import log = require("winston");
import { Client, Pool, QueryResult } from "pg";
import { SQLCommand } from "../post_put_ts/repositories/sql-command";

export class DatabaseClient {
   private static pool: Pool;

   public static async connect(): Promise<Pool> {
      log.info(`About to connect to:${process.env.DB_HOST}`);

      this.pool = new Pool({
         user: process.env.DB_USER,
         host: process.env.DB_HOST,
         database: process.env.DB_NAME,
         password: process.env.DB_PASS,
         port: +process.env.DB_PORT
      });

      await this.pool.connect();

      log.info(`Connected Successfully to:${process.env.DB_HOST}`);

      return this.pool;
   }

   public static async execute(command: SQLCommand): Promise<QueryResult> {
      try {
         if (!this.pool) {
            await this.connect();
         }

         return await this.pool.query(command.sql, command.params);
      } catch (err) {
         throw (`An error occured executing sql command: ${command.sql}`)
      }
      finally {
         // how do we do a finally block here?
      }

   }
}