package org.kuali.student.lum.program.server;

 import java.util.List;

 import org.kuali.student.common.dto.DtoConstants;

 import org.kuali.student.common.exceptions.DoesNotExistException;

 import org.kuali.student.common.exceptions.InvalidParameterException;

 import org.kuali.student.common.versionmanagement.dto.VersionDisplayInfo;

 import org.kuali.student.core.statement.dto.StatementTreeViewInfo;

 import org.kuali.student.lum.common.server.StatementUtil;

 import org.kuali.student.lum.program.dto.CredentialProgramInfo;

 import org.kuali.student.lum.program.dto.ProgramRequirementInfo;

 import org.kuali.student.lum.program.service.ProgramService;

 import org.kuali.student.lum.program.service.ProgramServiceConstants;

 import org.springframework.transaction.annotation.Transactional;

 /**

  * This class is called whenever the state of a major discipline changes.

  * <p>

  * We have a separate class because the operations need to be marked with the @Transactional annotation.

  * <p>

  * THIS CLASS IS DUPLICATED FOR MAJOR DISCIPLINE, CORE, AND CREDENTIAL PROGRAMS SINCE THERE ARE DIFFERENT SERVICE METHODS FOR

  * EACH OF THESE TYPES (THOUGH THEY ARE SIMILAR)

  * <P>

  * 

  * @author Kuali Rice Team (kuali-rice@googlegroups.com)

  */

 @Transactional(noRollbackFor = {DoesNotExistException.class}, rollbackFor = {Throwable.class})

 public class CredentialProgramStateChangeServiceImpl implements StateChangeService {

     /**

      * The program service - injected by spring.

      */

     private ProgramService programService;

     /**

      * This method is called by workflow when the state changes.

      * 

      * @param majorDisciplineId

      * @param state

      * @return

      * @throws Exception

      */

     public void changeState(String credentialProgramId, String newState) throws Exception {

         // This method will be called from workflow.

         // Since we cannot activate a program from the workflow we do not need to add endEntryTerm and endEnrollTerm

         changeState(null, null, null, credentialProgramId, newState);

     }

     /**

      * This method is called from the UI (servlet) when state changes.

      * 

      * @param endEntryTerm

      * @param endEnrollTerm

      * @param programType

      * @param majorDisciplineId

      * @param newState

      * @return

      * @throws Exception

      */

     public void changeState(String endEntryTerm, String endEnrollTerm, String endInstAdmitTerm, String credentialProgramId, String newState) throws Exception {

         // New state must not be null

         if (newState == null)

             throw new InvalidParameterException("new state cannot be null");

         // The version selected in the UI

         CredentialProgramInfo selectedVersion = programService.getCredentialProgram(credentialProgramId);

         // If we are activating this version we need to mark the previous version superseded,

         // update the previous version end terms, and make the selected version current.

         if (newState.equals(DtoConstants.STATE_ACTIVE)) {

             // Update previous versions to superseded and set end terms on previous current version.

                 updatePreviousVersions(selectedVersion, endEntryTerm, endEnrollTerm, endInstAdmitTerm);

             // Update state of all associated objects for current version

             // NOTE: we must update state BEFORE making the version current

             updateCredentialProgramInfoState(selectedVersion, newState);

             // Make this the current version

             makeCurrent(selectedVersion);

         } else {

             // Update state of all associated objects for current version

             updateCredentialProgramInfoState(selectedVersion, newState);

         }

     }

     /**

      * This method finds all previous versions of program and sets all previous ACTIVE,APPROVED,DRAFT versions to SUPERSEDED and

      * sets new end terms for previous current version.

      * @param selectedVersion The version of credential  program being activated

      * @param endEntryTerm The new end entry term to set on previous active version

      * @param endEnrollTerm The new end enroll term to set on previous active version

      * @throws Exception

      */

     private void updatePreviousVersions (CredentialProgramInfo selectedVersion, String endEntryTerm, String endEnrollTerm, String endInstAdmitTerm) throws Exception {

             // Get the current version of major discipline given the selected version

             CredentialProgramInfo currentVersion = getCurrentVersion(selectedVersion);

             boolean isSelectedVersionCurrent = selectedVersion.getId().equals(currentVersion.getId());

             //Set the end terms on the current version of major discipline and update it's state to superseded

             setEndTerms(currentVersion, endEntryTerm, endEnrollTerm);

             updateCredentialProgramInfoState(currentVersion, DtoConstants.STATE_SUPERSEDED);

                 // Loop through all previous active or approved programs and set the state to superseded.

                 // We should only need to evaluated versions with sequence number

                 // higher than previous active program

                 List<VersionDisplayInfo> versions = programService.getVersions(ProgramServiceConstants.PROGRAM_NAMESPACE_MAJOR_DISCIPLINE_URI, 

                                 selectedVersion.getVersionInfo().getVersionIndId());

                 Long startSeq = new Long(1);

                 if (!isSelectedVersionCurrent) {

                         startSeq = currentVersion.getVersionInfo().getSequenceNumber() + 1;

                 }

                 for (VersionDisplayInfo versionInfo : versions) {

                         boolean isVersionNewerThanCurrentVersion = versionInfo.getSequenceNumber() >= startSeq;

                         boolean isVersionSelectedVersion = versionInfo.getSequenceNumber().equals(selectedVersion.getVersionInfo().getSequenceNumber());  

                         boolean updateState = isVersionNewerThanCurrentVersion && !isVersionSelectedVersion;

                         if (updateState) {

                                 CredentialProgramInfo otherProgram = programService.getCredentialProgram(versionInfo.getId());

                                 if (otherProgram.getState().equals(DtoConstants.STATE_APPROVED) ||

                                         otherProgram.getState().equals(DtoConstants.STATE_ACTIVE)){

                                 updateCredentialProgramInfoState(otherProgram, DtoConstants.STATE_SUPERSEDED);

                                 }                

                         }

                 }            

     }

         /**

          * Get the current version of program given the selected version of program

          * 

          * @param verIndId

          */

         protected CredentialProgramInfo getCurrentVersion(CredentialProgramInfo credentialProgramInfo)

                         throws Exception {

                 // Get version independent id of program

                 String verIndId = credentialProgramInfo.getVersionInfo().getVersionIndId();

                 // Get id of current version of program given the version independent id

                 VersionDisplayInfo curVerDisplayInfo = programService.getCurrentVersion(

                                 ProgramServiceConstants.PROGRAM_NAMESPACE_MAJOR_DISCIPLINE_URI, verIndId);

                 String curVerId = curVerDisplayInfo.getId();

                 // Return the current version of the course

                 CredentialProgramInfo currentVersion = programService.getCredentialProgram(curVerId);

                 return currentVersion;

         }

     /**

      * This method updates the end terms for the major discipline passed into it.

      * <p>

      * You must still call updateState() to save the object using the web service.

      * 

      * @param credentialProgramInfo

      * @param endEntryTerm

      * @param endEnrollTerm

      */

     private void setEndTerms(CredentialProgramInfo credentialProgramInfo, String endEntryTerm, String endEnrollTerm) {

         credentialProgramInfo.setEndProgramEntryTerm(endEntryTerm);

         credentialProgramInfo.setEndTerm(endEnrollTerm);

     }

     /**

      * This method will update the state of this object and all associated objects.

      * <p>

      * It is needed because we need to make separate web service calls to update the state of these objects.

      * 

      * @param credentialProgramInfo

      * @param newState

      */

     private void updateCredentialProgramInfoState(CredentialProgramInfo credentialProgramInfo, String newState) throws Exception {

         // Update the statement tree

         List<String> programRequirementIds = credentialProgramInfo.getProgramRequirements();

         updateRequirementsState(programRequirementIds, newState);

         // Credential and core programs do not have variations

         // Update program

         credentialProgramInfo.setState(newState);

         programService.updateCredentialProgram(credentialProgramInfo);

     }

     /**

      * This method will make this version of the major discipline the current one.

      * 

      * @param credentialProgramInfo

      */

     private void makeCurrent(CredentialProgramInfo credentialProgramInfo) throws Exception {

         // Check if this is the current version before trying to make it current

         // (the web service will error if you try to make a version current that is already current)

         VersionDisplayInfo currentVersion = programService.getCurrentVersion(ProgramServiceConstants.PROGRAM_NAMESPACE_MAJOR_DISCIPLINE_URI, credentialProgramInfo.getVersionInfo().getVersionIndId());

         // If this is not the current version, then make it current

         if (!currentVersion.getSequenceNumber().equals(credentialProgramInfo.getVersionInfo().getSequenceNumber())) {

             programService.setCurrentCredentialProgramVersion(credentialProgramInfo.getId(), null);

         }

     }

     /**

      * This method will update the requirement state.

      * <p>

      * Note that it uses StatementUtil to update the statement tree.

      * 

      * @param credentialProgramInfo

      * @param newState

      * @throws Exception

      */

     public void updateRequirementsState(List<String> programRequirementIds, String newState) throws Exception {

         for (String programRequirementId : programRequirementIds) {

             // Get program requirement from the program service

             ProgramRequirementInfo programRequirementInfo = programService.getProgramRequirement(programRequirementId, null, null);

             // Look in the requirement for the statement tree

             StatementTreeViewInfo statementTree = programRequirementInfo.getStatement();

             // And recursively update the entire tree with the new state

             StatementUtil.updateStatementTreeViewInfoState(newState, statementTree);

             // Update the state of the requirement object

             programRequirementInfo.setState(newState);

             // The write the requirement back to the program service

             programService.updateProgramRequirement(programRequirementInfo);

         }

     }

     /**

      * This method is used by Spring to inject the program service into this bean.

      * 

      * @param programService

      */

     public void setProgramService(ProgramService programService) {

         this.programService = programService;

     }

 }