fix(merge-pdf): route result notifications through i18n

Fixes #825

public/locales/en/tools.json

@@ -20,7 +20,21 @@
     "subtitle": "Combine multiple PDFs into one file. Preserves Bookmarks.",
     "retainPageLabels": "Keep original page labels from each file",
     "retainPageLabelsHint": "Off (default): the merged PDF uses natural page numbering 1–N. On: each file's original page labels are preserved (may produce duplicate labels).",
-    "removeDuplicateFonts": "Remove duplicate fonts"
+    "removeDuplicateFonts": "Remove duplicate fonts",
+    "alert": {
+      "thumbnailError": "Failed to render page thumbnails",
+      "noSelection": "No files or pages selected to merge.",
+      "mergeSuccess": "PDFs merged successfully!",
+      "mergeFailed": "Failed to merge PDFs.",
+      "mergeError": "Failed to merge PDFs. Please check that all files are valid and not password-protected.",
+      "workerError": "An unexpected error occurred in the merge worker.",
+      "loadError": "Failed to load one or more PDF files"
+    },
+    "loader": {
+      "renderingPreviews": "Rendering page previews...",
+      "merging": "Merging PDFs...",
+      "loadingDocuments": "Loading PDF documents..."
+    }
   },
   "splitPdf": {
     "name": "Split PDF",

public/locales/fr/tools.json

@@ -19,7 +19,21 @@
     "name": "Fusionner des PDF",
     "subtitle": "Assembler plusieurs PDF en un seul fichier, tout en conservant les signets.",
     "retainPageLabels": "Conserver les étiquettes de page d'origine de chaque fichier",
-    "retainPageLabelsHint": "Désactivé (par défaut) : le PDF fusionné utilise une numérotation naturelle 1–N. Activé : les étiquettes de page d'origine de chaque fichier sont conservées (peut produire des étiquettes en double)."
+    "retainPageLabelsHint": "Désactivé (par défaut) : le PDF fusionné utilise une numérotation naturelle 1–N. Activé : les étiquettes de page d'origine de chaque fichier sont conservées (peut produire des étiquettes en double).",
+    "alert": {
+      "thumbnailError": "Échec du rendu des aperçus de pages",
+      "noSelection": "Aucun fichier ni page sélectionné pour la fusion.",
+      "mergeSuccess": "PDF fusionnés avec succès !",
+      "mergeFailed": "Échec de la fusion des PDF.",
+      "mergeError": "Échec de la fusion des PDF. Veuillez vérifier que tous les fichiers sont valides et non protégés par mot de passe.",
+      "workerError": "Une erreur inattendue s'est produite dans le worker de fusion.",
+      "loadError": "Impossible de charger un ou plusieurs fichiers PDF"
+    },
+    "loader": {
+      "renderingPreviews": "Génération des aperçus de pages…",
+      "merging": "Fusion des PDF…",
+      "loadingDocuments": "Chargement des documents PDF…"
+    }
   },
   "splitPdf": {
     "name": "Scinder un PDF",

src/js/logic/merge-pdf-page.ts

@@ -12,6 +12,7 @@ import {
   showWasmRequiredDialog,
   WasmProvider,
 } from '../utils/wasm-provider.js';
+import { t } from '../i18n/i18n';
 
 import { createIcons, icons } from 'lucide';
 import * as pdfjsLib from 'pdfjs-dist';
@@ -199,7 +200,7 @@ async function renderPageMergeThumbnails() {
           lazyLoadMargin: '300px',
           onProgress: () => {
             currentPageNumber++;
-            showLoader(`Rendering page previews...`);
+            showLoader(t('tools:mergePdf.loader.renderingPreviews'));
           },
           onBatchComplete: () => {
             createIcons({ icons });
@@ -216,7 +217,7 @@ async function renderPageMergeThumbnails() {
     initializePageThumbnailsSortable();
   } catch (error) {
     console.error('Error rendering page thumbnails:', error);
-    showAlert('Error', 'Failed to render page thumbnails');
+    showAlert(t('common.error'), t('tools:mergePdf.alert.thumbnailError'));
   } finally {
     hideLoader();
     mergeState.isRendering = false;
@@ -282,7 +283,7 @@ export async function merge() {
     return;
   }
 
-  showLoader('Merging PDFs...');
+  showLoader(t('tools:mergePdf.loader.merging'));
   try {
     const jobs: MergeJob[] = [];
     const filesToMerge: MergeFile[] = [];
@@ -369,7 +370,7 @@ export async function merge() {
     }
 
     if (jobs.length === 0) {
-      showAlert('Error', 'No files or pages selected to merge.');
+      showAlert(t('common.error'), t('tools:mergePdf.alert.noSelection'));
       hideLoader();
       return;
     }
@@ -410,8 +411,8 @@ export async function merge() {
         downloadFile(blob, 'merged.pdf');
         mergeState.mergeSuccess = true;
         showAlert(
-          'Success',
-          'PDFs merged successfully!',
+          t('common.success'),
+          t('tools:mergePdf.alert.mergeSuccess'),
           'success',
           async () => {
             await resetState();
@@ -419,21 +420,21 @@ export async function merge() {
         );
       } else {
         console.error('Worker merge error:', e.data.message);
-        showAlert('Error', e.data.message || 'Failed to merge PDFs.');
+        showAlert(
+          t('common.error'),
+          e.data.message || t('tools:mergePdf.alert.mergeFailed')
+        );
       }
     };
 
     mergeWorker.onerror = (e) => {
       hideLoader();
       console.error('Worker error:', e);
-      showAlert('Error', 'An unexpected error occurred in the merge worker.');
+      showAlert(t('common.error'), t('tools:mergePdf.alert.workerError'));
     };
   } catch (e) {
     console.error('Merge error:', e);
-    showAlert(
-      'Error',
-      'Failed to merge PDFs. Please check that all files are valid and not password-protected.'
-    );
+    showAlert(t('common.error'), t('tools:mergePdf.alert.mergeError'));
     hideLoader();
   }
 }
@@ -447,14 +448,14 @@ export async function refreshMergeUI() {
 
   const wasInPageMode = mergeState.activeMode === 'page';
 
-  showLoader('Loading PDF documents...');
+  showLoader(t('tools:mergePdf.loader.loadingDocuments'));
   try {
     mergeState.pdfDocs = {};
     mergeState.pdfBytes = {};
 
     hideLoader();
     state.files = await batchDecryptIfNeeded(state.files);
-    showLoader('Loading PDF documents...');
+    showLoader(t('tools:mergePdf.loader.loadingDocuments'));
 
     for (let i = 0; i < state.files.length; i++) {
       const file = state.files[i];
@@ -472,7 +473,7 @@ export async function refreshMergeUI() {
     }
   } catch (error) {
     console.error('Error loading PDFs:', error);
-    showAlert('Error', 'Failed to load one or more PDF files');
+    showAlert(t('common.error'), t('tools:mergePdf.alert.loadError'));
     return;
   } finally {
     hideLoader();

src/tests/merge-pdf-i18n.test.ts

@@ -0,0 +1,70 @@
+import { readFileSync } from 'node:fs';
+import { join } from 'node:path';
+import { describe, expect, it } from 'vitest';
+
+const ROOT = process.cwd();
+const LOGIC_FILE = join(ROOT, 'src/js/logic/merge-pdf-page.ts');
+const CHECKED_LANGUAGES = ['en', 'fr'] as const;
+
+const source = readFileSync(LOGIC_FILE, 'utf8');
+
+const loadLocale = (lang: string, namespace: 'common' | 'tools') =>
+  JSON.parse(
+    readFileSync(
+      join(ROOT, 'public/locales', lang, `${namespace}.json`),
+      'utf8'
+    )
+  ) as Record<string, unknown>;
+
+const resolveKey = (bundle: Record<string, unknown>, key: string): unknown =>
+  key
+    .split('.')
+    .reduce<unknown>(
+      (node, part) =>
+        node && typeof node === 'object'
+          ? (node as Record<string, unknown>)[part]
+          : undefined,
+      bundle
+    );
+
+const usedKeys = [...source.matchAll(/\bt\('([^']+)'/g)].map(
+  (match) => match[1]
+);
+
+describe('merge PDF notifications are localized', () => {
+  it('uses translation keys for every alert and loader message', () => {
+    const literalCalls = [
+      ...source.matchAll(/\bshow(?:Alert|Loader)\(\s*['"`]/g),
+    ];
+    expect(literalCalls).toHaveLength(0);
+  });
+
+  it('references at least the alert and loader keys added for the merge tool', () => {
+    expect(usedKeys).toContain('tools:mergePdf.alert.mergeSuccess');
+    expect(usedKeys).toContain('tools:mergePdf.loader.merging');
+    expect(usedKeys).toContain('common.success');
+    expect(usedKeys).toContain('common.error');
+  });
+
+  for (const lang of CHECKED_LANGUAGES) {
+    it(`resolves every key used by the merge tool in "${lang}"`, () => {
+      const bundles = {
+        common: loadLocale(lang, 'common'),
+        tools: loadLocale(lang, 'tools'),
+      };
+
+      const missing = usedKeys.filter((key) => {
+        const [namespace, plainKey] = key.startsWith('tools:')
+          ? ['tools', key.slice('tools:'.length)]
+          : ['common', key];
+        const value = resolveKey(
+          bundles[namespace as 'common' | 'tools'],
+          plainKey
+        );
+        return typeof value !== 'string' || value.length === 0;
+      });
+
+      expect(missing).toEqual([]);
+    });
+  }
+});