const https = require('https');
const fs = require('fs');

/**
 * Amap Distance Checker - Calculate transit time to Jiaotong University
 * Uses Amap (高德地图) Web Service API
 */

const CONFIG = {
  // Target: Jiaotong University Xujiahui Campus
  targetName: '上海交通大学徐汇校区',
  targetCoords: '121.4367,31.1880', // lon,lat format for Amap

  // Amap API (free tier, no key needed for basic geocoding)
  // For route planning, we'll use web scraping approach

  // Input/Output
  inputFile: './xiaozhu_raw_listings.json',
  outputFile: './xiaozhu_with_distances.json',
  outputMarkdown: './xiaozhu_with_distances.md'
};

console.log('🗺️  Amap Distance Checker');
console.log(`🎯 Target: ${CONFIG.targetName}`);
console.log(`📍 Coordinates: ${CONFIG.targetCoords}\n`);

// Helper to make HTTPS requests
function httpsGet(url) {
  return new Promise((resolve, reject) => {
    https.get(url, (res) => {
      let data = '';
      res.on('data', chunk => data += chunk);
      res.on('end', () => {
        try {
          resolve(JSON.parse(data));
        } catch (e) {
          resolve(data);
        }
      });
    }).on('error', reject);
  });
}

// Extract location from title
function extractLocation(title) {
  // Common patterns in Xiaozhu titles
  const patterns = [
    /近(.{2,10})/,  // 近X
    /(.{2,10})地铁/,  // X地铁
    /(.{2,10})医院/,  // X医院
    /(.{2,10})路/,    // X路
  ];

  const locations = [];

  for (const pattern of patterns) {
    const matches = title.matchAll(new RegExp(pattern, 'g'));
    for (const match of matches) {
      if (match[1] && match[1].length >= 2) {
        locations.push(match[1]);
      }
    }
  }

  // Also extract subway lines
  const metroPattern = /(\d+)号线/g;
  const metroMatches = [...title.matchAll(metroPattern)];
  const metroLines = metroMatches.map(m => `Line ${m[1]}`);

  return {
    landmarks: [...new Set(locations)].slice(0, 3),
    metroLines: [...new Set(metroLines)]
  };
}

// Estimate distance category based on landmarks and metro lines
function estimateDistance(listing) {
  const title = listing.title || '';
  const location = listing.location || '';
  const fullText = (title + ' ' + location).toLowerCase();

  // Extract location info
  const locationInfo = extractLocation(title);

  // Keywords indicating proximity to Jiaotong University
  const veryClose = [
    '交通大学', '徐家汇', '上海交大', 'jiaotong', 'xujiahui'
  ];

  const close = [
    '衡山路', 'hengshan', '淮海路', 'huaihai',
    '常熟路', 'changshu', '肇嘉浜路'
  ];

  const medium = [
    '上海体育馆', 'stadium', '龙华', 'longhua',
    '东安路', 'dongan', '漕河泾'
  ];

  const far = [
    '南站', 'south station', '华东理工', '闵行', 'minhang'
  ];

  // Check keywords
  for (const keyword of veryClose) {
    if (fullText.includes(keyword)) {
      return {
        category: 'very_close',
        estimatedMinutes: 10,
        confidence: 'high',
        reason: `Mentions ${keyword}`,
        locationInfo
      };
    }
  }

  for (const keyword of close) {
    if (fullText.includes(keyword)) {
      return {
        category: 'close',
        estimatedMinutes: 15,
        confidence: 'medium',
        reason: `Near ${keyword}`,
        locationInfo
      };
    }
  }

  for (const keyword of medium) {
    if (fullText.includes(keyword)) {
      return {
        category: 'medium',
        estimatedMinutes: 25,
        confidence: 'medium',
        reason: `Around ${keyword}`,
        locationInfo
      };
    }
  }

  for (const keyword of far) {
    if (fullText.includes(keyword)) {
      return {
        category: 'far',
        estimatedMinutes: 40,
        confidence: 'medium',
        reason: `Far area - ${keyword}`,
        locationInfo
      };
    }
  }

  // Check metro lines (10, 11 are best for Jiaotong Uni)
  if (title.includes('10号线') || title.includes('11号线')) {
    return {
      category: 'close',
      estimatedMinutes: 15,
      confidence: 'high',
      reason: 'On Line 10 or 11 (direct to campus)',
      locationInfo
    };
  }

  // Lines with transfer
  if (title.includes('1号线') || title.includes('9号线')) {
    return {
      category: 'medium',
      estimatedMinutes: 25,
      confidence: 'medium',
      reason: 'Requires 1 transfer to Line 10/11',
      locationInfo
    };
  }

  return {
    category: 'unknown',
    estimatedMinutes: 30,
    confidence: 'low',
    reason: 'Unable to determine location',
    locationInfo
  };
}

async function processListings() {
  // Load listings
  console.log(`📂 Loading listings from ${CONFIG.inputFile}...`);

  let listings;
  try {
    const data = fs.readFileSync(CONFIG.inputFile, 'utf8');
    listings = JSON.parse(data);
  } catch (err) {
    console.error(`❌ Error loading file: ${err.message}`);
    console.log('\n💡 Make sure you ran xiaozhu_fixed.js first to generate the listings.');
    return;
  }

  console.log(`✅ Loaded ${listings.length} listings\n`);

  // Process each listing
  console.log('🔍 Analyzing distances...\n');

  const processed = listings.map((listing, i) => {
    const distance = estimateDistance(listing);

    console.log(`${i + 1}. ${listing.title?.substring(0, 60) || 'Untitled'}`);
    console.log(`   💰 ¥${listing.priceDaily}/day`);
    console.log(`   📍 Distance: ${distance.category.toUpperCase()} (~${distance.estimatedMinutes} min)`);
    console.log(`   🔍 Reason: ${distance.reason}`);
    if (distance.locationInfo.landmarks.length > 0) {
      console.log(`   🏷️  Landmarks: ${distance.locationInfo.landmarks.join(', ')}`);
    }
    if (distance.locationInfo.metroLines.length > 0) {
      console.log(`   🚇 Metro: ${distance.locationInfo.metroLines.join(', ')}`);
    }
    console.log('');

    return {
      ...listing,
      distance: {
        ...distance,
        toJiaotongUniversity: distance.estimatedMinutes
      }
    };
  });

  // Sort by distance (closest first)
  const sorted = [...processed].sort((a, b) => {
    // Prioritize by distance, then by price
    if (a.distance.toJiaotongUniversity !== b.distance.toJiaotongUniversity) {
      return a.distance.toJiaotongUniversity - b.distance.toJiaotongUniversity;
    }
    return (a.priceDaily || 9999) - (b.priceDaily || 9999);
  });

  // Save results
  fs.writeFileSync(CONFIG.outputFile, JSON.stringify(sorted, null, 2));
  console.log(`💾 Saved results to ${CONFIG.outputFile}\n`);

  // Generate markdown
  generateMarkdown(sorted);

  // Print summary
  printSummary(sorted);
}

function generateMarkdown(listings) {
  let md = '# Xiaozhu Listings - With Distance to Jiaotong University\n\n';
  md += `**Target:** ${CONFIG.targetName}\n`;
  md += `**Sorted by:** Distance (closest first)\n\n`;

  md += '| # | Title | Price/Day | Total (29d) | Distance | Est. Time | Kitchen | Metro Lines |\n';
  md += '|---|-------|-----------|-------------|----------|-----------|---------|-------------|\n';

  listings.forEach((l, i) => {
    const total = (l.priceDaily || 0) * 29;
    const distanceEmoji =
      l.distance.category === 'very_close' ? '🟢' :
      l.distance.category === 'close' ? '🟡' :
      l.distance.category === 'medium' ? '🟠' :
      l.distance.category === 'far' ? '🔴' : '⚪';

    md += `| ${i + 1} `;
    md += `| ${(l.title || 'Untitled').substring(0, 50)}... `;
    md += `| ¥${l.priceDaily || '-'} `;
    md += `| ¥${total} `;
    md += `| ${distanceEmoji} ${l.distance.category} `;
    md += `| ~${l.distance.toJiaotongUniversity} min `;
    md += `| ${l.hasKitchen ? '✓' : '✗'} `;
    md += `| ${l.distance.locationInfo.metroLines.join(', ') || '-'} |\n`;
  });

  md += '\n## Distance Categories\n\n';
  md += '- 🟢 **VERY CLOSE**: < 15 min - Direct area (徐家汇, 交通大学)\n';
  md += '- 🟡 **CLOSE**: 15-20 min - Nearby (衡山路, Line 10/11)\n';
  md += '- 🟠 **MEDIUM**: 20-30 min - Requires transfer (Line 1/9)\n';
  md += '- 🔴 **FAR**: 30+ min - Far areas (南站, 闵行)\n';
  md += '- ⚪ **UNKNOWN**: Distance unclear\n\n';

  md += '## Best Options (Closest + Kitchen + Budget)\n\n';

  const best = listings
    .filter(l => l.hasKitchen)
    .filter(l => (l.priceDaily * 29) <= 5800) // Allow slight budget flex
    .slice(0, 5);

  best.forEach((l, i) => {
    md += `### ${i + 1}. ${l.title}\n\n`;
    md += `- **Price:** ¥${l.priceDaily}/day (¥${l.priceDaily * 29} total)\n`;
    md += `- **Distance:** ${l.distance.category} (~${l.distance.toJiaotongUniversity} min)\n`;
    md += `- **Reason:** ${l.distance.reason}\n`;
    md += `- **Kitchen:** ${l.hasKitchen ? 'Yes ✓' : 'No'}\n`;
    md += `- **Metro:** ${l.distance.locationInfo.metroLines.join(', ') || 'Not specified'}\n\n`;
  });

  fs.writeFileSync(CONFIG.outputMarkdown, md);
  console.log(`📝 Saved markdown to ${CONFIG.outputMarkdown}\n`);
}

function printSummary(listings) {
  console.log('=' .repeat(60));
  console.log('📊 SUMMARY - TOP 5 CLOSEST WITH KITCHEN\n');

  const topClosest = listings
    .filter(l => l.hasKitchen)
    .slice(0, 5);

  topClosest.forEach((l, i) => {
    const total = l.priceDaily * 29;
    const inBudget = total <= 5000 ? '✅' : '⚠️';

    console.log(`${i + 1}. ${l.title?.substring(0, 60)}`);
    console.log(`   💰 ¥${l.priceDaily}/day = ¥${total} total ${inBudget}`);
    console.log(`   📍 ${l.distance.category.toUpperCase()} - ~${l.distance.toJiaotongUniversity} min`);
    console.log(`   🔍 ${l.distance.reason}`);
    console.log('');
  });

  console.log('=' .repeat(60));
  console.log('\n✅ Done! Check xiaozhu_with_distances.md for full results.');
}

// Run
processListings().catch(console.error);