using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using MediaBrowser.Common.Extensions;
using MediaBrowser.Controller;
using MediaBrowser.Controller.Drawing;
using MediaBrowser.Controller.Entities;
using MediaBrowser.Controller.MediaEncoding;
using MediaBrowser.Model.Drawing;
using MediaBrowser.Model.Entities;
using MediaBrowser.Model.IO;
using MediaBrowser.Model.Net;
using Microsoft.Extensions.Logging;

namespace Emby.Drawing
{
    /// <summary>
    /// Class ImageProcessor.
    /// </summary>
    public sealed class ImageProcessor : IImageProcessor, IDisposable
    {
        // Increment this when there's a change requiring caches to be invalidated
        private const string Version = "3";

        private static readonly HashSet<string> _transparentImageTypes
            = new HashSet<string>(StringComparer.OrdinalIgnoreCase) { ".png", ".webp", ".gif" };

        private readonly ILogger _logger;
        private readonly IFileSystem _fileSystem;
        private readonly IServerApplicationPaths _appPaths;
        private readonly IImageEncoder _imageEncoder;
        private readonly IMediaEncoder _mediaEncoder;

        private bool _disposed = false;

        /// <summary>
        /// Initializes a new instance of the <see cref="ImageProcessor"/> class.
        /// </summary>
        /// <param name="logger">The logger.</param>
        /// <param name="appPaths">The server application paths.</param>
        /// <param name="fileSystem">The filesystem.</param>
        /// <param name="imageEncoder">The image encoder.</param>
        /// <param name="mediaEncoder">The media encoder.</param>
        public ImageProcessor(
            ILogger<ImageProcessor> logger,
            IServerApplicationPaths appPaths,
            IFileSystem fileSystem,
            IImageEncoder imageEncoder,
            IMediaEncoder mediaEncoder)
        {
            _logger = logger;
            _fileSystem = fileSystem;
            _imageEncoder = imageEncoder;
            _mediaEncoder = mediaEncoder;
            _appPaths = appPaths;
        }

        private string ResizedImageCachePath => Path.Combine(_appPaths.ImageCachePath, "resized-images");

        /// <inheritdoc />
        public IReadOnlyCollection<string> SupportedInputFormats =>
            new HashSet<string>(StringComparer.OrdinalIgnoreCase)
            {
                "tiff",
                "tif",
                "jpeg",
                "jpg",
                "png",
                "aiff",
                "cr2",
                "crw",
                "nef",
                "orf",
                "pef",
                "arw",
                "webp",
                "gif",
                "bmp",
                "erf",
                "raf",
                "rw2",
                "nrw",
                "dng",
                "ico",
                "astc",
                "ktx",
                "pkm",
                "wbmp"
            };

        /// <inheritdoc />
        public bool SupportsImageCollageCreation => _imageEncoder.SupportsImageCollageCreation;

        /// <inheritdoc />
        public async Task ProcessImage(ImageProcessingOptions options, Stream toStream)
        {
            var file = await ProcessImage(options).ConfigureAwait(false);

            using (var fileStream = new FileStream(file.Item1, FileMode.Open, FileAccess.Read, FileShare.Read, IODefaults.FileStreamBufferSize, true))
            {
                await fileStream.CopyToAsync(toStream).ConfigureAwait(false);
            }
        }

        /// <inheritdoc />
        public IReadOnlyCollection<ImageFormat> GetSupportedImageOutputFormats()
            => _imageEncoder.SupportedOutputFormats;

        /// <inheritdoc />
        public bool SupportsTransparency(string path)
            => _transparentImageTypes.Contains(Path.GetExtension(path));

        /// <inheritdoc />
        public async Task<(string path, string? mimeType, DateTime dateModified)> ProcessImage(ImageProcessingOptions options)
        {
            ItemImageInfo originalImage = options.Image;
            BaseItem item = options.Item;

            string originalImagePath = originalImage.Path;
            DateTime dateModified = originalImage.DateModified;
            ImageDimensions? originalImageSize = null;
            if (originalImage.Width > 0 && originalImage.Height > 0)
            {
                originalImageSize = new ImageDimensions(originalImage.Width, originalImage.Height);
            }

            if (!_imageEncoder.SupportsImageEncoding)
            {
                return (originalImagePath, MimeTypes.GetMimeType(originalImagePath), dateModified);
            }

            var supportedImageInfo = await GetSupportedImage(originalImagePath, dateModified).ConfigureAwait(false);
            originalImagePath = supportedImageInfo.path;

            if (!File.Exists(originalImagePath))
            {
                return (originalImagePath, MimeTypes.GetMimeType(originalImagePath), dateModified);
            }

            dateModified = supportedImageInfo.dateModified;
            bool requiresTransparency = _transparentImageTypes.Contains(Path.GetExtension(originalImagePath));

            bool autoOrient = false;
            ImageOrientation? orientation = null;
            if (item is Photo photo)
            {
                if (photo.Orientation.HasValue)
                {
                    if (photo.Orientation.Value != ImageOrientation.TopLeft)
                    {
                        autoOrient = true;
                        orientation = photo.Orientation;
                    }
                }
                else
                {
                    // Orientation unknown, so do it
                    autoOrient = true;
                    orientation = photo.Orientation;
                }
            }

            if (options.HasDefaultOptions(originalImagePath, originalImageSize) && (!autoOrient || !options.RequiresAutoOrientation))
            {
                // Just spit out the original file if all the options are default
                return (originalImagePath, MimeTypes.GetMimeType(originalImagePath), dateModified);
            }

            ImageDimensions newSize = ImageHelper.GetNewImageSize(options, null);
            int quality = options.Quality;

            ImageFormat outputFormat = GetOutputFormat(options.SupportedOutputFormats, requiresTransparency);
            string cacheFilePath = GetCacheFilePath(originalImagePath, newSize, quality, dateModified, outputFormat, options.AddPlayedIndicator, options.PercentPlayed, options.UnplayedCount, options.Blur, options.BackgroundColor, options.ForegroundLayer);

            try
            {
                if (!File.Exists(cacheFilePath))
                {
                    if (options.CropWhiteSpace && !SupportsTransparency(originalImagePath))
                    {
                        options.CropWhiteSpace = false;
                    }

                    string resultPath = _imageEncoder.EncodeImage(originalImagePath, dateModified, cacheFilePath, autoOrient, orientation, quality, options, outputFormat);

                    if (string.Equals(resultPath, originalImagePath, StringComparison.OrdinalIgnoreCase))
                    {
                        return (originalImagePath, MimeTypes.GetMimeType(originalImagePath), dateModified);
                    }
                }

                return (cacheFilePath, GetMimeType(outputFormat, cacheFilePath), _fileSystem.GetLastWriteTimeUtc(cacheFilePath));
            }
            catch (Exception ex)
            {
                // If it fails for whatever reason, return the original image
                _logger.LogError(ex, "Error encoding image");
                return (originalImagePath, MimeTypes.GetMimeType(originalImagePath), dateModified);
            }
        }

        private ImageFormat GetOutputFormat(IReadOnlyCollection<ImageFormat> clientSupportedFormats, bool requiresTransparency)
        {
            var serverFormats = GetSupportedImageOutputFormats();

            // Client doesn't care about format, so start with webp if supported
            if (serverFormats.Contains(ImageFormat.Webp) && clientSupportedFormats.Contains(ImageFormat.Webp))
            {
                return ImageFormat.Webp;
            }

            // If transparency is needed and webp isn't supported, than png is the only option
            if (requiresTransparency && clientSupportedFormats.Contains(ImageFormat.Png))
            {
                return ImageFormat.Png;
            }

            foreach (var format in clientSupportedFormats)
            {
                if (serverFormats.Contains(format))
                {
                    return format;
                }
            }

            // We should never actually get here
            return ImageFormat.Jpg;
        }

        private string? GetMimeType(ImageFormat format, string path)
            => format switch
            {
                ImageFormat.Bmp => MimeTypes.GetMimeType("i.bmp"),
                ImageFormat.Gif => MimeTypes.GetMimeType("i.gif"),
                ImageFormat.Jpg => MimeTypes.GetMimeType("i.jpg"),
                ImageFormat.Png => MimeTypes.GetMimeType("i.png"),
                ImageFormat.Webp => MimeTypes.GetMimeType("i.webp"),
                _ => MimeTypes.GetMimeType(path)
            };

        /// <summary>
        /// Gets the cache file path based on a set of parameters.
        /// </summary>
        private string GetCacheFilePath(string originalPath, ImageDimensions outputSize, int quality, DateTime dateModified, ImageFormat format, bool addPlayedIndicator, double percentPlayed, int? unwatchedCount, int? blur, string backgroundColor, string foregroundLayer)
        {
            var filename = originalPath
                + "width=" + outputSize.Width
                + "height=" + outputSize.Height
                + "quality=" + quality
                + "datemodified=" + dateModified.Ticks
                + "f=" + format;

            if (addPlayedIndicator)
            {
                filename += "pl=true";
            }

            if (percentPlayed > 0)
            {
                filename += "p=" + percentPlayed;
            }

            if (unwatchedCount.HasValue)
            {
                filename += "p=" + unwatchedCount.Value;
            }

            if (blur.HasValue)
            {
                filename += "blur=" + blur.Value;
            }

            if (!string.IsNullOrEmpty(backgroundColor))
            {
                filename += "b=" + backgroundColor;
            }

            if (!string.IsNullOrEmpty(foregroundLayer))
            {
                filename += "fl=" + foregroundLayer;
            }

            filename += "v=" + Version;

            return GetCachePath(ResizedImageCachePath, filename, "." + format.ToString().ToLowerInvariant());
        }

        /// <inheritdoc />
        public ImageDimensions GetImageDimensions(BaseItem item, ItemImageInfo info)
        {
            int width = info.Width;
            int height = info.Height;

            if (height > 0 && width > 0)
            {
                return new ImageDimensions(width, height);
            }

            string path = info.Path;
            _logger.LogDebug("Getting image size for item {ItemType} {Path}", item.GetType().Name, path);

            ImageDimensions size = GetImageDimensions(path);
            info.Width = size.Width;
            info.Height = size.Height;

            return size;
        }

        /// <inheritdoc />
        public ImageDimensions GetImageDimensions(string path)
            => _imageEncoder.GetImageSize(path);

        /// <inheritdoc />
        public string GetImageBlurHash(string path)
        {
            var size = GetImageDimensions(path);
            if (size.Width <= 0 || size.Height <= 0)
            {
                return string.Empty;
            }

            // We want tiles to be as close to square as possible, and to *mostly* keep under 16 tiles for performance.
            // One tile is (width / xComp) x (height / yComp) pixels, which means that ideally yComp = xComp * height / width.
            // See more at https://github.com/woltapp/blurhash/#how-do-i-pick-the-number-of-x-and-y-components
            float xCompF = MathF.Sqrt(16.0f * size.Width / size.Height);
            float yCompF = xCompF * size.Height / size.Width;

            int xComp = Math.Min((int)xCompF + 1, 9);
            int yComp = Math.Min((int)yCompF + 1, 9);

            return _imageEncoder.GetImageBlurHash(xComp, yComp, path);
        }

        /// <inheritdoc />
        public string GetImageCacheTag(BaseItem item, ItemImageInfo image)
            => (item.Path + image.DateModified.Ticks).GetMD5().ToString("N", CultureInfo.InvariantCulture);

        /// <inheritdoc />
        public string GetImageCacheTag(BaseItem item, ChapterInfo chapter)
        {
            return GetImageCacheTag(item, new ItemImageInfo
            {
                Path = chapter.ImagePath,
                Type = ImageType.Chapter,
                DateModified = chapter.ImageDateModified
            });
        }

        private async Task<(string path, DateTime dateModified)> GetSupportedImage(string originalImagePath, DateTime dateModified)
        {
            var inputFormat = Path.GetExtension(originalImagePath)
                .TrimStart('.')
                .Replace("jpeg", "jpg", StringComparison.OrdinalIgnoreCase);

            // These are just jpg files renamed as tbn
            if (string.Equals(inputFormat, "tbn", StringComparison.OrdinalIgnoreCase))
            {
                return (originalImagePath, dateModified);
            }

            if (!_imageEncoder.SupportedInputFormats.Contains(inputFormat))
            {
                try
                {
                    string filename = (originalImagePath + dateModified.Ticks.ToString(CultureInfo.InvariantCulture)).GetMD5().ToString("N", CultureInfo.InvariantCulture);

                    string cacheExtension = _mediaEncoder.SupportsEncoder("libwebp") ? ".webp" : ".png";
                    var outputPath = Path.Combine(_appPaths.ImageCachePath, "converted-images", filename + cacheExtension);

                    var file = _fileSystem.GetFileInfo(outputPath);
                    if (!file.Exists)
                    {
                        await _mediaEncoder.ConvertImage(originalImagePath, outputPath).ConfigureAwait(false);
                        dateModified = _fileSystem.GetLastWriteTimeUtc(outputPath);
                    }
                    else
                    {
                        dateModified = file.LastWriteTimeUtc;
                    }

                    originalImagePath = outputPath;
                }
                catch (Exception ex)
                {
                    _logger.LogError(ex, "Image conversion failed for {Path}", originalImagePath);
                }
            }

            return (originalImagePath, dateModified);
        }

        /// <summary>
        /// Gets the cache path.
        /// </summary>
        /// <param name="path">The path.</param>
        /// <param name="uniqueName">Name of the unique.</param>
        /// <param name="fileExtension">The file extension.</param>
        /// <returns>System.String.</returns>
        /// <exception cref="ArgumentNullException">
        /// path
        /// or
        /// uniqueName
        /// or
        /// fileExtension.
        /// </exception>
        public string GetCachePath(string path, string uniqueName, string fileExtension)
        {
            if (string.IsNullOrEmpty(path))
            {
                throw new ArgumentNullException(nameof(path));
            }

            if (string.IsNullOrEmpty(uniqueName))
            {
                throw new ArgumentNullException(nameof(uniqueName));
            }

            if (string.IsNullOrEmpty(fileExtension))
            {
                throw new ArgumentNullException(nameof(fileExtension));
            }

            var filename = uniqueName.GetMD5() + fileExtension;

            return GetCachePath(path, filename);
        }

        /// <summary>
        /// Gets the cache path.
        /// </summary>
        /// <param name="path">The path.</param>
        /// <param name="filename">The filename.</param>
        /// <returns>System.String.</returns>
        /// <exception cref="ArgumentNullException">
        /// path
        /// or
        /// filename.
        /// </exception>
        public string GetCachePath(string path, string filename)
        {
            if (string.IsNullOrEmpty(path))
            {
                throw new ArgumentNullException(nameof(path));
            }

            if (string.IsNullOrEmpty(filename))
            {
                throw new ArgumentNullException(nameof(filename));
            }

            var prefix = filename.Substring(0, 1);

            return Path.Combine(path, prefix, filename);
        }

        /// <inheritdoc />
        public void CreateImageCollage(ImageCollageOptions options)
        {
            _logger.LogInformation("Creating image collage and saving to {Path}", options.OutputPath);

            _imageEncoder.CreateImageCollage(options);

            _logger.LogInformation("Completed creation of image collage and saved to {Path}", options.OutputPath);
        }

        /// <inheritdoc />
        public void Dispose()
        {
            if (_disposed)
            {
                return;
            }

            if (_imageEncoder is IDisposable disposable)
            {
                disposable.Dispose();
            }

            _disposed = true;
        }
    }
}