package driver

import (
	"fmt"
	"net/url"
	"strconv"

	"git.unkin.net/unkin/waitfordb/internal/config"
	_ "github.com/jackc/pgx/v5/stdlib" // registers the "pgx" database/sql driver
)

func init() { register(postgres{}) }

type postgres struct{}

func (postgres) Name() string { return "postgres" }

func (postgres) Open(cfg config.Config) (Pinger, error) {
	dsn := cfg.DSN
	if dsn == "" {
		dsn = postgresDSN(cfg)
	}
	return openSQL("pgx", dsn)
}

// postgresDSN builds a URL-style DSN. net/url escapes the userinfo and query so
// passwords with special characters are handled safely.
func postgresDSN(cfg config.Config) string {
	u := url.URL{
		Scheme: "postgres",
		Host:   fmt.Sprintf("%s:%s", cfg.Host, cfg.Port),
		Path:   "/" + cfg.Database,
	}
	if cfg.User != "" {
		u.User = url.UserPassword(cfg.User, cfg.Password)
	}
	q := url.Values{}
	if cfg.SSLMode != "" {
		q.Set("sslmode", cfg.SSLMode)
	}
	// connect_timeout is a per-attempt safety net in addition to the context
	// deadline the wait loop applies; it is in whole seconds.
	if secs := int(cfg.ConnectTimeout.Seconds()); secs > 0 {
		q.Set("connect_timeout", strconv.Itoa(secs))
	}
	u.RawQuery = q.Encode()
	return u.String()
}