package mysql

import (
	"database/sql"
	"fmt"
	"time"
)

type Config struct {
	Username string `koanf:"username"`
	Password string `koanf:"password"`
	Port     int    `koanf:"port"`
	Host     string `koanf:"host"`
	DBName   string `koanf:"db_name"`
}

type DB struct {
	config Config
	db     *sql.DB
}

func (m *DB) Conn() *sql.DB {
	return m.db
}

// TODO: this temperary to ignore linter error (magic number).
const (
	dbMaxConnLifetime = time.Minute * 3
	dbMaxOpenConns    = 10
	dbMaxIdleConns    = 10
)

func New(config Config) *DB {
	// parseTime=true changes the output type of DATE and DATETIME values to time.Time
	// instead of []byte / string
	// The date or datetime like 0000-00-00 00:00:00 is converted into zero value of time.Time
	db, err := sql.Open("mysql", fmt.Sprintf("%s:%s@(%s:%d)/%s?parseTime=true",
		config.Username, config.Password, config.Host, config.Port, config.DBName))
	if err != nil {
		panic(fmt.Errorf("can't open mysql db: %w", err))
	}

	// See "Important settings" section.
	db.SetConnMaxLifetime(dbMaxConnLifetime)
	db.SetMaxOpenConns(dbMaxOpenConns)
	db.SetMaxIdleConns(dbMaxIdleConns)

	return &DB{config: config, db: db}
}