using System;
using System.IO;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using MediaBrowser.Controller.Drawing;
using MediaBrowser.Controller.Entities;
using MediaBrowser.Controller.Library;
using MediaBrowser.Controller.Providers;
using MediaBrowser.Model.Entities;
using MediaBrowser.Model.IO;
using MediaBrowser.Model.Logging;
using TagLib;
using TagLib.IFD;
using TagLib.IFD.Entries;
using TagLib.IFD.Tags;

namespace Emby.Photos
{
    public class PhotoProvider : ICustomMetadataProvider<Photo>, IHasItemChangeMonitor, IForcedProvider
    {
        private readonly ILogger _logger;
        private readonly IFileSystem _fileSystem;
        private IImageProcessor _imageProcessor;

        public PhotoProvider(ILogger logger, IFileSystem fileSystem, IImageProcessor imageProcessor)
        {
            _logger = logger;
            _fileSystem = fileSystem;
            _imageProcessor = imageProcessor;
        }

        // These are causing taglib to hang
        private string[] _excludeExtensions = new string[] { ".dng" };

        public Task<ItemUpdateType> FetchAsync(Photo item, MetadataRefreshOptions options, CancellationToken cancellationToken)
        {
            item.SetImagePath(ImageType.Primary, item.Path);

            // Examples: https://github.com/mono/taglib-sharp/blob/a5f6949a53d09ce63ee7495580d6802921a21f14/tests/fixtures/TagLib.Tests.Images/NullOrientationTest.cs
            if (!_excludeExtensions.Contains(Path.GetExtension(item.Path) ?? string.Empty, StringComparer.OrdinalIgnoreCase))
            {
                try
                {
                    using (var fileStream = _fileSystem.OpenRead(item.Path))
                    {
                        using (var file = TagLib.File.Create(new StreamFileAbstraction(Path.GetFileName(item.Path), fileStream, null)))
                        {
                            var image = file as TagLib.Image.File;

                            var tag = file.GetTag(TagTypes.TiffIFD) as IFDTag;

                            if (tag != null)
                            {
                                var structure = tag.Structure;

                                if (structure != null)
                                {
                                    var exif = structure.GetEntry(0, (ushort)IFDEntryTag.ExifIFD) as SubIFDEntry;

                                    if (exif != null)
                                    {
                                        var exifStructure = exif.Structure;

                                        if (exifStructure != null)
                                        {
                                            var entry = exifStructure.GetEntry(0, (ushort)ExifEntryTag.ApertureValue) as RationalIFDEntry;

                                            if (entry != null)
                                            {
                                                double val = entry.Value.Numerator;
                                                val /= entry.Value.Denominator;
                                                item.Aperture = val;
                                            }

                                            entry = exifStructure.GetEntry(0, (ushort)ExifEntryTag.ShutterSpeedValue) as RationalIFDEntry;

                                            if (entry != null)
                                            {
                                                double val = entry.Value.Numerator;
                                                val /= entry.Value.Denominator;
                                                item.ShutterSpeed = val;
                                            }
                                        }
                                    }
                                }
                            }

                            if (image != null)
                            {
                                item.CameraMake = image.ImageTag.Make;
                                item.CameraModel = image.ImageTag.Model;

                                item.Width = image.Properties.PhotoWidth;
                                item.Height = image.Properties.PhotoHeight;

                                var rating = image.ImageTag.Rating;
                                if (rating.HasValue)
                                {
                                    item.CommunityRating = rating;
                                }
                                else
                                {
                                    item.CommunityRating = null;
                                }

                                item.Overview = image.ImageTag.Comment;

                                if (!string.IsNullOrWhiteSpace(image.ImageTag.Title))
                                {
                                    item.Name = image.ImageTag.Title;
                                }

                                var dateTaken = image.ImageTag.DateTime;
                                if (dateTaken.HasValue)
                                {
                                    item.DateCreated = dateTaken.Value;
                                    item.PremiereDate = dateTaken.Value;
                                    item.ProductionYear = dateTaken.Value.Year;
                                }

                                item.Genres = image.ImageTag.Genres.ToList();
                                item.Tags = image.ImageTag.Keywords;
                                item.Software = image.ImageTag.Software;

                                if (image.ImageTag.Orientation == TagLib.Image.ImageOrientation.None)
                                {
                                    item.Orientation = null;
                                }
                                else
                                {
                                    MediaBrowser.Model.Drawing.ImageOrientation orientation;
                                    if (Enum.TryParse(image.ImageTag.Orientation.ToString(), true, out orientation))
                                    {
                                        item.Orientation = orientation;
                                    }
                                }

                                item.ExposureTime = image.ImageTag.ExposureTime;
                                item.FocalLength = image.ImageTag.FocalLength;

                                item.Latitude = image.ImageTag.Latitude;
                                item.Longitude = image.ImageTag.Longitude;
                                item.Altitude = image.ImageTag.Altitude;

                                if (image.ImageTag.ISOSpeedRatings.HasValue)
                                {
                                    item.IsoSpeedRating = Convert.ToInt32(image.ImageTag.ISOSpeedRatings.Value);
                                }
                                else
                                {
                                    item.IsoSpeedRating = null;
                                }
                            }
                        }
                    }
                }
                catch (Exception e)
                {
                    _logger.ErrorException("Image Provider - Error reading image tag for {0}", e, item.Path);
                }
            }

            if (!item.Width.HasValue || !item.Height.HasValue)
            {
                var size = _imageProcessor.GetImageSize(item.Path);

                item.Width = Convert.ToInt32(size.Width);
                item.Height = Convert.ToInt32(size.Height);
            }

            const ItemUpdateType result = ItemUpdateType.ImageUpdate | ItemUpdateType.MetadataImport;
            return Task.FromResult(result);
        }

        public string Name
        {
            get { return "Embedded Information"; }
        }

        public bool HasChanged(IHasMetadata item, IDirectoryService directoryService)
        {
            if (item.EnableRefreshOnDateModifiedChange && !string.IsNullOrWhiteSpace(item.Path) && item.LocationType == LocationType.FileSystem)
            {
                var file = directoryService.GetFile(item.Path);
                if (file != null && file.LastWriteTimeUtc != item.DateModified)
                {
                    return true;
                }
            }

            return false;
        }
    }
}