package gs.config.v0

/** Base class for most [[Configuration]] implementations. Provides standard
  * support for properly handling default values and parsing strings to the
  * correct type, returning the correct errors.
  */
abstract class BaseConfiguration[F[_]] extends Configuration[F]:

  protected def handleMissingValue[A](
    key: ConfigKey[A]
  ): Either[ConfigError, A] =
    key match
      case ConfigKey.WithDefaultValue(_, defaultValue) =>
        Right(defaultValue())
      case _ =>
        Left(ConfigError.MissingValue(key.name))

  protected def parse[A: Configurable](
    key: ConfigKey[A],
    raw: String,
    source: Option[String]
  ): Either[ConfigError, A] =
    Configurable[A].parse(raw) match
      case None =>
        Left(
          ConfigError.CannotParseValue(
            configName = key.name,
            candidateValue = raw,
            source = source.getOrElse("")
          )
        )
      case Some(parsed) => Right(parsed)