/**
 * Migration 004 — PID & Slug 字段
 *
 * - internal_pid: 系统内部编号，如 VPS-000001（唯一，自动生成）
 * - provider_pid: 商家产品 ID，从购买链接自动解析（如 pid=28）
 * - slug: 前台友好 URL，唯一
 */
const Database = require('better-sqlite3');
const path = require('path');
require('dotenv').config({ path: path.join(__dirname, '..', '.env') });

const dbPath = path.resolve(__dirname, '..', process.env.DB_PATH || 'db/monitor.sqlite');
const db = new Database(dbPath);
db.pragma('journal_mode = WAL');

function ensureColumn(table, column, sql) {
  const cols = db.prepare(`PRAGMA table_info(${table})`).all().map(c => c.name);
  if (!cols.includes(column)) {
    db.exec(`ALTER TABLE ${table} ADD COLUMN ${sql}`);
    console.log(`+ ${table}.${column}`);
  } else {
    console.log(`  ${table}.${column} (already exists)`);
  }
}

// 添加新字段
ensureColumn('products', 'internal_pid', 'internal_pid TEXT');
ensureColumn('products', 'provider_pid', 'provider_pid TEXT');
ensureColumn('products', 'slug', 'slug TEXT');

// 创建唯一索引（如果尚不存在）
try {
  db.exec('CREATE UNIQUE INDEX IF NOT EXISTS idx_products_internal_pid ON products(internal_pid) WHERE internal_pid IS NOT NULL');
  console.log('+ index: idx_products_internal_pid');
} catch (e) {
  console.log('  index idx_products_internal_pid:', e.message);
}
try {
  db.exec('CREATE UNIQUE INDEX IF NOT EXISTS idx_products_slug ON products(slug) WHERE slug IS NOT NULL');
  console.log('+ index: idx_products_slug');
} catch (e) {
  console.log('  index idx_products_slug:', e.message);
}

// 为已有产品回填 internal_pid 和 slug
const { generateInternalPid, generateSlug, parseProviderPid } = require('../src/utils/pidHelper');

const products = db.prepare('SELECT id, name, merchant_id, url, buy_url, internal_pid, slug, provider_pid FROM products').all();
const updateStmt = db.prepare('UPDATE products SET internal_pid = ?, slug = ?, provider_pid = ? WHERE id = ?');

const getMerchantName = db.prepare('SELECT name FROM merchants WHERE id = ?');
const existingSlugs = new Set(
  db.prepare("SELECT slug FROM products WHERE slug IS NOT NULL AND slug != ''").all().map(r => r.slug)
);

db.transaction(() => {
  for (const p of products) {
    let ipid = p.internal_pid;
    let slug = p.slug;
    let ppid = p.provider_pid;

    // 生成 internal_pid
    if (!ipid) {
      ipid = generateInternalPid(db);
    }

    // 生成 slug
    if (!slug) {
      const merchant = getMerchantName.get(p.merchant_id);
      const merchantName = merchant ? merchant.name : '';
      slug = generateSlug(p.name, merchantName, existingSlugs);
      existingSlugs.add(slug);
    }

    // 解析 provider_pid
    if (!ppid) {
      ppid = parseProviderPid(p.buy_url) || parseProviderPid(p.url) || null;
    }

    updateStmt.run(ipid, slug, ppid, p.id);
    console.log(`  product #${p.id}: internal_pid=${ipid}, slug=${slug}, provider_pid=${ppid || '(none)'}`);
  }
})();

console.log('✅ migration-004 done:', dbPath);
db.close();