ElasticSearch.scala

package lib.elasticsearch

import org.apache.pekko.actor.Scheduler
import com.gu.mediaservice.lib.ImageFields
import com.gu.mediaservice.lib.elasticsearch.filters
import com.gu.mediaservice.lib.elasticsearch.{ElasticSearchClient, ElasticSearchConfig, ElasticSearchExecutions, ReapableEligibility, Running}
import com.gu.mediaservice.lib.formatting.printDateTime
import com.gu.mediaservice.lib.logging.{LogMarker, MarkerMap}
import com.gu.mediaservice.model._
import com.gu.mediaservice.model.leases.MediaLease
import com.gu.mediaservice.model.usage.{Usage, UsageNotice}
import com.gu.mediaservice.syntax._
import com.sksamuel.elastic4s.ElasticDsl._
import com.sksamuel.elastic4s.requests.script.Script
import com.sksamuel.elastic4s.requests.searches.SearchResponse
import com.sksamuel.elastic4s.requests.searches.queries.Query
import com.sksamuel.elastic4s.requests.searches.queries.compound.BoolQuery
import com.sksamuel.elastic4s.requests.searches.sort.SortOrder
import com.sksamuel.elastic4s.requests.update.UpdateRequest
import com.sksamuel.elastic4s.{ElasticDsl, Executor, Functor, Handler, Response}
import lib.{BatchDeletionIds, ThrallMetrics}
import org.joda.time.DateTime
import play.api.libs.json.JsValue.jsValueToJsLookup
import play.api.libs.json._

import scala.annotation.nowarn
import scala.concurrent.duration.DurationInt
import scala.concurrent.{ExecutionContext, Future}

object ImageNotDeletable extends Throwable("Image cannot be deleted")

class ElasticSearch(
  config: ElasticSearchConfig,
  metrics: Option[ThrallMetrics],
  val scheduler: Scheduler
) extends ElasticSearchClient with ImageFields with ElasticSearchExecutions with ThrallMigrationClient {


  lazy val imagesCurrentAlias: String = config.aliases.current
  lazy val imagesMigrationAlias: String = config.aliases.migration
  lazy val url: String = config.url
  lazy val shards: Int = config.shards
  lazy val replicas: Int = config.replicas
  lazy val includeDenseVectorMappings: Boolean = config.includeDenseVectorMappings


  def migrationAwareUpdater[REQUEST, RESPONSE](
                                                requestFromIndexName: String => REQUEST,
                                                logMessageFromIndexName: String => String,
                                                notFoundSuccessful: Boolean = false,
                                              )(implicit
                                                ex: ExecutionContext,
                                                functor: Functor[Future],
                                                executor: Executor[Future],
                                                handler: Handler[REQUEST, RESPONSE],
                                                manifest: Manifest[RESPONSE],
                                                logMarkers: LogMarker
                                              ): Future[Response[RESPONSE]] = {
    // if doc does not exist in migration index, ignore (ie. mark as successful).
    // coalesce all other errors.
    val runForCurrentIndex: Future[Option[Response[RESPONSE]]] = executeAndLog(requestFromIndexName(imagesCurrentAlias), logMessageFromIndexName(imagesCurrentAlias), notFoundSuccessful).map(Some(_))
    // Update requests to the alias throw if the alias does not exist, but the exception is very generic and not cause is not obvious
    // ("index names must be all upper case")
    val runForMigrationIndex: Future[Option[Response[RESPONSE]]] = migrationStatus match {
      case _: Running => executeAndLog(requestFromIndexName(imagesMigrationAlias), logMessageFromIndexName(imagesMigrationAlias), notFoundSuccessful = true).map(Some(_))
      case _ => Future.successful(None)
    }
    // remove the optionality of the completed futures. runForCurrentIndex will always be Some, so there will always be a head.
    Future.sequence(List(runForCurrentIndex, runForMigrationIndex)).map(_.flatten.head)
  }

  def setMigrationInfo(imageId: String, migrationInfo: MigrationInfo)(implicit ex: ExecutionContext, logMarker: LogMarker): Future[Response[Any]] = {
    val esInfo = EsInfo(migration = Some(migrationInfo))
    val container = Json.obj("esInfo" -> Json.toJson(esInfo))

    val request = updateById(imagesCurrentAlias, imageId)
      .doc(Json.stringify(container))

    executeAndLog(request, s"Setting migration info on image id: ${imageId}")
  }

  private def prepareImageJson(json: JsObject): JsObject =
    if (includeDenseVectorMappings) json
    else json - "embedding"

  def directInsert(image: Image, indexName: String)(implicit ex: ExecutionContext, logMarker: LogMarker): Future[ElasticSearchInsertResponse] =
    executeAndLog(
      indexInto(indexName).id(image.id).source(Json.stringify(prepareImageJson(Json.toJson(image).as[JsObject]))),
      s"ES6 indexing image ${image.id} into index '$indexName'"
    ).map(indexResponse =>
      ElasticSearchInsertResponse(indexResponse.result.index)
    )


  def migrationAwareIndexImage(id: String, image: Image, lastModified: DateTime)
                              (implicit ex: ExecutionContext, logMarker: LogMarker): Future[ElasticSearchUpdateResponse] = {

    // On insert, we know we will not have a lastModified to consider, so we always take the one we get
    val insertImage = image.copy(lastModified = Some(lastModified))
    val insertImageAsJson = prepareImageJson(Json.toJson(insertImage).as[JsObject])

    def runUpsertIntoIndex(indexAlias: String, maybeEsInfo: Option[JsObject]) = {
      val esInfo = maybeEsInfo.getOrElse(JsObject.empty)

      // On update, we do not want to take the one we have been given unless it is newer - see updateLastModifiedScript script
      val updateImage = image.copy(lastModified = None)
      val upsertImageAsJson = prepareImageJson(Json.toJson(updateImage).as[JsObject])

      val painlessSource =
        // If there are old identifiers, then merge any new identifiers into old and use the merged results as the new identifiers
        """
          | if (ctx._source.identifiers != null) {
          |   ctx._source.identifiers.putAll(params.update_doc.identifiers);
          |   params.update_doc.identifiers = ctx._source.identifiers
          | }
          |
          | ctx._source.putAll(params.update_doc);
          |
          | if (ctx._source.metadata != null && ctx._source.metadata.credit != null) {
          |   ctx._source.suggestMetadataCredit = [ "input": [ ctx._source.metadata.credit ] ]
          | }
      """

      val scriptSource = loadUpdatingModificationPainless(
        s"""
           |$painlessSource
           |$refreshEditsScript
           | """)

      val script: Script = prepareScript(scriptSource, lastModified,
        ("update_doc", asNestedMap(asImageUpdate(upsertImageAsJson.as[JsObject] ++ esInfo)))
      )

      val indexRequest = updateById(indexAlias, id).
        upsert(Json.stringify(insertImageAsJson.as[JsObject] ++ esInfo)).
        script(script)

      executeAndLog(indexRequest, s"ES6 indexing image $id into index aliased by '$indexAlias'")
    }

    val runUpsertIntoMigrationIndexAndReturnEsInfoForCurrentIndex: Future[JsObject] = migrationStatus match {
      case running: Running =>
        runUpsertIntoIndex(imagesMigrationAlias, maybeEsInfo = None)
          .map(_ => EsInfo(Some(MigrationInfo(migratedTo = Some(running.migrationIndexName)))))
          .recover { case error => EsInfo(Some(MigrationInfo(failures = Some(Map(
            running.migrationIndexName -> error.getMessage
          )))))
          }
          .map(esInfo => Json.obj("esInfo" -> Json.toJson(esInfo)))
      case _ => Future.successful(JsObject.empty)
    }

    for {
      esInfo <- runUpsertIntoMigrationIndexAndReturnEsInfoForCurrentIndex
      _ <- runUpsertIntoIndex(imagesCurrentAlias, maybeEsInfo = Some(esInfo))
    } yield ElasticSearchUpdateResponse()
  }

  def getImage(id: String)(implicit ex: ExecutionContext, logMarker: LogMarker): Future[Option[Image]] = {
    executeAndLog(get(imagesCurrentAlias, id), s"ES6 get image by $id").map { r =>
      if (r.result.found) {
        Some(Json.parse(r.result.sourceAsString).as[Image])
      } else {
        None
      }
    }
  }

  def getImageVersion(id: String)(implicit ex: ExecutionContext, logMarker: LogMarker = MarkerMap()): Future[Option[Long]] = {
    executeAndLog(get(imagesCurrentAlias, id), s"ES6 get image version by $id").map { r =>
      if (r.result.found) {
        Some(r.result.version)
      } else {
        None
      }
    }
  }


  def updateImageUsages(id: String, usages: Seq[Usage], lastModified: DateTime)
                       (implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {
    val replaceUsagesScript = loadUpdatingModificationPainless(
      s"""
         | def lastUpdatedDate = ctx._source.usagesLastModified != null ? Date.from(Instant.from(DateTimeFormatter.ISO_DATE_TIME.parse(ctx._source.usagesLastModified))) : null;
         | if (lastUpdatedDate == null || modificationDate.after(lastUpdatedDate)) {
         |   ctx._source.usages = params.usages;
         |   ctx._source.usagesLastModified = params.lastModified;
         | }
    """)

    val usagesParameter = usages.map(i => asNestedMap(Json.toJson(i)))

    val eventualUpdateResponse = migrationAwareUpdater(
      requestFromIndexName = indexName => prepareUpdateRequest(indexName, id, replaceUsagesScript, lastModified, ("usages", usagesParameter)),
      logMessageFromIndexName = indexName => s"ES6 updating usages on image $id for index $indexName"
    ).incrementOnFailure(metrics.map(_.failedUsagesUpdates)) { case _ => true }

    List(eventualUpdateResponse.map(_ => ElasticSearchUpdateResponse()))
  }

  def updateImageSyndicationRights(id: String, rights: Option[SyndicationRights], lastModified: DateTime)
                                  (implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {

    val replaceSyndicationRightsScript =
      """
        | ctx._source.syndicationRights = params.syndicationRights;
      """.stripMargin

    val rightsParameter = rights.map(sr => asNestedMap(sr)).orNull

    val scriptSource = loadUpdatingModificationPainless(replaceSyndicationRightsScript)

    List(migrationAwareUpdater(
      requestFromIndexName = indexName => prepareUpdateRequest(indexName, id, scriptSource, lastModified, ("syndicationRights", rightsParameter)),
      logMessageFromIndexName = indexName => s"ES6 updating syndicationRights on image $id in index $indexName with rights $rightsParameter"
    ).map(_ => ElasticSearchUpdateResponse()))
  }

  def updateEmbedding(id: String, embedding: Embedding, lastModified: DateTime)
                     (implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {

    if (!includeDenseVectorMappings) {
      logger.info(s"Skipping embedding update for image $id: dense vector mappings are disabled")
      List(Future.successful(ElasticSearchUpdateResponse()))
    } else {

      val replaceEmbeddingScript = "ctx._source.embedding = params.embedding;"

      val scriptSource = loadPainless(replaceEmbeddingScript)

      val embeddingParameter = asNestedMap(Json.toJson(embedding))

      val eventualUpdateResponse = migrationAwareUpdater(
        requestFromIndexName = indexName => prepareUpdateRequest(indexName, id, scriptSource, lastModified, ("embedding", embeddingParameter)),
        logMessageFromIndexName = indexName => s"ES6 updating embedding on image $id in index $indexName"
      ).incrementOnFailure(metrics.map(_.failedEmbeddingUpdates)) { case _ => true }

      List(eventualUpdateResponse.map(_ => ElasticSearchUpdateResponse()))
    }
  }

  def applyImageMetadataOverride(id: String, metadata: Edits, lastModified: DateTime)
                                (implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {

    val photoshootSuggestionScript =
      """
        | if (ctx._source.userMetadata.photoshoot != null) {
        |   ctx._source.userMetadata.photoshoot.suggest = [ "input": [ ctx._source.userMetadata.photoshoot.title ] ];
        | }
    """.stripMargin

    val metadataParameter = JsDefined(Json.toJson(metadata)).toOption.map(asNestedMap).orNull

    val replaceUserMetadata =
      """
        | def lastUpdatedDate = ctx._source.userMetadataLastModified != null ? Date.from(Instant.from(DateTimeFormatter.ISO_DATE_TIME.parse(ctx._source.userMetadataLastModified))) : null;
        | if (lastUpdatedDate == null || modificationDate.after(lastUpdatedDate)) {
        |   ctx._source.userMetadata = params.userMetadata;
        |   ctx._source.userMetadataLastModified = params.lastModified;
        | }
        | """

    val scriptSource = loadUpdatingModificationPainless(
      s"""
         | $replaceUserMetadata
         | $refreshEditsScript
         | $photoshootSuggestionScript
       """
    )

    /* TODO: It should never be possible for Edits to have an empty lastModified although there will be
     * messages in the stream where it is missing until the stream content expires so we fall back for now but can
     * remove this in a week or so after merging */
    if (metadata.lastModified.isEmpty) logger.warn(logMarker, "edit object missing last modified value")
    val appliedLastModified = metadata.lastModified.getOrElse(lastModified)

    List(migrationAwareUpdater(
      requestFromIndexName = indexName => prepareUpdateRequest(
        indexName = indexName,
        id = id,
        scriptSource = scriptSource,
        lastModified = appliedLastModified,
        ("userMetadata", metadataParameter)
      ),
      logMessageFromIndexName = indexName => s"ES6 updating user metadata on image $id in index $indexName with lastModified $appliedLastModified"
    ).map(_ => ElasticSearchUpdateResponse()))
  }

  private def softDeletedMetadataAsPainlessScript(softDeletedMetadata: SoftDeletedMetadata) = {
    val applySoftDeleteScript = "ctx._source.softDeletedMetadata = params.softDeletedMetadata;"
    val softDeletedMetadataParameter = JsDefined(Json.toJson(softDeletedMetadata)).toOption.map(asNestedMap).orNull

    prepareScript(
      applySoftDeleteScript,
      lastModified = softDeletedMetadata.deleteTime,
      ("softDeletedMetadata", softDeletedMetadataParameter)
    )
  }

  def applySoftDelete(id: String, softDeletedMetadata: SoftDeletedMetadata, lastModified: DateTime)
                     (implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {

    List(migrationAwareUpdater(
      requestFromIndexName = indexName => prepareUpdateRequest(
        indexName,
        id,
        softDeletedMetadataAsPainlessScript(softDeletedMetadata),
      ),
      logMessageFromIndexName = indexName => s"ES7 soft delete image $id in $indexName by ${softDeletedMetadata.deletedBy}"
    ).map(_ => ElasticSearchUpdateResponse()))
  }

  def applyUnSoftDelete(id: String, lastModified: DateTime)
                       (implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {
    val applyUnSoftDeleteScript = "ctx._source.remove(\"softDeletedMetadata\");"

    List(migrationAwareUpdater(
      requestFromIndexName = indexName => prepareUpdateRequest(
        indexName,
        id,
        applyUnSoftDeleteScript,
        lastModified
      ),
      logMessageFromIndexName = indexName => s"ES7 un soft delete image $id in $indexName"
    ).map(_ => ElasticSearchUpdateResponse()))
  }

  private def getNextBatchOfImageIdsForDeletion(query: Query, count: Int, deletionType: String)
                                               (implicit ex: ExecutionContext, logMarker: LogMarker) =
    executeAndLog(
      ElasticDsl.search(imagesCurrentAlias) // current index is sufficient for producing the list of IDs to delete
        .query(query)
        .storedFields("_id")
        .sortByFieldAsc("uploadTime")
        .size(count),
      s"ES7 searching for oldest $count images to $deletionType delete"
    ).map(_.result.hits.hits.map(_.id).toSet)

  private def countTotalReapable(query: Query, deletionType: String)
                                (implicit ex: ExecutionContext, logMarker: LogMarker): Future[Long] = executeAndLog(
    ElasticDsl.count(imagesCurrentAlias).query(query),
    s"counting '$deletionType' reapable images"
  ).map(_.result.count)

  private def softReapableQuery(isReapable: ReapableEligibility) = must(
    isReapable.query,
    filters.existsOrMissing("softDeletedMetadata", exists = false) // not already soft deleted
  )

  def countTotalSoftReapable(isReapable: ReapableEligibility)(implicit ex: ExecutionContext, logMarker: LogMarker): Future[Long] =
    countTotalReapable(softReapableQuery(isReapable), "soft")

  def softDeleteNextBatchOfImages(isReapable: ReapableEligibility, count: Int, softDeletedMetadata: SoftDeletedMetadata)
                                 (implicit ex: ExecutionContext, logMarker: LogMarker): Future[BatchDeletionIds] = {

    val query = softReapableQuery(isReapable)

    for {
      // unfortunately 'updateByQuery' doesn't return the affected IDs so can't do this whole thing in one operation - https://github.com/elastic/elasticsearch/issues/48624
      ids <- getNextBatchOfImageIdsForDeletion(query, count, "soft")
      esResults <- if (ids.isEmpty) Future.successful(Seq.empty) else migrationAwareUpdater(
        requestFromIndexName = indexName =>
          bulk(ids.map(
            updateById(indexName, _)
              .script(softDeletedMetadataAsPainlessScript(softDeletedMetadata))
          )),
        logMessageFromIndexName = indexName => s"ES7 soft delete ${ids.size} images in $indexName by ${softDeletedMetadata.deletedBy}"
      ).map(_.result.items)
    } yield {
      if (ids.isEmpty) {
        logger.info(s"Although $count images were requested to be soft deleted, none were found to be soft deletable.")
      }
      esResults.filter(_.error.isDefined).foreach(item =>
        logger.error(logMarker, s"ES7 failed to soft delete image ${item.id} : ${item.error.get}")
      )
      BatchDeletionIds(ids, esResults.filter(_.error.isEmpty).map(_.id).toSet)
    }
  }

  private def hardReapableQuery(isReapable: ReapableEligibility, daysInSoftDeletedState: Int) = must(
    isReapable.query,
    filters.existsOrMissing("softDeletedMetadata", exists = true), // already soft deleted
    rangeQuery("softDeletedMetadata.deleteTime").lt(DateTime.now.minusDays(daysInSoftDeletedState).toString) // soft deleted more than 2 weeks ago (default)
  )

  def countTotalHardReapable(isReapable: ReapableEligibility, daysInSoftDeletedState: Int)(implicit ex: ExecutionContext, logMarker: LogMarker): Future[Long] =
    countTotalReapable(hardReapableQuery(isReapable, daysInSoftDeletedState), "hard")

  def hardDeleteNextBatchOfImages(isReapable: ReapableEligibility, count: Int, daysInSoftDeletedState: Int)
                                 (implicit ex: ExecutionContext, logMarker: LogMarker): Future[BatchDeletionIds] = {

    val query = hardReapableQuery(isReapable, daysInSoftDeletedState)

    for {
      // unfortunately 'deleteByQuery' doesn't return the affected IDs so can't do this whole thing in one operation - https://github.com/elastic/elasticsearch/issues/45460
      ids <- getNextBatchOfImageIdsForDeletion(query, count, "hard")
      esResults <- if (ids.isEmpty) Future.successful(Seq.empty) else migrationAwareUpdater(
        requestFromIndexName = indexName =>
          bulk(ids.map(
            deleteById(indexName, _)
          )),
        logMessageFromIndexName = indexName => s"ES7 hard delete ${ids.size} images in $indexName"
      ).map(_.result.items)
    } yield {
      if (ids.isEmpty) {
        logger.info(s"Although $count images were requested to be hard deleted, none were found to be hard deletable.")
      }
      esResults.filter(_.error.isDefined).foreach(item =>
        logger.error(logMarker, s"ES7 failed to hard delete image ${item.id} : ${item.error.get}")
      )
      BatchDeletionIds(ids, esResults.filter(_.error.isEmpty).map(_.id).toSet)
    }
  }

  def getInferredSyndicationRightsImages(photoshoot: Photoshoot, excludedImageId: Option[String])
                                        (implicit ex: ExecutionContext, logMarker: LogMarker): Future[List[Image]] = { // TODO could be a Seq
    val inferredSyndicationRights = not(termQuery("syndicationRights.isInferred", false)) // Using 'not' to include nulls

    val filter = excludedImageId match {
      case Some(imageId) => boolQuery() must(
        inferredSyndicationRights,
        not(idsQuery(imageId))
      )
      case _ => inferredSyndicationRights
    }

    val filteredMatches: BoolQuery = boolQuery() must(
      matchQuery(photoshootField("title"), photoshoot.title),
      filter
    )

    val request = search(imagesCurrentAlias) bool filteredMatches limit 200 // TODO no order?

    executeAndLog(request, s"ES6 get images in photoshoot ${photoshoot.title} with inferred syndication rights (excluding $excludedImageId)").map { r =>
      r.result.hits.hits.toList.map { h =>
        Json.parse(h.sourceAsString).as[Image]
      }
    }
  }

  def getLatestSyndicationRights(photoshoot: Photoshoot, excludedImageId: Option[String])
                                (implicit ex: ExecutionContext, logMarker: LogMarker): Future[Option[Image]] = {
    val nonInferredSyndicationRights = termQuery("syndicationRights.isInferred", false)

    val filter = excludedImageId match {
      case Some(imageId) => boolQuery() must(
        nonInferredSyndicationRights,
        not(idsQuery(imageId))
      )
      case _ => nonInferredSyndicationRights
    }

    val filteredMatches = boolQuery() must(
      matchQuery(photoshootField("title"), photoshoot.title),
      filter
    )

    val syndicationRightsPublishedDescending = fieldSort("syndicationRights.published").order(SortOrder.DESC)

    val request = search(imagesCurrentAlias) bool filteredMatches sortBy syndicationRightsPublishedDescending

    executeAndLog(request, s"ES6 get image in photoshoot ${photoshoot.title} with latest rcs syndication rights (excluding $excludedImageId)").map { r =>
      r.result.hits.hits.toList.headOption.map { h =>
        Json.parse(h.sourceAsString).as[Image]
      }
    }
  }

  private def deleteFromIndex(id: String, indexName: String, query: Query)(implicit ex: ExecutionContext, logMarker: LogMarker) = {
    executeAndLog(count(indexName).query(query), s"ES6 searching for image to delete: $id in index $indexName").flatMap { r =>
      val deleteFuture = r.result.count match {
        case 1 => executeAndLog(deleteById(indexName, id), s"ES6 deleting image $id from index $indexName")
        case _ => Future.failed(ImageNotDeletable)
      }
      deleteFuture
        .incrementOnSuccess(metrics.map(_.deletedImages))
        .incrementOnFailure(metrics.map(_.failedDeletedImages)) { case ImageNotDeletable => true }
    }
  }

  def deleteImage(id: String)
                 (implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchDeleteResponse]] = {
    // search for the image first, and then only delete and succeed
    // this is because the delete query does not respond with anything useful
    // TODO: is there a more efficient way to do this?

    val deletableImage = boolQuery().withMust(
      idsQuery(id)).withNot(
      existsQuery("exports"),
      nestedQuery(path = "usages", query = existsQuery("usages"))
    )

    (migrationStatus match {
      case running: Running => List(imagesCurrentAlias, running.migrationIndexName)
      case _ => List(imagesCurrentAlias)
    }).map { index =>
      deleteFromIndex(id, index, deletableImage).map { _ => ElasticSearchDeleteResponse() }
    }
  }

  def deleteSingleImageUsage(
                              id: String, usageId: String, lastModified: DateTime
                            )(implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {
    val deleteSingleUsageScript = loadUpdatingModificationPainless("ctx._source.usages.removeIf(usage -> usage.id == params.usageId);")

    val eventualUpdateResponse = migrationAwareUpdater(
      requestFromIndexName = indexName => prepareUpdateRequest(indexName, id, deleteSingleUsageScript, lastModified, "usageId" -> usageId),
      logMessageFromIndexName = indexName => s"ES6 removing usage $usageId on image $id in index $indexName",
      notFoundSuccessful = true
    ).incrementOnFailure(metrics.map(_.failedUsagesUpdates)) { case _ => true }

    List(eventualUpdateResponse.map(response => {
      if (response.status == 404) {
        logger.warn("Attempted to delete usage for non-existent image.")
      }
      ElasticSearchUpdateResponse()
    }))
  }

  def deleteAllImageUsages(
    id: String, lastModified: DateTime
  )(implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {
    val deleteUsagesScript = loadUpdatingModificationPainless("ctx._source.remove('usages');")

    val eventualUpdateResponse = migrationAwareUpdater(
      requestFromIndexName = indexName => prepareUpdateRequest(indexName, id, deleteUsagesScript, lastModified),
      logMessageFromIndexName = indexName => s"ES6 removing all usages on image $id in index $indexName",
      notFoundSuccessful = true
    ).incrementOnFailure(metrics.map(_.failedUsagesUpdates)){case _ => true}

    List(eventualUpdateResponse.map(response => {
      if(response.status == 404){
        logger.warn("Attempted to delete usages for non-existent image.")
      }
      ElasticSearchUpdateResponse()
    }))
  }

  def updateUsageStatus(id: String, usages: Seq[Usage], lastModified: DateTime)
                       (implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {

  val updateUsageStatusScript =
    s"""
       | for(int i = 0; i < ctx._source.usages.size(); i++) {
       |    if(ctx._source.usages[i].id == params.usage.id) {
       |        ctx._source.usages[i].status = params.usage.status;
       |        ctx._source.usages[i].lastModified = params.lastModified;
       |        ctx._source.usagesLastModified = params.lastModified;
       |    }
       | }
       |""".stripMargin

    val scriptSource = loadUpdatingModificationPainless(updateUsageStatusScript)

    val usageParameters = JsDefined(Json.toJson(usages.head)).toOption.map(_.as[Usage]).map(i => asNestedMap(Json.toJson(i))).orNull

    List(migrationAwareUpdater(
      requestFromIndexName = indexName =>
        prepareUpdateRequest(indexName, id, scriptSource, lastModified, ("usage", usageParameters)),
      logMessageFromIndexName = indexName =>
        s"ES6 updating usagesRights on image $id and usages id ${usageParameters.get("id")} " +
          s"in index $indexName with usage $usageParameters"
    ).map(_ => ElasticSearchUpdateResponse()))
  }

  def deleteSyndicationRights(id: String, lastModified: DateTime)
                             (implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {
    val deleteSyndicationRightsScript = s"""
        | $modificationDateFormatting
        | ctx._source.remove('syndicationRights');
        | $updateLastModifiedScript
      """.stripMargin

    val eventualUpdateResponse = migrationAwareUpdater(
      requestFromIndexName = indexName => prepareUpdateRequest(indexName, id, deleteSyndicationRightsScript, lastModified),
      logMessageFromIndexName = indexName => s"ES6 removing syndication rights on image $id in index $indexName",
      notFoundSuccessful = true
    ).incrementOnFailure(metrics.map(_.failedSyndicationRightsUpdates)){case _ => true}

    List(eventualUpdateResponse.map(_ => ElasticSearchUpdateResponse()))
  }

  def replaceImageLeases(id: String, leases: Seq[MediaLease], lastModified: DateTime)
                        (implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {
    val replaceLeasesScript =
      """
        | ctx._source.leases = ["leases": params.leases, "lastModified": params.lastModified];
        | """.stripMargin

    val scriptSource = loadUpdatingModificationPainless(replaceLeasesScript)

    val leasesParameter = leases.map(l => asNestedMap(Json.toJson(l)))

    val eventualUpdateResponse = migrationAwareUpdater(
      requestFromIndexName = indexName => prepareUpdateRequest(indexName, id, scriptSource, lastModified, ("leases", leasesParameter)),
      logMessageFromIndexName = indexName => s"ES6 updating all leases on image $id in index $indexName with: ${leases.toString}"
    ).incrementOnFailure(metrics.map(_.failedSyndicationRightsUpdates)){case _ => true}

    List(eventualUpdateResponse.map(_ => ElasticSearchUpdateResponse()))
  }

  private def prepareScript(scriptSource: String, lastModified: DateTime, params: (String, Object)*) =
    Script(script = scriptSource).lang("painless").param("lastModified", printDateTime(lastModified)).params(params)

  private def prepareUpdateRequest(indexName: String, id: String, script: Script): UpdateRequest =
    updateById(indexName, id).script(script)

  private def prepareUpdateRequest(indexName: String, id: String, scriptSource: String, lastModified: DateTime, params: (String, Object)*): UpdateRequest =
    prepareUpdateRequest(indexName, id, prepareScript(scriptSource, lastModified, params:_*))

  def addImageLease(id: String, lease: MediaLease, lastModified: DateTime)
                   (implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {

    val addLeaseScript =
      """| if (ctx._source.leases == null || ctx._source.leases.leases == null) {
         |   ctx._source.leases = ["leases": [params.lease], "lastModified": params.lastModified];
         | } else {
         |   ctx._source.leases.leases.add(params.lease);
         |   ctx._source.leases.lastModified = params.lastModified;
         | }
    """.stripMargin

    val scriptSource = loadUpdatingModificationPainless(addLeaseScript)

    val leaseParameter = JsDefined(Json.toJson(lease)).toOption.map(_.as[MediaLease]).map(i => asNestedMap(Json.toJson(i))).orNull

    val eventualUpdateResponse = migrationAwareUpdater(
      requestFromIndexName = indexName => prepareUpdateRequest(indexName, id, scriptSource, lastModified, ("lease", leaseParameter)),
      logMessageFromIndexName = indexName => s"ES6 adding lease on image $id in index $indexName with: $leaseParameter"
    ).incrementOnFailure(metrics.map(_.failedUsagesUpdates)){case _ => true}

    List(eventualUpdateResponse.map(_ => ElasticSearchUpdateResponse()))
  }

  def removeImageLease(id: String, leaseId: Option[String], lastModified: DateTime)
                      (implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {
    val removeLeaseScript =
      """|
         | for(int i = 0; i < ctx._source.leases.leases.size(); i++) {
         |    if (ctx._source.leases.leases[i].id == params.leaseId) {
         |      ctx._source.leases.leases.remove(i);
         |      ctx._source.leases.lastModified = params.lastModified;
         |    }
         | }
      """

    val scriptSource = loadUpdatingModificationPainless(removeLeaseScript)

    val leaseIdParameter = JsDefined(Json.toJson(leaseId)).toOption.map(_.as[String]).orNull

    val eventualUpdateResponse = migrationAwareUpdater(
      requestFromIndexName = indexName => prepareUpdateRequest(indexName, id, scriptSource, lastModified, ("leaseId", leaseIdParameter)),
      logMessageFromIndexName = indexName => s"ES6 removing lease with id $leaseIdParameter from image $id in index $indexName",
      notFoundSuccessful = true
    ).incrementOnFailure(metrics.map(_.failedUsagesUpdates)) { case _ => true }

    List(eventualUpdateResponse.map(_ => ElasticSearchUpdateResponse()))
  }

  def updateImageExports(id: String, exports: Seq[Crop], lastModified: DateTime)
                        (implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {
    val addExportsScript =
    """| if (ctx._source.exports == null) {
       |   ctx._source.exports = params.exports;
       | } else {
       |   ctx._source.exports.addAll(params.exports);
       | }
    """

    val scriptSource = loadUpdatingModificationPainless(addExportsScript)

    val exportsParameter = JsDefined(Json.toJson(exports)).toOption.map { cs: JsValue =>  // TODO deduplicate with set collections
      cs.as[JsArray].value.map { c =>
        asNestedMap(c)
      }.toSeq
    }.orNull

    val eventualUpdateResponse = migrationAwareUpdater(
      requestFromIndexName = indexName => prepareUpdateRequest(indexName, id, scriptSource, lastModified, ("exports", exportsParameter)),
      logMessageFromIndexName = indexName => s"ES6 updating exports on image $id in index $indexName"
    ).incrementOnFailure(metrics.map(_.failedExportsUpdates)) { case _ => true }

    List(eventualUpdateResponse.map(_ => ElasticSearchUpdateResponse()))
  }

  def deleteImageExports(id: String, lastModified: DateTime)
                        (implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {
    val deleteExportsScript = "ctx._source.remove('exports');"

    val scriptSource = loadUpdatingModificationPainless(deleteExportsScript)

    val eventualUpdateResponse = migrationAwareUpdater(
      requestFromIndexName = indexName => prepareUpdateRequest(indexName, id, scriptSource, lastModified),
      logMessageFromIndexName = indexName => s"ES6 removing exports from image $id in index $indexName",
      notFoundSuccessful = true
    ).incrementOnFailure(metrics.map(_.failedExportsUpdates)) { case _ => true }

    List(eventualUpdateResponse.map(_ => ElasticSearchUpdateResponse()))
  }

  def setImageCollections(id: String, collections: Seq[Collection], lastModified: DateTime)
                         (implicit ex: ExecutionContext, logMarker: LogMarker): List[Future[ElasticSearchUpdateResponse]] = {
    val setImagesCollectionScript = "ctx._source.collections = params.collections;"
    val setImageCollectionsScript = loadUpdatingModificationPainless(setImagesCollectionScript)

    val collectionsParameter = JsDefined(Json.toJson(collections)).toOption.map { cs: JsValue =>
      cs.as[JsArray].value.map { c =>
        asNestedMap(c)
      }.toSeq
    }.orNull

    val eventualUpdateResponse = migrationAwareUpdater(
      requestFromIndexName = indexName => prepareUpdateRequest(indexName, id, setImageCollectionsScript, lastModified, ("collections", collectionsParameter)),
      logMessageFromIndexName = indexName => s"ES6 setting collections on image $id in index $indexName"
    ).incrementOnFailure(metrics.map(_.failedCollectionsUpdates)) { case _ => true }

    List(eventualUpdateResponse.map(_ => ElasticSearchUpdateResponse()))
  }

  private val scrollPageSize = 10000

  private def handleImageIdScrollResponse(
    message: String, response: Response[SearchResponse]
  )(implicit ec: ExecutionContext, logMarker: LogMarker): Future[Seq[String]] = {
    val ids = response.result.hits.hits.toSeq.map(_.id)
    if (response.result.hits.size >= scrollPageSize && response.result.scrollId.isDefined) {
      continueScrollingImageIds(message, response.result.scrollId.get).map(ids ++ _)
    } else {
      if (response.result.scrollId.isDefined) {
        closeScroll(response.result.scrollId.get)
      }
      Future.successful(ids)
    }
  }
  private def continueScrollingImageIds(
    message: String, scrollId: String
  )(implicit ec: ExecutionContext, logMarker: LogMarker): Future[Seq[String]] = {
    val req = searchScroll(scrollId)
    executeAndLog(req, message)
      .flatMap(response => handleImageIdScrollResponse(message, response))
  }

  def listImageIdsWithPrefix(prefix: String)(
    implicit ec: ExecutionContext, logMarker: LogMarker
  ): Future[Seq[String]] = {
    val req = search(imagesCurrentAlias)
      .size(scrollPageSize)
      .fetchSource(false)
      .scroll(60.seconds)
      .query(prefixQuery("id", prefix))
    executeAndLog(req, s"listing ids with prefix $prefix")
      .flatMap(response => handleImageIdScrollResponse(s"listing ids with prefix $prefix", response))
  }

  def listImageIdsWithUnexpectedFormat()(implicit ec: ExecutionContext, logMarker: LogMarker) = {
    val req = search(imagesCurrentAlias)
      .size(scrollPageSize)
      .fetchSource(false)
      .scroll(60.seconds)
      .query(not(regexQuery("id", "[0-9a-f]{40}")))
    val message = s"listing ids with unexpected format"
    executeAndLog(req, message).flatMap(response => handleImageIdScrollResponse(message, response))
  }


  private val refreshMetadataScript = """
    | ctx._source.metadata = new HashMap();
    | if (ctx._source.originalMetadata != null) {
    |   ctx._source.metadata.putAll(ctx._source.originalMetadata);
    | }
    | if (ctx._source.userMetadata != null && ctx._source.userMetadata.metadata != null) {
    |   ctx._source.metadata.putAll(ctx._source.userMetadata.metadata);
    | }
    | ctx._source.metadata = ctx._source.metadata.entrySet().stream().filter(x -> x.value != "").collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
    """.stripMargin

  private val refreshUsageRightsScript = """
    | if (ctx._source.userMetadata != null && ctx._source.userMetadata.usageRights != null) {
    |   ctx._source.usageRights = new HashMap();
    |   ctx._source.usageRights.putAll(ctx._source.userMetadata.usageRights);
    | } else if (ctx._source.originalUsageRights == null){
    |   ctx._source.usageRights = null;
    | } else {
    |   ctx._source.usageRights = new HashMap();
    |   ctx._source.usageRights.putAll(ctx._source.originalUsageRights);
    | }
    """.stripMargin

  private val refreshEditsScript = refreshMetadataScript + refreshUsageRightsScript

  private def loadPainless(str: String) = str.stripMargin.split('\n').map(_.trim.filter(_ >= ' ')).mkString // remove ctrl chars and leading, trailing whitespace
  private def loadUpdatingModificationPainless(str: String) = loadPainless(modificationDateFormatting + "\n" + str + "\n" + updateLastModifiedScript)

  private val modificationDateFormatting =
    """
      | def modificationDate = Date.from(Instant.from(DateTimeFormatter.ISO_DATE_TIME.parse(params.lastModified)));
      """

  // Script that updates the "lastModified" property using the "lastModified" parameter
  private val updateLastModifiedScript =
    """
      | def lastModifiedDate = ctx._source.lastModified != null ? Date.from(Instant.from(DateTimeFormatter.ISO_DATE_TIME.parse(ctx._source.lastModified))) : null;
      | if (lastModifiedDate == null || modificationDate.after(lastModifiedDate)) {
      |   ctx._source.lastModified = params.lastModified;
      | }
    """.stripMargin

  @nowarn("cat=deprecation") // TODO ScalaObjectMapper is deprecated because unusable in Scala 3
  private def asNestedMap(sr: SyndicationRights) = { // TODO not great; there must be a better way to flatten a case class into a Map
    import com.fasterxml.jackson.databind.ObjectMapper
    import com.fasterxml.jackson.module.scala.DefaultScalaModule
    import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
    val mapper = new ObjectMapper() with ScalaObjectMapper
    mapper.registerModule(DefaultScalaModule)
    mapper.readValue[Map[String, Object]](Json.stringify(Json.toJson(sr)))
  }

  @nowarn("cat=deprecation") // TODO ScalaObjectMapper is deprecated because unusable in Scala 3
  private def asNestedMap(i: JsValue) = { // TODO not great; there must be a better way to flatten a case class into a Map
    import com.fasterxml.jackson.databind.ObjectMapper
    import com.fasterxml.jackson.module.scala.DefaultScalaModule
    import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
    val mapper = new ObjectMapper() with ScalaObjectMapper
    mapper.registerModule(DefaultScalaModule)
    mapper.readValue[Map[String, Object]](Json.stringify(i))
  }

  private def asImageUpdate(image: JsValue): JsValue = {
    def removeUploadInformation(): Reads[JsObject] =
      (__ \ "uploadTime").json.prune andThen
        (__ \ "userMetadata").json.prune andThen
        (__ \ "exports").json.prune andThen
        (__ \ "uploadedBy").json.prune andThen
        (__ \ "collections").json.prune andThen
        (__ \ "leases").json.prune andThen
        (__ \ "usages").json.prune

    image.transform(removeUploadInformation()).get
  }

}