using System;
using System.Threading;
using System.Windows;
using Moq;
using Xunit;
using XplorePlane.Services.Recording;
using XP.Common.Logging.Interfaces;
using XplorePlane.Services.Storage;

namespace XplorePlane.Tests.ViewModels
{
    /// <summary>
    /// Unit tests for MainViewModel recording state transitions and command behavior.
    /// Tests the integration between MainViewModel and IViewportRecordingService.
    /// 
    /// Note: These tests focus on the ViewportRecordingService behavior rather than
    /// full MainViewModel integration due to complex dependencies.
    /// </summary>
    public class MainViewModelRecordingTests
    {
        /// <summary>
        /// Test: RecordingService state transitions trigger correct state changes
        /// **Validates: Requirements 2.1, 3.3**
        /// </summary>
        [StaFact]
        public void RecordingService_StateChanged_IdleToRecording_TriggersEvent()
        {
            // Arrange
            var mockLogger = new Mock<ILoggerService>();
            var mockDataPathService = new Mock<IXpDataPathService>();
            mockLogger.Setup(x => x.ForModule<ViewportRecordingService>()).Returns(mockLogger.Object);
            
            string testPath = System.IO.Path.Combine(System.IO.Path.GetTempPath(), $"XP_Test_{Guid.NewGuid():N}");
            mockDataPathService.Setup(x => x.RootPath).Returns(testPath);

            var service = new ViewportRecordingService(mockDataPathService.Object, mockLogger.Object);
            
            RecordingState? newState = null;
            service.StateChanged += (sender, args) =>
            {
                newState = args.NewState;
            };

            // Act
            var captureTarget = CreateMockFrameworkElement(800, 600);
            bool started = service.StartRecording(captureTarget);

            // If codec not available, skip
            if (!started)
            {
                service.Dispose();
                return;
            }

            // Assert
            Assert.Equal(RecordingState.Recording, newState);
            Assert.Equal(RecordingState.Recording, service.CurrentState);

            // Cleanup
            service.Dispose();
            if (System.IO.Directory.Exists(testPath))
            {
                try { System.IO.Directory.Delete(testPath, true); } catch { }
            }
        }

        /// <summary>
        /// Test: RecordingService transitions from Recording to Saving to Idle
        /// **Validates: Requirements 3.1, 3.3**
        /// </summary>
        [StaFact]
        public void RecordingService_StopRecording_TransitionsToSavingThenIdle()
        {
            // Arrange
            var mockLogger = new Mock<ILoggerService>();
            var mockDataPathService = new Mock<IXpDataPathService>();
            mockLogger.Setup(x => x.ForModule<ViewportRecordingService>()).Returns(mockLogger.Object);
            
            string testPath = System.IO.Path.Combine(System.IO.Path.GetTempPath(), $"XP_Test_{Guid.NewGuid():N}");
            mockDataPathService.Setup(x => x.RootPath).Returns(testPath);

            var service = new ViewportRecordingService(mockDataPathService.Object, mockLogger.Object);
            
            var states = new System.Collections.Generic.List<RecordingState>();
            service.StateChanged += (sender, args) =>
            {
                states.Add(args.NewState);
            };

            var captureTarget = CreateMockFrameworkElement(640, 480);
            bool started = service.StartRecording(captureTarget);

            // If codec not available, skip
            if (!started)
            {
                service.Dispose();
                return;
            }

            // Act
            Thread.Sleep(100); // Let it record briefly
            service.StopRecording();

            // Wait for state to settle
            Thread.Sleep(500);

            // Assert
            Assert.Contains(RecordingState.Recording, states);
            Assert.Contains(RecordingState.Saving, states);
            Assert.Contains(RecordingState.Idle, states);
            Assert.Equal(RecordingState.Idle, service.CurrentState);

            // Cleanup
            service.Dispose();
            if (System.IO.Directory.Exists(testPath))
            {
                try { System.IO.Directory.Delete(testPath, true); } catch { }
            }
        }

        /// <summary>
        /// Test: RecordingService cannot start when already recording
        /// **Validates: Requirements 2.4**
        /// </summary>
        [StaFact]
        public void RecordingService_StartRecording_WhenAlreadyRecording_ReturnsFalse()
        {
            // Arrange
            var mockLogger = new Mock<ILoggerService>();
            var mockDataPathService = new Mock<IXpDataPathService>();
            mockLogger.Setup(x => x.ForModule<ViewportRecordingService>()).Returns(mockLogger.Object);
            
            string testPath = System.IO.Path.Combine(System.IO.Path.GetTempPath(), $"XP_Test_{Guid.NewGuid():N}");
            mockDataPathService.Setup(x => x.RootPath).Returns(testPath);

            var service = new ViewportRecordingService(mockDataPathService.Object, mockLogger.Object);
            
            var captureTarget = CreateMockFrameworkElement(800, 600);
            bool firstStart = service.StartRecording(captureTarget);

            // If codec not available, skip
            if (!firstStart)
            {
                service.Dispose();
                return;
            }

            // Act
            bool secondStartResult = service.StartRecording(captureTarget);

            // Assert
            Assert.False(secondStartResult);
            Assert.Equal(RecordingState.Recording, service.CurrentState);

            // Cleanup
            service.Dispose();
            if (System.IO.Directory.Exists(testPath))
            {
                try { System.IO.Directory.Delete(testPath, true); } catch { }
            }
        }

        /// <summary>
        /// Test: RecordingService ElapsedTime increases during recording
        /// **Validates: Requirements 2.2**
        /// </summary>
        [StaFact]
        public void RecordingService_ElapsedTime_IncreasesWhileRecording()
        {
            // Arrange
            var mockLogger = new Mock<ILoggerService>();
            var mockDataPathService = new Mock<IXpDataPathService>();
            mockLogger.Setup(x => x.ForModule<ViewportRecordingService>()).Returns(mockLogger.Object);
            
            string testPath = System.IO.Path.Combine(System.IO.Path.GetTempPath(), $"XP_Test_{Guid.NewGuid():N}");
            mockDataPathService.Setup(x => x.RootPath).Returns(testPath);

            var service = new ViewportRecordingService(mockDataPathService.Object, mockLogger.Object);
            
            var captureTarget = CreateMockFrameworkElement(640, 480);
            bool started = service.StartRecording(captureTarget);

            // If codec not available, skip
            if (!started)
            {
                service.Dispose();
                return;
            }

            // Act
            Thread.Sleep(1500); // Wait 1.5 seconds
            var elapsed = service.ElapsedTime;

            // Assert
            Assert.True(elapsed.TotalSeconds >= 1.0, $"Expected elapsed time >= 1 second, got {elapsed.TotalSeconds}");
            Assert.True(elapsed.TotalSeconds < 3.0, $"Expected elapsed time < 3 seconds, got {elapsed.TotalSeconds}");

            // Cleanup
            service.Dispose();
            if (System.IO.Directory.Exists(testPath))
            {
                try { System.IO.Directory.Delete(testPath, true); } catch { }
            }
        }

        /// <summary>
        /// Test: RecordingService ElapsedTime is zero when idle
        /// **Validates: Requirements 2.2**
        /// </summary>
        [Fact]
        public void RecordingService_ElapsedTime_IsZeroWhenIdle()
        {
            // Arrange
            var mockLogger = new Mock<ILoggerService>();
            var mockDataPathService = new Mock<IXpDataPathService>();
            mockLogger.Setup(x => x.ForModule<ViewportRecordingService>()).Returns(mockLogger.Object);
            mockDataPathService.Setup(x => x.RootPath).Returns(@"C:\TestPath");

            var service = new ViewportRecordingService(mockDataPathService.Object, mockLogger.Object);

            // Act & Assert
            Assert.Equal(TimeSpan.Zero, service.ElapsedTime);
            Assert.Equal(RecordingState.Idle, service.CurrentState);

            // Cleanup
            service.Dispose();
        }

        /// <summary>
        /// Test: FormatElapsedTime produces correct MM:SS format
        /// **Validates: Requirements 2.2**
        /// </summary>
        [Fact]
        public void FormatElapsedTime_ProducesCorrectFormat()
        {
            // Act & Assert
            Assert.Equal("00:00", ViewportRecordingService.FormatElapsedTime(0));
            Assert.Equal("00:30", ViewportRecordingService.FormatElapsedTime(30));
            Assert.Equal("01:00", ViewportRecordingService.FormatElapsedTime(60));
            Assert.Equal("02:30", ViewportRecordingService.FormatElapsedTime(150));
            Assert.Equal("59:59", ViewportRecordingService.FormatElapsedTime(3599));
        }

        // ── Helper Methods ───────────────────────────────────────────────────

        /// <summary>
        /// Creates a mock FrameworkElement with specified dimensions for testing.
        /// </summary>
        private FrameworkElement CreateMockFrameworkElement(int width, int height)
        {
            var canvas = new System.Windows.Controls.Canvas
            {
                Width = width,
                Height = height,
                Background = System.Windows.Media.Brushes.White
            };

            // Force layout to set ActualWidth/ActualHeight
            canvas.Measure(new Size(width, height));
            canvas.Arrange(new Rect(0, 0, width, height));

            return canvas;
        }
    }
}