feat: implement two-passage system to avoid OpenRouter rate limits

- Each round now loads two different passages from two books
- Added passage numbering (Passage 1/2, Passage 2/2)
- Modified nextPassage() method to handle second passage in same round
- Updated UI to show current passage number
- Added proper error handling for OpenRouter API errors
- This spreads out API calls to avoid rate limiting issues

src/aiService.js

@@ -139,8 +139,11 @@ Passage: "${passage}"`
 
       const data = await response.json();
       
-      // Debug: Log the actual API response
-      console.log('Word selection API response:', data);
+      // Check for OpenRouter error response
+      if (data.error) {
+        console.error('OpenRouter API error for word selection:', data.error);
+        throw new Error(`OpenRouter API error: ${data.error.message || JSON.stringify(data.error)}`);
+      }
       
       // Check if response has expected structure
       if (!data.choices || !data.choices[0] || !data.choices[0].message || !data.choices[0].message.content) {
@@ -218,8 +221,11 @@ Passage: "${passage}"`
 
       const data = await response.json();
       
-      // Debug: Log the actual API response
-      console.log('Contextualization API response:', data);
+      // Check for OpenRouter error response
+      if (data.error) {
+        console.error('OpenRouter API error for contextualization:', data.error);
+        throw new Error(`OpenRouter API error: ${data.error.message || JSON.stringify(data.error)}`);
+      }
       
       // Check if response has expected structure
       if (!data.choices || !data.choices[0] || !data.choices[0].message || !data.choices[0].message.content) {

src/app.js

@@ -69,10 +69,11 @@ class App {
       <strong>${roundData.title}</strong> by ${roundData.author}
     `;
 
-    // Show level information without round number
+    // Show level information with passage number
     const blanksCount = roundData.blanks.length;
     const difficultyText = blanksCount === 1 ? 'Easy' : blanksCount === 2 ? 'Medium' : 'Hard';
-    this.elements.roundInfo.innerHTML = `Level ${this.game.currentLevel} • ${blanksCount} blank${blanksCount > 1 ? 's' : ''} • ${difficultyText}`;
+    const passageInfo = roundData.passageNumber ? `Passage ${roundData.passageNumber}/${roundData.totalPassages} • ` : '';
+    this.elements.roundInfo.innerHTML = `Level ${this.game.currentLevel} • ${passageInfo}${blanksCount} blank${blanksCount > 1 ? 's' : ''} • ${difficultyText}`;
 
     // Show contextualization from AI agent
     this.elements.contextualization.innerHTML = `
@@ -206,15 +207,24 @@ class App {
       // Show loading immediately with specific message
       this.showLoading(true, 'Loading next passage...');
       
-      // Clear chat history when starting new round
+      // Clear chat history when starting new passage/round
       this.chatUI.clearChatHistory();
       
-      const roundData = await this.game.nextRound();
+      // Check if we should load next passage or next round
+      let roundData;
+      if (this.game.currentPassageIndex === 0) {
+        // Load second passage in current round
+        roundData = await this.game.nextPassage();
+      } else {
+        // Load next round (two new passages)
+        roundData = await this.game.nextRound();
+      }
+      
       this.displayRound(roundData);
       this.resetUI();
       this.showLoading(false);
     } catch (error) {
-      console.error('Error loading next round:', error);
+      console.error('Error loading next passage:', error);
       this.showError('Could not load next passage. Please try again.');
     }
   }

src/clozeGameEngine.js

@@ -19,6 +19,11 @@ class ClozeGame {
     this.hints = [];
     this.chatService = new ChatService(aiService);
     this.lastResults = null; // Store results for answer revelation
+    
+    // Two-passage system properties
+    this.currentBooks = []; // Array of two books per round
+    this.passages = []; // Array of two passages per round
+    this.currentPassageIndex = 0; // 0 for first passage, 1 for second
   }
 
   async initialize() {
@@ -33,14 +38,22 @@ class ClozeGame {
 
   async startNewRound() {
     try {
-      // Get a random book (now async with HF streaming)
-      this.currentBook = await bookDataService.getRandomBook();
+      // Get two random books for this round
+      const book1 = await bookDataService.getRandomBook();
+      const book2 = await bookDataService.getRandomBook();
+      
+      // Extract passages from both books
+      const passage1 = this.extractCoherentPassage(book1.text);
+      const passage2 = this.extractCoherentPassage(book2.text);
       
-      // Extract a coherent passage avoiding fragmented text
-      const fullText = this.currentBook.text;
-      let passage = this.extractCoherentPassage(fullText);
+      // Store both books and passages
+      this.currentBooks = [book1, book2];
+      this.passages = [passage1.trim(), passage2.trim()];
+      this.currentPassageIndex = 0;
       
-      this.originalText = passage.trim();
+      // Start with the first passage
+      this.currentBook = book1;
+      this.originalText = this.passages[0];
       
       // Run AI calls in parallel for faster loading
       const [clozeResult, contextualizationResult] = await Promise.all([
@@ -54,7 +67,9 @@ class ClozeGame {
         text: this.clozeText,
         blanks: this.blanks,
         contextualization: this.contextualization,
-        hints: this.hints
+        hints: this.hints,
+        passageNumber: 1,
+        totalPassages: 2
       };
     } catch (error) {
       console.error('Error starting new round:', error);
@@ -451,6 +466,46 @@ class ClozeGame {
     }));
   }
 
+  async nextPassage() {
+    try {
+      // Move to the second passage in the current round
+      if (this.currentPassageIndex === 0 && this.passages && this.passages.length > 1) {
+        this.currentPassageIndex = 1;
+        this.currentBook = this.currentBooks[1];
+        this.originalText = this.passages[1];
+        
+        // Clear chat conversations for new passage
+        this.chatService.clearConversations();
+        
+        // Clear last results
+        this.lastResults = null;
+        
+        // Generate new cloze text and contextualization for second passage
+        const [clozeResult, contextualizationResult] = await Promise.all([
+          this.createClozeText(),
+          this.generateContextualization()
+        ]);
+        
+        return {
+          title: this.currentBook.title,
+          author: this.currentBook.author,
+          text: this.clozeText,
+          blanks: this.blanks,
+          contextualization: this.contextualization,
+          hints: this.hints,
+          passageNumber: 2,
+          totalPassages: 2
+        };
+      } else {
+        // If we're already on the second passage, move to next round
+        return this.nextRound();
+      }
+    } catch (error) {
+      console.error('Error loading next passage:', error);
+      throw error;
+    }
+  }
+
   nextRound() {
     // Check if user passed the previous round
     const passed = this.lastResults && this.lastResults.passed;