import knex from 'knex';
import 'dotenv/config';
import executeJsonQuery from './jsonQueryExecutor.js';

/**
 * Knex configuration
 * Uses environment variables with sane defaults
 */
const config = {
  client: 'pg',
  connection: {
    host: process.env.PGHOST || '127.0.0.1',
    port: Number(process.env.PGPORT || 5432),
    user: process.env.PGUSER || 'postgres',
    password: process.env.PGPASSWORD || 'postgres',
    database: process.env.PGDATABASE || 'postgres',
  },
  pool: {
    min: 2,
    max: 10,
  },
};

const knexInstance = knex(config);

const dbClient = {

  async execute(query) {
    if (!query || typeof query !== 'object') {
      throw new Error('Invalid query object');
    }

    switch (query.type) {

      case 'json': {
        return await executeJsonQuery(knexInstance, query);
      }

      case 'raw-builder': {
        if (typeof query.handler !== 'function') {
          throw new Error('raw-builder requires a handler function');
        }
        return await query.handler(knexInstance);
      }

      case 'transaction': {
        if (typeof query.handler !== 'function') {
          throw new Error('transaction requires a handler function');
        }

        return await knexInstance.transaction(async (trx) => {
          return await query.handler(trx);
        });
      }

      default:
        throw new Error(`Unsupported query type: ${query.type}`);
    }
  },

  getKnex() {
    return knexInstance;
  },

  async destroy() {
    await knexInstance.destroy();
  }
};

export default dbClient;