using System;
using System.Globalization;
using System.IO;
using System.IO.Ports;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading;

namespace OpenHardwareMonitor.Hardware.Controller.Heatmaster;

internal sealed class Heatmaster : Hardware, IDisposable
{
    private readonly bool _available;
    private readonly StringBuilder _buffer = new();
    private readonly Sensor[] _controls;
    private readonly Sensor[] _fans;
    private readonly int _firmwareCrc;
    private readonly int _firmwareRevision;
    private readonly Sensor[] _flows;
    private readonly int _hardwareRevision;
    private readonly string _portName;
    private readonly Sensor[] _relays;
    private readonly Sensor[] _temperatures;
    private SerialPort _serialPort;

    public Heatmaster(string portName, ISettings settings) : base("Heatmaster", new Identifier("heatmaster", portName.TrimStart('/').ToLowerInvariant()), settings)
    {
        _portName = portName;
        try
        {
            _serialPort = new SerialPort(portName, 38400, Parity.None, 8, StopBits.One);
            _serialPort.Open();
            _serialPort.NewLine = ((char)0x0D).ToString();

            _hardwareRevision = ReadInteger(0, 'H');
            _firmwareRevision = ReadInteger(0, 'V');
            _firmwareCrc = ReadInteger(0, 'C');

            int fanCount = Math.Min(ReadInteger(32, '?'), 4);
            int temperatureCount = Math.Min(ReadInteger(48, '?'), 6);
            int flowCount = Math.Min(ReadInteger(64, '?'), 1);
            int relayCount = Math.Min(ReadInteger(80, '?'), 1);

            _fans = new Sensor[fanCount];
            _controls = new Sensor[fanCount];
            for (int i = 0; i < fanCount; i++)
            {
                int device = 33 + i;
                string name = ReadString(device, 'C');
                _fans[i] = new Sensor(name, device, SensorType.Fan, this, settings) { Value = ReadInteger(device, 'R') };
                ActivateSensor(_fans[i]);
                _controls[i] = new Sensor(name, device, SensorType.Control, this, settings) { Value = (100 / 255.0f) * ReadInteger(device, 'P') };
                ActivateSensor(_controls[i]);
            }

            _temperatures = new Sensor[temperatureCount];
            for (int i = 0; i < temperatureCount; i++)
            {
                int device = 49 + i;
                string name = ReadString(device, 'C');
                _temperatures[i] = new Sensor(name, device, SensorType.Temperature, this, settings);
                int value = ReadInteger(device, 'T');
                _temperatures[i].Value = 0.1f * value;
                if (value != -32768)
                    ActivateSensor(_temperatures[i]);
            }

            _flows = new Sensor[flowCount];
            for (int i = 0; i < flowCount; i++)
            {
                int device = 65 + i;
                string name = ReadString(device, 'C');
                _flows[i] = new Sensor(name, device, SensorType.Flow, this, settings) { Value = 0.1f * ReadInteger(device, 'L') };
                ActivateSensor(_flows[i]);
            }

            _relays = new Sensor[relayCount];
            for (int i = 0; i < relayCount; i++)
            {
                int device = 81 + i;
                string name = ReadString(device, 'C');
                _relays[i] = new Sensor(name, device, SensorType.Control, this, settings)
                {
                    Value = 100 * ReadInteger(device, 'S')
                };
                ActivateSensor(_relays[i]);
            }

            // set the update rate to 2 Hz
            WriteInteger(0, 'L', 2);
            _available = true;
        }
        catch (IOException)
        { }
        catch (TimeoutException)
        { }
    }

    public override HardwareType HardwareType
    {
        get { return HardwareType.Cooler; }
    }

    public void Dispose()
    {
        if (_serialPort != null)
        {
            _serialPort.Dispose();
            _serialPort = null;
        }
    }

    private string ReadLine(int timeout)
    {
        int i = 0;
        StringBuilder builder = new();
        while (i <= timeout)
        {
            while (_serialPort.BytesToRead > 0)
            {
                byte b = (byte)_serialPort.ReadByte();
                switch (b)
                {
                    case 0xAA: return ((char)b).ToString();
                    case 0x0D: return builder.ToString();
                    default:
                        builder.Append((char)b);
                        break;
                }
            }

            i++;
            Thread.Sleep(1);
        }

        throw new TimeoutException();
    }

    private string ReadField(int device, char field)
    {
        _serialPort.WriteLine("[0:" + device + "]R" + field);
        for (int i = 0; i < 5; i++)
        {
            string s = ReadLine(200);
            Match match = Regex.Match(s, @"-\[0:" + device.ToString(CultureInfo.InvariantCulture) + @"\]R" + Regex.Escape(field.ToString(CultureInfo.InvariantCulture)) + ":(.*)");
            if (match.Success)
                return match.Groups[1].Value;
        }

        return null;
    }

    private string ReadString(int device, char field)
    {
        string s = ReadField(device, field);
        if (s?[0] == '"' && s[s.Length - 1] == '"')
            return s.Substring(1, s.Length - 2);

        return null;
    }

    private int ReadInteger(int device, char field)
    {
        string s = ReadField(device, field);
        if (int.TryParse(s, out int i))
            return i;

        return 0;
    }

    private void WriteField(int device, char field, string value)
    {
        _serialPort.WriteLine("[0:" + device + "]W" + field + ":" + value);
        for (int i = 0; i < 5; i++)
        {
            string s = ReadLine(200);
            Match match = Regex.Match(s, @"-\[0:" + device.ToString(CultureInfo.InvariantCulture) + @"\]W" + Regex.Escape(field.ToString(CultureInfo.InvariantCulture)) + ":" + value);
            if (match.Success)
                return;
        }
    }

    private void WriteInteger(int device, char field, int value)
    {
        WriteField(device, field, value.ToString(CultureInfo.InvariantCulture));
    }

    private void ProcessUpdateLine(string line)
    {
        Match match = Regex.Match(line, @">\[0:(\d+)\]([0-9:\|-]+)");
        if (match.Success && int.TryParse(match.Groups[1].Value, out int device))
        {
            foreach (string s in match.Groups[2].Value.Split('|'))
            {
                string[] strings = s.Split(':');
                int[] ints = new int[strings.Length];
                bool valid = true;
                for (int i = 0; i < ints.Length; i++)
                {
                    if (!int.TryParse(strings[i], out ints[i]))
                    {
                        valid = false;
                        break;
                    }
                }

                if (!valid)
                    continue;

                switch (device)
                {
                    case 32:
                        if (ints.Length == 3 && ints[0] <= _fans.Length)
                        {
                            _fans[ints[0] - 1].Value = ints[1];
                            _controls[ints[0] - 1].Value = (100 / 255.0f) * ints[2];
                        }

                        break;
                    case 48:
                        if (ints.Length == 2 && ints[0] <= _temperatures.Length)
                            _temperatures[ints[0] - 1].Value = 0.1f * ints[1];

                        break;
                    case 64:
                        if (ints.Length == 3 && ints[0] <= _flows.Length)
                            _flows[ints[0] - 1].Value = 0.1f * ints[1];

                        break;
                    case 80:
                        if (ints.Length == 2 && ints[0] <= _relays.Length)
                            _relays[ints[0] - 1].Value = 100 * ints[1];

                        break;
                }
            }
        }
    }

    public override void Update()
    {
        if (!_available)
            return;

        while (_serialPort.IsOpen && _serialPort.BytesToRead > 0)
        {
            byte b = (byte)_serialPort.ReadByte();
            if (b == 0x0D)
            {
                ProcessUpdateLine(_buffer.ToString());
                _buffer.Length = 0;
            }
            else
            {
                _buffer.Append((char)b);
            }
        }
    }

    public override string GetReport()
    {
        StringBuilder r = new();
        r.AppendLine("Heatmaster");
        r.AppendLine();
        r.Append("Port: ");
        r.AppendLine(_portName);
        r.Append("Hardware Revision: ");
        r.AppendLine(_hardwareRevision.ToString(CultureInfo.InvariantCulture));
        r.Append("Firmware Revision: ");
        r.AppendLine(_firmwareRevision.ToString(CultureInfo.InvariantCulture));
        r.Append("Firmware CRC: ");
        r.AppendLine(_firmwareCrc.ToString(CultureInfo.InvariantCulture));
        r.AppendLine();
        return r.ToString();
    }

    public override void Close()
    {
        _serialPort.Close();
        _serialPort.Dispose();
        _serialPort = null;
        base.Close();
    }
}
