using System.Text.Json;
using FrameProcessor.Domain;
using SixLabors.ImageSharp;
using SixLabors.ImageSharp.PixelFormats;

namespace FrameProcessor.Tests;

public class PaletteEntryTests
{
    [Fact]
    public void JsonDeserialize_ParsesHexIntoColor()
    {
        const string json = """{ "name": "black", "color": "#1F2226", "deviceColor": "#000000" }""";

        var entry = JsonSerializer.Deserialize<PaletteEntry>(json);

        Assert.NotNull(entry);
        Assert.Equal("black", entry!.Name);
        Assert.Equal(new Rgba32(0x1F, 0x22, 0x26, 0xFF), entry.DisplayColor.ToPixel<Rgba32>());
        Assert.Equal(new Rgba32(0x00, 0x00, 0x00, 0xFF), entry.DeviceColor.ToPixel<Rgba32>());
    }

    [Fact]
    public void JsonDeserialize_HexWithoutHashIsAccepted()
    {
        const string json = """{ "name": "red", "color": "62201E", "deviceColor": "FF0000" }""";

        var entry = JsonSerializer.Deserialize<PaletteEntry>(json);

        Assert.NotNull(entry);
        Assert.Equal(new Rgba32(0x62, 0x20, 0x1E, 0xFF), entry!.DisplayColor.ToPixel<Rgba32>());
        Assert.Equal(new Rgba32(0xFF, 0x00, 0x00, 0xFF), entry.DeviceColor.ToPixel<Rgba32>());
    }

    [Fact]
    public void JsonSerialize_EmitsHashPrefixedSixDigitHex()
    {
        var entry = new PaletteEntry(
            "yellow",
            Color.FromPixel(new Rgba32(0xC1, 0xBB, 0x1E, 0xFF)),
            Color.FromPixel(new Rgba32(0xFF, 0xFF, 0x00, 0xFF)));

        var json = JsonSerializer.Serialize(entry);

        Assert.Contains("\"name\":\"yellow\"", json);
        Assert.Contains("\"color\":\"#C1BB1E\"", json);
        Assert.Contains("\"deviceColor\":\"#FFFF00\"", json);
    }

    [Fact]
    public void JsonRoundTrip_PreservesValues()
    {
        var original = new PaletteEntry(
            "blue",
            Color.FromPixel(new Rgba32(0x23, 0x3F, 0x8E, 0xFF)),
            Color.FromPixel(new Rgba32(0x00, 0x00, 0xFF, 0xFF)));

        var json = JsonSerializer.Serialize(original);
        var roundTripped = JsonSerializer.Deserialize<PaletteEntry>(json);

        Assert.Equal(original, roundTripped);
    }

    [Theory]
    [InlineData("""{ "color": "#000000", "deviceColor": "#000000" }""")]
    [InlineData("""{ "name": "x", "deviceColor": "#000000" }""")]
    [InlineData("""{ "name": "x", "color": "#000000" }""")]
    public void JsonDeserialize_MissingField_Throws(string json)
    {
        Assert.Throws<JsonException>(() => JsonSerializer.Deserialize<PaletteEntry>(json));
    }

    [Theory]
    [InlineData("""{ "name": "x", "color": "not-a-color", "deviceColor": "#000000" }""")]
    [InlineData("""{ "name": "x", "color": "#000000", "deviceColor": "zzz" }""")]
    [InlineData("""{ "name": "x", "color": "", "deviceColor": "#000000" }""")]
    public void JsonDeserialize_InvalidHex_Throws(string json)
    {
        Assert.Throws<JsonException>(() => JsonSerializer.Deserialize<PaletteEntry>(json));
    }

    [Fact]
    public void JsonDeserialize_EmptyName_Throws()
    {
        const string json = """{ "name": "", "color": "#000000", "deviceColor": "#000000" }""";

        Assert.Throws<JsonException>(() => JsonSerializer.Deserialize<PaletteEntry>(json));
    }

    [Fact]
    public void JsonDeserialize_UnknownFields_AreIgnored()
    {
        const string json = """{ "name": "black", "color": "#000000", "deviceColor": "#000000", "extra": 42 }""";

        var entry = JsonSerializer.Deserialize<PaletteEntry>(json);

        Assert.NotNull(entry);
        Assert.Equal("black", entry!.Name);
    }

    [Fact]
    public void Equality_BasedOnNameAndColors()
    {
        var a = new PaletteEntry("black", Color.Black, Color.Black);
        var b = new PaletteEntry("black", Color.Black, Color.Black);
        var c = new PaletteEntry("white", Color.Black, Color.Black);

        Assert.Equal(a, b);
        Assert.NotEqual(a, c);
    }
}
