Add daily log rotation with monthly folder structure

All log output is now additionally written to daily log files:
  daily-logs/YYYY-MM/YYYY-MM-DD.log (main log)
  daily-logs/YYYY-MM/YYYY-MM-DD-rename.log (rename log)

Automatic cleanup of daily logs older than 30 days. The existing
rd_downloader.log and rename.log continue to work as before.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/main/app-controller.ts

@@ -40,6 +40,7 @@ import { getAuditLogPath, initAuditLog, logAuditEvent, shutdownAuditLog } from "
 import { getDebugSetupCheck } from "./debug-setup";
 import { buildLinkExportSelection, serializeLinkExportText } from "./link-export";
 import { getRenameLogPath, initRenameLog, shutdownRenameLog } from "./rename-log";
+import { initDailyLog, shutdownDailyLog } from "./daily-log";
 import { buildAccountSummary, diffAccountSummary } from "./support-data";
 import { buildSupportBundle, getSupportBundleDefaultFileName } from "./support-bundle";
 import { getTraceConfig, getTraceLogPath, initTraceLog, logTraceEvent, setTraceEnabled, shutdownTraceLog } from "./trace-log";
@@ -85,6 +86,7 @@ export class AppController {
     initItemLogs(this.storagePaths.baseDir);
     initAuditLog(this.storagePaths.baseDir);
     initRenameLog(this.storagePaths.baseDir);
+    initDailyLog(this.storagePaths.baseDir);
     initTraceLog(this.storagePaths.baseDir);
     this.settings = loadSettings(this.storagePaths);
     resetHistoryForRetention(this.storagePaths, this.settings.historyRetentionMode);
@@ -670,6 +672,7 @@ export class AppController {
     shutdownPackageLogs();
     shutdownItemLogs();
     shutdownRenameLog();
+    shutdownDailyLog();
     this.audit("INFO", "App beendet");
     shutdownTraceLog();
     shutdownAuditLog();

src/main/daily-log.ts

@@ -0,0 +1,193 @@
+import fs from "node:fs";
+import path from "node:path";
+import { addLogListener, removeLogListener } from "./logger";
+
+const DAILY_LOG_RETENTION_DAYS = 30;
+const CLEANUP_CHECK_INTERVAL_MS = 6 * 60 * 60 * 1000; // every 6 hours
+
+let dailyLogDir = "";
+let currentDayKey = "";
+let currentLogFd: number | null = null;
+let currentRenameFd: number | null = null;
+let logListener: ((line: string) => void) | null = null;
+let cleanupTimer: NodeJS.Timeout | null = null;
+let lastCleanupAt = 0;
+
+function getDayKey(now = new Date()): string {
+  const year = now.getFullYear();
+  const month = String(now.getMonth() + 1).padStart(2, "0");
+  const day = String(now.getDate()).padStart(2, "0");
+  return `${year}-${month}-${day}`;
+}
+
+function getMonthDir(dayKey: string): string {
+  return dayKey.slice(0, 7); // "YYYY-MM"
+}
+
+function ensureDayFile(dayKey: string): number | null {
+  if (currentDayKey === dayKey && currentLogFd !== null) {
+    return currentLogFd;
+  }
+
+  // Close previous day's fd
+  if (currentLogFd !== null) {
+    try { fs.closeSync(currentLogFd); } catch { /* ignore */ }
+    currentLogFd = null;
+  }
+  if (currentRenameFd !== null) {
+    try { fs.closeSync(currentRenameFd); } catch { /* ignore */ }
+    currentRenameFd = null;
+  }
+
+  currentDayKey = dayKey;
+  const monthDir = path.join(dailyLogDir, getMonthDir(dayKey));
+
+  try {
+    fs.mkdirSync(monthDir, { recursive: true });
+    const filePath = path.join(monthDir, `${dayKey}.log`);
+    currentLogFd = fs.openSync(filePath, "a");
+    return currentLogFd;
+  } catch {
+    return null;
+  }
+}
+
+function ensureRenameFd(dayKey: string): number | null {
+  if (currentDayKey === dayKey && currentRenameFd !== null) {
+    return currentRenameFd;
+  }
+
+  // ensureDayFile handles day transitions
+  if (currentDayKey !== dayKey) {
+    ensureDayFile(dayKey);
+  }
+
+  if (currentRenameFd !== null) {
+    return currentRenameFd;
+  }
+
+  const monthDir = path.join(dailyLogDir, getMonthDir(dayKey));
+  try {
+    fs.mkdirSync(monthDir, { recursive: true });
+    const filePath = path.join(monthDir, `${dayKey}-rename.log`);
+    currentRenameFd = fs.openSync(filePath, "a");
+    return currentRenameFd;
+  } catch {
+    return null;
+  }
+}
+
+function writeToDailyLog(line: string): void {
+  if (!dailyLogDir) return;
+
+  const dayKey = getDayKey();
+  const fd = ensureDayFile(dayKey);
+  if (fd === null) return;
+
+  try {
+    fs.writeSync(fd, line);
+  } catch {
+    // Close and retry on next write
+    try { fs.closeSync(fd); } catch { /* ignore */ }
+    currentLogFd = null;
+  }
+}
+
+export function writeToDailyRenameLog(line: string): void {
+  if (!dailyLogDir) return;
+
+  const dayKey = getDayKey();
+  const fd = ensureRenameFd(dayKey);
+  if (fd === null) return;
+
+  try {
+    fs.writeSync(fd, line);
+  } catch {
+    try { fs.closeSync(fd); } catch { /* ignore */ }
+    currentRenameFd = null;
+  }
+}
+
+function cleanupOldDailyLogs(): void {
+  if (!dailyLogDir) return;
+
+  const now = Date.now();
+  if (now - lastCleanupAt < CLEANUP_CHECK_INTERVAL_MS) return;
+  lastCleanupAt = now;
+
+  const cutoffMs = now - DAILY_LOG_RETENTION_DAYS * 24 * 60 * 60 * 1000;
+
+  try {
+    const monthDirs = fs.readdirSync(dailyLogDir, { withFileTypes: true })
+      .filter((e) => e.isDirectory() && /^\d{4}-\d{2}$/.test(e.name));
+
+    for (const monthDir of monthDirs) {
+      const monthPath = path.join(dailyLogDir, monthDir.name);
+      const files = fs.readdirSync(monthPath, { withFileTypes: true })
+        .filter((e) => e.isFile() && /^\d{4}-\d{2}-\d{2}/.test(e.name));
+
+      for (const file of files) {
+        const filePath = path.join(monthPath, file.name);
+        try {
+          const stat = fs.statSync(filePath);
+          if (stat.mtimeMs < cutoffMs) {
+            fs.rmSync(filePath, { force: true });
+          }
+        } catch { /* ignore */ }
+      }
+
+      // Remove empty month dirs
+      try {
+        const remaining = fs.readdirSync(monthPath);
+        if (remaining.length === 0) {
+          fs.rmdirSync(monthPath);
+        }
+      } catch { /* ignore */ }
+    }
+  } catch {
+    // ignore cleanup errors
+  }
+}
+
+export function initDailyLog(baseDir: string): void {
+  dailyLogDir = path.join(baseDir, "daily-logs");
+
+  try {
+    fs.mkdirSync(dailyLogDir, { recursive: true });
+  } catch { /* ignore */ }
+
+  // Attach listener to main logger
+  logListener = (line: string) => writeToDailyLog(line);
+  addLogListener(logListener);
+
+  // Initial cleanup
+  cleanupOldDailyLogs();
+
+  // Periodic cleanup
+  cleanupTimer = setInterval(cleanupOldDailyLogs, CLEANUP_CHECK_INTERVAL_MS);
+  if (cleanupTimer.unref) cleanupTimer.unref();
+}
+
+export function shutdownDailyLog(): void {
+  if (logListener) {
+    removeLogListener(logListener);
+    logListener = null;
+  }
+  if (cleanupTimer) {
+    clearInterval(cleanupTimer);
+    cleanupTimer = null;
+  }
+  if (currentLogFd !== null) {
+    try { fs.closeSync(currentLogFd); } catch { /* ignore */ }
+    currentLogFd = null;
+  }
+  if (currentRenameFd !== null) {
+    try { fs.closeSync(currentRenameFd); } catch { /* ignore */ }
+    currentRenameFd = null;
+  }
+  currentDayKey = "";
+}
+
+export function getDailyLogDir(): string {
+  return dailyLogDir;
+}

src/main/rename-log.ts

@@ -1,5 +1,6 @@
 import fs from "node:fs";
 import path from "node:path";
+import { writeToDailyRenameLog } from "./daily-log";
 
 type RenameLogLevel = "INFO" | "WARN" | "ERROR";
 
@@ -93,11 +94,9 @@ export function logRenameEvent(level: RenameLogLevel, message: string, fields?:
     if (!fs.existsSync(renameLogPath)) {
       fs.writeFileSync(renameLogPath, "", "utf8");
     }
-    fs.appendFileSync(
-      renameLogPath,
-      `${new Date().toISOString()} [${level}] ${message}${formatFields(fields)}\n`,
-      "utf8"
-    );
+    const line = `${new Date().toISOString()} [${level}] ${message}${formatFields(fields)}\n`;
+    fs.appendFileSync(renameLogPath, line, "utf8");
+    writeToDailyRenameLog(line);
   } catch {
     // ignore write errors
   }