1using System;
 2using System.IO;
 3using System.Diagnostics;
 4using System.Runtime.CompilerServices;
 5
 6namespace WindowCapture.App
 7{
 8    public static class PerformanceLogger
 9    {
10        private static readonly string LogPath = Path.Combine(
11            Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
12            "WindowCapture", "performance.log");
13        
14        private static readonly object LockObj = new object();
15        private static Stopwatch sessionStopwatch = Stopwatch.StartNew();
16
17        static PerformanceLogger()
18        {
19            try
20            {
21                string dir = Path.GetDirectoryName(LogPath);
22                if (!Directory.Exists(dir)) Directory.CreateDirectory(dir);
23                
24                // Clear log on startup or keep it? Let's append with a separator
25                File.AppendAllText(LogPath, "\n--- New Session: " + DateTime.Now.ToString() + " ---\n");
26            }
27            catch { }
28        }
29
30        public static void Log(string action, long elapsedMs = -1, string details = "")
31        {
32            try
33            {
34                string timestamp = DateTime.Now.ToString("HH:mm:ss.fff");
35                string sessionTime = sessionStopwatch.Elapsed.TotalMilliseconds.ToString("F1");
36                string message = string.Format("[{0}] [{1}ms] {2}", timestamp, sessionTime, action);
37                
38                if (elapsedMs >= 0)
39                    message += string.Format(" | Latency: {0}ms", elapsedMs);
40                
41                if (!string.IsNullOrEmpty(details))
42                    message += string.Format(" | {0}", details);
43
44                lock (LockObj)
45                {
46                    File.AppendAllText(LogPath, message + "\n");
47                }
48            }
49            catch { }
50        }
51
52        public static IDisposable Measure(string action, string details = "")
53        {
54            return new MeasureScope(action, details);
55        }
56
57        private class MeasureScope : IDisposable
58        {
59            private readonly string action;
60            private readonly string details;
61            private readonly Stopwatch sw;
62
63            public MeasureScope(string action, string details)
64            {
65                this.action = action;
66                this.details = details;
67                this.sw = Stopwatch.StartNew();
68            }
69
70            public void Dispose()
71            {
72                sw.Stop();
73                Log(action, sw.ElapsedMilliseconds, details);
74            }
75        }
76    }
77}