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using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.Diagnostics;
using System.IO;
using System.Runtime.InteropServices;
using System.Timers;
 
namespace WinWatcherLite
{
    public partial class MainForm : Form
    {
        string startTime;
        string lastWindow;
        string logFolder;
        Dictionary<string, Stopwatch> windowLog;
 
        public MainForm()
        {
            InitializeComponent();
            InitializeCustomObjects();
        }
 
        private void InitializeCustomObjects()
        {
            startTime = DateTime.Now.ToString("ddMMyyyy_hhmmss");
            lastWindow = string.Empty;
            logFolder = Path.GetDirectoryName(Application.ExecutablePath);
            windowLog = new Dictionary<string, Stopwatch>();
 
            System.Windows.Forms.Timer timer = new System.Windows.Forms.Timer();
            timer.Interval = 500;
            timer.Tick += new EventHandler(timer_Tick);
            timer.Start();
 
            System.Timers.Timer t = new System.Timers.Timer(60000);
            t.Elapsed += new ElapsedEventHandler(OnTimedEvent);
            t.Start();
        }
 
        #region user32.dll
 
        [DllImport("user32.dll")]
        public static extern IntPtr GetForegroundWindow();
 
        [DllImport("user32.dll")]
        public static extern int GetWindowText(IntPtr hWnd, StringBuilder lpWindowText, int nMaxCount);
 
        #endregion
 
        public void GetActiveWindow()
        {
            IntPtr win = GetForegroundWindow();
            StringBuilder sb = new StringBuilder(255);
            GetWindowText(win, sb, 256);
 
            string currentWindow = sb.ToString();
            if (lastWindow != currentWindow)
            {
                if (windowLog.ContainsKey(lastWindow))
                    windowLog[lastWindow].Stop();
 
                if (windowLog.ContainsKey(currentWindow))
                    windowLog[currentWindow].Start();
                else
                {
                    Stopwatch sw = new Stopwatch();
                    sw.Start();
                    windowLog.Add(currentWindow, sw);
                }
 
                lastWindow = currentWindow;
            }
        }
 
        private void OnTimedEvent(object sender, ElapsedEventArgs e)
        {
            WriteLog();
        }
 
        private void MainForm_FormClosing(object sender, FormClosingEventArgs e)
        {
            WriteLog();
        }
 
        private void timer_Tick(object sender, EventArgs e)
        {
            GetActiveWindow();
        }
 
        private void WriteLog()
        {
            string filePath = Path.Combine(logFolder, string.Format("WindowLog_{0}.txt", startTime));
            StringBuilder sb = new StringBuilder();
 
            foreach (KeyValuePair<string, Stopwatch> registry in windowLog)
            {
                TimeSpan ts = registry.Value.Elapsed;
                string elapsedTime = string.Format("{0:00}:{1:00}:{2:00}", ts.Hours, ts.Minutes, ts.Seconds);
                sb.AppendLine(string.Format("{0} => {1}", registry.Key, elapsedTime));
            }
 
            using (StreamWriter sw = new StreamWriter(filePath))
                sw.Write(sb.ToString());
        }
    }
}