// Copyright (c) Six Labors.
// Licensed under the Six Labors Split License.

using System.Collections.Concurrent;
using SixLabors.ImageSharp.Formats;
using SixLabors.ImageSharp.PixelFormats;

namespace SixLabors.ImageSharp.Tests;

/// <summary>
/// A test image file.
/// </summary>
public sealed class TestFile
{
    /// <summary>
    /// The test file cache.
    /// </summary>
    private static readonly ConcurrentDictionary<string, TestFile> Cache = new();

    /// <summary>
    /// The "Formats" directory, as lazy value
    /// </summary>
    // ReSharper disable once InconsistentNaming
    private static readonly Lazy<string> InputImagesDirectoryValue = new(() => TestEnvironment.InputImagesDirectoryFullPath);

    /// <summary>
    /// The image bytes
    /// </summary>
    private byte[] bytes;

    /// <summary>
    /// Initializes a new instance of the <see cref="TestFile"/> class.
    /// </summary>
    /// <param name="file">The file.</param>
    private TestFile(string file) => this.FullPath = file;

    /// <summary>
    /// Gets the image bytes.
    /// </summary>
    public byte[] Bytes => this.bytes ??= File.ReadAllBytes(this.FullPath);

    /// <summary>
    /// Gets the full path to file.
    /// </summary>
    public string FullPath { get; }

    /// <summary>
    /// Gets the file name.
    /// </summary>
    public string FileName => Path.GetFileName(this.FullPath);

    /// <summary>
    /// Gets the file name without extension.
    /// </summary>
    public string FileNameWithoutExtension => Path.GetFileNameWithoutExtension(this.FullPath);

    /// <summary>
    /// Gets the input image directory.
    /// </summary>
    private static string InputImagesDirectory => InputImagesDirectoryValue.Value;

    /// <summary>
    /// Gets the full qualified path to the input test file.
    /// </summary>
    /// <param name="file">
    /// The file path.
    /// </param>
    /// <returns>
    /// The <see cref="string"/>.
    /// </returns>
    public static string GetInputFileFullPath(string file)
        => Path.Combine(InputImagesDirectory, file).Replace('\\', Path.DirectorySeparatorChar);

    /// <summary>
    /// Creates a new test file or returns one from the cache.
    /// </summary>
    /// <param name="file">The file path.</param>
    /// <returns>
    /// The <see cref="TestFile"/>.
    /// </returns>
    public static TestFile Create(string file)
        => Cache.GetOrAdd(file, (string fileName) => new TestFile(GetInputFileFullPath(fileName)));

    /// <summary>
    /// Gets the file name.
    /// </summary>
    /// <param name="value">The value.</param>
    /// <returns>
    /// The <see cref="string"/>.
    /// </returns>
    public string GetFileName(object value)
        => $"{this.FileNameWithoutExtension}-{value}{Path.GetExtension(this.FullPath)}";

    /// <summary>
    /// Gets the file name without extension.
    /// </summary>
    /// <param name="value">The value.</param>
    /// <returns>
    /// The <see cref="string"/>.
    /// </returns>
    public string GetFileNameWithoutExtension(object value)
        => this.FileNameWithoutExtension + "-" + value;

    /// <summary>
    /// Creates a new <see cref="Rgba32"/> image.
    /// </summary>
    /// <returns>
    /// The <see cref="Image{Rgba32}"/>.
    /// </returns>
    public Image<Rgba32> CreateRgba32Image() => Image.Load<Rgba32>(this.Bytes);

    /// <summary>
    /// Creates a new <see cref="Rgba32"/> image.
    /// </summary>
    /// <param name="decoder">The image decoder.</param>
    /// <returns>
    /// The <see cref="Image{Rgba32}"/>.
    /// </returns>
    public Image<Rgba32> CreateRgba32Image(IImageDecoder decoder)
        => this.CreateRgba32Image(decoder, new DecoderOptions());

    /// <summary>
    /// Creates a new <see cref="Rgba32"/> image.
    /// </summary>
    /// <param name="decoder">The image decoder.</param>
    /// <param name="options">The general decoder options.</param>
    /// <returns>
    /// The <see cref="Image{Rgba32}"/>.
    /// </returns>
    public Image<Rgba32> CreateRgba32Image(IImageDecoder decoder, DecoderOptions options)
    {
        using MemoryStream stream = new(this.Bytes);
        return decoder.Decode<Rgba32>(options, stream);
    }
}