package cooler

import (
	"context"
	"errors"
	"strings"

	"github.com/redis/go-redis/v9"
	"github.com/redis/go-redis/v9/maintnotifications"
)

// errInvalidRedisURL is the only error OpenRedis returns for a URL that does
// not parse. It never wraps or quotes the parser's error: url.Parse echoes the
// whole URL, password included.
var errInvalidRedisURL = errors.New("cooler: " + RedisURLKey + " is not a valid redis://, rediss:// or unix:// URL")

// OpenRedis builds a go-redis client from a redis:// (plain), rediss:// (TLS)
// or unix:// URL, such as the value of redis.url. It does not dial: go-redis
// connects on the first command. A URL that does not parse yields an error that
// names redis.url and never contains the URL or its credentials.
//
// The client skips the CLIENT SETINFO and maintenance-notification handshakes,
// which older servers and test doubles do not know.
func OpenRedis(ctx context.Context, rawURL string) (*redis.Client, error) {
	_ = ctx // reserved: go-redis does not dial at construction
	rawURL = strings.TrimSpace(rawURL)
	if rawURL == "" {
		return nil, errors.New("cooler: " + RedisURLKey + " is empty")
	}
	opt, err := redis.ParseURL(rawURL)
	if err != nil {
		return nil, errInvalidRedisURL
	}
	opt.DisableIdentity = true
	opt.MaintNotificationsConfig = &maintnotifications.Config{Mode: maintnotifications.ModeDisabled}
	return redis.NewClient(opt), nil
}

// redisEndpoint is the part of a client's address that may be logged: the
// host and port (or socket path), never the URL, user or password.
func redisEndpoint(c *redis.Client) string {
	if c == nil {
		return ""
	}
	return c.Options().Addr
}