#nullable disable

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using MediaBrowser.Controller.Entities;
using MediaBrowser.Controller.Entities.Audio;
using MediaBrowser.Controller.Library;
using MediaBrowser.Controller.LiveTv;
using MediaBrowser.Controller.Providers;
using MediaBrowser.Model.Configuration;
using MediaBrowser.Model.Drawing;
using MediaBrowser.Model.Entities;
using MediaBrowser.Model.IO;
using MediaBrowser.Model.MediaInfo;
using MediaBrowser.Model.Net;
using MediaBrowser.Model.Providers;
using Microsoft.Extensions.Logging;

namespace MediaBrowser.Providers.Manager
{
    /// <summary>
    /// Utilities for managing images attached to items.
    /// </summary>
    public class ItemImageProvider
    {
        private readonly ILogger _logger;
        private readonly IProviderManager _providerManager;
        private readonly IFileSystem _fileSystem;

        /// <summary>
        /// Image types that are only one per item.
        /// </summary>
        private static readonly ImageType[] _singularImages =
        {
            ImageType.Primary,
            ImageType.Art,
            ImageType.Banner,
            ImageType.Box,
            ImageType.BoxRear,
            ImageType.Disc,
            ImageType.Logo,
            ImageType.Menu,
            ImageType.Thumb
        };

        /// <summary>
        /// Initializes a new instance of the <see cref="ItemImageProvider"/> class.
        /// </summary>
        /// <param name="logger">The logger.</param>
        /// <param name="providerManager">The provider manager for interacting with provider image references.</param>
        /// <param name="fileSystem">The filesystem.</param>
        public ItemImageProvider(ILogger logger, IProviderManager providerManager, IFileSystem fileSystem)
        {
            _logger = logger;
            _providerManager = providerManager;
            _fileSystem = fileSystem;
        }

        /// <summary>
        /// Removes all existing images from the provided item.
        /// </summary>
        /// <param name="item">The <see cref="BaseItem"/> to remove images from.</param>
        /// <returns><c>true</c> if changes were made to the item; otherwise <c>false</c>.</returns>
        public bool RemoveImages(BaseItem item)
        {
            var singular = new List<ItemImageInfo>();
            for (var i = 0; i < _singularImages.Length; i++)
            {
                var currentImage = item.GetImageInfo(_singularImages[i], 0);
                if (currentImage != null)
                {
                    singular.Add(currentImage);
                }
            }

            singular.AddRange(item.GetImages(ImageType.Backdrop));
            PruneImages(item, singular);

            return singular.Count > 0;
        }

        /// <summary>
        /// Verifies existing images have valid paths and adds any new local images provided.
        /// </summary>
        /// <param name="item">The <see cref="BaseItem"/> to validate images for.</param>
        /// <param name="providers">The providers to use, must include <see cref="ILocalImageProvider"/>(s) for local scanning.</param>
        /// <param name="directoryService">The directory service for <see cref="ILocalImageProvider"/>s to use.</param>
        /// <returns><c>true</c> if changes were made to the item; otherwise <c>false</c>.</returns>
        public bool ValidateImages(BaseItem item, IEnumerable<IImageProvider> providers, IDirectoryService directoryService)
        {
            var hasChanges = false;

            if (item is not Photo)
            {
                var images = providers.OfType<ILocalImageProvider>()
                    .SelectMany(i => i.GetImages(item, directoryService))
                    .ToList();

                if (MergeImages(item, images))
                {
                    hasChanges = true;
                }
            }

            return hasChanges;
        }

        /// <summary>
        /// Refreshes from the providers according to the given options.
        /// </summary>
        /// <param name="item">The <see cref="BaseItem"/> to gather images for.</param>
        /// <param name="libraryOptions">The library options.</param>
        /// <param name="providers">The providers to query for images.</param>
        /// <param name="refreshOptions">The refresh options.</param>
        /// <param name="cancellationToken">The cancellation token.</param>
        /// <returns>The refresh result.</returns>
        public async Task<RefreshResult> RefreshImages(
            BaseItem item,
            LibraryOptions libraryOptions,
            IEnumerable<IImageProvider> providers,
            ImageRefreshOptions refreshOptions,
            CancellationToken cancellationToken)
        {
            var oldBackdropImages = Array.Empty<ItemImageInfo>();
            if (refreshOptions.IsReplacingImage(ImageType.Backdrop))
            {
                oldBackdropImages = item.GetImages(ImageType.Backdrop).ToArray();
            }

            var result = new RefreshResult { UpdateType = ItemUpdateType.None };

            var typeName = item.GetType().Name;
            var typeOptions = libraryOptions.GetTypeOptions(typeName) ?? new TypeOptions { Type = typeName };

            // track library limits, adding buffer to allow lazy replacing of current images
            var backdropLimit = typeOptions.GetLimit(ImageType.Backdrop) + oldBackdropImages.Length;
            var downloadedImages = new List<ImageType>();

            foreach (var provider in providers)
            {
                if (provider is IRemoteImageProvider remoteProvider)
                {
                    await RefreshFromProvider(item, remoteProvider, refreshOptions, typeOptions, backdropLimit, downloadedImages, result, cancellationToken).ConfigureAwait(false);
                    continue;
                }

                if (provider is IDynamicImageProvider dynamicImageProvider)
                {
                    await RefreshFromProvider(item, dynamicImageProvider, refreshOptions, typeOptions, downloadedImages, result, cancellationToken).ConfigureAwait(false);
                }
            }

            // only delete existing multi-images if new ones were added
            if (oldBackdropImages.Length > 0 && oldBackdropImages.Length < item.GetImages(ImageType.Backdrop).Count())
            {
                PruneImages(item, oldBackdropImages);
            }

            return result;
        }

        /// <summary>
        /// Refreshes from a dynamic provider.
        /// </summary>
        private async Task RefreshFromProvider(
            BaseItem item,
            IDynamicImageProvider provider,
            ImageRefreshOptions refreshOptions,
            TypeOptions savedOptions,
            ICollection<ImageType> downloadedImages,
            RefreshResult result,
            CancellationToken cancellationToken)
        {
            try
            {
                var images = provider.GetSupportedImages(item);

                foreach (var imageType in images)
                {
                    if (!savedOptions.IsEnabled(imageType))
                    {
                        continue;
                    }

                    if (!item.HasImage(imageType) || (refreshOptions.IsReplacingImage(imageType) && !downloadedImages.Contains(imageType)))
                    {
                        _logger.LogDebug("Running {Provider} for {Item}", provider.GetType().Name, item.Path ?? item.Name);

                        var response = await provider.GetImage(item, imageType, cancellationToken).ConfigureAwait(false);

                        if (response.HasImage)
                        {
                            if (string.IsNullOrEmpty(response.Path))
                            {
                                var mimeType = response.Format.GetMimeType();

                                await _providerManager.SaveImage(item, response.Stream, mimeType, imageType, null, cancellationToken).ConfigureAwait(false);
                            }
                            else
                            {
                                if (response.Protocol == MediaProtocol.Http)
                                {
                                    _logger.LogDebug("Setting image url into item {Item}", item.Id);
                                    var index = item.AllowsMultipleImages(imageType) ? item.GetImages(imageType).Count() : 0;
                                    item.SetImage(
                                        new ItemImageInfo
                                        {
                                            Path = response.Path,
                                            Type = imageType
                                        },
                                        index);
                                }
                                else
                                {
                                    var mimeType = MimeTypes.GetMimeType(response.Path);

                                    var stream = AsyncFile.OpenRead(response.Path);

                                    await _providerManager.SaveImage(item, stream, mimeType, imageType, null, cancellationToken).ConfigureAwait(false);
                                }
                            }

                            downloadedImages.Add(imageType);
                            result.UpdateType |= ItemUpdateType.ImageUpdate;
                        }
                    }
                }
            }
            catch (OperationCanceledException)
            {
                throw;
            }
            catch (Exception ex)
            {
                result.ErrorMessage = ex.Message;
                _logger.LogError(ex, "Error in {Provider}", provider.Name);
            }
        }

        /// <summary>
        /// Refreshes from a remote provider.
        /// </summary>
        /// <param name="item">The item.</param>
        /// <param name="provider">The provider.</param>
        /// <param name="refreshOptions">The refresh options.</param>
        /// <param name="savedOptions">The saved options.</param>
        /// <param name="backdropLimit">The backdrop limit.</param>
        /// <param name="downloadedImages">The downloaded images.</param>
        /// <param name="result">The result.</param>
        /// <param name="cancellationToken">The cancellation token.</param>
        /// <returns>Task.</returns>
        private async Task RefreshFromProvider(
            BaseItem item,
            IRemoteImageProvider provider,
            ImageRefreshOptions refreshOptions,
            TypeOptions savedOptions,
            int backdropLimit,
            ICollection<ImageType> downloadedImages,
            RefreshResult result,
            CancellationToken cancellationToken)
        {
            try
            {
                if (!item.SupportsRemoteImageDownloading)
                {
                    return;
                }

                if (!refreshOptions.ReplaceAllImages &&
                    refreshOptions.ReplaceImages.Length == 0 &&
                    ContainsImages(item, provider.GetSupportedImages(item).ToList(), savedOptions, backdropLimit))
                {
                    return;
                }

                _logger.LogDebug("Running {Provider} for {Item}", provider.GetType().Name, item.Path ?? item.Name);

                var images = await _providerManager.GetAvailableRemoteImages(
                    item,
                    new RemoteImageQuery(provider.Name)
                    {
                        IncludeAllLanguages = true,
                        IncludeDisabledProviders = false,
                    },
                    cancellationToken).ConfigureAwait(false);

                var list = images.ToList();
                int minWidth;

                foreach (var imageType in _singularImages)
                {
                    if (!savedOptions.IsEnabled(imageType))
                    {
                        continue;
                    }

                    if (!item.HasImage(imageType) || (refreshOptions.IsReplacingImage(imageType) && !downloadedImages.Contains(imageType)))
                    {
                        minWidth = savedOptions.GetMinWidth(imageType);
                        var downloaded = await DownloadImage(item, provider, result, list, minWidth, imageType, cancellationToken).ConfigureAwait(false);

                        if (downloaded)
                        {
                            downloadedImages.Add(imageType);
                        }
                    }
                }

                minWidth = savedOptions.GetMinWidth(ImageType.Backdrop);
                await DownloadMultiImages(item, ImageType.Backdrop, refreshOptions, backdropLimit, provider, result, list, minWidth, cancellationToken).ConfigureAwait(false);
            }
            catch (OperationCanceledException)
            {
                throw;
            }
            catch (Exception ex)
            {
                result.ErrorMessage = ex.Message;
                _logger.LogError(ex, "Error in {Provider}", provider.Name);
            }
        }

        /// <summary>
        /// Determines if an item already contains the given images.
        /// </summary>
        /// <param name="item">The item.</param>
        /// <param name="images">The images.</param>
        /// <param name="savedOptions">The saved options.</param>
        /// <param name="backdropLimit">The backdrop limit.</param>
        /// <returns><c>true</c> if the specified item contains images; otherwise, <c>false</c>.</returns>
        private bool ContainsImages(BaseItem item, List<ImageType> images, TypeOptions savedOptions, int backdropLimit)
        {
            // Using .Any causes the creation of a DisplayClass aka. variable capture
            for (var i = 0; i < _singularImages.Length; i++)
            {
                var type = _singularImages[i];
                if (images.Contains(type) && !item.HasImage(type) && savedOptions.GetLimit(type) > 0)
                {
                    return false;
                }
            }

            if (images.Contains(ImageType.Backdrop) && item.GetImages(ImageType.Backdrop).Count() < backdropLimit)
            {
                return false;
            }

            return true;
        }

        private void PruneImages(BaseItem item, IReadOnlyList<ItemImageInfo> images)
        {
            for (var i = 0; i < images.Count; i++)
            {
                var image = images[i];

                if (image.IsLocalFile)
                {
                    try
                    {
                        _fileSystem.DeleteFile(image.Path);
                    }
                    catch (FileNotFoundException)
                    {
                        // nothing to do, already gone
                    }
                    catch (UnauthorizedAccessException ex)
                    {
                        _logger.LogWarning(ex, "Unable to delete {Image}", image.Path);
                    }
                }
            }

            item.RemoveImages(images);
        }

        /// <summary>
        /// Merges a list of images into the provided item, validating existing images and replacing them or adding new images as necessary.
        /// </summary>
        /// <param name="item">The <see cref="BaseItem"/> to modify.</param>
        /// <param name="images">The new images to place in <c>item</c>.</param>
        /// <returns><c>true</c> if changes were made to the item; otherwise <c>false</c>.</returns>
        public bool MergeImages(BaseItem item, IReadOnlyList<LocalImageInfo> images)
        {
            var changed = item.ValidateImages();

            for (var i = 0; i < _singularImages.Length; i++)
            {
                var type = _singularImages[i];
                var image = GetFirstLocalImageInfoByType(images, type);

                if (image != null)
                {
                    var currentImage = item.GetImageInfo(type, 0);

                    if (currentImage is null || !string.Equals(currentImage.Path, image.FileInfo.FullName, StringComparison.OrdinalIgnoreCase))
                    {
                        item.SetImagePath(type, image.FileInfo);
                        changed = true;
                    }
                    else
                    {
                        var newDateModified = _fileSystem.GetLastWriteTimeUtc(image.FileInfo);

                        // If date changed then we need to reset saved image dimensions
                        if (currentImage.DateModified != newDateModified && (currentImage.Width > 0 || currentImage.Height > 0))
                        {
                            currentImage.Width = 0;
                            currentImage.Height = 0;
                            changed = true;
                        }

                        currentImage.DateModified = newDateModified;
                    }
                }
            }

            if (UpdateMultiImages(item, images, ImageType.Backdrop))
            {
                changed = true;
            }

            return changed;
        }

        private static LocalImageInfo GetFirstLocalImageInfoByType(IReadOnlyList<LocalImageInfo> images, ImageType type)
        {
            var len = images.Count;
            for (var i = 0; i < len; i++)
            {
                var image = images[i];
                if (image.Type == type)
                {
                    return image;
                }
            }

            return null;
        }

        private bool UpdateMultiImages(BaseItem item, IReadOnlyList<LocalImageInfo> images, ImageType type)
        {
            var changed = false;

            var newImageFileInfos = images
                .Where(i => i.Type == type)
                .Select(i => i.FileInfo)
                .ToList();

            if (item.AddImages(type, newImageFileInfos))
            {
                changed = true;
            }

            return changed;
        }

        private async Task<bool> DownloadImage(
            BaseItem item,
            IRemoteImageProvider provider,
            RefreshResult result,
            IEnumerable<RemoteImageInfo> images,
            int minWidth,
            ImageType type,
            CancellationToken cancellationToken)
        {
            var eligibleImages = images
                .Where(i => i.Type == type && (i.Width is null || i.Width >= minWidth))
                .ToList();

            if (EnableImageStub(item) && eligibleImages.Count > 0)
            {
                SaveImageStub(item, type, eligibleImages.Select(i => i.Url));
                result.UpdateType |= ItemUpdateType.ImageUpdate;
                return true;
            }

            foreach (var image in eligibleImages)
            {
                var url = image.Url;

                try
                {
                    using var response = await provider.GetImageResponse(url, cancellationToken).ConfigureAwait(false);

                    // Sometimes providers send back bad urls. Just move to the next image
                    if (response.StatusCode == HttpStatusCode.NotFound || response.StatusCode == HttpStatusCode.Forbidden)
                    {
                        _logger.LogDebug("{Url} returned {StatusCode}, ignoring", url, response.StatusCode);
                        continue;
                    }

                    if (!response.IsSuccessStatusCode)
                    {
                        _logger.LogWarning("{Url} returned {StatusCode}, skipping all remaining requests", url, response.StatusCode);
                        break;
                    }

                    await using var stream = await response.Content.ReadAsStreamAsync(cancellationToken).ConfigureAwait(false);

                    await _providerManager.SaveImage(
                        item,
                        stream,
                        response.Content.Headers.ContentType?.MediaType,
                        type,
                        null,
                        cancellationToken).ConfigureAwait(false);

                    result.UpdateType |= ItemUpdateType.ImageUpdate;
                    return true;
                }
                catch (HttpRequestException)
                {
                    break;
                }
            }

            return false;
        }

        private bool EnableImageStub(BaseItem item)
        {
            if (item is LiveTvProgram)
            {
                return true;
            }

            if (!item.IsFileProtocol)
            {
                return true;
            }

            if (item is IItemByName and not MusicArtist)
            {
                var hasDualAccess = item as IHasDualAccess;
                if (hasDualAccess is null || hasDualAccess.IsAccessedByName)
                {
                    return true;
                }
            }

            // We always want to use prefetched images
            return false;
        }

        private void SaveImageStub(BaseItem item, ImageType imageType, IEnumerable<string> urls)
        {
            var newIndex = item.AllowsMultipleImages(imageType) ? item.GetImages(imageType).Count() : 0;

            SaveImageStub(item, imageType, urls, newIndex);
        }

        private void SaveImageStub(BaseItem item, ImageType imageType, IEnumerable<string> urls, int newIndex)
        {
            var path = string.Join('|', urls.Take(1));

            item.SetImage(
                new ItemImageInfo
                {
                    Path = path,
                    Type = imageType
                },
                newIndex);
        }

        private async Task DownloadMultiImages(BaseItem item, ImageType imageType, ImageRefreshOptions refreshOptions, int limit, IRemoteImageProvider provider, RefreshResult result, IEnumerable<RemoteImageInfo> images, int minWidth, CancellationToken cancellationToken)
        {
            foreach (var image in images.Where(i => i.Type == imageType))
            {
                if (item.GetImages(imageType).Count() >= limit)
                {
                    break;
                }

                if (image.Width.HasValue && image.Width.Value < minWidth)
                {
                    continue;
                }

                var url = image.Url;

                if (EnableImageStub(item))
                {
                    SaveImageStub(item, imageType, new[] { url });
                    result.UpdateType |= ItemUpdateType.ImageUpdate;
                    continue;
                }

                try
                {
                    using var response = await provider.GetImageResponse(url, cancellationToken).ConfigureAwait(false);

                    // Sometimes providers send back bad urls. Just move to the next image
                    if (response.StatusCode == HttpStatusCode.NotFound || response.StatusCode == HttpStatusCode.Forbidden)
                    {
                        _logger.LogDebug("{Url} returned {StatusCode}, ignoring", url, response.StatusCode);
                        continue;
                    }

                    if (!response.IsSuccessStatusCode)
                    {
                        _logger.LogWarning("{Url} returned {StatusCode}, skipping all remaining requests", url, response.StatusCode);
                        break;
                    }

                    // If there's already an image of the same file size, skip it unless doing a full refresh
                    if (response.Content.Headers.ContentLength.HasValue && !refreshOptions.IsReplacingImage(imageType))
                    {
                        try
                        {
                            if (item.GetImages(imageType).Any(i => _fileSystem.GetFileInfo(i.Path).Length == response.Content.Headers.ContentLength.Value))
                            {
                                response.Content.Dispose();
                                continue;
                            }
                        }
                        catch (IOException ex)
                        {
                            _logger.LogError(ex, "Error examining images");
                        }
                    }

                    await using var stream = await response.Content.ReadAsStreamAsync(cancellationToken).ConfigureAwait(false);
                    await _providerManager.SaveImage(
                        item,
                        stream,
                        response.Content.Headers.ContentType?.MediaType,
                        imageType,
                        null,
                        cancellationToken).ConfigureAwait(false);
                    result.UpdateType |= ItemUpdateType.ImageUpdate;
                }
                catch (HttpRequestException)
                {
                    break;
                }
            }
        }
    }
}