using EasyModbus;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Net.NetworkInformation;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Timers;
using ModbusSlave.Dialog;

namespace ModbusSlave
{
	public partial class MainForm : Form
	{
		private readonly int DATA_COUNT = 20;
		private ModbusServer server = new ModbusServer();
		private System.Timers.Timer updateTimer;

		private bool isFirstLog = true;

		public MainForm()
		{
			InitializeComponent();
			InitInstance();
		}

		private void btnRun_Click(object sender, EventArgs e)
		{
			try
			{
				server = new ModbusServer();
				server.Port = (int)nudPort.Value;
				server.UnitIdentifier = Convert.ToByte(nudIdentifier.Value);

				if (!CheckPortInUse(server.Port))
				{
					Log("[WARNING] unavailable port");
					return;
				}

				server.Listen();
				Log("--- Server start ---");

				btnRun.Enabled = false;
				nudIdentifier.Enabled = false;
				nudPort.Enabled = false;

				tbStatus.Text = "Run";
				tbStatus.BackColor = Color.Lime;

				updateTimer.Start();
			}
			catch (Exception ex)
			{
				Log("[ERROR] " + ex.Message);
			}
		}

		private void btnStop_Click(object sender, EventArgs e)
		{
			try
			{
				server.StopListening();
				Log("--- Server stop ---");

				btnRun.Enabled = true;
				nudIdentifier.Enabled = true;
				nudPort.Enabled = true;

				tbStatus.Text = "Stop";
				tbStatus.BackColor = Color.Silver;

				updateTimer.Stop();
			}
			catch (Exception ex)
			{
				Log("[ERROR] " + ex.Message);
			}
		}

		private void btnClear_Click(object sender, EventArgs e)
		{
			ClearLog();
		}

		private void Lv_MouseDoubleClick(object sender, MouseEventArgs e)
		{
			if (btnRun.Enabled)
				return;

			ListView lv = sender as ListView;
			if (lv.SelectedItems.Count < 1)
				return;

			int idx = lv.SelectedItems[0].Index;
			short tmp = 0;
			InputValueDialog dlg = new InputValueDialog();
			dlg.Value = lv.SelectedItems[0].SubItems[1].Text;
			dlg.StartPosition = FormStartPosition.CenterParent;
			switch (lv.Name)
			{
				case "lv0x":
					server.coils[idx + 1] = !server.coils[idx + 1];
					break;
				case "lv1x":
					server.discreteInputs[idx + 1] = !server.discreteInputs[idx + 1];
					break;
				case "lv3x":
					if (dlg.ShowDialog() != DialogResult.OK)
						return;

					if (!short.TryParse(dlg.Value, out tmp))
					{
						Log($"[ERROR] Value should be a number and in range of {short.MinValue} to {short.MaxValue}");
						return;
					}
					server.inputRegisters[idx + 1] = tmp;
					break;
				case "lv4x":
					if (dlg.ShowDialog() != DialogResult.OK)
						return;

					if (!short.TryParse(dlg.Value, out tmp))
					{
						Log($"[ERROR] Value should be a number and in range of {short.MinValue} to {short.MaxValue}");
						return;
					}
					server.holdingRegisters[idx + 1] = tmp;
					break;
			}
		}

		private void InitInstance()
		{
			server = new ModbusServer();
			updateTimer = new System.Timers.Timer();
			updateTimer.Interval = 1000;
			updateTimer.Elapsed += UpdateTimer_Elapsed;

			lv0x.MouseDoubleClick += Lv_MouseDoubleClick;
			lv1x.MouseDoubleClick += Lv_MouseDoubleClick;
			lv3x.MouseDoubleClick += Lv_MouseDoubleClick;
			lv4x.MouseDoubleClick += Lv_MouseDoubleClick;

			InitListView();
		}

		private void UpdateTimer_Elapsed(object sender, ElapsedEventArgs e)
		{
			UpdateListView(0);
			UpdateListView(1);
			UpdateListView(3);
			UpdateListView(4);
		}

		private void Log(string text)
		{
			rtbLog.AppendText((isFirstLog ? "" : Environment.NewLine) + text);
			isFirstLog = false;

			ScrollToEnd();
		}

		private void ScrollToEnd()
		{
			if (!chkAutoScroll.Checked)
				return;

			rtbLog.SelectionStart = rtbLog.Text.Length;
			rtbLog.ScrollToCaret();
		}

		private void ClearLog()
		{
			rtbLog.Clear();
			isFirstLog = true;
			ScrollToEnd();
		}

		private bool CheckPortInUse(int port)
		{
			bool isAvailable = true;
			var ipGlobalProperties = IPGlobalProperties.GetIPGlobalProperties();
			var tcpListenerArray = ipGlobalProperties.GetActiveTcpListeners();

			foreach (var ip in tcpListenerArray)
			{
				if (ip.Port == port)
				{
					isAvailable = false;
					break;
				}	
			}

			return isAvailable;
		}

		private void InitListView()
		{
			for (int i = 0; i < 5; i++)
			{
				if (i == 2)
					continue;

				string controlName = $"lv{i}x";
				Control[] foundControls = this.Controls.Find(controlName, true);
				if (foundControls.Length < 1 || !(foundControls[0] is ListView))
					continue;

				ListView listView = foundControls[0] as ListView;
				listView.GetType()
					.GetProperty("DoubleBuffered", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic)
					.SetValue(listView, true, null);
				listView.BeginUpdate();
				listView.Items.Clear();

				for (int j = 0; j < DATA_COUNT; j++)
				{
					ListViewItem item = new ListViewItem();
					
					switch(i)
					{
						case 0: // 0x: 00001 ~ 00010
							item.Text = string.Format("{0:D5}", j + 1);
							break;
						case 1: // 1x: 10001 ~ 10010
							item.Text = (10000 + j + 1).ToString();
							break;
						case 3: // 3x: 30001 ~ 30010
							item.Text = (30000 + j + 1).ToString();
							break;
						case 4: // 4x: 40001 ~ 40010
							item.Text = (40000 + j + 1).ToString();
							break;
					}

					item.SubItems.Add("0");
					listView.Items.Add(item);
				}

				listView.Columns[0].Width = -2;
				listView.Columns[1].Width = -2;

				listView.EndUpdate();
			}
		}

		private void UpdateListView(int regNum)
		{
			string controlName = $"lv{regNum}x";
			Control[] foundControls = this.Controls.Find(controlName, true);
			if (foundControls.Length < 1 || !(foundControls[0] is ListView))
				return;

			ListView listView = foundControls[0] as ListView;
			if (listView.InvokeRequired)
			{
				listView.BeginInvoke(new MethodInvoker(delegate
				{
					UpdateListView(regNum);
				}));

				return;
			}

			listView.BeginUpdate();

			for (int i = 0; i < DATA_COUNT; i++)
			{
				string value = "";
				switch (regNum)
				{
					case 0:
						value = server.coils[i + 1] ? "1" : "0";
						break;
					case 1:
						value = server.discreteInputs[i + 1] ? "1" : "0";
						break;
					case 3:
						value = server.inputRegisters[i + 1].ToString();
						break;
					case 4:
						value = server.holdingRegisters[i + 1].ToString();
						break;
				}

				listView.Items[i].SubItems[1].Text = value;
			}

			listView.EndUpdate();
		}
	}
}