using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Management;
using System.Threading;
using System.IO.Ports;
using System.Diagnostics;

namespace SafeMobileLib
{
    public class USBMonitoring
    {
        private Thread usbMonitoringThread;
        // the device which needs to be checked
        private DeviceInfo watchedDevice { get; set; }
        // refresh rate at which the usb detection should happen
        private int RefreshRateSeconds { get; set; }
        // remember the previous device status
        private bool previousDeviceStatus = false;
        // flag that the usb monitoring should be running or not
        private bool isRunning = false;


        public USBMonitoring(DeviceInfo watchedDecive, int refreshRateSeconds)
        {
            this.watchedDevice = watchedDecive;
            this.RefreshRateSeconds = refreshRateSeconds;
        }

        /// <summary>
        /// Start the thread which will manage the monitoring of the usb device plug & unplug
        /// </summary>
        public void StartUSBMonitoring()
        {
            if (this.isRunning)
                return;

            this.isRunning = true;
            usbMonitoringThread = new Thread(new ThreadStart(USBMonitoringThreadHandler));
            usbMonitoringThread.Start();
        }

        /// <summary>
        /// Stop the thread which is monitoring the detection of plug & unplug of the usb device
        /// </summary>
        public void StopUSBMonitoring()
        {
            this.isRunning = false;
        }

        /// <summary>
        /// Thread function
        /// </summary>
        private void USBMonitoringThreadHandler()
        {
            int count = -1;
            while (isRunning)
            {
                // wait until checking again
                Thread.Sleep(500);

                count++;

                if (count % (RefreshRateSeconds * 2) != 0)
                    continue;

                try
                {
                    bool crtDeviceStatus = false;

                    // get the list of attached usb device
                    var usbDevices = GetSerialPortDevices(); //GetUSBDevices();

                    if (watchedDevice != null && usbDevices != null)
                    {
                        foreach (var usbDevice in usbDevices)
                        {
                            //Console.WriteLine("DEV : " + usbDevice.vendorID + " | " + usbDevice.productID + " | " + usbDevice.COMPort);

                            // iterrate through all the device and see if the watched one is connected
                            if (usbDevice.vendorID.Equals(watchedDevice.vendorID) && usbDevice.productID.Equals(watchedDevice.productID))
                            {
                                crtDeviceStatus = true;
                                watchedDevice.COMPort = usbDevice.COMPort;

                                break;
                            }
                        }

                        // trigger event only when the device status has changed
                        if (previousDeviceStatus != crtDeviceStatus || count == 0)
                            OnDeviceStatusChanged(crtDeviceStatus, watchedDevice);

                        // update previous device status
                        previousDeviceStatus = crtDeviceStatus;
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine("USB Monitoring Evception: " + ex.ToString());
                }
            }

            Console.WriteLine("USB Monitoring Thread ended ♥♥♥");
        }

        /// <summary>
        /// Get a list of connected usb devices
        /// </summary>
        /// <returns>The list of usb devices</returns>
        private List<DeviceInfo> GetUSBDevices()
        {
            List<DeviceInfo> devices = new List<DeviceInfo>();

            ManagementObjectCollection collection;
            using (var searcher = new ManagementObjectSearcher(@"Select * From Win32_USBHub"))
                collection = searcher.Get();

            foreach (var device in collection)
            {
                devices.Add(new DeviceInfo(
                (string)device.GetPropertyValue("DeviceID"),
                (string)device.GetPropertyValue("PNPDeviceID"),
                (string)device.GetPropertyValue("Description")
                ));
            }

            collection.Dispose();
            return devices;
        }


        private List<DeviceInfo> GetSerialPortDevices()
        {
            List<DeviceInfo> devices = new List<DeviceInfo>();

            ManagementObjectSearcher searcher =
            new ManagementObjectSearcher("root\\CIMV2", "SELECT * FROM Win32_PnPEntity");

            if (searcher != null)
                foreach (ManagementObject queryObj in searcher.Get())
                {
                    string sInstanceName = string.Empty;
                    string portName = string.Empty;

                    if (queryObj["Caption"] != null && queryObj["Caption"].ToString().Contains("(COM"))
                    {
                        try
                        {
                            // get device vendor and product id
                            sInstanceName = queryObj["DeviceID"].ToString() + " | " + queryObj["PNPDeviceID"].ToString();
                            // save the com port for this device
                            portName = queryObj["Caption"].ToString();
                            // remove all characters before COM
                            portName = portName.Substring(portName.IndexOf("COM"));
                            // remove values after the COM 
                            if (portName.IndexOf(')') > 0)
                            {
                                portName = portName.Substring(0, portName.IndexOf(')'));
                            }

                            if (sInstanceName.Contains("VID_") && sInstanceName.Contains("PID_"))
                            {
                                string vid = sInstanceName.Substring(sInstanceName.IndexOf("VID_") + 4, 4);
                                string pid = sInstanceName.Substring(sInstanceName.IndexOf("PID_") + 4, 4);

                                devices.Add(new DeviceInfo(vid, pid, portName));
                            }
                        }
                        catch (Exception ex)
                        {
                            Utils.WriteLine(ex.ToString(), ConsoleColor.Red);
                        }
                    }
                }
            
            return devices;
        }


        /// <summary>
        /// Set The Baud Rate for a specific serial port
        /// </summary>
        /// <param name="baudRate">Baud Rate at which the device needs to communicate</param>
        /// <param name="comPort">COM port name. </param>
        public void SetBaudRate(Int64 baudRate, String comPort)
        {
            SerialPort serial = new SerialPort(comPort);
            serial.BaudRate = (int)baudRate;
        }

        /// <summary>
        /// Change or Set the Parameters for the device which is watched
        /// </summary>
        /// <param name="dev">Device parameters for the watched device</param>
        public void SetWatchedDevice(DeviceInfo dev)
        {
            watchedDevice = dev;
        }

        /// <summary>
        /// Change or Set the Parameters for the device which is watched
        /// </summary>
        /// <param name="vid">Vendor ID for the watched device (without VID_)</param>
        /// <param name="pid">Product ID for the watched device (without PID_)</param>
        public void SetWatchedDevice(string vid, string pid)
        {
            SetWatchedDevice(new DeviceInfo(vid, pid));
        }


        /// <summary>
        /// Get the status of the watched device, meaning if it is connected or not
        /// </summary>
        /// <returns>A boolean representing device status. True for connected and false otherwise</returns>
        public bool IsDeviceConnected()
        {
            return previousDeviceStatus;
        }


        /// <summary>
        /// Get the COM port name for the watched device. The name will contain even the
        /// COM prefix. eg.: COM32
        /// </summary>
        /// <returns>A string representing the COM file name (including COM prefix)</returns>
        public string GetComPortForWatchedDevice()
        {
            if (watchedDevice == null)
                return "";
            else
                return watchedDevice.COMPort;
        }
        
        public delegate void DeviceStatusChanged(bool isConnected, DeviceInfo device);
        public event DeviceStatusChanged OnDeviceStatusChanged;

    }

}