const logger = require(`${__base}/logger`);
const fs = require('fs');
const path = require('path');
const { Pool } = require('pg');

class PostgresDatabase {
  constructor(user, password='', host, database) {
    this.user = user;
    this.password = password;
    this.host = host;
    this.database = database;

    this.pool = new Pool({
      user,
      password,
      host,
      database,
      port: 5432
    });

    // save queries to postgres in local list
    // should prevent this from overflowing.
  }

  connect() {
    return this.pool.connect();
  }

  /**
   * Run a SQL query against the database and retrieve one row.
   * @param {String} sql SQL query
   * @param {Array} values in the SQL query
   * @returns {Promise}
   */
  query(sql, values) {
    const start = Date.now();

    return this.pool.query(sql, values)
      .then(res => {
        const duration = Date.now() - start;
        logger.debug("Executed query", {
          sql,
          values,
          duration,
          rows: res.rowCount
        });

        return res.rowCount;
      })
      .catch(err => {
        console.log('query db error:', err);
        // TODO log db error
        throw err;
      })
  };

 /**
  * Update w/ query and return true or false if update was successful.
  * @param {String} sql SQL query
  * @param {Array} values in the SQL query
  * @returns {Promise}
  */
  update(sql, values) {
    const start = Date.now();

    return this.pool.query(sql, values)
      .then(res => {
        const duration = Date.now() - start;
        logger.debug("Executed query", {
          sql,
          values,
          duration,
          rows: res.rowCount
        });

        if (res.rowCount > 0) {
          return true;
        }
        return false;
      })
      .catch(err => {
        console.log(err)
        // TODO log db error
        throw err;
      })
  }

  /**
   * Run a SQL query against the database and retrieve all the rows.
   * @param {String} sql SQL query
   * @param {Array} values in the SQL query
   * @returns {Promise}
   */
  all(sql, values) {
    const start = Date.now();

    return this.pool.query(sql, values)
      .then(res => res.rows)
      .catch(err => {
        // TODO log db error
        throw err;
      })
  }

  /**
   * Run a SQL query against the database and retrieve one row.
   * @param {String} sql SQL query
   * @param {Array} values in the SQL query
   * @returns {Promise}
   */
  get(sql, values) {
    return this.pool.query(sql, values)
    .then(res => res.rows[0])
    .catch(err => {
      // TODO log db error
      throw err;
    })
  }
}

module.exports = PostgresDatabase;