// ReSharper disable UnusedMethodReturnValue.Global
// ReSharper disable UnusedMember.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.Corsair.Native
{
    // ReSharper disable once InconsistentNaming
    internal static class _CUESDK
    {
        #region Libary Management

        private static IntPtr _dllHandle = IntPtr.Zero;

        /// <summary>
        /// Gets the loaded architecture (x64/x86).
        /// </summary>
        internal static string LoadedArchitecture { get; private set; }

        /// <summary>
        /// Reloads the SDK.
        /// </summary>
        internal static void Reload()
        {
            UnloadCUESDK();
            LoadCUESDK();
        }

        private static void LoadCUESDK()
        {
            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 ? CorsairDeviceProvider.PossibleX64NativePaths : CorsairDeviceProvider.PossibleX86NativePaths;
            string dllPath = possiblePathList.FirstOrDefault(File.Exists);
            if (dllPath == null) throw new RGBDeviceException($"Can't find the CUE-SDK at one of the expected locations:\r\n '{string.Join("\r\n", possiblePathList.Select(Path.GetFullPath))}'");

            _dllHandle = LoadLibrary(dllPath);

            _corsairSetLedsColorsBufferByDeviceIndexPointer = (CorsairSetLedsColorsBufferByDeviceIndexPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "CorsairSetLedsColorsBufferByDeviceIndex"), typeof(CorsairSetLedsColorsBufferByDeviceIndexPointer));
            _corsairSetLedsColorsFlushBufferPointer = (CorsairSetLedsColorsFlushBufferPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "CorsairSetLedsColorsFlushBuffer"), typeof(CorsairSetLedsColorsFlushBufferPointer));
            _corsairGetLedsColorsByDeviceIndexPointer = (CorsairGetLedsColorsByDeviceIndexPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "CorsairGetLedsColorsByDeviceIndex"), typeof(CorsairGetLedsColorsByDeviceIndexPointer));
            _corsairSetLayerPriorityPointer = (CorsairSetLayerPriorityPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "CorsairSetLayerPriority"), typeof(CorsairSetLayerPriorityPointer));
            _corsairGetDeviceCountPointer = (CorsairGetDeviceCountPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "CorsairGetDeviceCount"), typeof(CorsairGetDeviceCountPointer));
            _corsairGetDeviceInfoPointer = (CorsairGetDeviceInfoPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "CorsairGetDeviceInfo"), typeof(CorsairGetDeviceInfoPointer));
            _corsairGetLedPositionsByDeviceIndexPointer = (CorsairGetLedPositionsByDeviceIndexPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "CorsairGetLedPositionsByDeviceIndex"), typeof(CorsairGetLedPositionsByDeviceIndexPointer));
            _corsairGetLedIdForKeyNamePointer = (CorsairGetLedIdForKeyNamePointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "CorsairGetLedIdForKeyName"), typeof(CorsairGetLedIdForKeyNamePointer));
            _corsairRequestControlPointer = (CorsairRequestControlPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "CorsairRequestControl"), typeof(CorsairRequestControlPointer));
            _corsairReleaseControlPointer = (CorsairReleaseControlPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "CorsairReleaseControl"), typeof(CorsairReleaseControlPointer));
            _corsairPerformProtocolHandshakePointer = (CorsairPerformProtocolHandshakePointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "CorsairPerformProtocolHandshake"), typeof(CorsairPerformProtocolHandshakePointer));
            _corsairGetLastErrorPointer = (CorsairGetLastErrorPointer)Marshal.GetDelegateForFunctionPointer(GetProcAddress(_dllHandle, "CorsairGetLastError"), typeof(CorsairGetLastErrorPointer));
        }

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

            // 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 CorsairSetLedsColorsBufferByDeviceIndexPointer _corsairSetLedsColorsBufferByDeviceIndexPointer;
        private static CorsairSetLedsColorsFlushBufferPointer _corsairSetLedsColorsFlushBufferPointer;
        private static CorsairGetLedsColorsByDeviceIndexPointer _corsairGetLedsColorsByDeviceIndexPointer;
        private static CorsairSetLayerPriorityPointer _corsairSetLayerPriorityPointer;
        private static CorsairGetDeviceCountPointer _corsairGetDeviceCountPointer;
        private static CorsairGetDeviceInfoPointer _corsairGetDeviceInfoPointer;
        private static CorsairGetLedIdForKeyNamePointer _corsairGetLedIdForKeyNamePointer;
        private static CorsairGetLedPositionsByDeviceIndexPointer _corsairGetLedPositionsByDeviceIndexPointer;
        private static CorsairRequestControlPointer _corsairRequestControlPointer;
        private static CorsairReleaseControlPointer _corsairReleaseControlPointer;
        private static CorsairPerformProtocolHandshakePointer _corsairPerformProtocolHandshakePointer;
        private static CorsairGetLastErrorPointer _corsairGetLastErrorPointer;

        #endregion

        #region Delegates

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate bool CorsairSetLedsColorsBufferByDeviceIndexPointer(int deviceIndex, int size, IntPtr ledsColors);

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

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate bool CorsairGetLedsColorsByDeviceIndexPointer(int deviceIndex, int size, IntPtr ledsColors);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate bool CorsairSetLayerPriorityPointer(int priority);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate int CorsairGetDeviceCountPointer();

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate IntPtr CorsairGetDeviceInfoPointer(int deviceIndex);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate IntPtr CorsairGetLedPositionsByDeviceIndexPointer(int deviceIndex);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate CorsairLedId CorsairGetLedIdForKeyNamePointer(char keyName);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate bool CorsairRequestControlPointer(CorsairAccessMode accessMode);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate bool CorsairReleaseControlPointer(CorsairAccessMode accessMode);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate _CorsairProtocolDetails CorsairPerformProtocolHandshakePointer();

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate CorsairError CorsairGetLastErrorPointer();

        #endregion

        // ReSharper disable EventExceptionNotDocumented

        /// <summary>
        /// CUE-SDK: set specified LEDs to some colors.
        /// This function set LEDs colors in the buffer which is written to the devices via CorsairSetLedsColorsFlushBuffer or CorsairSetLedsColorsFlushBufferAsync.
        /// Typical usecase is next: CorsairSetLedsColorsFlushBuffer or CorsairSetLedsColorsFlushBufferAsync is called to write LEDs colors to the device
        /// and follows after one or more calls of CorsairSetLedsColorsBufferByDeviceIndex to set the LEDs buffer.
        /// This function does not take logical layout into account.
        /// </summary>
        internal static bool CorsairSetLedsColorsBufferByDeviceIndex(int deviceIndex, int size, IntPtr ledsColors) => _corsairSetLedsColorsBufferByDeviceIndexPointer(deviceIndex, size, ledsColors);

        /// <summary>
        /// CUE-SDK: writes to the devices LEDs colors buffer which is previously filled by the CorsairSetLedsColorsBufferByDeviceIndex function.
        /// This function executes synchronously, if you are concerned about delays consider using CorsairSetLedsColorsFlushBufferAsync
        /// </summary>
        internal static bool CorsairSetLedsColorsFlushBuffer() => _corsairSetLedsColorsFlushBufferPointer();

        /// <summary>
        /// CUE-SDK: get current color for the list of requested LEDs.
        /// The color should represent the actual state of the hardware LED, which could be a combination of SDK and/or CUE input.
        /// This function works for keyboard, mouse, mousemat, headset, headset stand and DIY-devices.
        /// </summary>
        internal static bool CorsairGetLedsColorsByDeviceIndex(int deviceIndex, int size, IntPtr ledsColors) => _corsairGetLedsColorsByDeviceIndexPointer(deviceIndex, size, ledsColors);

        /// <summary>
        /// CUE-SDK: set layer priority for this shared client.
        /// By default CUE has priority of 127 and all shared clients have priority of 128 if they don’t call this function.
        /// Layers with higher priority value are shown on top of layers with lower priority.
        /// </summary>
        internal static bool CorsairSetLayerPriority(int priority) => _corsairSetLayerPriorityPointer(priority);

        /// <summary>
        /// CUE-SDK: returns number of connected Corsair devices that support lighting control.
        /// </summary>
        internal static int CorsairGetDeviceCount() => _corsairGetDeviceCountPointer();

        /// <summary>
        /// CUE-SDK: returns information about device at provided index.
        /// </summary>
        internal static IntPtr CorsairGetDeviceInfo(int deviceIndex) => _corsairGetDeviceInfoPointer(deviceIndex);

        /// <summary>
        /// CUE-SDK: provides list of keyboard or mousepad LEDs with their physical positions.
        /// </summary>
        internal static IntPtr CorsairGetLedPositionsByDeviceIndex(int deviceIndex) => _corsairGetLedPositionsByDeviceIndexPointer(deviceIndex);

        /// <summary>
        /// CUE-SDK: retrieves led id for key name taking logical layout into account.
        /// </summary>
        internal static CorsairLedId CorsairGetLedIdForKeyName(char keyName) => _corsairGetLedIdForKeyNamePointer(keyName);

        /// <summary>
        /// CUE-SDK: requestes control using specified access mode.
        /// By default client has shared control over lighting so there is no need to call CorsairRequestControl unless client requires exclusive control.
        /// </summary>
        internal static bool CorsairRequestControl(CorsairAccessMode accessMode) => _corsairRequestControlPointer(accessMode);

        /// <summary>
        /// CUE-SDK: releases previously requested control for specified access mode.
        /// </summary>
        internal static bool CorsairReleaseControl(CorsairAccessMode accessMode) => _corsairReleaseControlPointer(accessMode);

        /// <summary>
        /// CUE-SDK: checks file and protocol version of CUE to understand which of SDK functions can be used with this version of CUE.
        /// </summary>
        internal static _CorsairProtocolDetails CorsairPerformProtocolHandshake() => _corsairPerformProtocolHandshakePointer();

        /// <summary>
        /// CUE-SDK: returns last error that occured while using any of Corsair* functions.
        /// </summary>
        internal static CorsairError CorsairGetLastError() => _corsairGetLastErrorPointer();

        // ReSharper restore EventExceptionNotDocumented

        #endregion
    }
}