using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace AxCopilot.Views;

/// <summary>
/// 전체 화면 스포이드 모드. 마우스를 따라다니는 돋보기와 HEX 코드를 표시하고,
/// 클릭 시 해당 픽셀 색상을 캡처하여 ColorPickResultWindow를 표시합니다.
/// </summary>
public partial class EyeDropperWindow : Window
{
    [DllImport("user32.dll")]
    private static extern bool GetCursorPos(out POINT lpPoint);

    [DllImport("gdi32.dll")]
    private static extern uint GetPixel(IntPtr hdc, int x, int y);

    [DllImport("user32.dll")]
    private static extern IntPtr GetDC(IntPtr hWnd);

    [DllImport("user32.dll")]
    private static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);

    [StructLayout(LayoutKind.Sequential)]
    private struct POINT { public int X, Y; }

    /// <summary>클릭으로 선택된 색상. null이면 취소.</summary>
    public System.Drawing.Color? PickedColor { get; private set; }
    public double PickX { get; private set; }
    public double PickY { get; private set; }

    private readonly System.Drawing.Rectangle _screenBounds;

    public EyeDropperWindow()
    {
        InitializeComponent();

        // 전체 모니터 영역
        _screenBounds = GetAllScreenBounds();
        Left   = _screenBounds.X;
        Top    = _screenBounds.Y;
        Width  = _screenBounds.Width;
        Height = _screenBounds.Height;

        Loaded += (_, _) =>
        {
            Magnifier.Visibility = Visibility.Visible;
            HexLabel.Visibility  = Visibility.Visible;
        };
    }

    private void Window_MouseMove(object sender, MouseEventArgs e)
    {
        var pos = e.GetPosition(RootCanvas);
        var color = GetScreenPixelColor();

        // 돋보기 위치 (커서 오른쪽 위)
        Canvas.SetLeft(Magnifier, pos.X + 16);
        Canvas.SetTop(Magnifier, pos.Y - 100);

        // HEX 레이블 위치
        Canvas.SetLeft(HexLabel, pos.X + 16);
        Canvas.SetTop(HexLabel, pos.Y - 10);

        // 돋보기 색상 미리보기
        var wpfColor = System.Windows.Media.Color.FromRgb(color.R, color.G, color.B);
        MagPreview.Fill = new SolidColorBrush(wpfColor);
        HexLabelText.Text = $"#{color.R:X2}{color.G:X2}{color.B:X2}";
    }

    private void Window_MouseDown(object sender, MouseButtonEventArgs e)
    {
        if (e.ChangedButton == MouseButton.Left)
        {
            PickedColor = GetScreenPixelColor();
            GetCursorPos(out var pt);
            PickX = pt.X;
            PickY = pt.Y;
            Close();
        }
        else if (e.ChangedButton == MouseButton.Right)
        {
            PickedColor = null;
            Close();
        }
    }

    private void Window_KeyDown(object sender, KeyEventArgs e)
    {
        if (e.Key == Key.Escape)
        {
            PickedColor = null;
            Close();
        }
    }

    private static System.Drawing.Color GetScreenPixelColor()
    {
        GetCursorPos(out var pt);
        var hdc = GetDC(IntPtr.Zero);
        try
        {
            uint pixel = GetPixel(hdc, pt.X, pt.Y);
            int r = (int)(pixel & 0xFF);
            int g = (int)((pixel >> 8) & 0xFF);
            int b = (int)((pixel >> 16) & 0xFF);
            return System.Drawing.Color.FromArgb(r, g, b);
        }
        finally
        {
            ReleaseDC(IntPtr.Zero, hdc);
        }
    }

    private static System.Drawing.Rectangle GetAllScreenBounds()
    {
        int left = 0, top = 0, right = 0, bottom = 0;
        foreach (var screen in System.Windows.Forms.Screen.AllScreens)
        {
            var b = screen.Bounds;
            left   = Math.Min(left, b.Left);
            top    = Math.Min(top, b.Top);
            right  = Math.Max(right, b.Right);
            bottom = Math.Max(bottom, b.Bottom);
        }
        return new System.Drawing.Rectangle(left, top, right - left, bottom - top);
    }
}