunchyroll;
using CRD.Utils;
using CRD.Utils.Files;
using CRD.Utils.Structs;
using CRD.Utils.Structs.Crunchyroll;

namespace CRD.ViewModels;

public partial class DownloadsPageViewModel : ViewModelBase{
    public ObservableCollection<DownloadItemModel> Items{ get; }

    [ObservableProperty]
    private bool shutdownWhenQueueEmpty;

    [ObservableProperty]
    private bool autoDownload;

    [ObservableProperty]
    private bool removeFinished;

    [ObservableProperty]
    private QueueManager queueManagerIns;

    public DownloadsPageViewModel(){
        QueueManagerIns = QueueManager.Instance;
        QueueManagerIns.UpdateDownloadListItems();
        Items = QueueManagerIns.DownloadItemModels;
        AutoDownload = CrunchyrollManager.Instance.CrunOptions.AutoDownload;
        RemoveFinished = CrunchyrollManager.Instance.CrunOptions.RemoveFinishedDownload;
        ShutdownWhenQueueEmpty = CrunchyrollManager.Instance.CrunOptions.ShutdownWhenQueueEmpty;
    }


    partial void OnAutoDownloadChanged(bool value){
        CrunchyrollManager.Instance.CrunOptions.AutoDownload = value;
        if (value){
            QueueManagerIns.UpdateDownloadListItems();
        }

        CfgManager.WriteCrSettings();
    }

    partial void OnRemoveFinishedChanged(bool value){
        CrunchyrollManager.Instance.CrunOptions.RemoveFinishedDownload = value;
        CfgManager.WriteCrSettings();
    }

    partial void OnShutdownWhenQueueEmptyChanged(bool value){
        CrunchyrollManager.Instance.CrunOptions.ShutdownWhenQueueEmpty = value;
        CfgManager.WriteCrSettings();
    }

    [RelayCommand]
    public void ClearQueue(){
        var items = QueueManagerIns.Queue;
        QueueManagerIns.ClearQueue();

        foreach (var crunchyEpMeta in items){
            if (!crunchyEpMeta.DownloadProgress.IsDone){
                foreach (var downloadItemDownloadedFile in crunchyEpMeta.downloadedFiles){
                    try{
                        if (File.Exists(downloadItemDownloadedFile)){
                            File.Delete(downloadItemDownloadedFile);
                        }
                    } catch (Exception){
                        // ignored
                    }
                }
            }
        }
    }

    [RelayCommand]
    public void RetryQueue(){
        var items = QueueManagerIns.Queue;

        foreach (var crunchyEpMeta in items){
            if (crunchyEpMeta.DownloadProgress.IsError){
                crunchyEpMeta.DownloadProgress.ResetForRetry();
            }
        }

        QueueManagerIns.UpdateDownloadListItems();
    }
    
    [RelayCommand]
    public void PauseQueue(){
        AutoDownload = false;
        foreach (var item in Items){
            if (item.epMeta.DownloadProgress.State is DownloadState.Downloading or DownloadState.Processing){
                item.ToggleIsDownloading();
            }
        }

        QueueManagerIns.UpdateDownloadListItems();
    }
    
}

public partial class DownloadItemModel : INotifyPropertyChanged{
    public string ImageUrl{ get; set; }
    public Bitmap? ImageBitmap{ get; set; }
    public string Title{ get; set; }

    public bool isDownloading{ get; set; }
    public bool Done{ get; set; }
    public bool Paused{ get; set; }

    public double Percent{ get; set; }
    public string Time{ get; set; }
    public string DoingWhat{ get; set; }
    public string DownloadSpeed{ get; set; }
    public string InfoText{ get; set; }
    public string InfoTextHover{ get; set; }
    public CrunchyEpMeta epMeta{ get; set; }


    public bool Error{ get; set; }
    public bool ShowPauseIcon{ get; set; }

    public DownloadItemModel(CrunchyEpMeta epMetaF){
        epMeta = epMetaF;

        ImageUrl = epMeta.Image ?? string.Empty;
        Title = epMeta.SeriesTitle + (!string.IsNullOrEmpty(epMeta.Season) ? " - S" + epMeta.Season + "E" + (epMeta.EpisodeNumber != string.Empty ? epMeta.EpisodeNumber : epMeta.AbsolutEpisodeNumberE) : "") + " - " +
                epMeta.EpisodeTitle;

        Done = epMeta.DownloadProgress.IsDone;
        isDownloading = epMeta.DownloadProgress.State is DownloadState.Downloading or DownloadState.Processing;
        ShowPauseIcon = isDownloading;
        Percent = epMeta.DownloadProgress.Percent;
        Time = "Estimated Time: " + TimeSpan.FromSeconds(epMeta.DownloadProgress.Time).ToString(@"hh\:mm\:ss");
        DownloadSpeed = CrunchyrollManager.Instance.CrunOptions.DownloadSpeedInBits
            ? $"{epMeta.DownloadProgress.DownloadSpeedBytes * 8 / 1000000.0:F2} Mb/s"
            : $"{epMeta.DownloadProgress.DownloadSpeedBytes / 1000000.0:F2} MB/s";

        ;
        Paused = epMeta.DownloadProgress.IsPaused;
        DoingWhat = Paused ? "Paused" :
            Done ? (epMeta.DownloadProgress.Doing != string.Empty ? epMeta.DownloadProgress.Doing : "Done") :
            epMeta.DownloadProgress.Doing != string.Empty ? epMeta.DownloadProgress.Doing : "Waiting";

        InfoText = JoinWithSeparator(
            GetDubString(),
            GetSubtitleString(),
            epMeta.Resolution
        );
        InfoTextHover = epMeta.AvailableQualities;

        Error = epMeta.DownloadProgress.IsError;
    }

    string JoinWithSeparator(params string[] parts){
        return string.Join(" - ", parts.Where(part => !string.IsNullOrEmpty(part)));
    }

    private string GetDubString(){
        if (epMeta.SelectedDubs == null || epMeta.SelectedDubs.Count < 1){
            return "";
        }

        return epMeta.SelectedDubs.Aggregate("Dub: ", (current, crunOptionsDlDub) => current + (crunOptionsDlDub + " "));
    }

    private string GetSubtitleString(){
        var hardSubs = epMeta.Hslang != "none" ? "Hardsub: " : "";
        if (hardSubs != string.Empty){
            var locale = Languages.Locale2language(epMeta.Hslang).CrLocale;
            if (epMeta.AvailableSubs != null && epMeta.AvailableSubs.Contains(locale)){
                hardSubs += locale + " ";
            }

            return hardSubs;
        }

        if (epMeta.DownloadSubs.Count < 1){
            return "";
        }

        var softSubs = "Softsub: ";

        if (epMeta.DownloadSubs.Contains("all")){
            if (epMeta.AvailableSubs != null){
                return epMeta.AvailableSubs.Aggregate(softSubs, (current, epMetaAvailableSub) => current + (epMetaAvailableSub + " "));
            }
        }

        foreach (var crunOptionsDlSub in epMeta.DownloadSubs){
            if (epMeta.AvailableSubs != null && epMeta.AvailableSubs.Contains(crunOptionsDlSub)){
                softSubs += crunOptionsDlSub + " ";
            }
        }

        return softSubs;
    }

    public void Refresh(){
        Done = epMeta.DownloadProgress.IsDone;
        isDownloading = epMeta.DownloadProgress.State is DownloadState.Downloading or DownloadState.Processing;
        ShowPauseIcon = isDownloading;
        Percent = epMeta.DownloadProgress.Percent;
        Time = "Estimated Time: " + TimeSpan.FromSeconds(epMeta.DownloadProgress.Time).ToString(@"hh\:mm\:ss");
        DownloadSpeed = CrunchyrollManager.Instance.CrunOptions.DownloadSpeedInBits
            ? $"{epMeta.DownloadProgress.DownloadSpeedBytes * 8 / 1000000.0:F2} Mb/s"
            : $"{epMeta.DownloadProgress.DownloadSpeedBytes / 1000000.0:F2} MB/s";

        Paused = epMeta.DownloadProgress.IsPaused;
        DoingWhat = Paused ? "Paused" :
            Done ? (epMeta.DownloadProgress.Doing != string.Empty ? epMeta.DownloadProgress.Doing : "Done") :
            epMeta.DownloadProgress.Doing != string.Empty ? epMeta.DownloadProgress.Doing : "Waiting";

        InfoText = JoinWithSeparator(
            GetDubString(),
            GetSubtitleString(),
            epMeta.Resolution
        );
        InfoTextHover = epMeta.AvailableQualities;
        Error = epMeta.DownloadProgress.IsError;


        if (PropertyChanged != null){
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(isDownloading)));
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(ShowPauseIcon)));
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Percent)));
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Time)));
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(DownloadSpeed)));
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(DoingWhat)));
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Error)));
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(InfoText)));
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(InfoTextHover)));
        }
    }


    public event PropertyChangedEventHandler? PropertyChanged;

    [RelayCommand]
    public void ToggleIsDownloading(){
        if (epMeta.DownloadProgress.State is DownloadState.Downloading or DownloadState.Processing){
            epMeta.DownloadProgress.ResumeState = epMeta.DownloadProgress.State;
            epMeta.DownloadProgress.State = DownloadState.Paused;
            isDownloading = false;
            Paused = true;
            ShowPauseIcon = false;

            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(isDownloading)));
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Paused)));
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(ShowPauseIcon)));

            QueueManager.Instance.ReleaseDownloadSlot(epMeta);
            QueueManager.Instance.RefreshQueue();
            return;
        }

        if (epMeta.DownloadProgress.IsPaused){
            if (!QueueManager.Instance.TryResumeDownload(epMeta))
                return;

            epMeta.DownloadProgress.State = epMeta.DownloadProgress.ResumeState;
            isDownloading = epMeta.DownloadProgress.State is DownloadState.Downloading or DownloadState.Processing;
            Paused = false;
            ShowPauseIcon = isDownloading;

            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(isDownloading)));
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Paused)));
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(ShowPauseIcon)));
            return;
        }

        StartDownload();
    }
    
    [RelayCommand]
    public void RetryDownload(){
        epMeta.DownloadProgress.ResetForRetry();
        isDownloading = false;
        Paused = false;
        ShowPauseIcon = false;

        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Paused)));
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(isDownloading)));
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(ShowPauseIcon)));
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Error)));
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Percent)));
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Time)));
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(DownloadSpeed)));
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(DoingWhat)));

        QueueManager.Instance.RefreshQueue();
        StartDownload();
    }

    public Task StartDownload(){
        QueueManager.Instance.TryStartDownload(this);
        return Task.CompletedTask;
    }

    internal async Task StartDownloadCore(){
        if (isDownloading)
            return;

        epMeta.RenewCancellationToken();
        isDownloading = true;
        epMeta.DownloadProgress.State = DownloadState.Downloading;
        Paused = false;
        ShowPauseIcon = true;

        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(isDownloading)));
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Paused)));
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(ShowPauseIcon)));

        CrDownloadOptions? newOptions = Helpers.DeepCopy(CrunchyrollManager.Instance.CrunOptions);

        if (epMeta.OnlySubs){
            newOptions?.Novids = true;
            newOptions?.Noaudio = true;
        }

        await CrunchyrollManager.Instance.DownloadEpisode(
            epMeta,
            epMeta.DownloadSettings ?? newOptions ?? CrunchyrollManager.Instance.CrunOptions);
    }

    [RelayCommand]
    public void RemoveFromQueue(){
        CrunchyEpMeta? downloadItem = QueueManager.Instance.Queue.FirstOrDefault(e => e.Equals(epMeta)) ?? null;
        if (downloadItem != null){
            QueueManager.Instance.RemoveFromQueue(downloadItem);
            epMeta.CancelDownload();
            if (!Done){
                foreach (var downloadItemDownloadedFile in downloadItem.downloadedFiles){
                    try{
                        if (File.Exists(downloadItemDownloadedFile)){
                            File.Delete(downloadItemDownloadedFile);
                        }
                    } catch (Exception){
                        // ignored
                    }
                }
            }
        }
    }

    public async Task LoadImage(){
        ImageBitmap = await Helpers.LoadImage(ImageUrl, 208, 117);
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(ImageBitmap)));
    }
}