using Xunit;
using TradingPlatform.BusinessLayer;
using TradingPlatform.BusinessLayer.Chart;
using System.Drawing;
using System.Reflection;

namespace QuanTAlib.Tests;

public class IndicatorExtensionsTests
{
    private sealed class TestIndicator : Indicator
    {
        public TestIndicator()
        {
            Name = "Test Indicator";
        }
    }

    private sealed class TestCoordinatesConverter : IChartWindowCoordinatesConverter
    {
        private readonly DateTime _time;
        public TestCoordinatesConverter(DateTime time) => _time = time;

        public DateTime GetTime(int x) => _time;
        public double GetChartX(DateTime time) => 10; // Return a fixed X for testing
        public double GetChartY(double value) => value; // Return value as Y for testing
    }

    [Fact]
    public void DataSourceInputAttribute_HasCorrectDefaults()
    {
        IndicatorExtensions.DataSourceInputAttribute attr = new();

        Assert.Equal("Data source", attr.Name);
        Assert.Equal(20, attr.SortIndex);
        Assert.NotNull(attr.Variants);
        Assert.NotEmpty(attr.Variants);
    }

    [Fact]
    public void GetInputValue_ReturnsCorrectValues_ForSourceTypes()
    {
        TestIndicator indicator = new();
        DateTime now = new(2024, 1, 1, 12, 0, 0, DateTimeKind.Utc);

        // Open=100, High=110, Low=90, Close=105, Volume=1000
        const double open = 100;
        const double high = 110;
        const double low = 90;
        const double close = 105;
        const double volume = 1000;

        indicator.HistoricalData.AddBar(now, open, high, low, close, volume);

        // Ensure Count is updated (mock implementation detail)
        // The mock HistoricalData.Count reflects added items.
        // Indicator.Count => HistoricalData.Count.

        UpdateArgs args = new(UpdateReason.NewBar);

        // Test each SourceType
        Assert.Equal(open, IndicatorExtensions.GetInputValue(indicator, args, SourceType.Open).Value);
        Assert.Equal(high, IndicatorExtensions.GetInputValue(indicator, args, SourceType.High).Value);
        Assert.Equal(low, IndicatorExtensions.GetInputValue(indicator, args, SourceType.Low).Value);
        Assert.Equal(close, IndicatorExtensions.GetInputValue(indicator, args, SourceType.Close).Value);

        // HL2 = (110 + 90) / 2 = 100
        Assert.Equal(100, IndicatorExtensions.GetInputValue(indicator, args, SourceType.HL2).Value);

        // OC2 = (100 + 105) / 2 = 102.5
        Assert.Equal(102.5, IndicatorExtensions.GetInputValue(indicator, args, SourceType.OC2).Value);

        // OHL3 = (100 + 110 + 90) / 3 = 100
        Assert.Equal(100, IndicatorExtensions.GetInputValue(indicator, args, SourceType.OHL3).Value);

        // HLC3 = (110 + 90 + 105) / 3 = 101.666...
        Assert.Equal(101.66666666666667, IndicatorExtensions.GetInputValue(indicator, args, SourceType.HLC3).Value, 5);

        // OHLC4 = (100 + 110 + 90 + 105) / 4 = 101.25
        Assert.Equal(101.25, IndicatorExtensions.GetInputValue(indicator, args, SourceType.OHLC4).Value);

        // HLCC4 = (110 + 90 + 105 + 105) / 4 = 102.5
        Assert.Equal(102.5, IndicatorExtensions.GetInputValue(indicator, args, SourceType.HLCC4).Value);
    }

    [Fact]
    public void GetInputBar_ReturnsCorrectBar()
    {
        TestIndicator indicator = new();
        DateTime now = new(2024, 1, 1, 12, 0, 0, DateTimeKind.Utc);

        const double open = 100;
        const double high = 110;
        const double low = 90;
        const double close = 105;
        const double volume = 1000;

        indicator.HistoricalData.AddBar(now, open, high, low, close, volume);
        UpdateArgs args = new(UpdateReason.NewBar);

        var bar = IndicatorExtensions.GetInputBar(indicator, args);

        Assert.Equal(now, bar.AsDateTime);
        Assert.Equal(open, bar.Open);
        Assert.Equal(high, bar.High);
        Assert.Equal(low, bar.Low);
        Assert.Equal(close, bar.Close);
        Assert.Equal(volume, bar.Volume);
    }

    [Fact]
    public void LogicMethods_CalculateCorrectly()
    {
        var indicator = new TestIndicator();
        indicator.CurrentChart = new MockChart();
        
        // Add some data
        var now = new DateTime(2024, 1, 1, 12, 0, 0, DateTimeKind.Utc);
        for (int i = 0; i < 20; i++)
        {
            indicator.HistoricalData.AddBar(now.AddMinutes(i), 100, 110, 90, 105);
        }

        // Setup converter
        var validTime = now.AddMinutes(10);
        var converter = new TestCoordinatesConverter(validTime);
        indicator.CurrentChart.MainWindow.CoordinatesConverter = converter;

        var clientRect = new Rectangle(0, 0, 100, 100);

        // 1. Test GetHLineY
        int y = IndicatorExtensions.GetHLineY(converter, 50.0);
        Assert.Equal(50, y); // Since our mock returns value as Y

        // 2. Test GetSmoothCurvePoints
        var series = new LineSeries("Test", Color.Blue, 1, LineStyle.Solid);
        for (int i = 0; i < 20; i++) series.AddValue(); 
        for (int i = 0; i < 20; i++) series.SetValue(100 + i, i); 

        var points = IndicatorExtensions.GetSmoothCurvePoints(indicator, converter, clientRect, series);
        Assert.NotEmpty(points);
        // Verify points logic: X should be 10 + halfBarWidth, Y should be value
        // MockChart.BarsWidth defaults to something? Let's assume 0 or check logic.
        // In GetSmoothCurvePoints: barX + halfBarWidth.
        // Our mock GetChartX returns 10.
        
        // 3. Test GetHistogramRectangles
        var histSeries = new LineSeries("Hist", Color.Blue, 1, LineStyle.Solid);
        for (int i = 0; i < 20; i++) histSeries.AddValue();
        for (int i = 0; i < 20; i++) 
        {
            double val = (i % 2 == 0) ? 10.0 : -10.0;
            histSeries.SetValue(val, i);
        }

        var rects = IndicatorExtensions.GetHistogramRectangles(indicator, converter, clientRect, histSeries);
        Assert.NotEmpty(rects);
        
        // Check value at offset 9 (i=9 in setup loop)
        // i=9 is odd -> -10.0 (Negative)
        // Color should be Red (150, 255, 0, 0)
        var first = rects.First();
        Assert.Equal(Color.FromArgb(150, 255, 0, 0), first.Color);
        
        // Verify geometry
        // Value is -10. GetChartY(-10) -> -10.
        // GetChartY(0) -> 0.
        // Height = Abs(0 - (-10)) = 10.
        // Y = 0 (since negative bars start at 0 and go down? No, GDI+ coords usually go down.
        // But here we are testing the logic in GetHistogramRectangles:
        // else { new Rectangle(barX, barY0, ...) } -> Y = barY0 = 0.
        Assert.Equal(0, first.Rect.Y);
        Assert.Equal(10, first.Rect.Height);
    }

    [Fact]
    [System.Runtime.Versioning.SupportedOSPlatform("windows")]
    public void PaintMethods_DoNotThrow_WithValidGraphics()
    {
        // This test attempts to verify that paint methods don't crash.
        // It requires System.Drawing.Common to be functional.
        
        // On non-Windows, this might fail if libgdiplus is not installed.
        // We'll try-catch the PlatformNotSupportedException to allow the test to pass (but not cover) on those systems.
        try 
        {
            using var bitmap = new Bitmap(100, 100);
            using var graphics = Graphics.FromImage(bitmap);
            RunPaintTests(graphics);
        }
        catch (TypeInitializationException) { return; } // System.Drawing.Common not supported
        catch (PlatformNotSupportedException) { return; } // GDI+ not available
        catch (DllNotFoundException) { return; } // libgdiplus not found
    }

    [System.Runtime.Versioning.SupportedOSPlatform("windows")]
    private void RunPaintTests(Graphics graphics)
    {
        var indicator = new TestIndicator();
        indicator.CurrentChart = new MockChart();
        
        // Add some data
        var now = new DateTime(2024, 1, 1, 12, 0, 0, DateTimeKind.Utc);
        for (int i = 0; i < 20; i++)
        {
            indicator.HistoricalData.AddBar(now.AddMinutes(i), 100, 110, 90, 105);
        }

        // Setup converter
        var validTime = now.AddMinutes(10);
        indicator.CurrentChart.MainWindow.CoordinatesConverter = new TestCoordinatesConverter(validTime);

        var args = new PaintChartEventArgs(graphics, new Rectangle(0, 0, 100, 100));
        using var pen = new Pen(Color.Red);
        
        // Test PaintHLine
        IndicatorExtensions.PaintHLine(indicator, args, 100, pen);

        // Test PaintSmoothCurve with different LineStyles and Warmup
        foreach (LineStyle style in Enum.GetValues(typeof(LineStyle)))
        {
            var series = new LineSeries("Test", Color.Blue, 1, style);
            for (int i = 0; i < 20; i++) series.AddValue(); 
            for (int i = 0; i < 20; i++) series.SetValue(100 + i, i); 
            
            // Test with warmup and cold values
            IndicatorExtensions.PaintSmoothCurve(indicator, args, series, warmupPeriod: 5, showColdValues: true);
            
            // Test without cold values
            IndicatorExtensions.PaintSmoothCurve(indicator, args, series, warmupPeriod: 5, showColdValues: false);
        }

        // Test PaintHistogram with Positive and Negative values
        var histSeries = new LineSeries("Hist", Color.Blue, 1, LineStyle.Solid);
        for (int i = 0; i < 20; i++) histSeries.AddValue();
        for (int i = 0; i < 20; i++) 
        {
            // Alternate positive and negative
            double val = (i % 2 == 0) ? 10.0 : -10.0;
            histSeries.SetValue(val, i);
        }
        IndicatorExtensions.PaintHistogram(indicator, args, histSeries, 0);

        // Test DrawText
        IndicatorExtensions.DrawText(indicator, args, "Test Text");
    }

    [Fact]
    public void GetInputValue_DefaultCase_ReturnsClose()
    {
        TestIndicator indicator = new();
        DateTime now = new(2024, 1, 1, 12, 0, 0, DateTimeKind.Utc);
        indicator.HistoricalData.AddBar(now, 100, 110, 90, 105, 1000);
        UpdateArgs args = new(UpdateReason.NewBar);

        // Cast to an invalid SourceType to trigger default case
        SourceType invalidType = (SourceType)999;
        
        var result = IndicatorExtensions.GetInputValue(indicator, args, invalidType);
        
        Assert.Equal(105, result.Value); // Should default to Close (105)
    }

}