using System.Collections.Generic;
using System.Linq;
using RGB.NET.Core;

namespace RGB.NET.Devices.WS281X.Arduino;

// ReSharper disable once InconsistentNaming
/// <inheritdoc />
/// <summary>
/// Represents the update-queue performing updates for arduino WS2812 devices.
/// </summary>
public sealed class ArduinoWS2812USBUpdateQueue : SerialConnectionUpdateQueue<byte[]>
{
    #region Constants

    private static readonly byte[] COUNT_COMMAND = [0x01];
    private static readonly byte[] UPDATE_COMMAND = [0x02];
    private static readonly byte[] ASK_PROMPT_COMMAND = [0x0F];

    #endregion

    #region Properties & Fields

    private readonly Dictionary<int, byte[]> _dataBuffer = [];

    #endregion

    #region Constructors

    /// <summary>
    /// Initializes a new instance of the <see cref="ArduinoWS2812USBUpdateQueue"/> class.
    /// </summary>
    /// <param name="updateTrigger">The update trigger used by this queue.</param>
    /// <param name="serialConnection">The serial connection used to access the device.</param>
    public ArduinoWS2812USBUpdateQueue(IDeviceUpdateTrigger updateTrigger, ISerialConnection serialConnection)
        : base(updateTrigger, serialConnection)
    { }

    #endregion

    #region Methods

    /// <inheritdoc />
    protected override void OnStartup(object? sender, CustomUpdateData customData)
    {
        base.OnStartup(sender, customData);

        SendCommand(ASK_PROMPT_COMMAND); // Get initial prompt
    }

    /// <inheritdoc />
    protected override IEnumerable<byte[]> GetCommands(IList<(object key, Color color)> dataSet)
    {
        foreach (IGrouping<int, ((int channel, int key), Color Value)> channelData in dataSet.Select(x => (((int channel, int key))x.key, x.color))
                     .GroupBy(x => x.Item1.channel))
        {
            int channel = channelData.Key;
            if (!_dataBuffer.TryGetValue(channel, out byte[]? dataBuffer) || (dataBuffer.Length != ((dataSet.Count * 3) + 1)))
                _dataBuffer[channel] = dataBuffer = new byte[(dataSet.Count * 3) + 1];

            dataBuffer[0] = (byte)((channel << 4) | UPDATE_COMMAND[0]);
            int i = 1;
            foreach ((byte _, byte r, byte g, byte b) in channelData.OrderBy(x => x.Item1.key)
                                                                    .Select(x => x.Value.GetRGBBytes()))
            {
                dataBuffer[i++] = r;
                dataBuffer[i++] = g;
                dataBuffer[i++] = b;
            }
            yield return dataBuffer;
        }

        yield return UPDATE_COMMAND;
    }

    /// <inheritdoc />
    protected override void SendCommand(byte[] command) => SerialConnection.Write(command, 0, command.Length);

    internal IEnumerable<(int channel, int ledCount)> GetChannels()
    {
        if (!SerialConnection.IsOpen)
            SerialConnection.Open();

        SerialConnection.DiscardInBuffer();
        SendCommand(ASK_PROMPT_COMMAND);

        SerialConnection.ReadTo(Prompt);
        SendCommand(COUNT_COMMAND);
        int channelCount = SerialConnection.ReadByte();

        for (int i = 1; i <= channelCount; i++)
        {
            SerialConnection.ReadTo(Prompt);
            byte[] channelLedCountCommand = [(byte)((i << 4) | COUNT_COMMAND[0])];
            SendCommand(channelLedCountCommand);
            int ledCount = SerialConnection.ReadByte();
            if (ledCount > 0)
                yield return (i, ledCount);
        }
    }

    #endregion
}