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package org.apache.james.jmap.method

import eu.timepit.refined.auto._
import javax.inject.Inject
import org.apache.james.core.Username
import org.apache.james.jmap.core.CapabilityIdentifier.{CapabilityIdentifier, JAMES_DELEGATION, JMAP_CORE}
import org.apache.james.jmap.core.Invocation.{Arguments, MethodName}
import org.apache.james.jmap.core.{ErrorCode, Invocation, Properties, SessionTranslator}
import org.apache.james.jmap.delegation.{Delegate, DelegateGet, DelegateGetRequest, DelegateGetResult, ForbiddenAccountManagementException}
import org.apache.james.jmap.delegation.{Delegate, DelegateGet, DelegateGetRequest, DelegateGetResult, DelegationId}
import org.apache.james.jmap.json.{DelegationSerializer, ResponseSerializer}
import org.apache.james.jmap.routes.SessionSupplier
import org.apache.james.mailbox.MailboxSession
import org.apache.james.metrics.api.MetricFactory
import org.apache.james.user.api.DelegationStore
import org.reactivestreams.Publisher
import play.api.libs.json.JsObject
import reactor.core.scala.publisher.{SFlux, SMono}

import scala.jdk.OptionConverters._


class DelegateGetMethod @Inject()(val metricFactory: MetricFactory,
                                  val sessionSupplier: SessionSupplier,
                                  val sessionTranslator: SessionTranslator,
                                  val delegationStore: DelegationStore) extends MethodRequiringAccountId[DelegateGetRequest] {

  override val methodName: MethodName = MethodName("Delegate/get")
  override val requiredCapabilities: Set[CapabilityIdentifier] = Set(JMAP_CORE, JAMES_DELEGATION)

  override def getRequest(mailboxSession: MailboxSession, invocation: Invocation): Either[Exception, DelegateGetRequest] =
    DelegationSerializer.deserializeDelegateGetRequest(invocation.arguments.value)
      .asEither.left.map(ResponseSerializer.asException)
  override def doProcess(capabilities: Set[CapabilityIdentifier], invocation: InvocationWithContext, mailboxSession: MailboxSession, request: DelegateGetRequest): Publisher[InvocationWithContext] = {
    val requestedProperties: Properties = request.properties.getOrElse(DelegateGet.allProperties)
    (requestedProperties -- DelegateGet.allProperties match {
      case invalidProperties if invalidProperties.isEmpty() => getDelegateGetResponse(request, mailboxSession)
      .map(result => result.asResponse(request.accountId))
        .map(response => Invocation(
          methodName = methodName,
          arguments = Arguments(DelegationSerializer.serialize(response, requestedProperties).as[JsObject]),
          methodCallId = invocation.invocation.methodCallId))
      case invalidProperties: Properties => SMono.just(Invocation.error(
        errorCode = ErrorCode.InvalidArguments,
        description = s"The following properties [${invalidProperties.format()}] do not exist.",
        methodCallId = invocation.invocation.methodCallId))
    }).map(InvocationWithContext(_, invocation.processingContext))
  }

  private def getDelegateGetResponse(request: DelegateGetRequest, mailboxSession: MailboxSession): SMono[DelegateGetResult] =
    SMono.just(isDelegatedRequest(mailboxSession))
      .filter(isDelegated => isDelegated)
      .flatMap(_ => SMono.error(ForbiddenAccountManagementException()))
      .switchIfEmpty(getAuthorizedUser(mailboxSession.getUser, request))

  private def getAuthorizedUser(baseUser: Username, request: DelegateGetRequest): SMono[DelegateGetResult] =
    SFlux(delegationStore.authorizedUsers(baseUser))
      .map(authorizedUser => Delegate(DelegationId.from(baseUser, authorizedUser), authorizedUser))
      .collectSeq()
      .map(delegates => DelegateGetResult.from(delegates, request.ids.map(_.value.map(_.id).toSet)))

  private def isDelegatedRequest(mailboxSession: MailboxSession): Boolean =
    mailboxSession.getLoggedInUser.toScala match {
      case None => false
      case Some(value) => !value.equals(mailboxSession.getUser)
    }
}
