using System;
using System.Text;
using System.Threading.Tasks;
using Paca.Core.QuickActions;
using Xunit;

namespace Paca.Tests.Core;

public class QuickActionsExtremeRedTests
{
    // ==========================================
    // 1. QuickActionFuzzyMatcher Memory & DoS
    // ==========================================

    [Fact]
    public void QuickActionFuzzyMatcher_LevenshteinDistance_LargeStrings_DoesNotThrowOutOfMemory()
    {
        // 5000 character strings would allocate ~100MB in 2D array if unbounded
        string large1 = new string('A', 3000);
        string large2 = new string('B', 3000);

        var ex = Record.Exception(() => QuickActionFuzzyMatcher.LevenshteinDistance(large1, large2));
        Assert.Null(ex);
    }

    [Theory]
    [InlineData(null, null)]
    [InlineData(null, "abc")]
    [InlineData("xyz", null)]
    public void QuickActionFuzzyMatcher_LevenshteinDistance_Nulls_HandledGracefully(string? s, string? t)
    {
        var ex = Record.Exception(() => QuickActionFuzzyMatcher.LevenshteinDistance(s, t));
        Assert.Null(ex);
    }

    // ==========================================
    // 2. QuickActionInlineEvaluator Hardening
    // ==========================================

    [Theory]
    [InlineData("-5 + 10", "5")]
    [InlineData("10 * -2", "-20")]
    [InlineData("-4 * -3", "12")]
    public void QuickActionInlineEvaluator_TryEvaluateMath_NegativeNumbers_CalculatesCorrectly(string expr, string expected)
    {
        var eval = new QuickActionInlineEvaluator();
        bool success = eval.TryEvaluate(expr, out var res);
        Assert.True(success, $"Expression '{expr}' should be successfully evaluated");
        Assert.NotNull(res);
        Assert.Equal(expected, res.Value);
    }

    [Theory]
    [InlineData("#fff", "rgb(255, 255, 255)")]
    [InlineData("#F00", "rgb(255, 0, 0)")]
    [InlineData("hex 000", "rgb(0, 0, 0)")]
    public void QuickActionInlineEvaluator_TryEvaluateDev_Hex3DigitShorthand_ExpandsCorrectly(string hexInput, string expectedRgb)
    {
        var eval = new QuickActionInlineEvaluator();
        bool success = eval.TryEvaluate(hexInput, out var res);
        Assert.True(success, $"Shorthand hex '{hexInput}' should be parsed");
        Assert.NotNull(res);
        Assert.Equal(expectedRgb, res.Value);
    }

    [Fact]
    public void QuickActionInlineEvaluator_TryEvaluateDev_Base64WithNullBytes_DoesNotReturnRawNullChars()
    {
        var eval = new QuickActionInlineEvaluator();
        // Base64 containing null bytes: "\0\0\0" -> "AAAA"
        bool success = eval.TryEvaluate("b64d AAAA", out var res);
        Assert.True(success);
        Assert.NotNull(res);
        Assert.DoesNotContain('\0', res.Value);
    }

    // ==========================================
    // 3. QuickActionClipboardDetector Security & Resilience
    // ==========================================

    [Fact]
    public void QuickActionClipboardDetector_DetectIntent_EnormousClipboard_DoesNotSpikeOrHang()
    {
        var detector = new QuickActionClipboardDetector();
        string hugeText = new string('x', 500_000); // 500KB

        var intent = detector.DetectIntent(hugeText);
        Assert.NotNull(intent);
        Assert.Equal(ClipboardIntentType.None, intent.IntentType);
    }

    [Theory]
    [InlineData("youtube.com/watch?v=dQw4w9WgXcQ")]
    [InlineData("www.youtube.com/watch?v=dQw4w9WgXcQ")]
    [InlineData("youtu.be/dQw4w9WgXcQ")]
    public void QuickActionClipboardDetector_DetectIntent_MediaUrlWithoutScheme_DetectedAsMediaDownload(string rawUrl)
    {
        var detector = new QuickActionClipboardDetector();
        var intent = detector.DetectIntent(rawUrl);
        Assert.NotNull(intent);
        Assert.Equal(ClipboardIntentType.MediaDownload, intent.IntentType);
    }

    // ==========================================
    // 4. QuickActionParameterRouter Null Context Defenses
    // ==========================================

    [Theory]
    [InlineData("b64 hello")]
    [InlineData("b64d aGVsbG8=")]
    [InlineData("hash password123")]
    [InlineData("note sample note")]
    public async Task QuickActionParameterRouter_Handlers_NullContext_DoesNotThrowNullReferenceException(string command)
    {
        var router = new QuickActionParameterRouter();
        bool parsed = router.TryParseCommand(command, out var action);
        Assert.True(parsed);
        Assert.NotNull(action);

        var ex = await Record.ExceptionAsync(async () => await action!.Handler!(null!));
        Assert.Null(ex);
    }
}