import fs from 'node:fs/promises';
import path from 'node:path';
import { fileURLToPath } from 'node:url';
import { Client } from 'pg';

import config from '../../src/config/config.js';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

function getEnv(name, fallback) {
  return process.env[name] ?? fallback;
}

function buildClientConfig(database) {
  const db = config.db;
  return {
    host: getEnv('PGHOST', db.host),
    port: Number(getEnv('PGPORT', db.port)),
    user: getEnv('PGUSER', db.user),
    password: getEnv('PGPASSWORD', db.password),
    database,
  };
}

async function runSqlFile(client, filePath) {
  const sql = await fs.readFile(filePath, 'utf8');
  const trimmed = sql.trim();
  if (!trimmed) return;
  await client.query(sql);
}

async function main() {
  const scriptsDir = __dirname;

  const schemaFile = path.join(scriptsDir, '010_heartbeat_schema.sql');
  const partitionFile = path.join(scriptsDir, '020_partitioning_auto_daily.sql');

  const targetDb = getEnv('PGTARGETDB', config.db.database);

  console.log(`[db] Connecting to target db: ${targetDb}`);
  const targetClient = new Client(buildClientConfig(targetDb));
  await targetClient.connect();

  try {
    const dbMeta = await targetClient.query(
      `SELECT
         current_database() AS db,
         pg_encoding_to_char(encoding) AS encoding,
         datcollate,
         datctype,
         datlocprovider
       FROM pg_database
       WHERE datname = current_database()`
    );
    if (dbMeta.rowCount === 1) {
      const m = dbMeta.rows[0];
      console.log(
        `[db] ${m.db} meta: encoding=${m.encoding} collate=${m.datcollate} ctype=${m.datctype} provider=${m.datlocprovider}`
      );
      if (String(m.encoding).toUpperCase() !== 'UTF8') {
        console.warn(`[db] WARN: ${m.db} encoding is not UTF8`);
      }
      const coll = String(m.datcollate ?? '').toLowerCase();
      if (coll && !coll.includes('zh') && !coll.includes('chinese')) {
        console.warn(
          `[db] WARN: ${m.db} collation is not obviously Chinese; if required, use ICU collation per-column or rebuild DB with zh locale`
        );
      }
    }

    console.log(`[db] Applying: ${path.basename(schemaFile)}`);
    await runSqlFile(targetClient, schemaFile);

    console.log(`[db] Applying: ${path.basename(partitionFile)}`);
    await runSqlFile(targetClient, partitionFile);

    const tableCheck = await targetClient.query(
      "SELECT to_regclass('heartbeat.heartbeat_events') AS reg"
    );
    if (!tableCheck.rows?.[0]?.reg) {
      throw new Error('heartbeat.heartbeat_events was not created');
    }

    const indexCheck = await targetClient.query(
      `SELECT indexname
       FROM pg_indexes
       WHERE schemaname = 'heartbeat'
         AND tablename = 'heartbeat_events'
       ORDER BY indexname`
    );

    console.log('[db] Parent table indexes:');
    for (const row of indexCheck.rows) {
      console.log(`  - ${row.indexname}`);
    }

    console.log('[db] Done');
  } finally {
    await targetClient.end();
  }
}

main().catch((err) => {
  console.error('[db] Failed:', err);
  process.exit(1);
});