Added support for mail digests

app/services/VulnerabilityNotificationService.scala

@@ -6,7 +6,10 @@ import com.mohiva.play.silhouette.api.LoginInfo
 import com.ysoft.odc.SetDiff
 import controllers.{ProjectsWithReports, ReportInfo}
 import models._
+import models.tables._
+import play.api.Logger
 import play.api.db.slick.{DatabaseConfigProvider, HasDatabaseConfigProvider}
+import slick.dbio.FutureAction
 import slick.jdbc.TransactionIsolation
 
 import scala.concurrent.{ExecutionContext, Future}
@@ -30,8 +33,25 @@ class VulnerabilityNotificationService @Inject() (protected val dbConfigProvider
   import dbConfig.driver.api._
   import models.tables._
 
+  def subscribers = db.run(vulnerabilitySubscriptions.result).map(_.groupBy(_.user))
   def watchedProjectsByUser(identity: LoginInfo) = db.run(vulnerabilitySubscriptions.filter(_.user === identity).result)
-  def subscribe(user: LoginInfo, project: String) = db.run(vulnerabilitySubscriptions += VulnerabilitySubscription(user = user, project = project))
+
+  def subscribe(user: LoginInfo, project: String) = db.run(
+    DBIO.seq(
+      ensureUserHasNotificationDigestStatus(user),
+      vulnerabilitySubscriptions += VulnerabilitySubscription(user = user, project = project)
+    )
+  )
+
+  private def ensureUserHasNotificationDigestStatus(user: LoginInfo): DBIOAction[Unit, slick.dbio.NoStream, Effect.Read with Effect.Write] = (
+    notificationDigestStatuses.filter(_.user === user).result.map(_.nonEmpty) flatMap {
+      case true => DBIO.seq()
+      case false => for{
+        changelogTopIdOption <- changelogTopIdOptionQuery
+        (res: Int) <- notificationDigestStatuses += NotificationDigestStatus(user = user, lastChangelogIdOption = changelogTopIdOption)
+      } yield ()
+    }
+  ).withTransactionIsolation(TransactionIsolation.Serializable)
 
   def unsubscribe(user: LoginInfo, project: String) = db.run(vulnerabilitySubscriptions.filter(vs => vs.user === user && vs.project === project).delete)
 
@@ -85,7 +105,13 @@ class VulnerabilityNotificationService @Inject() (protected val dbConfigProvider
 
   def changeAffectedProjects(vulnerabilityName: String, affectedProjectsDiff: SetDiff[String]): Future[Unit] = {
     val time = DateTime.now()
-    def createRecord(projectName: String, direction: Change.Direction) = Change(time, vulnerabilityName, projectName, direction)
+    def createRecord(projectName: String, direction: Change.Direction) = Change(
+      time = time,
+      vulnerabilityName = vulnerabilityName,
+      projectName = projectName,
+      direction = direction,
+      notifiedToSomebody = false
+    )
     val recordsToAdd = affectedProjectsDiff.added.map(projectName => createRecord(projectName, Change.Direction.Added)) ++
       affectedProjectsDiff.removed.map(projectName => createRecord(projectName, Change.Direction.Removed))
     /*
@@ -98,6 +124,34 @@ class VulnerabilityNotificationService @Inject() (protected val dbConfigProvider
     ).map(_ => ()))
   }
 
+  private def changelogTopIdOptionQuery = changelog.map(_.id).max.result
+
+  def sendDigestToSubscriber(subscriber: LoginInfo, subscriptions: Seq[VulnerabilitySubscription])(sendDigest: Seq[Change] => Future[Unit]): Future[Unit] = {
+    def subscriptionCondition(change: Changes, subscription: VulnerabilitySubscription):  Rep[Boolean] = {
+      //noinspection ScalaUnnecessaryParentheses – because it looks less confusing
+      (change.projectName === subscription.project) ||
+        (if (subscription.project contains '/') (false: Rep[Boolean]) else change.projectName.startsWith(subscription.project + "/"))
+    }
+    val projectCondition: Changes => Rep[Boolean] = (change) =>
+      subscriptions.foldLeft(false: Rep[Boolean])((cond, subscription) => cond || subscriptionCondition(change, subscription))
+    val notificationDigestStatusSelection = notificationDigestStatuses.filter(_.user === subscriber)
+    db.run(
+      (
+        for{
+          oldStatus <- notificationDigestStatusSelection.result.map(_.head)
+          _ = println(oldStatus.lastChangelogIdOption.fold(changelog.filter(_ => true: Rep[Boolean]))(lastChangelogId => changelog.filter(_.id > lastChangelogId)).filter(projectCondition).result.statements.mkString("\n"))
+          changelogSinceLastNotified <- oldStatus.lastChangelogIdOption.fold(changelog.filter(_ => true: Rep[Boolean]))(lastChangelogId => changelog.filter(_.id > lastChangelogId)).filter(projectCondition).result
+          changelogIds = changelogSinceLastNotified.map(_._1)
+          changelogTopIdOption <- changelogTopIdOptionQuery
+          newLastChangelogIdOption = changelogTopIdOption.orElse(oldStatus.lastChangelogIdOption)
+          (_: Unit) <- FutureAction(sendDigest(changelogSinceLastNotified.map(_._2))) // Yes, we are waiting for user to be notified over some slow I/O when having an open transaction
+          (_: Int) <- notificationDigestStatusSelection.map(_.lastChangelogId).update(newLastChangelogIdOption)
+          (_: Int) <- changelog.filter(_.id inSet changelogIds).map(_.notifiedToSomebody).update(true)
+        } yield ()
+      ).withTransactionIsolation(TransactionIsolation.Serializable)
+    )
+  }
+
   val issueTrackerExport = new ExportPlatform(tables.issueTrackerExportTables)
 
   val mailExport = new ExportPlatform(tables.mailExportTables)