using System;
using System.Runtime.InteropServices;


namespace Magpie.CursorHook {
	// Win32 API
	internal static class NativeMethods {
		[DllImport("user32.dll")]
		public static extern IntPtr SetCursor(IntPtr hCursor);

		[DllImport("user32.dll", CharSet = CharSet.Unicode)]
		public static extern IntPtr LoadCursor(IntPtr hInstance, IntPtr lpCursorName);

		public static readonly IntPtr IDC_ARROW = new IntPtr(32512);
		public static readonly IntPtr IDC_HAND = new IntPtr(32649);
		public static readonly IntPtr IDC_APPSTARTING = new IntPtr(32650);
		public static readonly IntPtr IDC_IBEAM = new IntPtr(32513);

		public const int GCLP_HCURSOR = -12;

		[DllImport("user32.dll", CharSet = CharSet.Unicode)]
		private static extern long GetClassLongPtr(IntPtr hWnd, int nIndex);

		[DllImport("user32.dll", CharSet = CharSet.Unicode)]
		private static extern int GetClassLong(IntPtr hWnd, int nIndex);

		[DllImport("user32.dll", CharSet = CharSet.Unicode)]
		private static extern long SetClassLongPtr(IntPtr hWnd, int nIndex, long dwNewLong);

		[DllImport("user32.dll", CharSet = CharSet.Unicode)]
		private static extern int SetClassLong(IntPtr hWnd, int nIndex, int dwNewLong);

		public static long GetClassAuto(IntPtr hWnd, int nIndex) {
			// 尽管文档表示 GetClassLongPtr 可以在 32 位程序里使用，但实际上会失败
			return EasyHook.NativeAPI.Is64Bit ? GetClassLongPtr(hWnd, nIndex) : GetClassLong(hWnd, nIndex);
		}

		public static long SetClassAuto(IntPtr hWnd, int nIndex, long dwNew) {
			return EasyHook.NativeAPI.Is64Bit ? SetClassLongPtr(hWnd, nIndex, dwNew) : SetClassLong(hWnd, nIndex, (int)dwNew);
		}

		public delegate bool EnumWindowsProc(IntPtr hwnd, int lParam);

		[DllImport("user32.dll")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool EnumChildWindows(IntPtr hWndParent, EnumWindowsProc lpEnumFunc, IntPtr lParam);

		[DllImport("user32.dll")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool EnumWindows(EnumWindowsProc lpEnumFunc, IntPtr lParam);

		[DllImport("user32.dll", CharSet = CharSet.Unicode)]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool PostMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

		[DllImport("user32.dll", CharSet = CharSet.Unicode)]
		public static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

		public const uint WM_SETCURSOR = 0x0020;
		public const int HTCLIENT = 1;

		[StructLayout(LayoutKind.Sequential)]
		public struct POINT {
			public int x;
			public int y;
		}

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

		[DllImport("user32.dll")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool GetCursorInfo(ref CURSORINFO pci);

		[DllImport("user32.dll")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool DestroyCursor(IntPtr hCursor);

		[StructLayout(LayoutKind.Sequential)]
		public struct ICONINFO {
			public int fIcon;
			public uint xHotspot;
			public uint yHotspot;
			public IntPtr hbmMask;
			public IntPtr hbmColor;
		}

		[DllImport("user32.dll")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool GetIconInfo(IntPtr hIcon, out ICONINFO piconinfo);

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

		[DllImport("gdi32.dll")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool DeleteObject(IntPtr ho);

		[DllImport("user32.dll", CharSet = CharSet.Unicode)]
		public static extern uint RegisterWindowMessage([MarshalAs(UnmanagedType.LPWStr)] string lpString);

		private const int SM_CXCURSOR = 13;
		private const int SM_CYCURSOR = 14;

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

		public static (int x, int y) GetCursorSize() {
			return (GetSystemMetrics(SM_CXCURSOR), GetSystemMetrics(SM_CYCURSOR));
		}

		[DllImport("user32.dll")]
		public static extern SafeCursorHandle CreateCursor(IntPtr hInst, int xHotSpot, int yHotSpot, int nWidth, int nHeight, byte[] pvANDPlane, byte[] pvXORPlane);

		[DllImport("kernel32.dll", CharSet = CharSet.Unicode)]
		private static extern IntPtr GetModuleHandle(IntPtr lpModuleName);

		public static IntPtr GetModule() {
			return GetModuleHandle(IntPtr.Zero);
		}

		[DllImport("user32.dll")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool IsWindow(IntPtr hWnd);


		[DllImport("user32.dll")]
		private static extern int GetWindowThreadProcessId(IntPtr hWnd, ref int lpdwProcessId);

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

		public static int GetWindowProcessId(IntPtr hWnd) {
			if (hWnd == IntPtr.Zero) {
				return 0;
			}

			int processId = 0;
			return GetWindowThreadProcessId(hWnd, ref processId) != 0 ? processId : 0;
		}

		public static int GetWindowThreadId(IntPtr hWnd) {
			return hWnd == IntPtr.Zero ? 0 : GetWindowThreadProcessId(hWnd, IntPtr.Zero);
		}

		[DllImport("user32.dll", CharSet = CharSet.Unicode)]
		public static extern IntPtr FindWindow(
			[MarshalAs(UnmanagedType.LPWStr)] string lpClassName,
			IntPtr lpWindowName
		);

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