'use strict';

const { Pool } = require('pg');

const STOPWORDS = new Set(['the', 'a', 'an', 'and', 'or', 'for', 'to', 'of', 'in', 'on', 'with', 'do', 'does', 'is', 'are', 'how', 'what', 'can', 'you', 'my', 'your', 'i', 'we', 'it', 'please', 'show', 'me']);

// 全量商品页站点地图（bridge_site_map_urls）：服务端匹配，不进 LLM/向量库。
function createSiteMap(cfg) {
  if (!cfg.pgUrl) return { enabled: false, search: async () => [] };
  const pool = new Pool({ connectionString: cfg.pgUrl, max: 2, connectionTimeoutMillis: 5000 });

  function tokensFor(query) {
    return String(query || '')
      .toLowerCase()
      .replace(/[^\p{L}\p{N}\s-]+/gu, ' ')
      .split(/\s+/)
      .filter((w) => w && w.length > 1 && !STOPWORDS.has(w))
      .slice(0, 8);
  }

  function nameFromUrl(url) {
    const seg = String(url || '').split('/').filter(Boolean).pop() || '';
    return seg
      .replace(/\.html$/, '')
      .replace(/-?\d+$/, '')
      .split('-')
      .filter((w) => w && w.length > 1)
      .map((w) => w.charAt(0).toUpperCase() + w.slice(1))
      .join(' ');
  }

  async function search(query, site = 'www', limit = 3) {
    const tokens = tokensFor(query);
    if (tokens.length < 2) return [];
    try {
      const patterns = tokens.map((t) => `%${t}%`);
      const r = await pool.query(
        `SELECT path, url, is_product, level, slug_tokens
         FROM bridge_site_map_urls
         WHERE site = $1 AND slug_tokens ILIKE ALL($2::text[])
         ORDER BY is_product DESC, char_length(slug_tokens) ASC, level ASC
         LIMIT $3`,
        [site, patterns, Math.min(Number(limit) || 3, 5)]
      );
      return r.rows.map((row) => ({ name: nameFromUrl(row.url), url: row.url, is_product: row.is_product, path: row.path }));
    } catch (err) {
      console.error(JSON.stringify({ ts: new Date().toISOString(), warn: `sitemap search failed: ${err.message}` }));
      return [];
    }
  }

  return { enabled: true, search, pool };
}

module.exports = { createSiteMap };