// Copyright (c) Microsoft Corporation
// The Microsoft Corporation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System;
using System.Globalization;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using CommunityToolkit.Mvvm.ComponentModel;
using Microsoft.PowerToys.Telemetry;
using Microsoft.UI.Xaml;
using Microsoft.UI.Xaml.Controls;
using Microsoft.UI.Xaml.Input;
using Microsoft.Web.WebView2.Core;
using Peek.Common.Extensions;
using Peek.Common.Helpers;
using Peek.Common.Models;
using Peek.FilePreviewer.Models;
using Peek.FilePreviewer.Previewers;
using Peek.FilePreviewer.Previewers.Interfaces;
using Peek.UI.Telemetry.Events;
using Windows.ApplicationModel.Resources;

namespace Peek.FilePreviewer
{
    [INotifyPropertyChanged]
    public sealed partial class FilePreview : UserControl, IDisposable
    {
        private readonly PreviewerFactory previewerFactory = new();

        public event EventHandler<PreviewSizeChangedArgs>? PreviewSizeChanged;

        public static readonly DependencyProperty ItemProperty =
        DependencyProperty.Register(
            nameof(Item),
            typeof(IFileSystemItem),
            typeof(FilePreview),
            new PropertyMetadata(false, async (d, e) => await ((FilePreview)d).OnItemPropertyChanged()));

        public static readonly DependencyProperty ScalingFactorProperty =
            DependencyProperty.Register(
                nameof(ScalingFactor),
                typeof(double),
                typeof(FilePreview),
                new PropertyMetadata(false, async (d, e) => await ((FilePreview)d).OnScalingFactorPropertyChanged()));

        [ObservableProperty]
        [NotifyPropertyChangedFor(nameof(ImagePreviewer))]
        [NotifyPropertyChangedFor(nameof(VideoPreviewer))]
        [NotifyPropertyChangedFor(nameof(BrowserPreviewer))]
        [NotifyPropertyChangedFor(nameof(UnsupportedFilePreviewer))]

        private IPreviewer? previewer;

        [ObservableProperty]
        private string imageInfoTooltip = ResourceLoader.GetForViewIndependentUse().GetString("PreviewTooltip_Blank");

        private CancellationTokenSource _cancellationTokenSource = new();

        public FilePreview()
        {
            InitializeComponent();
        }

        public void Dispose()
        {
            _cancellationTokenSource.Dispose();
        }

        private async void Previewer_PropertyChanged(object? sender, System.ComponentModel.PropertyChangedEventArgs e)
        {
            // Fallback on DefaultPreviewer if we fail to load the correct Preview
            if (e.PropertyName == nameof(IPreviewer.State))
            {
                if (Previewer?.State == PreviewState.Error)
                {
                    // Cancel previous loading task
                    _cancellationTokenSource.Cancel();
                    _cancellationTokenSource = new();

                    if (Previewer is not IUnsupportedFilePreviewer)
                    {
                        Previewer = previewerFactory.CreateDefaultPreviewer(Item);
                        await UpdatePreviewAsync(_cancellationTokenSource.Token);
                    }
                }
            }
        }

        public IImagePreviewer? ImagePreviewer => Previewer as IImagePreviewer;

        public IVideoPreviewer? VideoPreviewer => Previewer as IVideoPreviewer;

        public IBrowserPreviewer? BrowserPreviewer => Previewer as IBrowserPreviewer;

        public IUnsupportedFilePreviewer? UnsupportedFilePreviewer => Previewer as IUnsupportedFilePreviewer;

        public IFileSystemItem Item
        {
            get => (IFileSystemItem)GetValue(ItemProperty);
            set => SetValue(ItemProperty, value);
        }

        public double ScalingFactor
        {
            get => (double)GetValue(ScalingFactorProperty);
            set
            {
                SetValue(ScalingFactorProperty, value);

                if (Previewer is IImagePreviewer imagePreviewer)
                {
                    imagePreviewer.ScalingFactor = ScalingFactor;
                }
            }
        }

        public bool MatchPreviewState(PreviewState? value, PreviewState stateToMatch)
        {
            return value == stateToMatch;
        }

        public Visibility IsPreviewVisible(IPreviewer? previewer, PreviewState? state)
        {
            var isValidPreview = previewer != null && MatchPreviewState(state, PreviewState.Loaded);
            return isValidPreview ? Visibility.Visible : Visibility.Collapsed;
        }

        public Visibility IsUnsupportedPreviewVisible(IUnsupportedFilePreviewer? previewer, PreviewState state)
        {
            var isValidPreview = previewer != null && (MatchPreviewState(state, PreviewState.Loaded) || MatchPreviewState(state, PreviewState.Error));
            return isValidPreview ? Visibility.Visible : Visibility.Collapsed;
        }

        private async Task OnItemPropertyChanged()
        {
            // Cancel previous loading task
            _cancellationTokenSource.Cancel();
            _cancellationTokenSource = new();

            if (Item == null)
            {
                Previewer = null;
                ImagePreview.Visibility = Visibility.Collapsed;
                VideoPreview.Visibility = Visibility.Collapsed;
                BrowserPreview.Visibility = Visibility.Collapsed;
                UnsupportedFilePreview.Visibility = Visibility.Collapsed;
                return;
            }

            Previewer = previewerFactory.Create(Item);
            if (Previewer is IImagePreviewer imagePreviewer)
            {
                imagePreviewer.ScalingFactor = ScalingFactor;
            }

            await UpdatePreviewAsync(_cancellationTokenSource.Token);
        }

        private async Task OnScalingFactorPropertyChanged()
        {
            await UpdatePreviewSizeAsync(_cancellationTokenSource.Token);
        }

        private async Task UpdatePreviewSizeAsync(CancellationToken cancellationToken)
        {
            if (Previewer != null)
            {
                var previewSize = await Previewer.GetPreviewSizeAsync(cancellationToken);
                PreviewSizeChanged?.Invoke(this, new PreviewSizeChangedArgs(previewSize));
            }
        }

        private async Task UpdatePreviewAsync(CancellationToken cancellationToken)
        {
            if (Previewer != null)
            {
                try
                {
                    cancellationToken.ThrowIfCancellationRequested();
                    await UpdatePreviewSizeAsync(cancellationToken);

                    cancellationToken.ThrowIfCancellationRequested();
                    await Previewer.LoadPreviewAsync(cancellationToken);

                    cancellationToken.ThrowIfCancellationRequested();
                    await UpdateImageTooltipAsync(cancellationToken);
                }
                catch (OperationCanceledException)
                {
                    // TODO: Log task cancelled exception?
                }
                catch (Exception ex)
                {
                    // Fall back to Default previewer
                    PowerToysTelemetry.Log.WriteEvent(new ErrorEvent() { HResult = (Common.Models.HResult)ex.HResult, Message = ex.Message, Failure = ErrorEvent.FailureType.PreviewFail });
                    Logger.LogError("Error in UpdatePreviewAsync, falling back to default previewer: " + ex.Message);
                    Previewer.State = PreviewState.Error;
                }
            }
        }

        partial void OnPreviewerChanging(IPreviewer? value)
        {
            VideoPreview.MediaPlayer.Pause();
            VideoPreview.Source = null;

            ImagePreview.Source = null;
            BrowserPreview.Source = null;

            if (Previewer != null)
            {
                Previewer.PropertyChanged -= Previewer_PropertyChanged;
            }

            if (value != null)
            {
                value.PropertyChanged += Previewer_PropertyChanged;
            }
        }

        private void BrowserPreview_DOMContentLoaded(Microsoft.Web.WebView2.Core.CoreWebView2 sender, Microsoft.Web.WebView2.Core.CoreWebView2DOMContentLoadedEventArgs args)
        {
            /*
             * There is an odd behavior where the WebView2 would not raise the NavigationCompleted event
             * for certain HTML files, even though it has already been loaded. Probably related to certain
             * extra module that require more time to load. One example is saving and opening google.com locally.
             *
             * So to address this, we will make the Browser visible and display it as "Loaded" as soon the HTML document
             * has been parsed and loaded with the DOMContentLoaded event.
             *
             * Similar issue: https://github.com/MicrosoftEdge/WebView2Feedback/issues/998
             */
            if (BrowserPreviewer != null)
            {
                BrowserPreviewer.State = PreviewState.Loaded;
            }
        }

        private void PreviewBrowser_NavigationCompleted(WebView2 sender, CoreWebView2NavigationCompletedEventArgs args)
        {
            /*
             * In theory most of navigation should work after DOM is loaded.
             * But in case something fails we check NavigationCompleted event
             * for failure and switch visibility accordingly.
             *
             * As an alternative, in the future, the preview Browser control
             * could also display error content.
             */
            if (!args.IsSuccess)
            {
                if (BrowserPreviewer != null)
                {
                    BrowserPreviewer.State = PreviewState.Error;
                }
            }
        }

        private async void KeyboardAccelerator_CtrlC_Invoked(KeyboardAccelerator sender, KeyboardAcceleratorInvokedEventArgs args)
        {
            if (Previewer != null)
            {
                await Previewer.CopyAsync();
            }
        }

        private async Task UpdateImageTooltipAsync(CancellationToken cancellationToken)
        {
            if (Item == null)
            {
                return;
            }

            // Fetch and format available file properties
            var sb = new StringBuilder();

            string fileNameFormatted = ReadableStringHelper.FormatResourceString("PreviewTooltip_FileName", Item.Name);
            sb.Append(fileNameFormatted);

            cancellationToken.ThrowIfCancellationRequested();
            string fileType = await Task.Run(Item.GetContentTypeAsync);
            string fileTypeFormatted = string.IsNullOrEmpty(fileType) ? string.Empty : "\n" + ReadableStringHelper.FormatResourceString("PreviewTooltip_FileType", fileType);
            sb.Append(fileTypeFormatted);

            string dateModified = Item.DateModified?.ToString(CultureInfo.CurrentCulture) ?? string.Empty;
            string dateModifiedFormatted = string.IsNullOrEmpty(dateModified) ? string.Empty : "\n" + ReadableStringHelper.FormatResourceString("PreviewTooltip_DateModified", dateModified);
            sb.Append(dateModifiedFormatted);

            cancellationToken.ThrowIfCancellationRequested();
            ulong bytes = await Task.Run(Item.GetSizeInBytes);
            string fileSize = ReadableStringHelper.BytesToReadableString(bytes);
            string fileSizeFormatted = string.IsNullOrEmpty(fileSize) ? string.Empty : "\n" + ReadableStringHelper.FormatResourceString("PreviewTooltip_FileSize", fileSize);
            sb.Append(fileSizeFormatted);

            ImageInfoTooltip = sb.ToString();
        }
    }
}