package postgres

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

	_ "github.com/lib/pq"
)

type Config struct {
	DSN             string
	MaxOpenConns    int
	MaxIdleConns    int
	ConnMaxLifetime time.Duration
}

func Open(cfg Config) (*sql.DB, error) {
	if cfg.DSN == "" {
		return nil, fmt.Errorf("dsn is required")
	}
	db, err := sql.Open("postgres", cfg.DSN)
	if err != nil {
		return nil, err
	}
	if cfg.MaxOpenConns > 0 {
		db.SetMaxOpenConns(cfg.MaxOpenConns)
	}
	if cfg.MaxIdleConns > 0 {
		db.SetMaxIdleConns(cfg.MaxIdleConns)
	}
	if cfg.ConnMaxLifetime > 0 {
		db.SetConnMaxLifetime(cfg.ConnMaxLifetime)
	}
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	if err := db.PingContext(ctx); err != nil {
		_ = db.Close()
		return nil, err
	}
	return db, nil
}