const express = require('express');
const puppeteer = require('puppeteer');
const fs = require('fs');
const path = require('path');

const app = express();
const PORT = 3000;

app.use(express.static('public'));

const cache = new Map();
const CACHE_DURATION = 24 * 60 * 60 * 1000;

async function scrapePDGARating(pdgaNumber) {
  const cacheKey = `player-${pdgaNumber}`;
  const cached = cache.get(cacheKey);
  
  if (cached && Date.now() - cached.timestamp < CACHE_DURATION) {
    console.log(`Using cached data for PDGA ${pdgaNumber}`);
    return cached.data;
  }
  
  const browser = await puppeteer.launch({ headless: true });
  const page = await browser.newPage();
  
  try {
    const url = `https://www.pdga.com/player/${pdgaNumber}`;
    await page.goto(url, { waitUntil: 'networkidle2' });
    
    const playerName = await page.$eval('h1', el => {
      const text = el.innerText.trim();
      return text.replace(/\s*#\d+$/, '');
    });
    
    const ratingData = await page.evaluate(() => {
      const elements = document.querySelectorAll('li');
      for (const el of elements) {
        const text = el.innerText || el.textContent;
        if (text.includes('Current Rating:')) {
          console.log('Found rating text:', text);
          const ratingMatch = text.match(/Current Rating:\s*(\d+)/);
          
          // Try different patterns for rating change
          const changePatterns = [
            /\[(\+\d+)\]/,
            /\[(\-\d+)\]/,
            /(\+\d+)/,
            /(\-\d+)/
          ];
          
          let change = null;
          for (const pattern of changePatterns) {
            const match = text.match(pattern);
            if (match) {
              change = match[1];
              break;
            }
          }
          
          return {
            rating: ratingMatch ? ratingMatch[1] : null,
            change: change
          };
        }
      }
      return { rating: null, change: null };
    });
    
    await browser.close();
    
    const result = {
      pdgaNumber,
      name: playerName,
      rating: ratingData.rating ? parseInt(ratingData.rating) : 0,
      ratingChange: ratingData.change ? parseInt(ratingData.change) : null,
      predictedRating: null
    };
    
    cache.set(cacheKey, {
      data: result,
      timestamp: Date.now()
    });
    
    return result;
  } catch (error) {
    console.error(`Error scraping PDGA ${pdgaNumber}:`, error);
    await browser.close();
    return {
      pdgaNumber,
      name: 'Error',
      rating: 0,
      ratingChange: null,
      predictedRating: null
    };
  }
}

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 getPlayerCompetitionRatings(browser, pdgaNumber) {
  const page = await browser.newPage();
  let allRatings = [];
  
  try {
    const url = `https://www.pdga.com/player/${pdgaNumber}`;
    await page.goto(url, { waitUntil: 'networkidle2' });
    
    const tournamentUrls = await page.evaluate(() => {
      const tables = document.querySelectorAll('table[id*="player-results"]');
      const urls = [];
      
      tables.forEach(table => {
        const rows = table.querySelectorAll('tbody tr');
        rows.forEach(row => {
          const dateCell = row.querySelector('.dates');
          const tournamentCell = row.querySelector('.tournament a');
          
          if (dateCell && tournamentCell) {
            const dateText = dateCell.innerText.trim();
            const dateMatch = dateText.match(/\d{1,2}-[A-Za-z]{3}-\d{4}/);
            
            if (dateMatch) {
              const dateStr = dateMatch[0];
              const date = new Date(dateStr);
              const twoYearsAgo = new Date();
              twoYearsAgo.setFullYear(twoYearsAgo.getFullYear() - 2);
              
              if (date > twoYearsAgo) {
                const href = tournamentCell.getAttribute('href');
                if (href) {
                  urls.push({
                    url: `https://www.pdga.com${href}`,
                    date: dateStr
                  });
                }
              }
            }
          }
        });
      });
      
      return urls.slice(0, 15);
    });
    
    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);
        
        const roundRatings = await page.evaluate((pdgaNum) => {
          const rows = document.querySelectorAll('tr');
          
          for (const row of rows) {
            const cells = row.querySelectorAll('td');
            const hasPlayerNumber = Array.from(cells).some(cell => 
              cell.innerText && cell.innerText.includes(pdgaNum.toString())
            );
            
            if (hasPlayerNumber) {
              const roundRatingCells = row.querySelectorAll('td.round-rating');
              const ratings = [];
              
              roundRatingCells.forEach(cell => {
                const rating = parseInt(cell.innerText.trim());
                if (!isNaN(rating) && rating > 0) {
                  ratings.push(rating);
                }
              });
              
              return ratings;
            }
          }
          
          return [];
        }, pdgaNumber);
        
        if (roundRatings.length > 0) {
          const parsedDate = parseDate(tournamentData.date);
          roundRatings.forEach(rating => {
            allRatings.push({
              rating,
              date: parsedDate
            });
          });
          console.log(`Found ${roundRatings.length} round ratings for ${tournamentData.url}`);
        }
        
      } catch (error) {
        console.error(`Error scraping tournament ${tournamentData.url}:`, error);
      }
    }
    
  } catch (error) {
    console.error(`Error getting competition ratings for PDGA ${pdgaNumber}:`, error);
  } finally {
    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;
}

function parseDate(dateStr) {
  const formats = [
    /^(\d{1,2})-([A-Za-z]{3})-(\d{4})$/,
    /^(\d{1,2})\/(\d{1,2})\/(\d{4})$/
  ];
  
  for (const format of formats) {
    const match = dateStr.match(format);
    if (match) {
      if (format === formats[0]) {
        const monthMap = {
          'Jan': 0, 'Feb': 1, 'Mar': 2, 'Apr': 3, 'May': 4, 'Jun': 5,
          'Jul': 6, 'Aug': 7, 'Sep': 8, 'Oct': 9, 'Nov': 10, 'Dec': 11
        };
        const day = parseInt(match[1]);
        const month = monthMap[match[2]];
        const year = parseInt(match[3]);
        return new Date(year, month, day);
      }
    }
  }
  
  return new Date(dateStr);
}

function calculatePredictedRating(roundRatings) {
  if (!roundRatings || roundRatings.length === 0) return 0;
  
  const ratings = roundRatings
    .sort((a, b) => b.date - a.date)
    .map(r => r.rating);
  
  const weightedRatings = [];
  const oneFourth = ratings.length > 9 ? Math.round(ratings.length * 0.25) : -1;
  
  for (let i = 0; i < ratings.length; i++) {
    const rating = ratings[i];
    weightedRatings.push(rating);
    
    if (i < oneFourth) {
      weightedRatings.push(rating);
    }
  }
  
  const validRatings = weightedRatings.filter(r => r > 0);
  if (validRatings.length === 0) return 0;
  
  const mean = validRatings.reduce((sum, r) => sum + r, 0) / validRatings.length;
  const stdDev = calculateStandardDeviation(ratings);
  const deviation = Math.min(stdDev * 2.5, 100);
  
  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);
}

function calculateStandardDeviation(ratings) {
  if (!ratings || ratings.length === 0) return 0;
  
  const mean = ratings.reduce((sum, r) => sum + r, 0) / ratings.length;
  const variance = ratings.reduce((sum, r) => sum + Math.pow(r - mean, 2), 0) / ratings.length;
  
  return Math.sqrt(variance);
}

async function getAllRatings() {
  try {
    const pdgaNumbers = fs.readFileSync('pdga-numbers.txt', 'utf-8')
      .split('\n')
      .map(num => num.trim())
      .filter(num => num);
    
    const ratings = [];
    
    for (const pdgaNumber of pdgaNumbers) {
      console.log(`Scraping PDGA ${pdgaNumber}...`);
      const playerData = await scrapePDGARating(pdgaNumber);
      ratings.push(playerData);
    }
    
    return ratings.sort((a, b) => b.rating - a.rating);
  } catch (error) {
    console.error('Error reading PDGA numbers:', error);
    return [];
  }
}

app.get('/', (req, res) => {
  res.sendFile(path.join(__dirname, 'index.html'));
});

app.get('/api/ratings', async (req, res) => {
  try {
    const ratings = await getAllRatings();
    res.json(ratings);
  } catch (error) {
    res.status(500).json({ error: 'Failed to fetch ratings' });
  }
});

app.post('/api/predicted-rating/:pdgaNumber', async (req, res) => {
  try {
    const { pdgaNumber } = req.params;
    const browser = await puppeteer.launch({ headless: true });
    
    console.log(`Calculating predicted rating for PDGA ${pdgaNumber}...`);
    const predictedRating = await getPredictedRating(browser, pdgaNumber);
    
    await browser.close();
    
    res.json({ 
      pdgaNumber: parseInt(pdgaNumber),
      predictedRating 
    });
  } catch (error) {
    console.error('Error calculating predicted rating:', error);
    res.status(500).json({ error: 'Failed to calculate predicted rating' });
  }
});

app.listen(PORT, () => {
  console.log(`PDGA Ratings app running on http://localhost:${PORT}`);
});