using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using libWin32.Win32.Exceptions;

namespace libWin32.Win32.Input
{
    public class KeyTranslator
    {
        const uint MAPVK_VK_TO_VSC = 0x00;
        const uint MAPVK_VSC_TO_VK = 0x01;
        const uint MAPVK_VK_TO_CHAR = 0x02;
        const uint MAPVK_VSC_TO_VK_EX = 0x03;
        const uint MAPVK_VK_TO_VSC_EX = 0x04;
        [DllImport("user32.dll")]
        static extern uint MapVirtualKey(uint uCode, uint uMapType);

        public static void MapVirtualKeyToScanCode(short VKKey, out short ScanCode)
        {
            ScanCode = 0;
            short scanCode = (short)KeyTranslator.MapVirtualKey((uint)VKKey, MAPVK_VK_TO_VSC);
            try
            {
                ScanCode = scanCode;
            }
            catch (InvalidCastException ex)
            {
                ScanCode = scanCode;
                StringBuilder builder = new StringBuilder();
                builder.AppendFormat("VirtualKey: 0x{0:x2} translates to ScanCode: 0x{1:x8} which is not implemented.", VKKey, scanCode);
                throw new UnimplimentedDirectXScanCodeException(builder.ToString(), ex);
            }
        }
        public static void MapVirtualKeyToExtendedScanCode(short VKKey, out short ScanCode)
        {
            ScanCode = 0;
            short scanCode = (short)KeyTranslator.MapVirtualKey((uint)VKKey, MAPVK_VK_TO_VSC_EX);
            try
            {
                ScanCode = scanCode;
            }
            catch (InvalidCastException ex)
            {
                ScanCode = scanCode;
                StringBuilder builder = new StringBuilder();
                builder.AppendFormat("VirtualKey: 0x{0:x2} translates to ScanCode: 0x{1:x8} which is not implemented.", VKKey, scanCode);
                throw new UnimplimentedDirectXScanCodeException(builder.ToString(), ex);
            }
        }

        public static void MapScanCodeToVirtualKey(short ScanCode, out uint VKKey)
        {
            uint vkKey = KeyTranslator.MapVirtualKey((uint)ScanCode, MAPVK_VSC_TO_VK);
            VKKey = vkKey;
        }
        public static void MapScanCodeToExtendedVirtualKey(short ScanCode, out uint VKKey)
        {
            uint vkKey = KeyTranslator.MapVirtualKey((uint)ScanCode, MAPVK_VSC_TO_VK_EX);
            VKKey = vkKey;
        }

        public static void MapVirtualKeyToChar(byte VKKey, out char ScanCode)
        {
            uint scanCode = KeyTranslator.MapVirtualKey((uint)VKKey, MAPVK_VK_TO_CHAR);
            ScanCode = (char)scanCode;
        }
    }
}