// <copyright file="DecodeJpegMultiple.cs" company="James Jackson-South">
// Copyright (c) James Jackson-South and contributors.
// Licensed under the Apache License, Version 2.0.
// </copyright>

namespace ImageSharp.Benchmarks.Image
{
    using System;
    using System.Collections.Generic;
    using System.Drawing;
    using System.IO;
    using System.Linq;

    using BenchmarkDotNet.Attributes;

    using Image = ImageSharp.Image;
    using ImageSharpSize = ImageSharp.Size;

    public class DecodeJpegMultiple
    {
        private const string Folder = "../ImageSharp.Tests/TestImages/Formats/Jpg/";

        private Dictionary<string, byte[]> fileNamesToBytes;

        public enum JpegTestingMode
        {
            All,

            SmallImagesOnly,

            LargeImagesOnly,

            CalliphoraOnly,
        }

        [Params(JpegTestingMode.All, JpegTestingMode.SmallImagesOnly, JpegTestingMode.LargeImagesOnly,
             JpegTestingMode.CalliphoraOnly)]
        public JpegTestingMode Mode { get; set; }

        private IEnumerable<KeyValuePair<string, byte[]>> RequestedImages
        {
            get
            {
                int thresholdInBytes = 100000;

                switch (this.Mode)
                {
                    case JpegTestingMode.All:
                        return this.fileNamesToBytes;
                    case JpegTestingMode.SmallImagesOnly:
                        return this.fileNamesToBytes.Where(kv => kv.Value.Length < thresholdInBytes);
                    case JpegTestingMode.LargeImagesOnly:
                        return this.fileNamesToBytes.Where(kv => kv.Value.Length >= thresholdInBytes);
                    case JpegTestingMode.CalliphoraOnly:
                        return new[] { this.fileNamesToBytes.First(kv => kv.Key.ToLower().Contains("calliphora")) };
                    default:
                        throw new ArgumentOutOfRangeException();
                }
            }
        }

        [Benchmark(Description = "DecodeJpegMultiple - ImageSharp")]
        public ImageSharpSize JpegImageSharp()
        {
            ImageSharpSize lastSize = new ImageSharpSize();
            foreach (var kv in this.RequestedImages)
            {
                using (MemoryStream memoryStream = new MemoryStream(kv.Value))
                {
                    Image image = new Image(memoryStream);
                    lastSize = new ImageSharpSize(image.Width, image.Height);
                }
            }

            return lastSize;
        }

        [Benchmark(Baseline = true, Description = "DecodeJpegMultiple - System.Drawing")]
        public Size JpegSystemDrawing()
        {
            Size lastSize = new Size();
            foreach (var kv in this.RequestedImages)
            {
                using (MemoryStream memoryStream = new MemoryStream(kv.Value))
                {
                    using (System.Drawing.Image image = System.Drawing.Image.FromStream(memoryStream))
                    {
                        lastSize = image.Size;
                    }
                }
            }

            return lastSize;
        }

        [Setup]
        public void ReadImages()
        {
            if (this.fileNamesToBytes != null) return;

            var allFiles = Directory.EnumerateFiles(Folder, "*.jpg", SearchOption.AllDirectories).ToArray();

            this.fileNamesToBytes = allFiles.ToDictionary(fn => fn, File.ReadAllBytes);
        }
    }
}