From 3fb2f95e8a11249d5dfbd816fa9d8a1f18dce6f0 Mon Sep 17 00:00:00 2001
From: Flavio Fois <f.fois@3git.eu>
Date: Thu, 5 Feb 2026 12:39:11 +0100
Subject: [PATCH] feat: implement console logger with backend integration and
 file logging

---
 frontend/src/lib/utils/logger-hook.ts     | 56 +++++++++++++++++++++++
 frontend/src/lib/wailsjs/go/main/App.d.ts |  2 +
 frontend/src/lib/wailsjs/go/main/App.js   |  4 ++
 frontend/src/routes/+layout.svelte        |  2 +
 logger.go                                 | 54 +++++++++++++++++++++-
 main.go                                   |  5 ++
 6 files changed, 122 insertions(+), 1 deletion(-)
 create mode 100644 frontend/src/lib/utils/logger-hook.ts

diff --git a/frontend/src/lib/utils/logger-hook.ts b/frontend/src/lib/utils/logger-hook.ts
new file mode 100644
index 0000000..e18b8c3
--- /dev/null
+++ b/frontend/src/lib/utils/logger-hook.ts
@@ -0,0 +1,56 @@
+import { FrontendLog } from '$lib/wailsjs/go/main/App';
+
+function safeStringify(obj: any): string {
+    try {
+        if (typeof obj === 'object' && obj !== null) {
+             return JSON.stringify(obj);
+        }
+        return String(obj);
+    } catch (e) {
+        return '[Circular/Error]';
+    }
+}
+
+export function setupConsoleLogger() {
+    if ((window as any).__logger_initialized__) return;
+    (window as any).__logger_initialized__ = true;
+
+    const originalLog = console.log;
+    const originalWarn = console.warn;
+    const originalError = console.error;
+    const originalInfo = console.info;
+
+    function logToBackend(level: string, args: any[]) {
+        try {
+            // Avoid logging if wails runtime is not ready or function is missing
+            if (typeof FrontendLog !== 'function') return;
+
+            const message = args.map(arg => safeStringify(arg)).join(' ');
+            FrontendLog(level, message).catch(() => {});
+        } catch (e) {
+            // ignore
+        }
+    }
+
+    console.log = (...args) => {
+        originalLog(...args);
+        logToBackend("INFO", args);
+    };
+
+    console.warn = (...args) => {
+        originalWarn(...args);
+        logToBackend("WARN", args);
+    };
+
+    console.error = (...args) => {
+        originalError(...args);
+        logToBackend("ERROR", args);
+    };
+
+    console.info = (...args) => {
+        originalInfo(...args);
+        logToBackend("INFO", args);
+    };
+
+    originalLog("Console logger hooked to Wails backend");
+}
diff --git a/frontend/src/lib/wailsjs/go/main/App.d.ts b/frontend/src/lib/wailsjs/go/main/App.d.ts
index 2db9d0a..c53e5d7 100644
--- a/frontend/src/lib/wailsjs/go/main/App.d.ts
+++ b/frontend/src/lib/wailsjs/go/main/App.d.ts
@@ -6,6 +6,8 @@ import {internal} from '../models';
 
 export function CheckIsDefaultEMLHandler():Promise<boolean>;
 
+export function FrontendLog(arg1:string,arg2:string):Promise<void>;
+
 export function GetConfig():Promise<utils.Config>;
 
 export function GetImageViewerData():Promise<main.ImageViewerData>;
diff --git a/frontend/src/lib/wailsjs/go/main/App.js b/frontend/src/lib/wailsjs/go/main/App.js
index badfacd..228744d 100644
--- a/frontend/src/lib/wailsjs/go/main/App.js
+++ b/frontend/src/lib/wailsjs/go/main/App.js
@@ -6,6 +6,10 @@ export function CheckIsDefaultEMLHandler() {
   return window['go']['main']['App']['CheckIsDefaultEMLHandler']();
 }
 
+export function FrontendLog(arg1, arg2) {
+  return window['go']['main']['App']['FrontendLog'](arg1, arg2);
+}
+
 export function GetConfig() {
   return window['go']['main']['App']['GetConfig']();
 }
diff --git a/frontend/src/routes/+layout.svelte b/frontend/src/routes/+layout.svelte
index 0cd5cab..a27fe7b 100644
--- a/frontend/src/routes/+layout.svelte
+++ b/frontend/src/routes/+layout.svelte
@@ -1,9 +1,11 @@
 <script lang="ts">
 	import { onMount } from 'svelte';
+	import { setupConsoleLogger } from '$lib/utils/logger-hook';
 
 	let { children } = $props();
 
 	onMount(() => {
+		setupConsoleLogger();
 		const loader = document.getElementById('app-loading');
 		if (loader) {
 			loader.style.opacity = '0';
diff --git a/logger.go b/logger.go
index bb23c65..36f9811 100644
--- a/logger.go
+++ b/logger.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"io"
 	"log"
 	"os"
 	"path/filepath"
@@ -10,7 +11,47 @@ import (
 	"time"
 )
 
-var logger = log.New(os.Stdout, "", 0)
+var (
+	logger  = log.New(os.Stdout, "", 0)
+	logFile *os.File
+)
+
+// InitLogger initializes the logger to write to both stdout and a file in AppData
+func InitLogger() error {
+	configDir, err := os.UserConfigDir()
+	if err != nil {
+		return err
+	}
+
+	appDir := filepath.Join(configDir, "EMLy")
+	logsDir := filepath.Join(appDir, "logs")
+
+	if err := os.MkdirAll(logsDir, 0755); err != nil {
+		return err
+	}
+
+	logPath := filepath.Join(logsDir, "app.log")
+	// Open file in Append mode
+	file, err := os.OpenFile(logPath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+	if err != nil {
+		return err
+	}
+	logFile = file
+
+	// MultiWriter to write to both stdout and file
+	multi := io.MultiWriter(os.Stdout, file)
+	logger = log.New(multi, "", 0)
+
+	Log("Logger initialized. Writing to: " + logPath)
+	return nil
+}
+
+// CloseLogger closes the log file
+func CloseLogger() {
+	if logFile != nil {
+		logFile.Close()
+	}
+}
 
 // Log prints a timestamped, file:line tagged log line.
 func Log(args ...any) {
@@ -27,3 +68,14 @@ func Log(args ...any) {
 	msg := fmt.Sprintln(args...)
 	logger.Printf("[%s] - [%s] - [%s] - %s", date, tm, loc, strings.TrimRight(msg, "\n"))
 }
+
+// FrontendLog allows the frontend to send logs to the backend logger
+func (a *App) FrontendLog(level string, message string) {
+	now := time.Now()
+	date := now.Format("2006-01-02")
+	tm := now.Format("15:04:05")
+
+	// We don't use runtime.Caller here because it would point to this function
+	// Instead we tag it as [FRONTEND]
+	logger.Printf("[%s] - [%s] - [FRONTEND] - [%s] %s", date, tm, level, message)
+}
diff --git a/main.go b/main.go
index c7fb12c..0f59780 100644
--- a/main.go
+++ b/main.go
@@ -28,6 +28,11 @@ func (a *App) onSecondInstanceLaunch(secondInstanceData options.SecondInstanceDa
 }
 
 func main() {
+	if err := InitLogger(); err != nil {
+		log.Println("Error initializing logger:", err)
+	}
+	defer CloseLogger()
+
 	// Check for custom args
 	args := os.Args
 	uniqueId := "emly-app-lock"