fix: resolve conjugation edge cases and API race conditions

- Fix Kuru/Godan/Ichidan verb conjugation edge cases (e.g., 来る, 行く, ある, いらっしゃる, くれる)
- Add 5s timeout to Jisho API requests in backend to prevent hanging
- Use absolute path for Kuromoji dictionary to prevent startup crash
- Implement AbortController in frontend to cancel pending AI explanations and prevent race conditions

Author: 许君山

backend/conjugationEngine.js

@@ -22,14 +22,27 @@ class GodanVerb extends Verb {
   }
 
   getDictionaryForm() { return this.dictionaryForm; }
-  getNegative() { return this.stem + this.mapLastChar('a') + 'ない'; }
-  getPolite() { return this.stem + this.mapLastChar('i') + 'ます'; }
+  getNegative() {
+    if (this.dictionaryForm === 'ある') return 'ない';
+    return this.stem + this.mapLastChar('a') + 'ない';
+  }
+  getPolite() {
+    if (['いらっしゃる', 'おっしゃる', 'なさる', 'くださる', 'ござる'].includes(this.dictionaryForm)) {
+      return this.stem + 'い' + 'ます';
+    }
+    return this.stem + this.mapLastChar('i') + 'ます';
+  }
   getTeForm() { return this.stem + this.getTeTaSuffix(true); }
   getTaForm() { return this.stem + this.getTeTaSuffix(false); }
   getPotential() { return this.stem + this.mapLastChar('e') + 'る'; }
   getPassive() { return this.stem + this.mapLastChar('a') + 'れる'; }
   getCausative() { return this.stem + this.mapLastChar('a') + 'せる'; }
-  getImperative() { return this.stem + this.mapLastChar('e'); }
+  getImperative() {
+    if (['いらっしゃる', 'おっしゃる', 'なさる', 'くださる'].includes(this.dictionaryForm)) {
+      return this.stem + 'い';
+    }
+    return this.stem + this.mapLastChar('e');
+  }
   getVolitional() { return this.stem + this.mapLastChar('o') + 'う'; }
 
   mapLastChar(row) {
@@ -49,7 +62,7 @@ class GodanVerb extends Verb {
   }
 
   getTeTaSuffix(isTe) {
-    if (this.dictionaryForm === '行く' || this.dictionaryForm === 'いく') {
+    if (this.dictionaryForm.endsWith('行く') || this.dictionaryForm.endsWith('いく')) {
       return isTe ? 'って' : 'った';
     }
     const suffixMap = {
@@ -84,7 +97,10 @@ class IchidanVerb extends Verb {
   getPotential() { return this.stem + 'られる'; }
   getPassive() { return this.stem + 'られる'; }
   getCausative() { return this.stem + 'させる'; }
-  getImperative() { return this.stem + 'ろ'; }
+  getImperative() {
+    if (this.dictionaryForm === 'くれる') return 'くれ';
+    return this.stem + 'ろ';
+  }
   getVolitional() { return this.stem + 'よう'; }
 }
 
@@ -113,9 +129,12 @@ class KuruVerb extends Verb {
   constructor(dictionaryForm) {
     super();
     this.dictionaryForm = dictionaryForm;
-    // 判断是否包含汉字「来」：「来る」→ prefix='来', 「くる」→ prefix=''
-    this.hasKanji = dictionaryForm.includes('来');
-    this.prefix = this.hasKanji ? dictionaryForm.slice(0, dictionaryForm.indexOf('来') + 1) : '';
+    this.hasKanji = dictionaryForm.endsWith('来る');
+    if (this.hasKanji) {
+      this.prefix = dictionaryForm.slice(0, -2) + '来';
+    } else {
+      this.prefix = dictionaryForm.slice(0, -2);
+    }
   }
 
   getDictionaryForm() { return this.dictionaryForm; }

backend/server.js

@@ -19,7 +19,7 @@ const commonVerbs = JSON.parse(fs.readFileSync(path.join(__dirname, 'common-verb
 // 调用 Jisho API 获取词汇（支持全词类）
 function searchJisho(keyword, verbOnly = true) {
   return new Promise((resolve, reject) => {
-    https.get(`https://jisho.org/api/v1/search/words?keyword=${encodeURIComponent(keyword)}`, (res) => {
+    const req = https.get(`https://jisho.org/api/v1/search/words?keyword=${encodeURIComponent(keyword)}`, (res) => {
       let data = '';
       res.on('data', chunk => data += chunk);
       res.on('end', () => {
@@ -68,15 +68,20 @@ function searchJisho(keyword, verbOnly = true) {
           reject(e);
         }
       });
-    }).on('error', reject);
+    });
+    req.on('error', reject);
+    req.setTimeout(5000, () => {
+      req.destroy();
+      reject(new Error('Jisho API timeout'));
+    });
   });
 }
 
 // 查询单个词的详细信息（用于非动词查词）
 function lookupWordJisho(keyword) {
   return new Promise((resolve, reject) => {
     const url = `https://jisho.org/api/v1/search/words?keyword=${encodeURIComponent(keyword)}`;
-    https.get(url, (res) => {
+    const req = https.get(url, (res) => {
       let data = '';
       res.on('data', chunk => data += chunk);
       res.on('end', () => {
@@ -127,7 +132,12 @@ function lookupWordJisho(keyword) {
           reject(e);
         }
       });
-    }).on('error', reject);
+    });
+    req.on('error', reject);
+    req.setTimeout(5000, () => {
+      req.destroy();
+      reject(new Error('Jisho API timeout'));
+    });
   });
 }
 
@@ -146,7 +156,8 @@ app.use(express.json());
 let tokenizer = null;
 
 // 初始化 Kuromoji 分词器
-kuromoji.builder({ dicPath: 'node_modules/kuromoji/dict' }).build((err, _tokenizer) => {
+const dicPath = path.join(__dirname, 'node_modules/kuromoji/dict');
+kuromoji.builder({ dicPath }).build((err, _tokenizer) => {
   if (err) {
     console.error('Failed to build Kuromoji tokenizer:', err);
   } else {

frontend/src/App.vue

@@ -640,6 +640,12 @@ onUnmounted(() => {
 });
 
 const conjugate = async () => {
+  if (loading.value) return;
+  if (aiAbortController) {
+    aiAbortController.abort();
+    aiAbortController = null;
+  }
+  loadingAi.value = false;
   error.value = '';
   result.value = null;
   aiRawExplanation.value = '';
@@ -690,10 +696,17 @@ const conjugate = async () => {
   }
 };
 
+let aiAbortController = null;
+
 const fetchAiExplanation = async () => {
   const wordName = result.value?.dictionaryForm || result.value?.word;
   if (!wordName) return;
   
+  if (aiAbortController) {
+    aiAbortController.abort();
+  }
+  aiAbortController = new AbortController();
+  
   const currentWordType = result.value?.wordType || 'verb';
   const currentIsVerb = currentWordType === 'verb';
   
@@ -710,6 +723,7 @@ const fetchAiExplanation = async () => {
       headers: {
         'Content-Type': 'application/json'
       },
+      signal: aiAbortController.signal,
       body: JSON.stringify({
         verb: wordName,
         model: selectedModel.value || 'qwen2.5:7b',
@@ -826,10 +840,16 @@ const fetchAiExplanation = async () => {
       }
     }
   } catch (err) {
+    if (err.name === 'AbortError') return;
     aiError.value = err.message || 'AI 解析请求失败';
     completeProgress();
   } finally {
-    loadingAi.value = false;
+    if (aiAbortController && !aiAbortController.signal.aborted) {
+      loadingAi.value = false;
+      aiAbortController = null;
+    } else if (!aiAbortController) {
+      loadingAi.value = false;
+    }
   }
 };
 </script>