Show last log lines for generic ffmpeg erros

Author: n00mkrad

ff-utils-winforms/IO/Logger.cs

@@ -18,6 +18,7 @@ class Logger
         public const string defaultLogName = "sessionlog";
         public static long id;
 
+        private static Dictionary<string, string> sessionLogs = new Dictionary<string, string>();
         private static string _lastUi = "";
         public static string LastUiLine { get { return _lastUi; } }
         private static string _lastLog = "";
@@ -110,10 +111,9 @@ public static void LogToFile(string logStr, bool noLineBreak, string filename)
 
             try
             {
-                if (!noLineBreak)
-                    File.AppendAllText(file, $"{Environment.NewLine}[{id}] [{time}]: {logStr}");
-                else
-                    File.AppendAllText(file, " " + logStr);
+                string appendStr = noLineBreak ? $" {logStr}" : $"{Environment.NewLine}[{id}] [{time}]: {logStr}";
+                sessionLogs[filename] = (sessionLogs.ContainsKey(filename) ? sessionLogs[filename] : "") + appendStr;
+                File.AppendAllText(file, appendStr);
                 id++;
             }
             catch
@@ -122,35 +122,28 @@ public static void LogToFile(string logStr, bool noLineBreak, string filename)
             }
         }
 
-        public static void LogIfLastLineDoesNotContainMsg(string s, bool hidden = false, bool replaceLastLine = false, string filename = "")
+        public static string GetSessionLog(string filename)
         {
-            if (!GetLastLine().Contains(s))
-                Log(s, hidden, replaceLastLine, filename);
-        }
-
-        public static void WriteToFile(string content, bool append, string filename)
-        {
-            if (string.IsNullOrWhiteSpace(filename))
-                filename = defaultLogName;
-
-            if (Path.GetExtension(filename) != ".txt")
+            if (!filename.Contains(".txt"))
                 filename = Path.ChangeExtension(filename, "txt");
 
-            file = Path.Combine(Paths.GetLogPath(), filename);
-
-            string time = DT.Now.Month + "-" + DT.Now.Day + "-" + DT.Now.Year + " " + DT.Now.Hour + ":" + DT.Now.Minute + ":" + DT.Now.Second;
+            if (sessionLogs.ContainsKey(filename))
+                return sessionLogs[filename];
+            else
+                return "";
+        }
 
-            try
-            {
-                if (append)
-                    File.AppendAllText(file, Environment.NewLine + time + ":" + Environment.NewLine + content);
-                else
-                    File.WriteAllText(file, Environment.NewLine + time + ":" + Environment.NewLine + content);
-            }
-            catch
-            {
+        public static List<string> GetSessionLogLastLines(string filename, int linesCount = 5)
+        {
+            string log = GetSessionLog(filename);
+            string[] lines = log.SplitIntoLines();
+            return lines.Reverse().Take(linesCount).Reverse().ToList();
+        }
 
-            }
+        public static void LogIfLastLineDoesNotContainMsg(string s, bool hidden = false, bool replaceLastLine = false, string filename = "")
+        {
+            if (!GetLastLine().Contains(s))
+                Log(s, hidden, replaceLastLine, filename);
         }
 
         public static void ClearLogBox()

ff-utils-winforms/Media/FfmpegOutputHandler.cs

@@ -42,10 +42,11 @@ public static void LogOutput(string line, string[] ignoreStrings, ref string app
             }
 
             string lineWithoutPath = RemoveStringsFromLine(line, ignoreStrings);
+            string log = $"Last 4 log lines:\n{string.Join(Environment.NewLine, Logger.GetSessionLogLastLines("ffmpeg", 4))}"; 
 
             if (lineWithoutPath.Contains("Error ") || lineWithoutPath.Contains("Unable to ") || lineWithoutPath.Contains("Could not open file"))
             {
-                RunTask.Cancel($"Error: {line}");
+                RunTask.Cancel($"Error: {line}\n\n{log}");
                 return;
             }