/*******************************************************************************
 * Copyright 2013 SAP AG
 * 
 * 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 com.sap.core.odata.processor.core.jpa.model;

import com.sap.core.odata.api.edm.provider.ReferentialConstraint;
import com.sap.core.odata.processor.api.jpa.access.JPAEdmBuilder;
import com.sap.core.odata.processor.api.jpa.exception.ODataJPAModelException;
import com.sap.core.odata.processor.api.jpa.exception.ODataJPARuntimeException;
import com.sap.core.odata.processor.api.jpa.model.JPAEdmAssociationView;
import com.sap.core.odata.processor.api.jpa.model.JPAEdmEntityTypeView;
import com.sap.core.odata.processor.api.jpa.model.JPAEdmPropertyView;
import com.sap.core.odata.processor.api.jpa.model.JPAEdmReferentialConstraintRoleView;
import com.sap.core.odata.processor.api.jpa.model.JPAEdmReferentialConstraintRoleView.RoleType;
import com.sap.core.odata.processor.api.jpa.model.JPAEdmReferentialConstraintView;

public class JPAEdmReferentialConstraint extends JPAEdmBaseViewImpl implements
    JPAEdmReferentialConstraintView {

  private JPAEdmRefConstraintBuilder builder = null;

  private boolean exists = false;
  private boolean firstBuild = true;

  private JPAEdmAssociationView associationView;
  private JPAEdmPropertyView propertyView;
  private JPAEdmEntityTypeView entityTypeView;

  private ReferentialConstraint referentialConstraint;

  private JPAEdmReferentialConstraintRoleView principalRoleView;
  private JPAEdmReferentialConstraintRoleView dependentRoleView;

  private String relationShipName;

  public JPAEdmReferentialConstraint(final JPAEdmAssociationView associationView,
      final JPAEdmEntityTypeView entityTypeView, final JPAEdmPropertyView propertyView) {
    super(associationView);
    this.associationView = associationView;
    this.propertyView = propertyView;
    this.entityTypeView = entityTypeView;

    relationShipName = associationView.getEdmAssociation().getName();
  }

  @Override
  public JPAEdmBuilder getBuilder() {
    if (builder == null) {
      builder = new JPAEdmRefConstraintBuilder();
    }

    return builder;
  }

  @Override
  public ReferentialConstraint getEdmReferentialConstraint() {
    return referentialConstraint;
  }

  @Override
  public boolean isExists() {
    return exists;
  }

  @Override
  public String getEdmRelationShipName() {
    return relationShipName;
  }

  private class JPAEdmRefConstraintBuilder implements JPAEdmBuilder {
    /*
     * Check if Ref Constraint was already Built. If Ref constraint was
     * already built consistently then do not build referential constraint.
     * 
     * For Ref Constraint to be consistently built Principal and Dependent
     * roles must be consistently built. If Principal or Dependent roles are
     * not consistently built then try building them again.
     * 
     * The Principal and Dependent roles could be have been built
     * inconsistently if the required EDM Entity Types or EDM properties are
     * yet to be built. In such cases rebuilding these roles would make them
     * consistent.
     */
    @Override
    public void build() throws ODataJPAModelException, ODataJPARuntimeException {

      if (firstBuild) {
        firstBuild();
      } else {
        if (exists && !firstBuild
            && principalRoleView.isConsistent() == false) {
          principalRoleView.getBuilder().build();
        }

        if (exists && !firstBuild
            && dependentRoleView.isConsistent() == false) {
          dependentRoleView.getBuilder().build();
        }
      }

      if (principalRoleView.isConsistent()) {
        referentialConstraint.setPrincipal(principalRoleView
            .getEdmReferentialConstraintRole());
      }

      if (dependentRoleView.isConsistent()) {
        referentialConstraint.setDependent(dependentRoleView
            .getEdmReferentialConstraintRole());
      }

      exists = principalRoleView.isExists()
          & dependentRoleView.isExists();

      isConsistent = principalRoleView.isConsistent()
          & dependentRoleView.isConsistent();

    }

    private void firstBuild() throws ODataJPAModelException, ODataJPARuntimeException {
      firstBuild = false;
      if (principalRoleView == null && dependentRoleView == null) {

        principalRoleView = new JPAEdmReferentialConstraintRole(
            RoleType.PRINCIPAL, entityTypeView, propertyView,
            associationView);
        principalRoleView.getBuilder().build();

        dependentRoleView = new JPAEdmReferentialConstraintRole(
            RoleType.DEPENDENT, entityTypeView, propertyView,
            associationView);
        dependentRoleView.getBuilder().build();

        if (referentialConstraint == null) {
          referentialConstraint = new ReferentialConstraint();
        }
      }

    }
  }

}