we're about to port the chrome-extension. everything else mostly works

backend/routes/picker.js

@@ -3,6 +3,68 @@ const db = require('../database');
 
 const router = express.Router();
 
+/**
+ * Select a game using weighted random selection based on favor bias
+ * 
+ * Bias system:
+ * - favor_bias = 1 (favored): 3x weight
+ * - favor_bias = 0 (neutral): 1x weight
+ * - favor_bias = -1 (disfavored): 0.2x weight (still possible but less likely)
+ * 
+ * Also considers pack-level bias
+ */
+function selectGameWithBias(games) {
+  if (games.length === 0) return null;
+  if (games.length === 1) return games[0];
+
+  // Get pack biases
+  const packs = db.prepare('SELECT name, favor_bias FROM packs').all();
+  const packBiasMap = {};
+  packs.forEach(pack => {
+    packBiasMap[pack.name] = pack.favor_bias || 0;
+  });
+
+  // Calculate weights for each game
+  const weights = games.map(game => {
+    let weight = 1.0; // Base weight
+
+    // Apply game-level bias
+    const gameBias = game.favor_bias || 0;
+    if (gameBias === 1) {
+      weight *= 3.0; // Favored games are 3x more likely
+    } else if (gameBias === -1) {
+      weight *= 0.2; // Disfavored games are 5x less likely
+    }
+
+    // Apply pack-level bias
+    const packBias = packBiasMap[game.pack_name] || 0;
+    if (packBias === 1) {
+      weight *= 2.0; // Favored packs are 2x more likely
+    } else if (packBias === -1) {
+      weight *= 0.3; // Disfavored packs are ~3x less likely
+    }
+
+    return weight;
+  });
+
+  // Calculate total weight
+  const totalWeight = weights.reduce((sum, w) => sum + w, 0);
+
+  // Pick a random number between 0 and totalWeight
+  let random = Math.random() * totalWeight;
+
+  // Select game based on weighted random
+  for (let i = 0; i < games.length; i++) {
+    random -= weights[i];
+    if (random <= 0) {
+      return games[i];
+    }
+  }
+
+  // Fallback (shouldn't reach here)
+  return games[games.length - 1];
+}
+
 // Pick a random game with filters and repeat avoidance
 router.post('/pick', (req, res) => {
   try {
@@ -11,7 +73,8 @@ router.post('/pick', (req, res) => {
       drawing,
       length,
       familyFriendly,
-      sessionId
+      sessionId,
+      excludePlayed
     } = req.body;
 
     // Build query for eligible games
@@ -60,14 +123,25 @@ router.post('/pick', (req, res) => {
 
     // Apply repeat avoidance if session provided
     if (sessionId) {
-      const lastGames = db.prepare(`
-        SELECT game_id FROM session_games
-        WHERE session_id = ?
-        ORDER BY played_at DESC
-        LIMIT 2
-      `).all(sessionId);
+      let lastGamesQuery;
+      
+      if (excludePlayed) {
+        // Exclude ALL previously played games in this session
+        lastGamesQuery = db.prepare(`
+          SELECT DISTINCT game_id FROM session_games
+          WHERE session_id = ?
+        `).all(sessionId);
+      } else {
+        // Default: only exclude last 2 games
+        lastGamesQuery = db.prepare(`
+          SELECT game_id FROM session_games
+          WHERE session_id = ?
+          ORDER BY played_at DESC
+          LIMIT 2
+        `).all(sessionId);
+      }
 
-      const excludeIds = lastGames.map(g => g.game_id);
+      const excludeIds = lastGamesQuery.map(g => g.game_id);
       
       if (excludeIds.length > 0) {
         eligibleGames = eligibleGames.filter(game => !excludeIds.includes(game.id));
@@ -75,16 +149,17 @@ router.post('/pick', (req, res) => {
 
       if (eligibleGames.length === 0) {
         return res.status(404).json({
-          error: 'All eligible games have been played recently',
+          error: excludePlayed 
+            ? 'All eligible games have been played in this session' 
+            : 'All eligible games have been played recently',
           suggestion: 'Enable more games or adjust your filters',
           recentlyPlayed: excludeIds
         });
       }
     }
 
-    // Pick random game from eligible pool
-    const randomIndex = Math.floor(Math.random() * eligibleGames.length);
-    const selectedGame = eligibleGames[randomIndex];
+    // Apply favor biasing to selection
+    const selectedGame = selectGameWithBias(eligibleGames);
 
     res.json({
       game: selectedGame,