using System;
using System.Collections.Generic;
using System.Windows;
using Paca.App.Core;
using Xunit;

namespace Paca.Tests.App;

public class MultiDisplayLayoutEngineGateTests
{
    [Fact]
    public void Gate269_MultiDisplayLayoutEngine_ClampsWindow_WithinSingleMonitorBounds()
    {
        var workArea = new Rect(0, 0, 1920, 1080);
        // Window 400x300 requested at (1800, 950) -> exceeds 1920 and 1080
        var clamped = MultiDisplayLayoutEngine.ClampToWorkArea(
            requestedLeft: 1800,
            requestedTop: 950,
            windowWidth: 400,
            windowHeight: 300,
            workArea: workArea,
            margin: 16
        );

        Assert.Equal(1920 - 400 - 16, clamped.X);
        Assert.Equal(1080 - 300 - 16, clamped.Y);
    }

    [Fact]
    public void Gate270_MultiDisplayLayoutEngine_HandlesNegativeCoordinates_OnSecondaryLeftMonitor()
    {
        var leftMonitorWorkArea = new Rect(-1920, 0, 1920, 1080);
        
        // Window 400x300 requested at -2000 (beyond left edge)
        var clamped = MultiDisplayLayoutEngine.ClampToWorkArea(
            requestedLeft: -2000,
            requestedTop: 100,
            windowWidth: 400,
            windowHeight: 300,
            workArea: leftMonitorWorkArea,
            margin: 16
        );

        Assert.Equal(-1920 + 16, clamped.X);
        Assert.Equal(100, clamped.Y);
    }

    [Fact]
    public void Gate271_MultiDisplayLayoutEngine_ConvertsDpiToDips()
    {
        // Standard 96 DPI = 1.0 scale
        Assert.Equal(100.0, MultiDisplayLayoutEngine.PixelsToDips(100, 96));

        // 144 DPI (150% scaling) -> 150 pixels = 100 DIPs
        Assert.Equal(100.0, MultiDisplayLayoutEngine.PixelsToDips(150, 144));
    }

    [Fact]
    public void Gate272_MultiDisplayLayoutEngine_FindsBestScreen_ForWindow()
    {
        var screens = new List<Rect>
        {
            new(0, 0, 1920, 1080),       // Primary screen
            new(1920, 0, 1920, 1080)     // Secondary screen to the right
        };

        // Window placed mostly on secondary screen (e.g. x=2000)
        var bestScreen = MultiDisplayLayoutEngine.FindBestScreen(new Rect(2000, 200, 400, 300), screens);
        Assert.Equal(1920, bestScreen.X);
    }
}