using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using RGB.NET.Core;
using RGB.NET.Devices.Corsair.Native;

namespace RGB.NET.Devices.Corsair
{
    /// <inheritdoc cref="AbstractRGBDevice{TDeviceInfo}" />
    /// <inheritdoc cref="ICorsairRGBDevice" />
    /// <summary>
    /// Represents a generic CUE-device. (keyboard, mouse, headset, mousepad).
    /// </summary>
    public abstract class CorsairRGBDevice<TDeviceInfo> : AbstractRGBDevice<TDeviceInfo>, ICorsairRGBDevice
        where TDeviceInfo : CorsairRGBDeviceInfo
    {
        #region Properties & Fields

        /// <inheritdoc />
        /// <summary>
        /// Gets information about the <see cref="T:RGB.NET.Devices.Corsair.CorsairRGBDevice" />.
        /// </summary>
        public override TDeviceInfo DeviceInfo { get; }

        /// <summary>
        /// Gets a dictionary containing all <see cref="Led"/> of the <see cref="CorsairRGBDevice{TDeviceInfo}"/>.
        /// </summary>
        // ReSharper disable once MemberCanBePrivate.Global
        protected Dictionary<CorsairLedId, Led> InternalLedMapping { get; } = new Dictionary<CorsairLedId, Led>();

        #endregion

        #region Indexer

        /// <summary>
        /// Gets the <see cref="Led"/> with the specified <see cref="CorsairLedId"/>.
        /// </summary>
        /// <param name="ledId">The <see cref="CorsairLedId"/> of the <see cref="Led"/> to get.</param>
        /// <returns>The <see cref="Led"/> with the specified <see cref="CorsairLedId"/> or null if no <see cref="Led"/> is found.</returns>
        // ReSharper disable once MemberCanBePrivate.Global
        public Led this[CorsairLedId ledId] => InternalLedMapping.TryGetValue(ledId, out Led led) ? led : null;

        #endregion

        #region Constructors

        /// <summary>
        /// Initializes a new instance of the <see cref="CorsairRGBDevice{TDeviceInfo}"/> class.
        /// </summary>
        /// <param name="info">The generic information provided by CUE for the device.</param>
        protected CorsairRGBDevice(TDeviceInfo info)
        {
            this.DeviceInfo = info;
        }

        #endregion

        #region Methods

        /// <summary>
        /// Initializes the device.
        /// </summary>
        public void Initialize()
        {
            InitializeLayout();

            foreach (Led led in LedMapping.Values)
            {
                CorsairLedId ledId = (CorsairLedId)led.CustomData;
                if (ledId != CorsairLedId.Invalid)
                    InternalLedMapping.Add(ledId, led);
            }

            if (Size == Size.Invalid)
            {
                Rectangle ledRectangle = new Rectangle(this.Select(x => x.LedRectangle));
                Size = ledRectangle.Size + new Size(ledRectangle.Location.X, ledRectangle.Location.Y);
            }
        }

        /// <summary>
        /// Initializes the <see cref="Led"/> and <see cref="Size"/> of the device.
        /// </summary>
        protected abstract void InitializeLayout();

        /// <inheritdoc />
        protected override void UpdateLeds(IEnumerable<Led> ledsToUpdate)
        {
            List<Led> leds = ledsToUpdate.Where(x => (x.Color.A > 0) && (x.CustomData is CorsairLedId ledId && (ledId != CorsairLedId.Invalid))).ToList();

            if (leds.Count > 0) // CUE seems to crash if 'CorsairSetLedsColors' is called with a zero length array
            {
                int structSize = Marshal.SizeOf(typeof(_CorsairLedColor));
                IntPtr ptr = Marshal.AllocHGlobal(structSize * leds.Count);
                IntPtr addPtr = new IntPtr(ptr.ToInt64());
                foreach (Led led in leds)
                {
                    _CorsairLedColor color = new _CorsairLedColor
                    {
                        ledId = (int)led.CustomData,
                        r = led.Color.R,
                        g = led.Color.G,
                        b = led.Color.B
                    };

                    Marshal.StructureToPtr(color, addPtr, false);
                    addPtr = new IntPtr(addPtr.ToInt64() + structSize);
                }
                _CUESDK.CorsairSetLedsColors(leds.Count, ptr);
                Marshal.FreeHGlobal(ptr);
            }
        }

        /// <inheritdoc cref="IRGBDevice.SyncBack" />
        public override void SyncBack()
        {
            int structSize = Marshal.SizeOf(typeof(_CorsairLedColor));
            IntPtr ptr = Marshal.AllocHGlobal(structSize * LedMapping.Count);
            IntPtr addPtr = new IntPtr(ptr.ToInt64());
            foreach (Led led in this)
            {
                _CorsairLedColor color = new _CorsairLedColor { ledId = (int)led.CustomData };
                Marshal.StructureToPtr(color, addPtr, false);
                addPtr = new IntPtr(addPtr.ToInt64() + structSize);
            }
            _CUESDK.CorsairGetLedsColors(LedMapping.Count, ptr);

            IntPtr readPtr = ptr;
            for (int i = 0; i < LedMapping.Count; i++)
            {
                _CorsairLedColor ledColor = (_CorsairLedColor)Marshal.PtrToStructure(readPtr, typeof(_CorsairLedColor));
                this[(CorsairLedId)ledColor.ledId].Color = new Color(ledColor.r, ledColor.g, ledColor.b);

                readPtr = new IntPtr(readPtr.ToInt64() + structSize);
            }

            Marshal.FreeHGlobal(ptr);
        }

        #endregion
    }
}