Add English to Katakana and Romaji conversion support

services/text-converter.ts

@@ -0,0 +1,192 @@
+import Kuroshiro from "kuroshiro";
+import KuroshiroAnalyzerMecab from "kuroshiro-analyzer-mecab";
+import { toKatakana } from "wanakana";
+
+// Global instance to avoid recreating the analyzer
+let kuroshiroInstance: Kuroshiro | null = null;
+
+// Basic English to Katakana mapping for common words
+const englishToKatakanaMap: Record<string, string> = {
+  "hello": "ハロー",
+  "world": "ワールド",
+  "this": "ディス",
+  "is": "イズ",
+  "a": "ア",
+  "test": "テスト",
+  "javascript": "ジャバスクリプト",
+  "typescript": "タイプスクリプト",
+  "and": "アンド",
+  "api": "エーピーアイ",
+  "endpoint": "エンドポイント",
+  "machine": "マシン",
+  "learning": "ラーニング",
+  "model": "モデル",
+  "analysis": "アナリシス",
+  "computer": "コンピューター",
+  "data": "データ",
+  "software": "ソフトウェア",
+  "program": "プログラム",
+  "system": "システム",
+  "network": "ネットワーク",
+  "server": "サーバー",
+  "client": "クライアント",
+  "database": "データベース",
+  "file": "ファイル",
+  "user": "ユーザー",
+  "password": "パスワード",
+  "login": "ログイン",
+  "logout": "ログアウト",
+  "website": "ウェブサイト",
+  "browser": "ブラウザー",
+  "application": "アプリケーション",
+  "service": "サービス"
+};
+
+/**
+ * Convert English word to Katakana using predefined mapping or phonetic approximation
+ */
+function convertEnglishWordToKatakana(word: string): string {
+  const lowerWord = word.toLowerCase();
+  
+  // Check predefined mapping first
+  if (englishToKatakanaMap[lowerWord]) {
+    return englishToKatakanaMap[lowerWord];
+  }
+  
+  // Try using wanakana for romanized pronunciation
+  try {
+    // Convert to a rough romanized version and then to katakana
+    const katakana = toKatakana(word.toLowerCase());
+    if (katakana && katakana !== word.toLowerCase()) {
+      return katakana;
+    }
+  } catch {
+    // Fallback if wanakana fails
+  }
+  
+  // Fallback: simple phonetic approximation
+  return approximateEnglishToKatakana(word);
+}
+
+/**
+ * Simple phonetic approximation for English to Katakana
+ */
+function approximateEnglishToKatakana(word: string): string {
+  const phoneticMap: Record<string, string> = {
+    'a': 'ア', 'b': 'ブ', 'c': 'ク', 'd': 'ド', 'e': 'エ',
+    'f': 'フ', 'g': 'グ', 'h': 'ハ', 'i': 'イ', 'j': 'ジ',
+    'k': 'ク', 'l': 'ル', 'm': 'ム', 'n': 'ン', 'o': 'オ',
+    'p': 'プ', 'q': 'ク', 'r': 'ル', 's': 'ス', 't': 'ト',
+    'u': 'ウ', 'v': 'ブ', 'w': 'ワ', 'x': 'クス', 'y': 'ワイ', 'z': 'ズ'
+  };
+  
+  return word.toLowerCase()
+    .split('')
+    .map(char => phoneticMap[char] || char)
+    .join('');
+}
+
+/**
+ * Initialize kuroshiro with MeCab analyzer
+ * This should be called once during application startup
+ */
+export async function initializeTextConverter(): Promise<void> {
+  if (kuroshiroInstance) {
+    return; // Already initialized
+  }
+
+  try {
+    console.log("Kuroshiroテキストコンバーターを初期化中...");
+    kuroshiroInstance = new Kuroshiro();
+    await kuroshiroInstance.init(new KuroshiroAnalyzerMecab());
+    console.log("Kuroshiroテキストコンバーター初期化完了");
+  } catch (error) {
+    console.error("Kuroshiroの初期化に失敗しました:", error);
+    throw error;
+  }
+}
+
+/**
+ * Convert English words and mixed text to katakana
+ * @param text - Input text (may contain Japanese, English, and other characters)
+ * @returns Text with English words converted to katakana
+ */
+export async function convertEnglishToKatakana(text: string): Promise<string> {
+  if (!kuroshiroInstance) {
+    await initializeTextConverter();
+  }
+
+  if (!kuroshiroInstance) {
+    throw new Error("Failed to initialize kuroshiro");
+  }
+
+  try {
+    // Convert the entire text to katakana
+    // This will convert both Japanese hiragana and English words to katakana
+    const convertedText = await kuroshiroInstance.convert(text, {
+      to: "katakana",
+      mode: "normal",
+    });
+
+    return convertedText;
+  } catch (error) {
+    console.error("テキスト変換エラー:", error);
+    // Return original text if conversion fails
+    return text;
+  }
+}
+
+/**
+ * Convert only English words to katakana while preserving Japanese text
+ * This is a more selective approach that tries to preserve Japanese characters
+ * @param text - Input text
+ * @returns Text with only English words converted to katakana
+ */
+export async function convertEnglishWordsOnly(text: string): Promise<string> {
+  if (!kuroshiroInstance) {
+    await initializeTextConverter();
+  }
+
+  if (!kuroshiroInstance) {
+    throw new Error("Failed to initialize kuroshiro");
+  }
+
+  try {
+    // Extract English words using regex
+    const englishWordPattern = /\b[a-zA-Z]+\b/g;
+    let result = text;
+    
+    // Find all English words
+    const matches = text.match(englishWordPattern);
+    
+    if (matches) {
+      for (const englishWord of matches) {
+        try {
+          // Convert each English word to katakana using our custom function
+          const converted = convertEnglishWordToKatakana(englishWord);
+          
+          // Replace the English word with its katakana equivalent
+          // Use word boundary to avoid partial replacements
+          const wordRegex = new RegExp(`\\b${englishWord.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')}\\b`, 'g');
+          result = result.replace(wordRegex, converted);
+        } catch (convertError) {
+          console.warn(`Failed to convert word "${englishWord}":`, convertError);
+          // Keep original word if conversion fails
+        }
+      }
+    }
+
+    return result;
+  } catch (error) {
+    console.error("選択的テキスト変換エラー:", error);
+    // Fallback to full conversion
+    return convertEnglishToKatakana(text);
+  }
+}
+
+/**
+ * Check if kuroshiro is initialized
+ */
+export function isTextConverterInitialized(): boolean {
+  return kuroshiroInstance !== null;
+}