#!/usr/bin/env node
const { pool, query } = require("./config/database");

async function analyzeQueryPatterns() {
  console.log("🔍 Analyzing Query Patterns...\n");

  try {
    // 1. Check for missing indexes on frequently queried columns
    console.log("1️⃣ Checking Query Performance:");

    // Test products query (most common)
    const productsExplain = await query(`
      EXPLAIN ANALYZE
      SELECT p.id, p.name, p.slug, p.price, p.category, p.createdat
      FROM products p
      WHERE p.isactive = true
      ORDER BY p.createdat DESC
      LIMIT 20
    `);
    console.log("   Products listing:");
    productsExplain.rows.forEach((row) => {
      if (
        row["QUERY PLAN"].includes("Index") ||
        row["QUERY PLAN"].includes("Seq Scan")
      ) {
        console.log(`      ${row["QUERY PLAN"]}`);
      }
    });

    // Test portfolio query
    const portfolioExplain = await query(`
      EXPLAIN ANALYZE
      SELECT id, title, category, displayorder, createdat
      FROM portfolioprojects
      WHERE isactive = true
      ORDER BY displayorder ASC, createdat DESC
    `);
    console.log("\n   Portfolio listing:");
    portfolioExplain.rows.slice(0, 3).forEach((row) => {
      console.log(`      ${row["QUERY PLAN"]}`);
    });

    // Test product with images (JOIN query)
    const productWithImagesExplain = await query(`
      EXPLAIN ANALYZE
      SELECT p.*, pi.image_url, pi.color_variant
      FROM products p
      LEFT JOIN product_images pi ON pi.product_id = p.id
      WHERE p.isactive = true
      LIMIT 10
    `);
    console.log("\n   Products with images (JOIN):");
    productWithImagesExplain.rows.slice(0, 5).forEach((row) => {
      console.log(`      ${row["QUERY PLAN"]}`);
    });

    // 2. Check for slow queries
    console.log("\n2️⃣ Checking Table Statistics:");
    const stats = await query(`
      SELECT 
        schemaname,
        relname as tablename,
        n_live_tup as row_count,
        n_dead_tup as dead_rows,
        CASE 
          WHEN n_live_tup > 0 THEN round(100.0 * n_dead_tup / n_live_tup, 2)
          ELSE 0
        END as bloat_pct,
        last_vacuum,
        last_analyze
      FROM pg_stat_user_tables
      WHERE schemaname = 'public'
        AND relname IN ('products', 'product_images', 'portfolioprojects', 'blogposts', 'pages')
      ORDER BY n_live_tup DESC
    `);

    console.log("   Table health:");
    stats.rows.forEach((row) => {
      console.log(
        `      ${row.tablename.padEnd(20)} ${String(row.row_count).padStart(
          6
        )} rows, ${String(row.dead_rows).padStart(4)} dead (${String(
          row.bloat_pct
        ).padStart(5)}% bloat)`
      );
    });

    // 3. Check index usage
    console.log("\n3️⃣ Index Usage Statistics:");
    const indexUsage = await query(`
      SELECT
        schemaname,
        relname as tablename,
        indexrelname as indexname,
        idx_scan as scans,
        idx_tup_read as rows_read,
        idx_tup_fetch as rows_fetched
      FROM pg_stat_user_indexes
      WHERE schemaname = 'public'
        AND relname IN ('products', 'product_images', 'portfolioprojects', 'blogposts', 'pages')
        AND idx_scan > 0
      ORDER BY idx_scan DESC
      LIMIT 15
    `);

    console.log("   Most used indexes:");
    indexUsage.rows.forEach((row) => {
      console.log(
        `      ${row.indexname.padEnd(40)} ${String(row.scans).padStart(
          6
        )} scans`
      );
    });

    // 4. Check for unused indexes
    const unusedIndexes = await query(`
      SELECT
        schemaname,
        relname as tablename,
        indexrelname as indexname
      FROM pg_stat_user_indexes
      WHERE schemaname = 'public'
        AND relname IN ('products', 'product_images', 'portfolioprojects', 'blogposts', 'pages')
        AND idx_scan = 0
        AND indexrelname NOT LIKE '%_pkey'
      ORDER BY relname, indexrelname
    `);

    if (unusedIndexes.rows.length > 0) {
      console.log("\n4️⃣ Unused Indexes (consider removing):");
      unusedIndexes.rows.forEach((row) => {
        console.log(`      ${row.tablename}.${row.indexname}`);
      });
    } else {
      console.log("\n4️⃣ ✅ All indexes are being used");
    }

    // 5. Check cache hit ratio
    console.log("\n5️⃣ Cache Hit Ratio:");
    const cacheHit = await query(`
      SELECT 
        sum(heap_blks_read) as heap_read,
        sum(heap_blks_hit) as heap_hit,
        CASE 
          WHEN sum(heap_blks_hit) + sum(heap_blks_read) > 0 THEN
            round(100.0 * sum(heap_blks_hit) / (sum(heap_blks_hit) + sum(heap_blks_read)), 2)
          ELSE 0
        END as cache_hit_ratio
      FROM pg_statio_user_tables
      WHERE schemaname = 'public'
    `);

    const ratio = cacheHit.rows[0].cache_hit_ratio;
    const status = ratio > 99 ? "✅" : ratio > 95 ? "⚠️" : "❌";
    console.log(`      ${status} ${ratio}% (target: >99%)`);

    console.log("\n✅ Analysis complete!");
  } catch (error) {
    console.error("❌ Error:", error.message);
  } finally {
    await pool.end();
  }
}

analyzeQueryPatterns();