import fp from 'fastify-plugin';
import pg from 'pg';
import { Kysely, PostgresDialect } from 'kysely';
import type { Database } from '../db/schema';

// Parse int8 (OID 20) as a JS number. Safe well past any realistic message
// count (Number.MAX_SAFE_INTEGER ≈ 9e15); revisit if a counter could exceed it.
pg.types.setTypeParser(20, (value) => Number(value));

declare module 'fastify' {
  interface FastifyInstance {
    db: Kysely<Database>;
  }
}

// Postgres connection pool wrapped in a typed Kysely instance. Registered via
// fastify-plugin so the `db` decoration is visible app-wide, not just in scope.
export const dbPlugin = fp(
  (app) => {
    const pool = new pg.Pool({ connectionString: app.config.databaseUrl });
    const db = new Kysely<Database>({ dialect: new PostgresDialect({ pool }) });

    app.decorate('db', db);
    app.addHook('onClose', async () => {
      await db.destroy();
    });

    return Promise.resolve();
  },
  { name: 'db' },
);