gs-predicate/src/main/scala/gs/predicate/v0/kv/ValueStartsWith.scala

76 lines
2.2 KiB
Scala

package gs.predicate.v0.kv
import cats.Functor
import cats.syntax.all.*
import gs.predicate.v0.api.Messages
import gs.predicate.v0.api.Predicate
import gs.predicate.v0.serde.json.JsonKeys
import io.circe.Decoder
import io.circe.DecodingFailure
import io.circe.Encoder
import io.circe.Json
/** Predicate that matches if some [[KeyValueProvider]] contains the given key,
* and the string value associated with that key starts with some other string.
*
* @param key
* The key that should exist.
* @param prefix
* The substring that must be the prefix of the value.
*/
final class ValueStartsWith[F[_]: Functor: KeyValueProvider](
val key: String,
val prefix: String
) extends Predicate[F]:
/** @inheritDocs
*/
override def predicateType: String = ValueStartsWith.PredicateType
/** @inheritDocs
*/
override def eval(): F[Predicate.Result] =
KeyValueProvider[F].get(key).map {
case Some(value) => Predicate.Result(value.startsWith(prefix))
case _ => Predicate.Result.missed()
}
object ValueStartsWith:
final val PredicateType: String = "kv-string-starts-with"
def apply[F[_]: Functor: KeyValueProvider](
key: String,
prefix: String
): ValueStartsWith[F] =
new ValueStartsWith[F](key, prefix)
given valueStartsWithEncoder[F[_]]: Encoder[ValueStartsWith[F]] =
Encoder.instance[ValueStartsWith[F]] { p =>
Json.obj(
(JsonKeys.predicateType, Json.fromString(PredicateType)),
(JsonKeys.key, Json.fromString(p.key)),
(JsonKeys.value, Json.fromString(p.prefix))
)
}
given valueStartsWithDecoder[F[_]: Functor: KeyValueProvider]
: Decoder[ValueStartsWith[F]] =
Decoder.instance[ValueStartsWith[F]] { cursor =>
cursor.downField(JsonKeys.predicateType).as[String].flatMap {
case PredicateType =>
for
key <- cursor.downField(JsonKeys.key).as[String]
value <- cursor.downField(JsonKeys.value).as[String]
yield new ValueStartsWith(key, value)
case candidate =>
Left(
DecodingFailure(
Messages.invalidPredicateType(candidate, PredicateType),
Nil
)
)
}
}
end ValueStartsWith