using System;
using System.Drawing;
using System.Runtime.InteropServices;

namespace ScreenTranslator
{
    /// <summary>P/Invoke. Всё, что здесь возвращает координаты, отдаёт их в ФИЗИЧЕСКИХ пикселях
    /// (процесс помечен PerMonitorV2 в app.manifest), поэтому они напрямую совпадают с пикселями
    /// скриншота и с координатами боксов OCR.</summary>
    internal static class Native
    {
        // ---- горячие клавиши ----
        public const int WM_HOTKEY = 0x0312;
        public const uint MOD_ALT = 0x0001, MOD_CONTROL = 0x0002, MOD_SHIFT = 0x0004, MOD_WIN = 0x0008;
        public const uint MOD_NOREPEAT = 0x4000;

        [DllImport("user32.dll", SetLastError = true)]
        public static extern bool RegisterHotKey(IntPtr hWnd, int id, uint fsModifiers, uint vk);

        [DllImport("user32.dll", SetLastError = true)]
        public static extern bool UnregisterHotKey(IntPtr hWnd, int id);

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

        [StructLayout(LayoutKind.Sequential)]
        public struct RECT
        {
            public int Left, Top, Right, Bottom;
            public Rectangle ToRectangle() { return Rectangle.FromLTRB(Left, Top, Right, Bottom); }
        }

        [StructLayout(LayoutKind.Sequential)]
        public struct MONITORINFO
        {
            public int cbSize;
            public RECT rcMonitor;
            public RECT rcWork;
            public uint dwFlags;
        }

        public const uint MONITOR_DEFAULTTONEAREST = 2;

        [DllImport("user32.dll")]
        public static extern bool GetCursorPos(out POINT lpPoint);

        [DllImport("user32.dll")]
        public static extern IntPtr MonitorFromPoint(POINT pt, uint dwFlags);

        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        public static extern bool GetMonitorInfo(IntPtr hMonitor, ref MONITORINFO lpmi);

        /// <summary>Границы монитора под курсором, физические пиксели.</summary>
        public static Rectangle MonitorUnderCursor()
        {
            POINT p;
            if (!GetCursorPos(out p)) return VirtualScreen();
            IntPtr h = MonitorFromPoint(p, MONITOR_DEFAULTTONEAREST);
            var mi = new MONITORINFO();
            mi.cbSize = Marshal.SizeOf(typeof(MONITORINFO));
            if (!GetMonitorInfo(h, ref mi)) return VirtualScreen();
            return mi.rcMonitor.ToRectangle();
        }

        public const int SM_XVIRTUALSCREEN = 76, SM_YVIRTUALSCREEN = 77,
                         SM_CXVIRTUALSCREEN = 78, SM_CYVIRTUALSCREEN = 79;

        [DllImport("user32.dll")]
        public static extern int GetSystemMetrics(int nIndex);

        public static Rectangle VirtualScreen()
        {
            return new Rectangle(
                GetSystemMetrics(SM_XVIRTUALSCREEN), GetSystemMetrics(SM_YVIRTUALSCREEN),
                GetSystemMetrics(SM_CXVIRTUALSCREEN), GetSystemMetrics(SM_CYVIRTUALSCREEN));
        }

        // ---- окна ----
        public const int GWL_EXSTYLE = -20;
        public const int WS_EX_TOOLWINDOW = 0x00000080;
        public const int WS_EX_NOACTIVATE = 0x08000000;
        public const int WS_EX_TRANSPARENT = 0x00000020;
        public const int WS_EX_LAYERED = 0x00080000;

        [DllImport("user32.dll", SetLastError = true)]
        public static extern int GetWindowLong(IntPtr hWnd, int nIndex);

        [DllImport("user32.dll", SetLastError = true)]
        public static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);

        [DllImport("user32.dll")]
        public static extern IntPtr GetForegroundWindow();

        [DllImport("user32.dll")]
        public static extern bool SetForegroundWindow(IntPtr hWnd);

        public static readonly IntPtr HWND_TOPMOST = new IntPtr(-1);
        public const uint SWP_NOACTIVATE = 0x0010, SWP_SHOWWINDOW = 0x0040;

        [DllImport("user32.dll", SetLastError = true)]
        public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter,
            int X, int Y, int cx, int cy, uint uFlags);

        // ---- курсор для скриншота ----
        [StructLayout(LayoutKind.Sequential)]
        public struct CURSORINFO
        {
            public int cbSize;
            public int flags;
            public IntPtr hCursor;
            public POINT ptScreenPos;
        }

        [DllImport("user32.dll")]
        public static extern bool GetCursorInfo(out CURSORINFO pci);
    }
}