using CaptchaKit.AspNetCore;
using CaptchaKit;
using Microsoft.Extensions.DependencyInjection;
using SkiaSharp;

namespace Jiaowu.Api.Tests;

public sealed class CaptchaKitIntegrationTests
{
    [Fact]
    public async Task Challenge_is_valid_once_and_the_default_generator_returns_a_png()
    {
        var services = new ServiceCollection();
        services.AddDistributedMemoryCache();
        services.AddCaptchaKit();
        services.AddSingleton<ICaptchaGenerator, KnownGenerator>();
        using var provider = services.BuildServiceProvider();
        var captcha = provider.GetRequiredService<ICaptchaKitService>();

        var challenge = await captcha.CreateAsync();

        Assert.Equal("image/png", challenge.ContentType);
        Assert.True(challenge.ImageBytes!.AsSpan().StartsWith(new byte[] { 137, 80, 78, 71 }));
        Assert.True(await captcha.VerifyAsync(challenge.Id, "a1b2"));
        Assert.False(await captcha.VerifyAsync(challenge.Id, "a1b2"));
    }

    [Fact]
    public void Default_generator_returns_png_bytes()
    {
        var challenge = new SkiaTextCaptchaGenerator().Generate(
            new CaptchaGenerationRequest("test", DateTimeOffset.UtcNow.AddMinutes(1), 5));

        Assert.Equal("image/png", challenge.Challenge.ContentType);
        Assert.True(challenge.Challenge.ImageBytes!.AsSpan().StartsWith(new byte[] { 137, 80, 78, 71 }));
    }

    [Fact]
    public void Selection_visual_keeps_the_target_character_visible_above_noise()
    {
        var challenge = new SkiaTextCaptchaGenerator().CreateVisualChallenge(
            new CaptchaGenerationRequest("test", DateTimeOffset.UtcNow.AddMinutes(1), 5),
            "A", "choice-A", CaptchaChallengeType.Selection, "请选择对应字符");

        using var bitmap = SKBitmap.Decode(challenge.Challenge.ImageBytes!);
        Assert.NotNull(bitmap);

        var targetPixelCount = 0;
        for (var y = 0; y < bitmap!.Height; y++)
        for (var x = bitmap.Width / 4; x < bitmap.Width * 3 / 4; x++)
        {
            var pixel = bitmap.GetPixel(x, y);
            if (pixel.Red <= 30 && pixel.Green is >= 40 and <= 60 && pixel.Blue is >= 70 and <= 90)
                targetPixelCount++;
        }

        Assert.True(targetPixelCount > 20, "The target character should be visibly rendered in the image center.");
    }

    [Fact]
    public void Random_generator_produces_each_enabled_challenge_type()
    {
        var generator = new RandomCaptchaGenerator(new CaptchaKitOptions());
        var types = new HashSet<CaptchaChallengeType>();
        for (var index = 0; index < 100; index++)
        {
            var generated = generator.Generate(new CaptchaGenerationRequest(
                index.ToString(), DateTimeOffset.UtcNow.AddMinutes(1), 5));
            types.Add(generated.Challenge.Type);
            if (generated.Challenge.Type == CaptchaChallengeType.Selection)
                Assert.Contains(generated.Challenge.Choices!, x => x.Id == generated.Answer);
        }

        Assert.Contains(CaptchaChallengeType.TextImage, types);
        Assert.Contains(CaptchaChallengeType.Selection, types);
        Assert.Contains(CaptchaChallengeType.MathImage, types);
    }

    private sealed class KnownGenerator : ICaptchaGenerator
    {
        public GeneratedCaptcha Generate(CaptchaGenerationRequest request) => new(
            new CaptchaChallenge(request.Id, CaptchaChallengeType.TextImage, request.ExpiresAt,
                "请输入图中的字符", null, "image/png", new byte[] { 137, 80, 78, 71 }),
            "A1B2");
    }
}