using System;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using FsCheck;
using FsCheck.Fluent;
using FsCheck.Xunit;
using Moq;
using XP.Common.Logging.Interfaces;
using XplorePlane.Services.MainViewport;

namespace XplorePlane.Tests.Services
{
    /// <summary>
    /// FsCheck property-based tests for MainViewportService.
    /// Uses the real MainViewportService (no mocking of the service itself).
    /// </summary>
    public class MainViewportServicePropertyTests
    {
        // ── Helpers ──────────────────────────────────────────────────────────

        private static MainViewportService CreateService()
        {
            var mockLogger = new Mock<ILoggerService>();
            mockLogger.Setup(l => l.ForModule<MainViewportService>()).Returns(mockLogger.Object);
            return new MainViewportService(mockLogger.Object);
        }

        /// <summary>
        /// Creates a frozen BitmapSource suitable for cross-thread use in tests.
        /// </summary>
        private static BitmapSource CreateFrozenBitmap(int width = 4, int height = 4)
        {
            var pixels = new byte[width * height * 4];
            var bitmap = BitmapSource.Create(
                width, height, 96, 96,
                PixelFormats.Bgra32, null,
                pixels, width * 4);
            bitmap.Freeze();
            return bitmap;
        }

        /// <summary>
        /// Generator for DetectorFrame with a frozen BitmapSource.
        /// </summary>
        private static Gen<DetectorFrame> DetectorFrameGen =>
            from frameId in Gen.Choose(1, 100000).Select(i => (long)i)
            from width in Gen.Choose(1, 64)
            from height in Gen.Choose(1, 64)
            select new DetectorFrame(
                frameId: frameId,
                captureTime: DateTime.UtcNow,
                width: width,
                height: height,
                rawPixels: new ushort[width * height],
                previewImage: CreateFrozenBitmap(width, height));

        // ── Property 1 ───────────────────────────────────────────────────────

        // Feature: live-image-display, Property 1: 实时模式下帧更新触发显示刷新
        // Validates: Requirements 3.2
        [Property(MaxTest = 100)]
        public Property LiveDetector_RealtimeEnabled_UpdateDetectorFrame_UpdatesDisplayAndRaisesEvent()
        {
            return Prop.ForAll(
                DetectorFrameGen.ToArbitrary(),
                frame =>
                {
                    var service = CreateService();

                    // Ensure we are in LiveDetector mode with realtime enabled (default state)
                    service.SetSourceMode(MainViewportSourceMode.LiveDetector);
                    service.SetRealtimeDisplayEnabled(true);

                    bool stateChangedRaised = false;
                    service.StateChanged += (_, __) => stateChangedRaised = true;

                    service.UpdateDetectorFrame(frame);

                    bool imageMatches = ReferenceEquals(service.CurrentDisplayImage, frame.PreviewImage);
                    bool eventRaised = stateChangedRaised;

                    return imageMatches && eventRaised;
                });
        }

        // ── Property 2 ───────────────────────────────────────────────────────

        // Feature: live-image-display, Property 2: 实时关闭时帧更新不触发显示刷新
        // Validates: Requirements 3.3
        [Property(MaxTest = 100)]
        public Property LiveDetector_RealtimeDisabled_UpdateDetectorFrame_NoEventAndImageUnchanged()
        {
            return Prop.ForAll(
                DetectorFrameGen.ToArbitrary(),
                frame =>
                {
                    var service = CreateService();

                    // Set up: LiveDetector mode, realtime disabled
                    service.SetSourceMode(MainViewportSourceMode.LiveDetector);
                    service.SetRealtimeDisplayEnabled(false);

                    // Capture the display image before the update
                    var imageBefore = service.CurrentDisplayImage;

                    bool stateChangedRaised = false;
                    service.StateChanged += (_, __) => stateChangedRaised = true;

                    service.UpdateDetectorFrame(frame);

                    bool noEvent = !stateChangedRaised;
                    bool imageUnchanged = ReferenceEquals(service.CurrentDisplayImage, imageBefore);

                    return noEvent && imageUnchanged;
                });
        }

        // ── Property 3 ───────────────────────────────────────────────────────

        // Feature: live-image-display, Property 3: ManualImage 模式下探测器帧不覆盖显示图像
        // Validates: Requirements 3.4
        [Property(MaxTest = 100)]
        public Property ManualImage_MultipleUpdateDetectorFrame_DisplayAlwaysManualImage()
        {
            var gen =
                from frameCount in Gen.Choose(1, 10)
                from frames in Gen.ListOf<DetectorFrame>(DetectorFrameGen, frameCount)
                select frames;

            return Prop.ForAll(
                gen.ToArbitrary(),
                frames =>
                {
                    var service = CreateService();

                    // Set a manual image first
                    var manualImage = CreateFrozenBitmap(8, 8);
                    service.SetManualImage(manualImage, "test.png");

                    // Verify we are in ManualImage mode
                    if (service.CurrentSourceMode != MainViewportSourceMode.ManualImage)
                        return false;

                    // Call UpdateDetectorFrame multiple times
                    foreach (var frame in (System.Collections.Generic.IEnumerable<DetectorFrame>)frames)
                    {
                        service.UpdateDetectorFrame(frame);
                    }

                    // CurrentDisplayImage must still be the manual image
                    return ReferenceEquals(service.CurrentDisplayImage, manualImage);
                });
        }

        // ── Property 4 ───────────────────────────────────────────────────────

        // Feature: live-image-display, Property 4: CNC 运行时 SetManualImage 被忽略
        // Validates: Requirements 3.10
        [Property(MaxTest = 100)]
        public Property CncRunning_SetManualImage_SourceModeRemainsLiveDetector()
        {
            return Prop.ForAll(
                DetectorFrameGen.ToArbitrary(),
                frame =>
                {
                    var service = CreateService();

                    // Start CNC running
                    service.SetCncRunning(true);

                    // Attempt to set a manual image
                    var manualImage = CreateFrozenBitmap(4, 4);
                    service.SetManualImage(manualImage, "manual.png");

                    // CurrentSourceMode must remain LiveDetector
                    return service.CurrentSourceMode == MainViewportSourceMode.LiveDetector;
                });
        }

        // ── Property 5 ───────────────────────────────────────────────────────

        // Feature: live-image-display, Property 5: CNC 运行时无法关闭实时刷新
        // Validates: Requirements 3.11
        [Property(MaxTest = 100)]
        public Property CncRunning_SetRealtimeDisplayEnabledFalse_IsRealtimeDisplayEnabledRemainsTrue()
        {
            // No generator needed — fixed input
            return Prop.ForAll(
                Gen.Constant(true).ToArbitrary(),
                _ =>
                {
                    var service = CreateService();

                    // Ensure realtime is enabled first
                    service.SetRealtimeDisplayEnabled(true);

                    // Start CNC running
                    service.SetCncRunning(true);

                    // Attempt to disable realtime display
                    service.SetRealtimeDisplayEnabled(false);

                    // IsRealtimeDisplayEnabled must remain true
                    return service.IsRealtimeDisplayEnabled;
                });
        }
    }
}