// ReSharper disable UnusedMethodReturnValue.Global
// ReSharper disable UnusedMember.Global
// ReSharper disable MemberCanBePrivate.Global

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using RGB.NET.Core;

namespace RGB.NET.Devices.Logitech.Native
{
    // ReSharper disable once InconsistentNaming
    internal class _LogitechGSDK
    {
        #region Libary Management

        private static IntPtr _dllHandle = IntPtr.Zero;
        
        /// <summary>
        /// Reloads the SDK.
        /// </summary>
        internal static void Reload()
        {
            UnloadLogitechGSDK();
            LoadLogitechGSDK();
        }

        private static void LoadLogitechGSDK()
        {
            if (_dllHandle != IntPtr.Zero) return;

            // HACK: Load library at runtime to support both, x86 and x64 with one managed dll
            List<string> possiblePathList = Environment.Is64BitProcess ? LogitechDeviceProvider.PossibleX64NativePaths : LogitechDeviceProvider.PossibleX86NativePaths;
            string? dllPath = possiblePathList.FirstOrDefault(File.Exists);
            if (dllPath == null) throw new RGBDeviceException($"Can't find the Logitech-SDK at one of the expected locations:\r\n '{string.Join("\r\n", possiblePathList.Select(Path.GetFullPath))}'");

            _dllHandle = LoadLibrary(dllPath);

            _logiLedInitPointer = (LogiLedInitPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "LogiLedInit"), typeof(LogiLedInitPointer));
            _logiLedShutdownPointer = (LogiLedShutdownPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "LogiLedShutdown"), typeof(LogiLedShutdownPointer));
            _logiLedSetTargetDevicePointer = (LogiLedSetTargetDevicePointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "LogiLedSetTargetDevice"), typeof(LogiLedSetTargetDevicePointer));
            _logiLedGetSdkVersionPointer = (LogiLedGetSdkVersionPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "LogiLedGetSdkVersion"), typeof(LogiLedGetSdkVersionPointer));
            _lgiLedSaveCurrentLightingPointer = (LogiLedSaveCurrentLightingPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "LogiLedSaveCurrentLighting"), typeof(LogiLedSaveCurrentLightingPointer));
            _logiLedRestoreLightingPointer = (LogiLedRestoreLightingPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "LogiLedRestoreLighting"), typeof(LogiLedRestoreLightingPointer));
            _logiLedSetLightingPointer = (LogiLedSetLightingPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "LogiLedSetLighting"), typeof(LogiLedSetLightingPointer));
            _logiLedSetLightingForKeyWithKeyNamePointer = (LogiLedSetLightingForKeyWithKeyNamePointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "LogiLedSetLightingForKeyWithKeyName"), typeof(LogiLedSetLightingForKeyWithKeyNamePointer));
            _logiLedSetLightingFromBitmapPointer = (LogiLedSetLightingFromBitmapPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "LogiLedSetLightingFromBitmap"), typeof(LogiLedSetLightingFromBitmapPointer));
            _logiLedSetLightingForTargetZonePointer = (LogiLedSetLightingForTargetZonePointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "LogiLedSetLightingForTargetZone"), typeof(LogiLedSetLightingForTargetZonePointer));
        }

        internal static void UnloadLogitechGSDK()
        {
            if (_dllHandle == IntPtr.Zero) return;

            LogiLedShutdown();

            // ReSharper disable once EmptyEmbeddedStatement - DarthAffe 20.02.2016: We might need to reduce the internal reference counter more than once to set the library free
            while (FreeLibrary(_dllHandle)) ;
            _dllHandle = IntPtr.Zero;
        }

        [DllImport("kernel32.dll")]
        private static extern IntPtr LoadLibrary(string dllToLoad);

        [DllImport("kernel32.dll")]
        private static extern bool FreeLibrary(IntPtr dllHandle);

        [DllImport("kernel32.dll")]
        private static extern IntPtr GetProcAddress(IntPtr dllHandle, string name);

        #endregion

        #region SDK-METHODS

        #region Pointers

        private static LogiLedInitPointer? _logiLedInitPointer;
        private static LogiLedShutdownPointer? _logiLedShutdownPointer;
        private static LogiLedSetTargetDevicePointer? _logiLedSetTargetDevicePointer;
        private static LogiLedGetSdkVersionPointer? _logiLedGetSdkVersionPointer;
        private static LogiLedSaveCurrentLightingPointer? _lgiLedSaveCurrentLightingPointer;
        private static LogiLedRestoreLightingPointer? _logiLedRestoreLightingPointer;
        private static LogiLedSetLightingPointer? _logiLedSetLightingPointer;
        private static LogiLedSetLightingForKeyWithKeyNamePointer? _logiLedSetLightingForKeyWithKeyNamePointer;
        private static LogiLedSetLightingFromBitmapPointer? _logiLedSetLightingFromBitmapPointer;
        private static LogiLedSetLightingForTargetZonePointer? _logiLedSetLightingForTargetZonePointer;

        #endregion

        #region Delegates

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate bool LogiLedInitPointer();

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate void LogiLedShutdownPointer();

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate bool LogiLedSetTargetDevicePointer(int targetDevice);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate bool LogiLedGetSdkVersionPointer(ref int majorNum, ref int minorNum, ref int buildNum);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate bool LogiLedSaveCurrentLightingPointer();

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate bool LogiLedRestoreLightingPointer();

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate bool LogiLedSetLightingPointer(int redPercentage, int greenPercentage, int bluePercentage);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate bool LogiLedSetLightingForKeyWithKeyNamePointer(int keyCode, int redPercentage, int greenPercentage, int bluePercentage);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate bool LogiLedSetLightingFromBitmapPointer(byte[] bitmap);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate bool LogiLedSetLightingForTargetZonePointer(LogitechDeviceType deviceType, int zone, int redPercentage, int greenPercentage, int bluePercentage);

        #endregion

        // ReSharper disable EventExceptionNotDocumented

        internal static bool LogiLedInit() => (_logiLedInitPointer ?? throw new RGBDeviceException("The Logitech-GSDK is not initialized.")).Invoke();

        internal static void LogiLedShutdown() => (_logiLedShutdownPointer ?? throw new RGBDeviceException("The Logitech-GSDK is not initialized.")).Invoke();

        internal static bool LogiLedSetTargetDevice(LogitechDeviceCaps targetDevice) => (_logiLedSetTargetDevicePointer ?? throw new RGBDeviceException("The Logitech-GSDK is not initialized.")).Invoke((int)targetDevice);

        internal static string LogiLedGetSdkVersion()
        {
            int major = 0;
            int minor = 0;
            int build = 0;
            LogiLedGetSdkVersion(ref major, ref minor, ref build);

            return $"{major}.{minor}.{build}";
        }

        internal static bool LogiLedGetSdkVersion(ref int majorNum, ref int minorNum, ref int buildNum) =>
            (_logiLedGetSdkVersionPointer ?? throw new RGBDeviceException("The Logitech-GSDK is not initialized.")).Invoke(ref majorNum, ref minorNum, ref buildNum);

        internal static bool LogiLedSaveCurrentLighting() => (_lgiLedSaveCurrentLightingPointer ?? throw new RGBDeviceException("The Logitech-GSDK is not initialized.")).Invoke();

        internal static bool LogiLedRestoreLighting() => (_logiLedRestoreLightingPointer ?? throw new RGBDeviceException("The Logitech-GSDK is not initialized.")).Invoke();

        internal static bool LogiLedSetLighting(int redPercentage, int greenPercentage, int bluePercentage) =>
            (_logiLedSetLightingPointer ?? throw new RGBDeviceException("The Logitech-GSDK is not initialized.")).Invoke(redPercentage, greenPercentage, bluePercentage);

        internal static bool LogiLedSetLightingForKeyWithKeyName(int keyCode, int redPercentage, int greenPercentage, int bluePercentage)
            => (_logiLedSetLightingForKeyWithKeyNamePointer ?? throw new RGBDeviceException("The Logitech-GSDK is not initialized.")).Invoke(keyCode, redPercentage, greenPercentage, bluePercentage);

        internal static bool LogiLedSetLightingFromBitmap(byte[] bitmap) => (_logiLedSetLightingFromBitmapPointer ?? throw new RGBDeviceException("The Logitech-GSDK is not initialized.")).Invoke(bitmap);

        internal static bool LogiLedSetLightingForTargetZone(LogitechDeviceType deviceType, int zone, int redPercentage, int greenPercentage, int bluePercentage)
            => (_logiLedSetLightingForTargetZonePointer ?? throw new RGBDeviceException("The Logitech-GSDK is not initialized.")).Invoke(deviceType, zone, redPercentage, greenPercentage, bluePercentage);

        // ReSharper restore EventExceptionNotDocumented

        #endregion
    }
}