Foundation PR for Tax Calc: Conditional BYS page + journey skeleton added

app/controllers/taxCalculation/TaxCalculationBeforeYouStartController.scala

@@ -17,24 +17,63 @@
 package controllers.taxCalculation
 
 import controllers.actions.*
+import controllers.routes.*
+import models.NormalMode
+import models.prelimQuestions.TransactionType
+import models.prelimQuestions.TransactionType.GrantOfLease
+import models.taxCalculation.{MissingFullReturnError, TaxCalculationResult}
+import navigation.Navigator
+import pages.preliminary.TransactionTypePage
+import pages.taxCalculation.{IsLeaseholdAndSelfAssessedPage, TaxCalculationBeforeYouStartPage}
 import play.api.i18n.{I18nSupport, MessagesApi}
 import play.api.mvc.{Action, AnyContent, MessagesControllerComponents}
+import repositories.SessionRepository
+import services.taxCalculation.SdltCalculationService
+import uk.gov.hmrc.http.HeaderCarrier
 import uk.gov.hmrc.play.bootstrap.frontend.controller.FrontendBaseController
+import uk.gov.hmrc.play.http.HeaderCarrierConverter
+import utils.TaxCalculationHelper.*
 import views.html.taxCalculation.TaxCalculationBeforeYouStartView
 
 import javax.inject.Inject
+import scala.concurrent.{ExecutionContext, Future}
 
 class TaxCalculationBeforeYouStartController @Inject()(
-                                       override val messagesApi: MessagesApi,
-                                       identify: IdentifierAction,
-                                       getData: DataRetrievalAction,
-                                       requireData: DataRequiredAction,
-                                       val controllerComponents: MessagesControllerComponents,
-                                       view: TaxCalculationBeforeYouStartView
-                                     ) extends FrontendBaseController with I18nSupport {
-
-  def onPageLoad: Action[AnyContent] = (identify andThen getData andThen requireData) {
+                                        override val messagesApi: MessagesApi,
+                                        identify: IdentifierAction,
+                                        getData: DataRetrievalAction,
+                                        requireData: DataRequiredAction,
+                                        sdltCalculationService: SdltCalculationService,
+                                        sessionRepository: SessionRepository,
+                                        navigator: Navigator,
+                                        val controllerComponents: MessagesControllerComponents,
+                                        view: TaxCalculationBeforeYouStartView
+                                      )(implicit ec: ExecutionContext) extends FrontendBaseController with I18nSupport {
+
+  def onPageLoad: Action[AnyContent] = (identify andThen getData andThen requireData).async {
+    implicit request =>
+
+      implicit val hc: HeaderCarrier = HeaderCarrierConverter.fromRequestAndSession(request, request.session)
+
+      sdltCalculationService.calculateStampDutyLandTax(request.userAnswers).flatMap {
+        case Right(result)                =>
+
+          val isLeasehold: Boolean = request.userAnswers.get(TransactionTypePage).contains(GrantOfLease)
+
+          val leaseholdSelfAssessedFlag = isLeasehold && isSelfAssessedResponse(result)
+
+          for {
+            updatedAnswers <- Future.fromTry(request.userAnswers.set(IsLeaseholdAndSelfAssessedPage, leaseholdSelfAssessedFlag))
+                         _ <- sessionRepository.set(updatedAnswers)
+          } yield Ok(view(leaseholdSelfAssessedFlag))
+
+        case Left(MissingFullReturnError) => Future.successful(Redirect(NoReturnReferenceController.onPageLoad()))
+        case Left(_)                      => Future.successful(Redirect(ReturnTaskListController.onPageLoad()))
+      }
+  }
+
+  def onSubmit: Action[AnyContent] = (identify andThen getData andThen requireData) {
     implicit request =>
-      Ok(view())
+      Redirect(navigator.nextPage(TaxCalculationBeforeYouStartPage, NormalMode, request.userAnswers))
   }
 }

app/navigation/Navigator.scala

@@ -26,6 +26,7 @@ import pages.vendor.*
 import pages.vendorAgent.*
 import pages.land.*
 import pages.transaction.*
+import pages.taxCalculation.*
 import pages.ukResidency.*
 import play.api.mvc.Call
 
@@ -65,6 +66,7 @@ class Navigator @Inject()() {
     case landPage if isLandSection(landPage) => landRoutes(landPage)
     case residencyPage if isResidencySection(residencyPage) => residencyRoutes(residencyPage)
     case transactionPage if isTransactionSection(transactionPage) => transactionRoutes(transactionPage)
+    case taxCalcPage if isTaxCalculationSection(taxCalcPage) => taxCalculationRoutes(taxCalcPage)
     case _ => _ => routes.IndexController.onPageLoad()
   }
 
@@ -254,6 +256,30 @@ class Navigator @Inject()() {
     case _ => _ => routes.IndexController.onPageLoad()
   }
 
+  private def isTaxCalculationSection(page: Page): Boolean = page match {
+    case TaxCalculationBeforeYouStartPage | CalculatedSdltPage | CalculatedSdltBreakdownPage
+       | SelfAssessmentAmountPage | PremiumPayableTaxPage | NpvTaxPage
+       | TotalAmountDuePage | PenaltiesAndInterestPage | TaxCalculationCheckYourAnswersPage => true
+    case _ => false
+  }
+
+  private def taxCalculationRoutes(page: Page): UserAnswers => Call = page match {
+
+    case TaxCalculationBeforeYouStartPage => answers =>
+      if (answers.get(IsLeaseholdAndSelfAssessedPage).contains(true)) routes.IndexController.onPageLoad() // TODO: replace -> PremiumPayableTaxController
+      else                                                            routes.IndexController.onPageLoad() // TODO: replace -> CalculatedSdltController
+    case CalculatedSdltPage                 => _ => routes.IndexController.onPageLoad() // TODO: replace -> SelfAssessmentAmountController
+    case CalculatedSdltBreakdownPage        => _ => routes.IndexController.onPageLoad() // TODO: replace -> CalculatedSdltController
+    case SelfAssessmentAmountPage           => _ => routes.IndexController.onPageLoad() // TODO: replace -> TotalAmountDueController
+    case PremiumPayableTaxPage              => _ => routes.IndexController.onPageLoad() // TODO: replace -> NpvTaxController
+    case NpvTaxPage                         => _ => routes.IndexController.onPageLoad() // TODO: replace -> TotalAmountDueController
+    case TotalAmountDuePage                 => _ => routes.IndexController.onPageLoad() // TODO: replace -> PenaltiesAndInterestController
+    case PenaltiesAndInterestPage           => _ => routes.IndexController.onPageLoad() // TODO: replace -> TaxCalculationCheckYourAnswersController
+    case TaxCalculationCheckYourAnswersPage => _ => routes.ReturnTaskListController.onPageLoad()
+
+    case _ => _ => routes.IndexController.onPageLoad()
+  }
+
   private val checkRouteMap: Page => UserAnswers => Call = {
     case WhoIsMakingThePurchasePage => _ => controllers.purchaser.routes.PurchaserCheckYourAnswersController.onPageLoad()
     case NameOfPurchaserPage => _ => controllers.purchaser.routes.PurchaserCheckYourAnswersController.onPageLoad()
@@ -315,6 +341,13 @@ class Navigator @Inject()() {
     case LandMineralsOrMineralRightsPage => _ => controllers.land.routes.LandCheckYourAnswersController.onPageLoad()
     case LandSelectMeasurementUnitPage => _ => controllers.land.routes.AreaOfLandController.onPageLoad(CheckMode)
 
+    // TODO: replace -> TaxCalculationCheckYourAnswersController
+    case SelfAssessmentAmountPage => _ => routes.IndexController.onPageLoad()
+    case PremiumPayableTaxPage    => _ => routes.IndexController.onPageLoad()
+    case NpvTaxPage               => _ => routes.IndexController.onPageLoad()
+    case TotalAmountDuePage       => _ => routes.IndexController.onPageLoad()
+    case PenaltiesAndInterestPage => _ => routes.IndexController.onPageLoad()
+
     case _ => _ => controllers.routes.ReturnTaskListController.onPageLoad()
   }
 

app/pages/taxCalculation/CalculatedSdltBreakdownPage.scala

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2026 HM Revenue & Customs
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package pages.taxCalculation
+
+import pages.QuestionPage
+import play.api.libs.json.JsPath
+
+case object CalculatedSdltBreakdownPage extends QuestionPage[Boolean] {
+
+  override def path: JsPath = JsPath \ "taxCalculationCurrent" \ toString
+
+  override def toString: String = "calculatedSdltBreakdown"
+}

app/pages/taxCalculation/CalculatedSdltPage.scala

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2026 HM Revenue & Customs
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package pages.taxCalculation
+
+import pages.QuestionPage
+import play.api.libs.json.JsPath
+
+case object CalculatedSdltPage extends QuestionPage[Boolean] {
+
+  override def path: JsPath = JsPath \ "taxCalculationCurrent" \ toString
+
+  override def toString: String = "calculatedSdlt"
+}

app/pages/taxCalculation/IsLeaseholdAndSelfAssessedPage.scala

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2026 HM Revenue & Customs
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package pages.taxCalculation
+
+import pages.QuestionPage
+import play.api.libs.json.JsPath
+
+case object IsLeaseholdAndSelfAssessedPage extends QuestionPage[Boolean] {
+
+  override def path: JsPath = JsPath \ "taxCalculationCurrent" \ toString
+
+  override def toString: String = "isLeaseholdAndSelfAssessed"
+}

app/pages/taxCalculation/NpvTaxPage.scala

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2026 HM Revenue & Customs
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package pages.taxCalculation
+
+import pages.QuestionPage
+import play.api.libs.json.JsPath
+
+case object NpvTaxPage extends QuestionPage[BigDecimal] {
+
+  override def path: JsPath = JsPath \ "taxCalculationCurrent" \ toString
+
+  override def toString: String = "npvTax"
+}

app/pages/taxCalculation/PenaltiesAndInterestPage.scala

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2026 HM Revenue & Customs
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package pages.taxCalculation
+
+import pages.QuestionPage
+import play.api.libs.json.JsPath
+
+case object PenaltiesAndInterestPage extends QuestionPage[Boolean] {
+
+  override def path: JsPath = JsPath \ "taxCalculationCurrent" \ toString
+
+  override def toString: String = "penaltiesAndInterest"
+}

app/pages/taxCalculation/PremiumPayableTaxPage.scala

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2026 HM Revenue & Customs
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package pages.taxCalculation
+
+import pages.QuestionPage
+import play.api.libs.json.JsPath
+
+case object PremiumPayableTaxPage extends QuestionPage[BigDecimal] {
+
+  override def path: JsPath = JsPath \ "taxCalculationCurrent" \ toString
+
+  override def toString: String = "premiumPayableTax"
+}

app/pages/taxCalculation/SelfAssessmentAmountPage.scala

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2026 HM Revenue & Customs
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package pages.taxCalculation
+
+import pages.QuestionPage
+import play.api.libs.json.JsPath
+
+case object SelfAssessmentAmountPage extends QuestionPage[BigDecimal] {
+
+  override def path: JsPath = JsPath \ "taxCalculationCurrent" \ toString
+
+  override def toString: String = "selfAssessmentAmount"
+}

app/pages/taxCalculation/TaxCalculationBeforeYouStartPage.scala

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2026 HM Revenue & Customs
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package pages.taxCalculation
+
+import pages.QuestionPage
+import play.api.libs.json.JsPath
+
+case object TaxCalculationBeforeYouStartPage extends QuestionPage[Boolean] {
+
+  override def path: JsPath = JsPath \ "taxCalculationCurrent" \ toString
+
+  override def toString: String = "taxCalculationBeforeYouStart"
+}

app/pages/taxCalculation/TaxCalculationCheckYourAnswersPage.scala

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2026 HM Revenue & Customs
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package pages.taxCalculation
+
+import pages.QuestionPage
+import play.api.libs.json.JsPath
+
+case object TaxCalculationCheckYourAnswersPage extends QuestionPage[Boolean] {
+
+  override def path: JsPath = JsPath \ "taxCalculationCurrent" \ toString
+
+  override def toString: String = "taxCalculationCheckYourAnswers"
+}