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/*
 * Copyright 2023-2023 etspaceman
 *
 * 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 kinesis4cats.compat

import cats.syntax.apply._
import cats.syntax.flatMap._
import cats.syntax.functor._
import cats.{Monad, MonadError}

// Ported over from cats-retry so that native is supported.
// Should be removed when cats-retry is merged into CE
package object retry {

  /*
   * API
   */

  private[kinesis4cats] def retryingOnFailures[A] =
    new RetryingOnFailuresPartiallyApplied[A]

  private[kinesis4cats] def retryingOnSomeErrors[A] =
    new RetryingOnSomeErrorsPartiallyApplied[A]

  private[kinesis4cats] def retryingOnAllErrors[A] =
    new RetryingOnAllErrorsPartiallyApplied[A]

  private[kinesis4cats] def retryingOnFailuresAndSomeErrors[A] =
    new RetryingOnFailuresAndSomeErrorsPartiallyApplied[A]

  private[kinesis4cats] def retryingOnFailuresAndAllErrors[A] =
    new RetryingOnFailuresAndAllErrorsPartiallyApplied[A]

  private[kinesis4cats] def noop[M[_]: Monad, A]: (A, RetryDetails) => M[Unit] =
    (_, _) => Monad[M].pure(())

  /*
   * Implementation
   */

  private[retry] def retryingOnFailuresImpl[M[_], A](
      policy: RetryPolicy[M],
      wasSuccessful: A => M[Boolean],
      onFailure: (A, RetryDetails) => M[Unit],
      status: RetryStatus,
      a: A
  )(implicit
      M: Monad[M],
      S: Sleep[M]
  ): M[Either[RetryStatus, A]] = {

    def onFalse: M[Either[RetryStatus, A]] = for {
      nextStep <- applyPolicy(policy, status)
      _ <- onFailure(a, buildRetryDetails(status, nextStep))
      result <- nextStep match {
        case NextStep.RetryAfterDelay(delay, updatedStatus) =>
          S.sleep(delay) *>
            M.pure(Left(updatedStatus)) // continue recursion
        case NextStep.GiveUp =>
          M.pure(Right(a)) // stop the recursion
      }
    } yield result

    wasSuccessful(a).ifM(
      M.pure(Right(a)), // stop the recursion
      onFalse
    )
  }

  private[retry] def retryingOnSomeErrorsImpl[M[_], A, E](
      policy: RetryPolicy[M],
      isWorthRetrying: E => M[Boolean],
      onError: (E, RetryDetails) => M[Unit],
      status: RetryStatus,
      attempt: Either[E, A]
  )(implicit
      ME: MonadError[M, E],
      S: Sleep[M]
  ): M[Either[RetryStatus, A]] = attempt match {
    case Left(error) =>
      isWorthRetrying(error).ifM(
        for {
          nextStep <- applyPolicy(policy, status)
          _ <- onError(error, buildRetryDetails(status, nextStep))
          result <- nextStep match {
            case NextStep.RetryAfterDelay(delay, updatedStatus) =>
              S.sleep(delay) *>
                ME.pure(Left(updatedStatus)) // continue recursion
            case NextStep.GiveUp =>
              ME.raiseError[A](error).map(Right(_)) // stop the recursion
          }
        } yield result,
        ME.raiseError[A](error).map(Right(_)) // stop the recursion
      )
    case Right(success) =>
      ME.pure(Right(success)) // stop the recursion
  }

  private[retry] def applyPolicy[M[_]: Monad](
      policy: RetryPolicy[M],
      retryStatus: RetryStatus
  ): M[NextStep] =
    policy.decideNextRetry(retryStatus).map {
      case PolicyDecision.DelayAndRetry(delay) =>
        NextStep.RetryAfterDelay(delay, retryStatus.addRetry(delay))
      case PolicyDecision.GiveUp =>
        NextStep.GiveUp
    }

  private[retry] def buildRetryDetails(
      currentStatus: RetryStatus,
      nextStep: NextStep
  ): RetryDetails =
    nextStep match {
      case NextStep.RetryAfterDelay(delay, _) =>
        RetryDetails.WillDelayAndRetry(
          delay,
          currentStatus.retriesSoFar,
          currentStatus.cumulativeDelay
        )
      case NextStep.GiveUp =>
        RetryDetails.GivingUp(
          currentStatus.retriesSoFar,
          currentStatus.cumulativeDelay
        )
    }
}