Canonical collections

facia-json/src/main/scala/com/gu/facia/client/models/Config.scala

@@ -76,7 +76,8 @@ case class FrontJson(
   imageHeight: Option[Int],
   isImageDisplayed: Option[Boolean],
   priority: Option[String],
-  isHidden: Option[Boolean]
+  isHidden: Option[Boolean],
+  canonical: Option[String]
 )
 
 object ConfigJson {

fapi-client/src/main/scala/com/gu/facia/api/models/front.scala

@@ -23,7 +23,8 @@ case class Front(
                   frontImage: Option[FrontImage],
                   isImageDisplayed: Boolean,
                   priority: FrontPriority,
-                  isHidden: Boolean)
+                  isHidden: Boolean,
+                  canonicalCollection: String)
 
 object Front {
   private def getFrontPriority(frontJson: FrontJson): FrontPriority =
@@ -39,7 +40,7 @@ object Front {
       imageWidth <- frontJson.imageWidth
     } yield FrontImage(imageUrl, imageHeight, imageWidth)
 
-  def fromFrontJson(id: String, frontJson: FrontJson): Front =
+  def fromFrontJson(id: String, frontJson: FrontJson): Front = {
     Front(
       id,
       frontJson.collections,
@@ -51,8 +52,29 @@ object Front {
       getImageUrl(frontJson),
       frontJson.isImageDisplayed.getOrElse(false),
       getFrontPriority(frontJson),
-      frontJson.isHidden.getOrElse(false)
+      frontJson.isHidden.getOrElse(false),
+      canonicalCollection(id, frontJson)
     )
+  }
+
+  /**
+   * If we're on a network front, try hard-coded headlines ids, otherwise use editorially
+   * chosen canonical container if present, falling back to the first available collection.
+   * We should never have a front with no containers so final fallback is a placeholder.
+   */
+  private def canonicalCollection(id: String, frontJson: FrontJson): String = {
+    val frontHeadlineCollections = id match {
+      //                PROD                             CODE
+      case "uk" => List("uk-alpha/news/regular-stories", "f3d7d2bc-e667-4a86-974f-fe27daeaebcc")
+      case "us" => List("us-alpha/news/regular-stories")
+      case "au" => List("au-alpha/news/regular-stories")
+      case _ => Nil
+    }
+    frontHeadlineCollections.find(frontJson.collections.contains)
+      .orElse(frontJson.canonical.filter(frontJson.collections.contains))
+      .orElse(frontJson.collections.headOption)
+      .getOrElse("no collections")
+  }
 
   def frontsFromConfig(configJson: ConfigJson): Set[Front] = {
     configJson.fronts

fapi-client/src/test/scala/com/gu/facia/api/models/FrontTest.scala

@@ -0,0 +1,52 @@
+package com.gu.facia.api.models
+
+import com.gu.facia.client.models.FrontJson
+import org.scalatest._
+import org.scalatest.mock.MockitoSugar
+
+class FrontTest extends FreeSpec with ShouldMatchers with MockitoSugar with OneInstancePerTest {
+  "fromFrontJson" - {
+    "when generating the canonical field" - {
+      val frontJson = FrontJson(
+        collections = List("collection1", "collection2", "collection3", "collection4"),
+        None, None, None, None, None, None, None, None, None, None, None, None
+      )
+
+      "uses the fronts config field if present" in {
+        val frontJsonWithCanonical = frontJson.copy(canonical = Some("collection2"))
+        Front.fromFrontJson("frontId", frontJsonWithCanonical).canonicalCollection should equal("collection2")
+      }
+
+      "in the absence of a fronts config field, takes the first present collection" in {
+        Front.fromFrontJson("frontId", frontJson).canonicalCollection should equal("collection1")
+      }
+
+      "on the uk front, takes the editorially-chosen PROD uk headlines collection if it is present" in {
+        val ukFrontJson = frontJson.copy(collections = frontJson.collections :+ "uk-alpha/news/regular-stories")
+        Front.fromFrontJson("uk", ukFrontJson).canonicalCollection should equal("uk-alpha/news/regular-stories")
+      }
+
+      "on the uk front, takes the first collection if the editorially-chosen uk headlines collection is not present" in {
+        Front.fromFrontJson("uk", frontJson).canonicalCollection should equal("collection1")
+      }
+
+      "on the us front, takes the editorially-chosen PROD us headlines collection if it is present" in {
+        val usFrontJson = frontJson.copy(collections = frontJson.collections :+ "us-alpha/news/regular-stories")
+        Front.fromFrontJson("us", usFrontJson).canonicalCollection should equal("us-alpha/news/regular-stories")
+      }
+
+      "on the us front, takes the first collection if the editorially-chosen us headlines collection is not present" in {
+        Front.fromFrontJson("us", frontJson).canonicalCollection should equal("collection1")
+      }
+
+      "on the au front, takes the editorially-chosen PROD au headlines collection if it is present" in {
+        val auFrontJson = frontJson.copy(collections = frontJson.collections :+ "au-alpha/news/regular-stories")
+        Front.fromFrontJson("au", auFrontJson).canonicalCollection should equal("au-alpha/news/regular-stories")
+      }
+
+      "on the au front, takes the first collection if the editorially-chosen au headlines collection is not present" in {
+        Front.fromFrontJson("au", frontJson).canonicalCollection should equal("collection1")
+      }
+    }
+  }
+}