LogToFile in standalone builds for unity

LogToFile.cs

using System;
using System.IO;
using UnityEngine;

public class LogToFile : MonoBehaviour
{
    #if !UNITY_EDITOR && !UNITY_WEBGL
    private string logFilePath;
    private StreamWriter logWriter;
    private int logCounter = 0;
    private int maxLinesPerFile = 10000; // Adjust this as needed

    void Awake()
    {
        DontDestroyOnLoad(gameObject);
        
        // Get the directory where the executable is located
        string executablePath = System.Diagnostics.Process.GetCurrentProcess().MainModule.FileName;
        string executableDirectory = Path.GetDirectoryName(executablePath);
        
        // Create logs directory if it doesn't exist
        string logsDirectory = Path.Combine(executableDirectory, "Logs");
        if (!Directory.Exists(logsDirectory))
        {
            Directory.CreateDirectory(logsDirectory);
        }
        
        // Create log file with timestamp in the name
        string timestamp = DateTime.Now.ToString("yyyy-MM-dd_HH-mm-ss");
        logFilePath = Path.Combine(logsDirectory, $"AppLog_{timestamp}.log");
        
        InitializeLogFile();
        
        // Subscribe to log message events
        Application.logMessageReceived += HandleLog;
        
        Debug.Log($"Application started. Version: {Application.version}");
        Debug.Log($"Log file initialized at: {logFilePath}");
    }

    private void InitializeLogFile()
    {
        try
        {
            logWriter = new StreamWriter(logFilePath, true);
            logWriter.AutoFlush = true;
            
            // Write header with system info
            logWriter.WriteLine("==================================================");
            logWriter.WriteLine($"=== Log Session: {DateTime.Now} ===");
            logWriter.WriteLine($"=== Unity Version: {Application.unityVersion} ===");
            logWriter.WriteLine($"=== App Version: {Application.version} ===");
            logWriter.WriteLine($"=== OS: {SystemInfo.operatingSystem} ===");
            logWriter.WriteLine($"=== Device: {SystemInfo.deviceModel} ===");
            logWriter.WriteLine($"=== Processor: {SystemInfo.processorType} ===");
            logWriter.WriteLine($"=== Graphics: {SystemInfo.graphicsDeviceName} ===");
            logWriter.WriteLine("==================================================");
            logWriter.WriteLine();
        }
        catch (Exception e)
        {
            Debug.LogError($"Failed to initialize log file: {e.Message}");
        }
    }

    void HandleLog(string logString, string stackTrace, LogType type)
    {
        if (logWriter == null) return;
        
        try
        {
            // Write the log message to the file
            logWriter.WriteLine($"{DateTime.Now.ToString("HH:mm:ss.fff")} [{type}] {logString}");
            
            // For errors and exceptions, also write the stack trace
            if (type == LogType.Error || type == LogType.Exception)
            {
                logWriter.WriteLine(stackTrace);
            }
            
            // Increment the log counter
            logCounter++;
            
            // Check if we need to create a new log file (to avoid huge files)
            if (logCounter >= maxLinesPerFile)
            {
                RotateLogFile();
            }
        }
        catch (Exception e)
        {
            // If we can't write to the file, at least try to log the error to the console
            Debug.LogError($"Failed to write to log file: {e.Message}");
        }
    }
    
    private void RotateLogFile()
    {
        // Close current log file
        logWriter.WriteLine($"=== Log file continued in next file (reached {maxLinesPerFile} lines) ===");
        logWriter.Close();
        logWriter.Dispose();
        
        // Create new log file with updated timestamp
        string timestamp = DateTime.Now.ToString("yyyy-MM-dd_HH-mm-ss");
        string executableDirectory = Path.GetDirectoryName(System.Diagnostics.Process.GetCurrentProcess().MainModule.FileName);
        string logsDirectory = Path.Combine(executableDirectory, "Logs");
        logFilePath = Path.Combine(logsDirectory, $"AppLog_{timestamp}_continued.log");
        
        // Initialize the new log file
        InitializeLogFile();
        
        // Reset counter
        logCounter = 0;
    }

    void OnApplicationPause(bool pause)
    {
        if (logWriter != null)
        {
            if (pause)
            {
                logWriter.WriteLine($"=== Application Paused: {DateTime.Now} ===");
            }
            else
            {
                logWriter.WriteLine($"=== Application Resumed: {DateTime.Now} ===");
            }
        }
    }

    void OnApplicationQuit()
    {
        Debug.Log("Application shutting down");
    }

    void OnDestroy()
    {
        // Clean up
        if (logWriter != null)
        {
            Application.logMessageReceived -= HandleLog;
            logWriter.WriteLine();
            logWriter.WriteLine($"=== End Log Session: {DateTime.Now} ===");
            logWriter.Close();
            logWriter.Dispose();
        }
    }
    #endif
}