using System;
using System.Collections.Generic;
using System.Data;
using System.IO.Ports;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SerialCommApp.SeriallLibs
{
	public class PSerialComm
	{
		private readonly string CRLF = "\r\n";

		private SerialPort _serialPort;
		private string _stringBuffer;

		private object _receiveLock = new object();

		public event EventHandler<string> OnDataReceived;

		public PMessageHistory<string> History { get; set; }
		public PSerialCommSetting SerialCommSetting { get; set; }

		public bool IsOpen { get { return _serialPort.IsOpen; } }

		public string PortName 
		{
			get
			{
				return _serialPort.PortName;
			}
			set
			{
				_serialPort.PortName = value;
			}
		}

		public PSerialComm()
        {
			InitInstance();
        }

        public PSerialComm(string port)
        {
			InitInstance();
			this.PortName = port;
        }

        private void InitInstance()
		{
			if (_serialPort != null)
				_serialPort.Close();

			_serialPort = new SerialPort();
			_serialPort.DataReceived += SerialPort_DataReceived;

			SerialCommSetting = new PSerialCommSetting();

			this.History = new PMessageHistory<string>(10);
		}

		private void SerialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
		{
			SerialPort serialPort = sender as SerialPort;
			if (serialPort == null)
				return;

			string data = serialPort.ReadExisting();
			if (data.Length < 1)
				return;

			HandleData(data);
		}

		public static string[] GetPortNames()
		{
			return SerialPort.GetPortNames();
		}

		public void Write(string message)
		{
			_serialPort.Write(message);
		}

		private void HandleData(string data)
		{
			_stringBuffer = string.Concat(_stringBuffer, data);


			if (this.OnDataReceived == null)
				return;

			while (true)
			{
				int subStringIdx = _stringBuffer.IndexOf(CRLF);
				if (subStringIdx < 0)
					break;

				string message = _stringBuffer.Substring(0, subStringIdx);
				History.Add(message);

				if (this.OnDataReceived != null)
					this.OnDataReceived(this, message);

				_stringBuffer = _stringBuffer.Remove(0, subStringIdx + CRLF.Length);
			}
		}

		public void Open()
		{
			if (string.IsNullOrEmpty(this.PortName))
				throw new Exception("Port name is cannot be empty.");

			if (!_serialPort.IsOpen)
				_serialPort.Open();
		}

		public void Close()
		{
			if (string.IsNullOrEmpty(this.PortName))
				throw new Exception("Port name is cannot be empty.");

			if (_serialPort.IsOpen)
				_serialPort.Close();
		}
    }
}