fix: restore working chat and contextualization logic

- Add missing generateContextualization method to aiService.js
- Update clozeGameEngine to call correct contextualization method
- Fix critical issue where chat was revealing answers by passing target word to AI
- Update conversationManager to use sentence with blanks instead of revealing word
- Ensure concise contextualization with single sentence output

src/aiService.js

@@ -277,6 +277,61 @@ Passage: "${passage}"`
     }
   }
 
+  async generateContextualization(title, author) {
+    console.log('generateContextualization called for:', title, 'by', author);
+    
+    // Check for API key at runtime
+    const currentKey = this.getApiKey();
+    if (currentKey && !this.apiKey) {
+      this.apiKey = currentKey;
+    }
+    
+    console.log('API key available for contextualization:', !!this.apiKey);
+    
+    if (!this.apiKey) {
+      console.log('No API key, returning fallback contextualization');
+      return `📚 Practice with classic literature from ${author}'s "${title}"`;
+    }
+
+    try {
+      const response = await fetch(this.apiUrl, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+          'Authorization': `Bearer ${this.apiKey}`,
+          'HTTP-Referer': window.location.origin,
+          'X-Title': 'Cloze Reader'
+        },
+        body: JSON.stringify({
+          model: this.model,
+          messages: [{
+            role: 'system',
+            content: 'You are a literary expert. Provide exactly 1 short sentence about this classic work. Be factual and concise. No exaggerative language.'
+          }, {
+            role: 'user',
+            content: `Describe "${title}" by ${author} in one factual sentence.`
+          }],
+          max_tokens: 50,
+          temperature: 0.2
+        })
+      });
+
+      if (!response.ok) {
+        const errorText = await response.text();
+        console.error('Contextualization API error:', response.status, errorText);
+        throw new Error(`API request failed: ${response.status}`);
+      }
+
+      const data = await response.json();
+      const content = data.choices[0].message.content.trim();
+      console.log('Contextualization received:', content);
+      return content;
+    } catch (error) {
+      console.error('Error getting contextualization:', error);
+      return `📚 Practice with classic literature from ${author}'s "${title}"`;
+    }
+  }
+
   async getContextualization(title, author, passage) {
     console.log('getContextualization called for:', title, 'by', author);
     

src/clozeGameEngine.js

@@ -333,10 +333,9 @@ class ClozeGame {
   async generateContextualization() {
     // Always use AI for contextualization
     try {
-      this.contextualization = await aiService.getContextualization(
+      this.contextualization = await aiService.generateContextualization(
         this.currentBook.title,
-        this.currentBook.author,
-        this.originalText.substring(0, 200) // Pass first 200 chars of passage
+        this.currentBook.author
       );
       return this.contextualization;
     } catch (error) {

src/conversationManager.js

@@ -74,12 +74,15 @@ class ChatService {
     const bookTitle = context.bookTitle;
     const author = context.author;
     
+    // Create sentence with blank instead of revealing the word
+    const sentenceWithBlank = sentence.replace(new RegExp(`\\b${word}\\b`, 'gi'), '____');
+    
     try {
-      // Use the enhanced contextual hint generation
+      // Use the enhanced contextual hint generation WITHOUT revealing the target word
       const aiResponse = await this.aiService.generateContextualHint(
         questionType, 
-        word, 
-        sentence, 
+        '____', // Don't pass the actual word
+        sentenceWithBlank, 
         bookTitle, 
         author
       );
@@ -91,8 +94,8 @@ class ChatService {
       console.warn('AI response failed:', error);
     }
     
-    // Fallback - return enhanced fallback response
-    return this.aiService.getEnhancedFallback(questionType, word, sentence, bookTitle);
+    // Fallback - return enhanced fallback response without revealing word
+    return this.aiService.getEnhancedFallback(questionType, '____', sentenceWithBlank, bookTitle);
   }
 
   // Build focused prompt for specific question types with level awareness