using System.Text.Json;
using AcDream.App.Diagnostics;
using AcDream.App.Rendering;
using AcDream.App.Streaming;
using AcDream.App.UI.Testing;
using SixLabors.ImageSharp;

namespace AcDream.App.Tests.Diagnostics;

public sealed class WorldLifecycleAutomationControllerTests
{
    private static readonly RenderFrameInput FrameInput = new(1d / 60d, 1280, 720);
    private static readonly RenderFrameOutcome FrameOutcome = new(
        new WorldRenderFrameOutcome(4, 17, NormalWorldDrawn: true),
        new PrivatePresentationFrameOutcome(
            PortalViewportDrawn: false,
            ScreenshotCaptured: true));

    [Fact]
    public void ScreenshotCapture_FlipsGlRowsAndWritesACompletePng()
    {
        string directory = NewDirectory();
        // GL order: bottom row red/green, top row blue/white.
        byte[] rgba =
        [
            255, 0, 0, 255, 0, 255, 0, 255,
            0, 0, 255, 255, 255, 255, 255, 255,
        ];
        var logs = new List<string>();
        var controller = new FrameScreenshotController(
            (_, _) => rgba,
            directory,
            logs.Add);

        try
        {
            Assert.True(controller.TryRequest("login_stable", out string error), error);
            Assert.False(controller.IsComplete("login_stable"));

            Assert.True(controller.CapturePending(2, 2));

            Assert.True(controller.IsComplete("login_stable"));
            string path = Path.Combine(directory, "login_stable.png");
            using Image image = Image.Load(path);
            Assert.Equal(2, image.Width);
            Assert.Equal(2, image.Height);
            Assert.Contains(logs, line => line.Contains("screenshot-complete", StringComparison.Ordinal));

            byte[] flipped = FrameScreenshotController.FlipRows(rgba, 2, 2);
            Assert.Equal(rgba.AsSpan(8, 8).ToArray(), flipped.AsSpan(0, 8).ToArray());
            Assert.Equal(rgba.AsSpan(0, 8).ToArray(), flipped.AsSpan(8, 8).ToArray());
        }
        finally
        {
            Directory.Delete(directory, recursive: true);
        }
    }

    [Fact]
    public void ScreenshotCapture_ReportsNoWorkAndFailedCapture()
    {
        string directory = NewDirectory();
        var controller = new FrameScreenshotController(
            (_, _) => [],
            directory);

        try
        {
            Assert.False(controller.CapturePending(0, 0));
            Assert.True(controller.TryRequest("bad_frame", out string error), error);
            Assert.False(controller.CapturePending(0, 0));
            Assert.False(controller.IsComplete("bad_frame"));
        }
        finally
        {
            if (Directory.Exists(directory))
                Directory.Delete(directory, recursive: true);
        }
    }

    [Theory]
    [InlineData("")]
    [InlineData("../escape")]
    [InlineData("has spaces")]
    [InlineData("name.png")]
    public void ArtifactNames_RejectPathsAndAmbiguousCharacters(string name)
    {
        Assert.False(AutomationArtifactName.TryValidate(name, out string error));
        Assert.NotEmpty(error);
    }

    [Fact]
    public void Checkpoint_WritesCanonicalRevealAndResourceSnapshot()
    {
        string directory = NewDirectory();
        var reveal = new WorldRevealLifecycleSnapshot(
            Generation: 7,
            Kind: WorldRevealKind.Portal,
            Readiness: new WorldRevealReadinessSnapshot(
                0x8A020164u,
                IsIndoor: true,
                IsUnhydratable: false,
                RequiredRenderRadius: 0,
                IsRenderNeighborhoodReady: true,
                AreCompositeTexturesReady: true,
                IsCollisionReady: true),
            Materialized: true,
            Completed: true,
            Cancelled: false,
            WorldViewportObserved: true,
            InvariantFailureCount: 0);
        var resources = EmptyResources() with
        {
            LoadedLandblocks = 1,
            WorldEntities = 42,
            TrackedGpuBytes = 1234,
        };
        var screenshots = new FrameScreenshotController(
            (_, _) => [0, 0, 0, 255],
            Path.Combine(directory, "screenshots"));
        var controller = new WorldLifecycleAutomationController(
            () => reveal,
            () => 3,
            _ => resources,
            screenshots,
            directory);

        try
        {
            Assert.True(controller.IsWorldReady);
            Assert.True(controller.IsWorldViewportVisible);
            Assert.Equal(3, controller.PortalMaterializationCount);
            Assert.True(controller.TryRequestCheckpoint(
                "dungeon",
                out IRetailUiAutomationCheckpoint? request,
                out string error), error);
            Assert.NotNull(request);
            Assert.Equal(RetailUiAutomationCheckpointStatus.Pending, request.Status);

            controller.Process(FrameInput, FrameOutcome);

            Assert.Equal(RetailUiAutomationCheckpointStatus.Succeeded, request.Status);

            string line = Assert.Single(File.ReadAllLines(
                Path.Combine(directory, "world-lifecycle.checkpoints.jsonl")));
            using JsonDocument json = JsonDocument.Parse(line);
            Assert.Equal("dungeon", json.RootElement.GetProperty("name").GetString());
            Assert.Equal(7, json.RootElement.GetProperty("reveal").GetProperty("generation").GetInt64());
            Assert.Equal(4, json.RootElement.GetProperty("render").GetProperty("world")
                .GetProperty("visibleLandblocks").GetInt32());
            Assert.True(json.RootElement.GetProperty("render").GetProperty("presentation")
                .GetProperty("screenshotCaptured").GetBoolean());
            Assert.Equal(42, json.RootElement.GetProperty("resources").GetProperty("worldEntities").GetInt32());
            Assert.True(File.Exists(Path.Combine(directory, "checkpoint-dungeon.json")));
        }
        finally
        {
            Directory.Delete(directory, recursive: true);
        }
    }

    [Fact]
    public void CheckpointRequests_DrainInFifoOrderOnce()
    {
        string directory = NewDirectory();
        int captures = 0;
        var controller = CreateController(
            directory,
            _ =>
            {
                captures++;
                return EmptyResources();
            });

        try
        {
            Assert.True(controller.TryRequestCheckpoint(
                "first", out IRetailUiAutomationCheckpoint? first, out _));
            Assert.True(controller.TryRequestCheckpoint(
                "second", out IRetailUiAutomationCheckpoint? second, out _));

            controller.Process(FrameInput, FrameOutcome);
            controller.Process(FrameInput, FrameOutcome);

            Assert.NotNull(first);
            Assert.NotNull(second);
            Assert.Equal(1, first.Sequence);
            Assert.Equal(2, second.Sequence);
            Assert.Equal(RetailUiAutomationCheckpointStatus.Succeeded, first.Status);
            Assert.Equal(RetailUiAutomationCheckpointStatus.Succeeded, second.Status);
            Assert.Equal(2, captures);
            string[] lines = File.ReadAllLines(
                Path.Combine(directory, "world-lifecycle.checkpoints.jsonl"));
            Assert.Equal(2, lines.Length);
            Assert.Contains("\"name\":\"first\"", lines[0], StringComparison.Ordinal);
            Assert.Contains("\"name\":\"second\"", lines[1], StringComparison.Ordinal);
        }
        finally
        {
            controller.Dispose();
            Directory.Delete(directory, recursive: true);
        }
    }

    [Fact]
    public void CheckpointWriteFailure_IsReportedOnTokenWithoutThrowingFromFrame()
    {
        string directory = NewDirectory();
        string blockedPath = Path.Combine(directory, "not-a-directory");
        File.WriteAllText(blockedPath, "occupied");
        var controller = CreateController(blockedPath, _ => EmptyResources());

        try
        {
            Assert.True(controller.TryRequestCheckpoint(
                "failed", out IRetailUiAutomationCheckpoint? request, out _));

            controller.Process(FrameInput, FrameOutcome);

            Assert.NotNull(request);
            Assert.Equal(RetailUiAutomationCheckpointStatus.Failed, request.Status);
            Assert.Contains("checkpoint 'failed' sequence 1 failed", request.Error);
        }
        finally
        {
            controller.Dispose();
            Directory.Delete(directory, recursive: true);
        }
    }

    [Fact]
    public void CheckpointCancellationAndShutdown_AreExplicitAndNeverWritten()
    {
        string directory = NewDirectory();
        var controller = CreateController(directory, _ => EmptyResources());

        try
        {
            Assert.True(controller.TryRequestCheckpoint(
                "caller", out IRetailUiAutomationCheckpoint? caller, out _));
            Assert.True(controller.TryRequestCheckpoint(
                "shutdown", out IRetailUiAutomationCheckpoint? shutdown, out _));
            Assert.NotNull(caller);
            Assert.NotNull(shutdown);

            controller.CancelCheckpoint(caller);
            controller.Dispose();
            controller.Process(FrameInput, FrameOutcome);

            Assert.Equal(RetailUiAutomationCheckpointStatus.Cancelled, caller.Status);
            Assert.Contains("cancelled before render-frame capture", caller.Error);
            Assert.Equal(RetailUiAutomationCheckpointStatus.Cancelled, shutdown.Status);
            Assert.Contains("cancelled during world lifecycle automation shutdown", shutdown.Error);
            Assert.False(controller.TryRequestCheckpoint(
                "late", out IRetailUiAutomationCheckpoint? late, out string error));
            Assert.Null(late);
            Assert.Contains("shutting down", error);
            Assert.False(File.Exists(Path.Combine(
                directory,
                "world-lifecycle.checkpoints.jsonl")));
        }
        finally
        {
            controller.Dispose();
            Directory.Delete(directory, recursive: true);
        }
    }

    private static WorldLifecycleAutomationController CreateController(
        string directory,
        Func<RenderFrameOutcome, WorldLifecycleResourceSnapshot> capture) =>
        new(
            () => default,
            () => 0,
            capture,
            new FrameScreenshotController((_, _) => [], directory),
            directory);

    private static WorldLifecycleResourceSnapshot EmptyResources() => new(
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0L, 0, 0L, 0L, 0, 0, 0, 0, 0, 0, 0, 0L, 0L, 0d, 0d, null);

    private static string NewDirectory()
    {
        string path = Path.Combine(Path.GetTempPath(), "acdream-world-gate-" + Guid.NewGuid().ToString("N"));
        Directory.CreateDirectory(path);
        return path;
    }
}