using System.Device.Gpio;
using System.Device.Pwm;

using Microsoft.Extensions.Logging;

using GSS2.Core.Abstractions;

namespace GSS2.Core.Hardware;

public class IlluminatorService : IDisposable
{
    public record IlluminatorServiceConfiguration : ServiceConfigurationBase
    {
        public static IlluminatorServiceConfiguration Default => new IlluminatorServiceConfiguration
        {
            WhitePwmPin = 13,
            Uv254PwmPin = 18,
            Uv365PwmPin = 12,
            WhiteRelayPin = 16,
            Uv254RelayPin = 15,
            Uv365RelayPin = 20,
            FanPin = 21,

            PwmFrequency = 200,

            MaxWhitePwmDuty = 1.0,
            MaxUv254PwmDuty = 1.0,
            MaxUv365PwmDuty = 1.0
        };

        public int WhitePwmPin { get; set; }
        public int Uv254PwmPin { get; set; }
        public int Uv365PwmPin { get; set; }
        public int WhiteRelayPin { get; set; }
        public int Uv254RelayPin { get; set; }
        public int Uv365RelayPin { get; set; }
        public int FanPin { get; set; }

        public int PwmFrequency { get; set; }

        public double MaxWhitePwmDuty { get; set; }
        public double MaxUv254PwmDuty { get; set; }
        public double MaxUv365PwmDuty { get; set; }
    }

    private static readonly Dictionary<int, int> PinPwmChips = new()
    {
        { 12, 0 },
        { 13, 0 },
        { 14, 0 },
        { 15, 0 },
        { 18, 0 },
        { 19, 0 },
    };
    private static readonly Dictionary<int, int> PinPwmChannels = new()
    {
        { 12, 0 },
        { 13, 1 },
        { 14, 2 },
        { 15, 3 },
        { 18, 2 },
        { 19, 3 }
    };

    private bool _disposedValue;
    private readonly ILogger<IlluminatorService> _logger;
    private readonly IlluminatorServiceConfiguration _configuration;

    private readonly GpioController _gpio;
    private readonly PwmChannel _whitePwm;
    private readonly PwmChannel _uv254Pwm;
    private readonly PwmChannel _uv365Pwm;
    private readonly GpioPin _whiteRelay;
    private readonly GpioPin _uv254Relay;
    private readonly GpioPin _uv365Relay;
    private readonly GpioPin _fanRelay;

    public IlluminatorService(ILogger<IlluminatorService> logger, IlluminatorServiceConfiguration? configuration = null)
    {
        _logger = logger;

        _logger.LogInformation("Initialization");

        try
        {
            if (configuration is null)
            {
                configuration = IlluminatorServiceConfiguration.Default;
                _logger.LogWarning("Configuration not set. Using default configuration.");
            }
            _configuration = configuration;
            _logger.LogInformation("Using following configuration: \n{}", _configuration.ToString("\n", 4));

            CheckPwmPin(_configuration.WhitePwmPin);
            CheckPwmPin(_configuration.Uv254PwmPin);
            CheckPwmPin(_configuration.Uv365PwmPin);

            _gpio = new GpioController();
            _whitePwm = PwmChannel.Create(PinPwmChips[_configuration.WhitePwmPin], PinPwmChannels[_configuration.WhitePwmPin], _configuration.PwmFrequency, CalculateDuty(0, _configuration.MaxWhitePwmDuty));
            _uv254Pwm = PwmChannel.Create(PinPwmChips[_configuration.Uv254PwmPin], PinPwmChannels[_configuration.Uv254PwmPin], _configuration.PwmFrequency, CalculateDuty(0, _configuration.MaxUv254PwmDuty));
            _uv365Pwm = PwmChannel.Create(PinPwmChips[_configuration.Uv365PwmPin], PinPwmChannels[_configuration.Uv365PwmPin], _configuration.PwmFrequency, CalculateDuty(0, _configuration.MaxUv365PwmDuty));

            _whiteRelay = _gpio.OpenPin(_configuration.WhiteRelayPin, PinMode.Output, PinValue.Low);
            _uv254Relay = _gpio.OpenPin(_configuration.Uv254RelayPin, PinMode.Output, PinValue.Low);
            _uv365Relay = _gpio.OpenPin(_configuration.Uv365RelayPin, PinMode.Output, PinValue.Low);
            _fanRelay = _gpio.OpenPin(_configuration.FanPin, PinMode.Output, PinValue.Low);
        }
        catch (Exception e)
        {
            _logger.LogCritical(e, "An exception occurred while initialization");
            throw;
        }

        _logger.LogInformation("Initialized");
    }

    public void SetIntensity(double? white = null, double? uv365 = null, double? uv254 = null)
    {
        try
        {
            if (white is not null) _whitePwm.DutyCycle = CalculateDuty(white.Value, _configuration.MaxWhitePwmDuty);
            if (uv365 is not null) _uv365Pwm.DutyCycle = CalculateDuty(uv365.Value, _configuration.MaxUv365PwmDuty);
            if (uv254 is not null) _uv254Pwm.DutyCycle = CalculateDuty(uv254.Value, _configuration.MaxUv254PwmDuty);
        }
        catch (Exception e)
        {
            _logger.LogError(e, "An exception occurred while setting illuminator intensity");
        }
    }
    public void TurnOn()
    {
        try
        {
            _fanRelay.Write(PinValue.High);

            _whitePwm.Start();
            _uv254Pwm.Start();
            _uv365Pwm.Start();

            _whiteRelay.Write(PinValue.High);
            _uv254Relay.Write(PinValue.High);
            _uv365Relay.Write(PinValue.High);
        }
        catch (Exception e)
        {
            _logger.LogError(e, "An exception occurred while turning on illuminator");
        }
    }
    public void TurnOff()
    {
        try
        {
            _whitePwm.Stop();
            _uv254Pwm.Stop();
            _uv365Pwm.Stop();

            _whiteRelay.Write(PinValue.Low);
            _uv254Relay.Write(PinValue.Low);
            _uv365Relay.Write(PinValue.Low);

            _fanRelay.Write(PinValue.Low);
        }
        catch (Exception e)
        {
            _logger.LogError(e, "An exception occurred while turning off illuminator");
        }
    }

    protected virtual void Dispose(bool disposing)
    {
        if (!_disposedValue)
        {
            if (disposing)
            {
                try
                {
                    TurnOff();
                }
                catch { }

                _whiteRelay?.Dispose();
                _uv254Relay?.Dispose();
                _uv365Relay?.Dispose();
                _fanRelay?.Dispose();
                _whitePwm?.Dispose();
                _uv254Pwm?.Dispose();
                _uv365Pwm?.Dispose();
                _gpio?.Dispose();
            }

            _disposedValue = true;
        }
    }
    void IDisposable.Dispose()
    {
        Dispose(disposing: true);
        GC.SuppressFinalize(this);
    }

    private static void CheckPwmPin(int pin)
    {
        if (!PinPwmChips.TryGetValue(pin, out var _) || !PinPwmChannels.TryGetValue(pin, out var _))
            throw new ArgumentException($"Unsupported PWM pin {pin}");
    }
    private static double CalculateDuty(double intensity, double maxDuty) => Math.Clamp(intensity, 0.0, 1.0) * Math.Clamp(maxDuty, 0.0, 1.0);
}