Implement official PDGA rating calculation methodology

- Update predicted rating algorithm to match PDGA rating guide
- Focus on tournaments from last 12 months only (improved accuracy)
- Add proper outlier exclusion: rounds >2.5 std dev below average
- Implement double weighting for most recent 25% of rounds (9+ rounds)
- Apply PDGA minimum data requirements (7 rounds for outlier exclusion)
- Improve error handling and rate limiting for tournament scraping
- Add user-friendly error messages for failed calculations
- Reduce tournament scraping from 15 to 8 tournaments to avoid rate limits

🤖 Generated with [Claude Code](https://claude.ai/code)

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

server.js

@@ -130,14 +130,31 @@ async function scrapePDGARating(pdgaNumber, retries = 3) {
   }
 }
 
-async function getPredictedRating(browser, pdgaNumber) {
-  try {
-    const roundRatings = await getPlayerCompetitionRatings(browser, pdgaNumber);
-    return calculatePredictedRating(roundRatings);
-  } catch (error) {
-    console.error(`Error getting predicted rating for ${pdgaNumber}:`, error);
-    return 0;
+async function getPredictedRating(browser, pdgaNumber, retries = 2) {
+  for (let attempt = 1; attempt <= retries; attempt++) {
+    try {
+      console.log(`Predicted rating attempt ${attempt}/${retries} for PDGA ${pdgaNumber}`);
+      const roundRatings = await getPlayerCompetitionRatings(browser, pdgaNumber);
+      const predictedRating = calculatePredictedRating(roundRatings);
+      
+      if (predictedRating > 0) {
+        return predictedRating;
+      }
+      
+      if (attempt < retries) {
+        console.log(`No ratings found, waiting before retry...`);
+        await new Promise(resolve => setTimeout(resolve, 5000));
+      }
+    } catch (error) {
+      console.error(`Predicted rating attempt ${attempt}/${retries} failed for ${pdgaNumber}:`, error.message);
+      if (attempt < retries) {
+        await new Promise(resolve => setTimeout(resolve, 5000));
+      }
+    }
   }
+  
+  console.log(`All attempts failed for predicted rating of PDGA ${pdgaNumber}`);
+  return 0;
 }
 
 async function getPlayerCompetitionRatings(browser, pdgaNumber) {
@@ -165,10 +182,10 @@ async function getPlayerCompetitionRatings(browser, pdgaNumber) {
             if (dateMatch) {
               const dateStr = dateMatch[0];
               const date = new Date(dateStr);
-              const twoYearsAgo = new Date();
-              twoYearsAgo.setFullYear(twoYearsAgo.getFullYear() - 2);
+              const oneYearAgo = new Date();
+              oneYearAgo.setFullYear(oneYearAgo.getFullYear() - 1);
               
-              if (date > twoYearsAgo) {
+              if (date > oneYearAgo) {
                 const href = tournamentCell.getAttribute('href');
                 if (href) {
                   urls.push({
@@ -182,15 +199,15 @@ async function getPlayerCompetitionRatings(browser, pdgaNumber) {
         });
       });
       
-      return urls.slice(0, 15);
+      return urls.slice(0, 8); // Reduce number of tournaments to scrape
     });
     
     console.log(`Found ${tournamentUrls.length} recent tournaments for PDGA ${pdgaNumber}`);
     
     for (const tournamentData of tournamentUrls) {
       try {
-        await page.goto(tournamentData.url, { waitUntil: 'networkidle2' });
-        await page.waitForTimeout(2000);
+        await page.goto(tournamentData.url, { waitUntil: 'domcontentloaded', timeout: 45000 });
+        await page.waitForTimeout(3000); // Longer delay between requests
         
         const roundRatings = await page.evaluate((pdgaNum) => {
           const rows = document.querySelectorAll('tr');
@@ -241,11 +258,8 @@ async function getPlayerCompetitionRatings(browser, pdgaNumber) {
     await page.close();
   }
   
-  const oneYearAgo = new Date();
-  oneYearAgo.setFullYear(oneYearAgo.getFullYear() - 1);
-  
-  const recentRatings = allRatings.filter(r => r.date > oneYearAgo);
-  return recentRatings.length > 8 ? recentRatings : allRatings;
+  // Return all ratings from the last year (already filtered above)
+  return allRatings;
 }
 
 function parseDate(dateStr) {
@@ -276,34 +290,52 @@ function parseDate(dateStr) {
 function calculatePredictedRating(roundRatings) {
   if (!roundRatings || roundRatings.length === 0) return 0;
   
-  const ratings = roundRatings
+  // Sort by date (most recent first) and extract ratings
+  const sortedRatings = roundRatings
     .sort((a, b) => b.date - a.date)
-    .map(r => r.rating);
+    .map(r => r.rating)
+    .filter(r => r > 0);
   
-  const weightedRatings = [];
-  const oneFourth = ratings.length > 9 ? Math.round(ratings.length * 0.25) : -1;
+  if (sortedRatings.length === 0) return 0;
   
-  for (let i = 0; i < ratings.length; i++) {
-    const rating = ratings[i];
-    weightedRatings.push(rating);
+  // PDGA Rule: Need at least 7 rounds to apply outlier exclusion
+  if (sortedRatings.length >= 7) {
+    // Calculate standard deviation for outlier detection
+    const mean = sortedRatings.reduce((sum, r) => sum + r, 0) / sortedRatings.length;
+    const stdDev = calculateStandardDeviation(sortedRatings);
     
-    if (i < oneFourth) {
-      weightedRatings.push(rating);
+    // PDGA Rule: Exclude rounds more than 2.5 standard deviations below average
+    const filteredRatings = sortedRatings.filter(rating => 
+      rating >= (mean - 2.5 * stdDev)
+    );
+    
+    // Use filtered ratings if we still have enough data
+    if (filteredRatings.length >= 4) {
+      sortedRatings.splice(0, sortedRatings.length, ...filteredRatings);
     }
   }
   
-  const validRatings = weightedRatings.filter(r => r > 0);
-  if (validRatings.length === 0) return 0;
+  // PDGA Rule: Most recent 25% of rounds count double if 9+ rounds
+  const weightedRatings = [];
+  if (sortedRatings.length >= 9) {
+    const recentCount = Math.round(sortedRatings.length * 0.25);
+    
+    // Add all ratings once
+    weightedRatings.push(...sortedRatings);
+    
+    // Add the most recent 25% again (double weight)
+    for (let i = 0; i < recentCount; i++) {
+      weightedRatings.push(sortedRatings[i]);
+    }
+  } else {
+    // If fewer than 9 rounds, no double weighting
+    weightedRatings.push(...sortedRatings);
+  }
   
-  const mean = validRatings.reduce((sum, r) => sum + r, 0) / validRatings.length;
-  const stdDev = calculateStandardDeviation(ratings);
-  const deviation = Math.min(stdDev * 2.5, 100);
+  // Calculate final average
+  const finalRating = weightedRatings.reduce((sum, r) => sum + r, 0) / weightedRatings.length;
   
-  const filteredRatings = validRatings.filter(rating => Math.abs(mean - rating) < deviation);
-  
-  if (filteredRatings.length === 0) return Math.round(mean);
-  
-  return Math.round(filteredRatings.reduce((sum, r) => sum + r, 0) / filteredRatings.length);
+  return Math.round(finalRating);
 }
 
 function calculateStandardDeviation(ratings) {