// 2026-03-21 — js-pg-batch: вставляет N строк через parameterized bulk query.
// Тестирует: async/await PG с пакетной вставкой, Node.js под нагрузкой.
const { Client } = require('pg');

async function run(event) {
    const n = Math.min(parseInt(event.n ?? 20, 10) || 20, 200);
    const prefix = String(event.prefix ?? 'js-batch').slice(0, 40);

    const client = new Client({
        host: process.env.PGHOST,
        port: parseInt(process.env.PGPORT ?? '5432'),
        database: process.env.PGDATABASE,
        user: process.env.PGUSER,
        password: process.env.PGPASSWORD,
        ssl: { rejectUnauthorized: false },
    });
    await client.connect();

    try {
        const ts = Date.now();
        // Строим multi-value INSERT: INSERT INTO ... VALUES ($1), ($2), ...
        const placeholders = [];
        const values = [];
        for (let i = 0; i < n; i++) {
            placeholders.push(`($${i + 1})`);
            values.push(`${prefix}-${ts}-${i}`);
        }
        const sql = `INSERT INTO terraform_demo_table (title) VALUES ${placeholders.join(',')} RETURNING id`;
        const t0 = Date.now();
        const res = await client.query(sql, values);
        const elapsed = (Date.now() - t0) / 1000;

        return {
            inserted: res.rowCount,
            first_id: res.rows[0]?.id ?? null,
            elapsed_sec: elapsed,
        };
    } finally {
        await client.end();
    }
}

module.exports = { run };