epus-std_native0.4_3.0.5.3.source-code.TopicNameEncoder.scala Maven / Gradle / Ivy

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/*
 * Copyright 2021 Hossein Naderi
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package lepus.std

import cats.syntax.all.*

import scala.compiletime.*
import scala.deriving.Mirror

/** Encoder that encodes types to a [[lepus.std.TopicName]]
  *
  * Note that this is not a typeclass and it is not used in implicit scope and
  * there are no instances of it.
  */
final class TopicNameEncoder[A](private val build: A => String) extends AnyVal {
  def get: A => Either[String, TopicName] = build.andThen(TopicName.from)
  def contramap[B](f: B => A): TopicNameEncoder[B] =
    TopicNameEncoder(build.compose(f))

  def prefixed(prefix: String): TopicNameEncoder[A] =
    TopicNameEncoder(a => prefix + build(a))

  def transform(f: String => String): TopicNameEncoder[A] =
    TopicNameEncoder(build.andThen(f))
}

object TopicNameEncoder {
  def from[A](f: A => String): TopicNameEncoder[A] = TopicNameEncoder(f)

  inline def of[T](using m: Mirror.Of[T]): TopicNameEncoder[T] =
    inline m match
      case s: Mirror.SumOf[T]     => sumInst(s)
      case p: Mirror.ProductOf[T] => productInst(p)

  private inline def productInst[T](
      m: Mirror.ProductOf[T]
  ): TopicNameEncoder[T] =
    TopicNameEncoder(_ => TopicName(constValue[m.MirroredLabel]))

  private inline def summonAll[T <: Tuple]: List[TopicNameEncoder[?]] =
    inline erasedValue[T] match {
      case _: EmptyTuple => Nil
      case _: (h *: t)   => of(using summonInline[Mirror.Of[h]]) +: summonAll[t]
    }

  private inline def sumInst[T](
      m: Mirror.SumOf[T]
  ): TopicNameEncoder[T] = {
    val enc = summonAll[m.MirroredElemTypes]
    TopicNameEncoder(t =>
      enc(m.ordinal(t)).asInstanceOf[TopicNameEncoder[T]].build(t)
    )
  }

}