package database

import (
	"database/sql"
	"errors"
	"fmt"
	"os"
)

// Will try to connect to the database defined by the env variables. If the
// connection fails a error will be returned. Ensure that the returned sql.DB
// object is closed after use.
func DbConnection() (*sql.DB, error) {
	// collect environement variables
	dbPass := os.Getenv("DB_PASS")
	if dbPass == "" {
		return nil, errors.New("empty env. variable DB_PASS")
	}
	dbHost := os.Getenv("DB_HOST")
	if dbHost == "" {
		return nil, errors.New("empty env. variable DB_HOST")
	}
	dbPort := os.Getenv("DB_PORT")
	if dbPort == "" {
		dbPort = "5432"
	}
	dbUser := os.Getenv("DB_USER")
	if dbUser == "" {
		dbUser = "postgres"
	}
	dbName := os.Getenv("DB_NAME")

	// connect to database
	databaseURL := fmt.Sprintf("user=%s password=%s dbname=%s host=%s port=%s sslmode=disable",
		dbUser, dbPass, dbName, dbHost, dbPort)
	db, err := sql.Open("postgres", databaseURL)
	if err != nil {
		return nil, err
	}
	if err = db.Ping(); err != nil {
		return nil, err
	}

	return db, nil
}