Fix Amazon multi-price extraction and prevent AI override

Amazon products can have multiple prices:
- Main buy box price
- "Other Sellers" prices
- Subscribe & Save prices
- New & Used prices

The scraper now extracts ALL prices, not just the main one. This allows
anchor price matching to find the specific price the user selected.

Also fixed AI verification overriding user's anchor price selection.
When user deliberately chose a price (e.g., "other sellers" at $52.91),
don't let AI "correct" it to the main buy box price ($79.99).

Changes:
- Amazon scraper now collects all price variants
- extractSiteSpecificCandidates handles allPrices array
- Anchor matching now always returns (no fall-through to AI override)
- Increased anchor tolerance from 10% to 15% for small sales
- Added debug logging showing all candidate prices

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: clucraft

backend/src/services/scraper.ts

@@ -132,14 +132,33 @@ function extractSiteSpecificCandidates($: CheerioAPI, url: string): { candidates
 
   const siteScraper = siteScrapers.find((s) => s.match(url));
   if (siteScraper) {
-    const siteResult = siteScraper.scrape($, url);
-    if (siteResult.price) {
+    const siteResult = siteScraper.scrape($, url) as {
+      price?: ParsedPrice | null;
+      name?: string | null;
+      imageUrl?: string | null;
+      stockStatus?: StockStatus;
+      allPrices?: ParsedPrice[];  // Some scrapers return multiple prices (e.g., Amazon)
+    };
+
+    // If scraper returned multiple prices, add them all as candidates
+    if (siteResult.allPrices && siteResult.allPrices.length > 0) {
+      for (const p of siteResult.allPrices) {
+        candidates.push({
+          price: p.price,
+          currency: p.currency,
+          method: 'site-specific',
+          context: `Site-specific extractor for ${new URL(url).hostname}`,
+          confidence: 0.85,
+        });
+      }
+    } else if (siteResult.price) {
+      // Single price result
       candidates.push({
         price: siteResult.price.price,
         currency: siteResult.price.currency,
         method: 'site-specific',
         context: `Site-specific extractor for ${new URL(url).hostname}`,
-        confidence: 0.85, // Site-specific scrapers are well-tested
+        confidence: 0.85,
       });
     }
     name = siteResult.name || null;
@@ -336,85 +355,129 @@ const siteScrapers: SiteScraper[] = [
         return false;
       };
 
-      // Try to get the main displayed price from specific containers first
-      // These are the primary price display areas on Amazon
+      // Collect ALL prices found on the page (for variant/seller support)
+      const allPrices: ParsedPrice[] = [];
+      const seenPrices = new Set<number>();
+
+      const addPrice = (parsed: ParsedPrice | null) => {
+        if (parsed && parsed.price >= 2 && !seenPrices.has(parsed.price)) {
+          seenPrices.add(parsed.price);
+          allPrices.push(parsed);
+        }
+      };
+
+      // 1. Main buy box price
       const primaryPriceContainers = [
         '#corePrice_feature_div',
         '#corePriceDisplay_desktop_feature_div',
         '#apex_desktop_newAccordionRow',
         '#apex_offerDisplay_desktop',
       ];
 
-      let price: ParsedPrice | null = null;
+      let mainPrice: ParsedPrice | null = null;
 
-      // First, try the primary price containers
       for (const containerId of primaryPriceContainers) {
         const container = $(containerId);
         if (!container.length) continue;
 
-        // Look for the main price display (not savings/coupons)
         const priceElements = container.find('.a-price .a-offscreen');
 
         for (let i = 0; i < priceElements.length; i++) {
           const el = $(priceElements[i]);
-
-          // Skip if this is inside a coupon container
           if (isInCouponContainer(el)) continue;
 
-          // Skip if the parent has "savings" or similar class
           const parentClass = el.parent().attr('class') || '';
           if (/savings|coupon|save/i.test(parentClass)) continue;
 
           const text = el.text().trim();
           const parsed = parsePrice(text);
 
-          // Validate the price is reasonable (not a $1 coupon)
           if (parsed && parsed.price >= 2) {
-            price = parsed;
-            break;
+            if (!mainPrice) mainPrice = parsed;
+            addPrice(parsed);
           }
         }
+      }
 
-        if (price) break;
+      // 2. "Other Sellers" / "New & Used" prices
+      // Look for "Other Sellers on Amazon" section
+      const otherSellersSelectors = [
+        '#aod-offer-price .a-offscreen',  // "All Offers" display
+        '#olp-upd-new .a-color-price',     // "New from $X"
+        '#olp-upd-used .a-color-price',    // "Used from $X"
+        '#usedBuySection .a-color-price',
+        '#newBuySection .a-color-price',
+        '.olp-from-new-price',
+        '.olp-from-used-price',
+        '#buyNew_noncbb .a-color-price',   // "Buy New" non-buy-box
+      ];
+
+      for (const selector of otherSellersSelectors) {
+        $(selector).each((_, el) => {
+          const text = $(el).text().trim();
+          addPrice(parsePrice(text));
+        });
       }
 
-      // Fallback: try other known price selectors
-      if (!price) {
-        const fallbackSelectors = [
-          '#priceblock_dealprice',
-          '#priceblock_saleprice',
-          '#priceblock_ourprice',
-          '#price_inside_buybox',
-          '#newBuyBoxPrice',
-          'span[data-a-color="price"] .a-offscreen',
-        ];
+      // 3. "New & Used from $X" link text
+      const newUsedLink = $('#usedAndNewBuySection, #newUsedBuyBox, [id*="olp"]').text();
+      const newUsedMatch = newUsedLink.match(/\$[\d,]+\.?\d*/g);
+      if (newUsedMatch) {
+        for (const priceStr of newUsedMatch) {
+          addPrice(parsePrice(priceStr));
+        }
+      }
 
-        for (const selector of fallbackSelectors) {
-          const el = $(selector).first();
-          if (el.length && !isInCouponContainer(el)) {
-            const text = el.text().trim();
-            const parsed = parsePrice(text);
-            if (parsed && parsed.price >= 2) {
-              price = parsed;
-              break;
-            }
+      // 4. Subscribe & Save price
+      const snsPrice = $('#subscribeAndSavePrice, #sns-price, .sns-price-block .a-offscreen').first().text();
+      if (snsPrice) {
+        addPrice(parsePrice(snsPrice));
+      }
+
+      // 5. Fallback selectors
+      const fallbackSelectors = [
+        '#priceblock_dealprice',
+        '#priceblock_saleprice',
+        '#priceblock_ourprice',
+        '#price_inside_buybox',
+        '#newBuyBoxPrice',
+        'span[data-a-color="price"] .a-offscreen',
+      ];
+
+      for (const selector of fallbackSelectors) {
+        const el = $(selector).first();
+        if (el.length && !isInCouponContainer(el)) {
+          const text = el.text().trim();
+          const parsed = parsePrice(text);
+          if (parsed && parsed.price >= 2) {
+            if (!mainPrice) mainPrice = parsed;
+            addPrice(parsed);
           }
         }
       }
 
-      // Last resort: look for the whole/fraction price format
-      if (!price) {
+      // 6. Whole/fraction price format
+      if (!mainPrice) {
         const whole = $('#corePrice_feature_div .a-price-whole').first().text().replace(',', '');
         const fraction = $('#corePrice_feature_div .a-price-fraction').first().text();
         if (whole) {
           const priceStr = `$${whole}${fraction ? '.' + fraction : ''}`;
           const parsed = parsePrice(priceStr);
           if (parsed && parsed.price >= 2) {
-            price = parsed;
+            mainPrice = parsed;
+            addPrice(parsed);
           }
         }
       }
 
+      // Use main price as the primary, but we've collected all prices for candidate matching
+      const price = mainPrice;
+
+      // Log what we found for debugging
+      if (allPrices.length > 1) {
+        console.log(`[Amazon] Found ${allPrices.length} prices: ${allPrices.map(p => p.price).join(', ')}`);
+      }
+
       // Product name
       const name = $('#productTitle').text().trim() ||
                    $('h1.a-size-large').text().trim() ||
@@ -432,15 +495,13 @@ const siteScrapers: SiteScraper[] = [
       const outOfStockDiv = $('#outOfStock').length > 0;
       const unavailableText = $('body').text().toLowerCase();
 
-      // Check for out of stock indicators
       if (
         outOfStockDiv ||
         availabilityText.includes('currently unavailable') ||
         availabilityText.includes('out of stock') ||
         availabilityText.includes('not available') ||
-        $('#add-to-cart-button').length === 0 && $('#buy-now-button').length === 0
+        ($('#add-to-cart-button').length === 0 && $('#buy-now-button').length === 0)
       ) {
-        // Verify it's truly out of stock by checking for unavailable messaging
         if (
           unavailableText.includes('currently unavailable') ||
           unavailableText.includes("we don't know when or if this item will be back in stock") ||
@@ -457,7 +518,7 @@ const siteScrapers: SiteScraper[] = [
         stockStatus = 'in_stock';
       }
 
-      return { name, price, imageUrl, stockStatus };
+      return { name, price, imageUrl, stockStatus, allPrices };
     },
   },
 
@@ -1429,10 +1490,13 @@ export async function scrapeProductWithVoting(
     // Store all candidates
     result.priceCandidates = allCandidates;
 
+    // Track if we used anchor price (to prevent AI from overriding user's choice)
+    let usedAnchorPrice = false;
+
     // PRIORITY 1: If we have an anchor price, it takes precedence (user confirmed this price)
     // This handles variant products where multiple prices exist on the page
     if (anchorPrice && allCandidates.length > 0) {
-      console.log(`[Voting] Have anchor price ${anchorPrice}, searching ${allCandidates.length} candidates...`);
+      console.log(`[Voting] Have anchor price ${anchorPrice}, searching ${allCandidates.length} candidates: ${allCandidates.map(c => c.price).join(', ')}`);
 
       // Find the candidate closest to the anchor price
       const closestCandidate = allCandidates.reduce((closest, candidate) => {
@@ -1443,17 +1507,27 @@ export async function scrapeProductWithVoting(
 
       const priceDiff = Math.abs(closestCandidate.price - anchorPrice) / anchorPrice;
 
-      // Use anchor matching if within 10% (tight tolerance for variants)
+      // Use anchor matching if within 15% (allows for small sales)
       // or if it's an exact match
-      if (closestCandidate.price === anchorPrice || priceDiff < 0.10) {
+      if (closestCandidate.price === anchorPrice || priceDiff < 0.15) {
         console.log(`[Voting] Found match for anchor price ${anchorPrice}: ${closestCandidate.price} via ${closestCandidate.method} (${(priceDiff * 100).toFixed(1)}% diff)`);
         result.price = { price: closestCandidate.price, currency: closestCandidate.currency };
         result.selectedMethod = closestCandidate.method;
+        usedAnchorPrice = true;
+        result.aiStatus = 'verified';  // Mark as verified to skip AI override
         return result;
       } else {
-        // No close match - price may have legitimately changed
-        console.log(`[Voting] No candidate close to anchor price ${anchorPrice} (closest: ${closestCandidate.price}, ${(priceDiff * 100).toFixed(1)}% diff)`);
-        // Fall through to preferred method or consensus
+        // No close match - still use the closest candidate
+        // This prevents AI from picking a completely different price (like main buy box vs other sellers)
+        console.log(`[Voting] No close match for anchor ${anchorPrice}, using closest: ${closestCandidate.price} (${(priceDiff * 100).toFixed(1)}% diff) - may be a price change`);
+        result.price = { price: closestCandidate.price, currency: closestCandidate.currency };
+        result.selectedMethod = closestCandidate.method;
+        usedAnchorPrice = true;
+        // IMPORTANT: Mark as verified to prevent AI from overriding user's deliberate choice
+        // The user selected a specific price (e.g., "other sellers" on Amazon), don't let AI
+        // "correct" it to the main buy box price
+        result.aiStatus = 'verified';
+        return result;
       }
     }