Added a proper error message for a missing library

app/controllers/Statistics.scala

@@ -318,10 +318,10 @@ class Statistics @Inject()(
     val (lastRefreshTime, resultsFuture) = projectReportsProvider.resultsForVersions(versions)
     resultsFuture flatMap { allResults =>
       select(allResults, selectorOption).fold(Future.successful(notFound())) { selection =>
-        Future.successful(Ok(views.html.library(
-          dep = selection.result.groupedDependenciesByHashes(depId),
-          selectorOption = selectorOption
-        )))
+        Future.successful(selection.result.groupedDependenciesByHashes.get(depId) match {
+          case None => NotFound(views.html.libraryNotFound(depId = depId, selectorOption = selectorOption))
+          case Some(dep) => Ok(views.html.library(dep = dep, selectorOption = selectorOption))
+        })
       }
     }
   }

app/views/libraryNotFound.scala.html

@@ -0,0 +1,5 @@
+@import com.ysoft.odc.Hashes
+@(depId: Hashes, selectorOption: Option[String])(implicit header: DefaultRequest, mainTemplateData: MainTemplateData)
+@main(title=s"Unknown library"){
+    There is no library found for hashes @depId.hashTuples.map{case (hashType, hashValue) => @hashType=@hashValue}.mkString(", "). It might have been removed or updated to a newer version.
+}