using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.IO;

namespace USB_Lockdown
{
    class authentication
    {
        internal static Thread authenticationThread;
        internal static Thread deviceScanner;
        internal static void startScanning()
        {
            Thread authenticationThread = new Thread(beginAuthentication);
        }

        internal static void beginAuthentication()
        {
            deviceScan.calculateHash();
            Thread deviceScanner = new Thread(deviceScan.scanDevices);
            deviceScanner.Join(); //the thread will exit when a valid drive has been found

            //code here to unlock computer and stuff
        }
    }
    class deviceScan
    {
        internal static DriveInfo validDrive;
        internal static DriveInfo[] driveListing;
        private static bool driveFound = false;
        internal static string originalHash;

        internal static void calculateHash()
        {
            //decide how to do this!

        }
        internal static void scanDevices()
        {
            while (!driveFound) {
                driveListing = DriveInfo.GetDrives();
                foreach (DriveInfo currentDrive in driveListing)
                {
                    try { string driveName = currentDrive.VolumeLabel; string driveLabel = currentDrive.Name; }
                    catch { }
                    if (File.Exists(currentDrive.Name + "\\LockDown.config")) // the first check for a valid drive. Could be something else, but this is a lightweight test to be done first!
                    {
                        if (driveValidate(currentDrive)) //runs the full validation of the drive
                        {
                            validDrive = currentDrive;
                            driveFound = true;
                            break;
                        }
                    }
                }
            }
        }

        internal static bool driveValidate(DriveInfo drive){
            if (!checkHash(drive)) {
                return false;
            }
            return true;
        }

        private static bool checkHash(DriveInfo drive)
        {
            string fileName = drive.Name + "";
            if (!File.Exists(fileName)) { return false; }

            using (BinaryReader reader = new BinaryReader(File.Open(fileName, FileMode.Open)))
            {
                string hashFromDrive = reader.ReadString();
                if (hashFromDrive != )
            }
            return true;
        }


        internal static void resetValues()
        {
            validDrive = null;
            driveListing = null;
            driveFound = false;
        }
    }
}