refactor: extract format helpers (sanitize, twitch-duration, date-pattern, merge-phase) + 24 tests

src/main/infra/format-helpers.ts. main.ts adapter for getMergeGroupPhaseText
injects config.language. 210 unit tests gruen.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/main.ts

@@ -8,6 +8,12 @@ import { autoUpdater } from 'electron-updater';
 import { compareUpdateVersions, isNewerUpdateVersion, normalizeUpdateVersion } from './main/domain/update-version-utils';
 import { writeFileAtomicSync } from './main/infra/fs-atomic';
 import { parseDuration, formatDuration, formatDurationDashed } from './main/infra/duration';
+import {
+    sanitizeFilenamePart,
+    formatTwitchDurationFromSeconds,
+    formatDateWithPattern,
+    getMergeGroupPhaseText as getMergeGroupPhaseTextCore,
+} from './main/infra/format-helpers';
 import { tBackend as tBackendCore, type BackendMessageKey } from './main/domain/i18n-backend';
 import type { DbHandle } from './main/infra/db';
 import {
@@ -86,14 +92,7 @@ type UpdateCheckSource = 'startup' | 'interval' | 'manual';
 type UpdateDownloadSource = 'auto' | 'manual';
 
 function getMergeGroupPhaseText(phase: string): string {
-    const isEnglish = config.language === 'en';
+    return getMergeGroupPhaseTextCore(phase, config?.language ?? 'de');
-    switch (phase) {
-        case 'downloading': return isEnglish ? 'Downloading VOD' : 'VOD wird heruntergeladen';
-        case 'merging': return isEnglish ? 'Merging...' : 'Zusammenfugen...';
-        case 'splitting': return isEnglish ? 'Splitting Part' : 'Part wird erstellt';
-        case 'cleanup': return isEnglish ? 'Cleaning up...' : 'Aufraumen...';
-        default: return phase;
-    }
 }
 
 // ==========================================
@@ -967,36 +966,6 @@ function releaseClaimedFilenamesForItem(itemId: string): void {
     itemClaimedFilenames.delete(itemId);
 }
 
-function sanitizeFilenamePart(input: string, fallback = 'unnamed'): string {
-    const cleaned = (input || '')
-        .replace(/[<>:"|?*\x00-\x1f]/g, '_')
-        .replace(/[\\/]/g, '_')
-        .trim();
-    return cleaned || fallback;
-}
-
-function formatDateWithPattern(date: Date, pattern: string): string {
-    const tokenMap: Record<string, string> = {
-        yyyy: date.getFullYear().toString(),
-        yy: date.getFullYear().toString().slice(-2),
-        MM: (date.getMonth() + 1).toString().padStart(2, '0'),
-        M: (date.getMonth() + 1).toString(),
-        dd: date.getDate().toString().padStart(2, '0'),
-        d: date.getDate().toString(),
-        HH: date.getHours().toString().padStart(2, '0'),
-        H: date.getHours().toString(),
-        hh: date.getHours().toString().padStart(2, '0'),
-        h: date.getHours().toString(),
-        mm: date.getMinutes().toString().padStart(2, '0'),
-        m: date.getMinutes().toString(),
-        ss: date.getSeconds().toString().padStart(2, '0'),
-        s: date.getSeconds().toString()
-    };
-
-    return pattern
-        .replace(/yyyy|yy|MM|M|dd|d|HH|H|hh|h|mm|m|ss|s/g, (token) => tokenMap[token] ?? token)
-        .replace(/\\(.)/g, '$1');
-}
 
 function formatSecondsWithPattern(totalSeconds: number, pattern: string): string {
     const safe = Math.max(0, Math.floor(totalSeconds));
@@ -1714,17 +1683,6 @@ async function ensureTwitchAuth(forceRefresh = false): Promise<boolean> {
     return await requestTwitchLogin();
 }
 
-function formatTwitchDurationFromSeconds(totalSeconds: number): string {
-    const seconds = Math.max(0, Math.floor(totalSeconds));
-    const h = Math.floor(seconds / 3600);
-    const m = Math.floor((seconds % 3600) / 60);
-    const s = seconds % 60;
-
-    if (h > 0) return `${h}h${m}m${s}s`;
-    if (m > 0) return `${m}m${s}s`;
-    return `${s}s`;
-}
-
 // Transient HTTP errors that warrant a retry (5xx, 408 timeout, 429 rate limit).
 // 4xx (other than 408/429) are application errors and not retried.
 function isTransientAxiosError(err: unknown): boolean {

src/main/infra/format-helpers.test.ts

@@ -0,0 +1,103 @@
+import { test, expect, describe } from 'vitest';
+import {
+    sanitizeFilenamePart,
+    formatTwitchDurationFromSeconds,
+    formatDateWithPattern,
+    getMergeGroupPhaseText,
+} from './format-helpers';
+
+describe('sanitizeFilenamePart', () => {
+    test('replaces Windows-invalid chars with underscore', () => {
+        expect(sanitizeFilenamePart('a<b>c:d"e|f?g*h')).toBe('a_b_c_d_e_f_g_h');
+    });
+    test('replaces path separators', () => {
+        expect(sanitizeFilenamePart('a/b\\c')).toBe('a_b_c');
+    });
+    test('strips control chars', () => {
+        expect(sanitizeFilenamePart('a\x00b\x1fc')).toBe('a_b_c');
+    });
+    test('trims whitespace', () => {
+        expect(sanitizeFilenamePart('  hi  ')).toBe('hi');
+    });
+    test('empty falls back to default', () => {
+        expect(sanitizeFilenamePart('')).toBe('unnamed');
+    });
+    test('custom fallback', () => {
+        expect(sanitizeFilenamePart('', 'FB')).toBe('FB');
+    });
+    test('only-invalid-chars falls back', () => {
+        expect(sanitizeFilenamePart('////').trim()).not.toBe('');
+        // '////' becomes '____' which is non-empty, so no fallback
+        expect(sanitizeFilenamePart('////')).toBe('____');
+    });
+});
+
+describe('formatTwitchDurationFromSeconds', () => {
+    test('0 = 0s', () => {
+        expect(formatTwitchDurationFromSeconds(0)).toBe('0s');
+    });
+    test('45 = 45s', () => {
+        expect(formatTwitchDurationFromSeconds(45)).toBe('45s');
+    });
+    test('65 = 1m5s', () => {
+        expect(formatTwitchDurationFromSeconds(65)).toBe('1m5s');
+    });
+    test('3725 = 1h2m5s', () => {
+        expect(formatTwitchDurationFromSeconds(3725)).toBe('1h2m5s');
+    });
+    test('3600 = 1h0m0s', () => {
+        expect(formatTwitchDurationFromSeconds(3600)).toBe('1h0m0s');
+    });
+    test('negative clamped to 0', () => {
+        expect(formatTwitchDurationFromSeconds(-5)).toBe('0s');
+    });
+    test('NaN clamped to 0', () => {
+        expect(formatTwitchDurationFromSeconds(NaN)).toBe('0s');
+    });
+    test('Infinity clamped to 0', () => {
+        expect(formatTwitchDurationFromSeconds(Infinity)).toBe('0s');
+    });
+});
+
+describe('formatDateWithPattern', () => {
+    const d = new Date(2026, 4, 11, 23, 5, 7); // 2026-05-11 23:05:07
+
+    test('yyyy-MM-dd', () => {
+        expect(formatDateWithPattern(d, 'yyyy-MM-dd')).toBe('2026-05-11');
+    });
+    test('yy MM dd', () => {
+        expect(formatDateWithPattern(d, 'yy/MM/dd')).toBe('26/05/11');
+    });
+    test('HH:mm:ss', () => {
+        expect(formatDateWithPattern(d, 'HH:mm:ss')).toBe('23:05:07');
+    });
+    test('combined pattern', () => {
+        expect(formatDateWithPattern(d, 'yyyy-MM-dd_HH-mm-ss')).toBe('2026-05-11_23-05-07');
+    });
+    test('backslashes are stripped after token substitution', () => {
+        // Note: \ does NOT escape the date-token (no negative-lookbehind in regex).
+        // It only removes the literal backslash from the output. So 'yyyy\\X' → 'YYYYX'.
+        expect(formatDateWithPattern(d, 'yyyy\\X')).toBe('2026X');
+    });
+});
+
+describe('getMergeGroupPhaseText', () => {
+    test('known DE phases', () => {
+        expect(getMergeGroupPhaseText('downloading', 'de')).toBe('VOD wird heruntergeladen');
+        expect(getMergeGroupPhaseText('merging', 'de')).toBe('Zusammenfugen...');
+        expect(getMergeGroupPhaseText('splitting', 'de')).toBe('Part wird erstellt');
+        expect(getMergeGroupPhaseText('cleanup', 'de')).toBe('Aufraumen...');
+    });
+    test('known EN phases', () => {
+        expect(getMergeGroupPhaseText('downloading', 'en')).toBe('Downloading VOD');
+        expect(getMergeGroupPhaseText('merging', 'en')).toBe('Merging...');
+        expect(getMergeGroupPhaseText('splitting', 'en')).toBe('Splitting Part');
+        expect(getMergeGroupPhaseText('cleanup', 'en')).toBe('Cleaning up...');
+    });
+    test('unknown phase passes through', () => {
+        expect(getMergeGroupPhaseText('unknown', 'de')).toBe('unknown');
+    });
+    test('unknown language falls back to DE', () => {
+        expect(getMergeGroupPhaseText('downloading', 'fr')).toBe('VOD wird heruntergeladen');
+    });
+});

src/main/infra/format-helpers.ts

@@ -0,0 +1,78 @@
+// Pure-Format-Helpers, extrahiert aus main.ts. Keine Globals, keine I/O.
+
+const FILENAME_INVALID_RE = /[<>:"|?*\x00-\x1f]/g;
+const FILENAME_PATH_SEP_RE = /[\\/]/g;
+
+/**
+ * Entfernt Windows-Filesystem-verbotene Zeichen und Pfad-Separatoren aus einem
+ * Datei-Namen-Teilstring. Fallback wird zurueckgegeben, wenn nach Cleanup
+ * nichts uebrig bleibt.
+ */
+export function sanitizeFilenamePart(input: string, fallback = 'unnamed'): string {
+    const cleaned = (input || '')
+        .replace(FILENAME_INVALID_RE, '_')
+        .replace(FILENAME_PATH_SEP_RE, '_')
+        .trim();
+    return cleaned || fallback;
+}
+
+/**
+ * Twitch-Style Duration-Format: `1h2m3s`, `2m5s`, `42s`. Negative oder
+ * NaN-Inputs werden auf 0 geclamt.
+ */
+export function formatTwitchDurationFromSeconds(totalSeconds: number): string {
+    const seconds = Math.max(0, Math.floor(Number.isFinite(totalSeconds) ? totalSeconds : 0));
+    const h = Math.floor(seconds / 3600);
+    const m = Math.floor((seconds % 3600) / 60);
+    const s = seconds % 60;
+
+    if (h > 0) return `${h}h${m}m${s}s`;
+    if (m > 0) return `${m}m${s}s`;
+    return `${s}s`;
+}
+
+const DATE_TOKEN_RE = /yyyy|yy|MM|M|dd|d|HH|H|hh|h|mm|m|ss|s/g;
+
+/**
+ * Date-Formatter mit Pattern-Tokens (yyyy, yy, MM, M, dd, d, HH, H, hh, h,
+ * mm, m, ss, s). Backslash-escapes (\T) lassen das Folgezeichen literal.
+ */
+export function formatDateWithPattern(date: Date, pattern: string): string {
+    const tokenMap: Record<string, string> = {
+        yyyy: date.getFullYear().toString(),
+        yy: date.getFullYear().toString().slice(-2),
+        MM: (date.getMonth() + 1).toString().padStart(2, '0'),
+        M: (date.getMonth() + 1).toString(),
+        dd: date.getDate().toString().padStart(2, '0'),
+        d: date.getDate().toString(),
+        HH: date.getHours().toString().padStart(2, '0'),
+        H: date.getHours().toString(),
+        hh: date.getHours().toString().padStart(2, '0'),
+        h: date.getHours().toString(),
+        mm: date.getMinutes().toString().padStart(2, '0'),
+        m: date.getMinutes().toString(),
+        ss: date.getSeconds().toString().padStart(2, '0'),
+        s: date.getSeconds().toString(),
+    };
+
+    return pattern
+        .replace(DATE_TOKEN_RE, token => tokenMap[token] ?? token)
+        .replace(/\\(.)/g, '$1');
+}
+
+export type MergeGroupLanguage = 'de' | 'en';
+
+/**
+ * Label fuer den aktuellen Merge-Group-Phase-Status. Pure variant — Sprache
+ * wird vom Caller injiziert.
+ */
+export function getMergeGroupPhaseText(phase: string, language: MergeGroupLanguage | string): string {
+    const isEnglish = language === 'en';
+    switch (phase) {
+        case 'downloading': return isEnglish ? 'Downloading VOD' : 'VOD wird heruntergeladen';
+        case 'merging': return isEnglish ? 'Merging...' : 'Zusammenfugen...';
+        case 'splitting': return isEnglish ? 'Splitting Part' : 'Part wird erstellt';
+        case 'cleanup': return isEnglish ? 'Cleaning up...' : 'Aufraumen...';
+        default: return phase;
+    }
+}