package org.cateproject.controller.interceptor;
   
   import java.util.UUID;
   
   import javax.servlet.http.HttpServletRequest;
   import javax.servlet.http.HttpServletResponse;
   
   import org.cateproject.controller.user.UserPreferences;
   import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.web.bind.ServletRequestUtils;
  import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
  
  import eu.etaxonomy.cdm.api.service.IAuditEventService;
  import eu.etaxonomy.cdm.model.view.AuditEvent;
  import eu.etaxonomy.cdm.model.view.context.AuditEventContextHolder;
  
  public class AuditEventContextHandlerInterceptor extends HandlerInterceptorAdapter {
  	public static String AUDIT_EVENT_CONTEXT_PARAM_NAME = "view"; 
  	private IAuditEventService auditEventService;
  	
  	private UserPreferences userPreferences;
  	
  	@Autowired
  	public void setAuditEventService(IAuditEventService auditEventService) {
  		this.auditEventService = auditEventService;
  	}
  	
  	@Autowired
  	public void setUserPreferences(UserPreferences userPreferences) {
  		this.userPreferences = userPreferences;
  	}
  	
  	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception{
  		
  		AuditEvent auditEvent = null;
  		
  		String auditEventUuidString = ServletRequestUtils.getStringParameter(request,AuditEventContextHandlerInterceptor.AUDIT_EVENT_CONTEXT_PARAM_NAME);
  		
  		if(auditEventUuidString != null) { // view param is not in the request
  			try {
  				  UUID auditEventUuid = UUID.fromString(auditEventUuidString);
  				  if(auditEventUuid.equals(AuditEvent.CURRENT_VIEW.getUuid())) {
  					  auditEvent = AuditEvent.CURRENT_VIEW; // it's static, don't fetch it!
  				  } else {
  					  auditEvent = auditEventService.find(auditEventUuid);
  				  }
  
  			} catch(IllegalArgumentException iae) {
  				// someone has passed an illegal uuid str, so move on. 
  			}
  		} 
  		
  		if(auditEvent == null) { // now try the session
  			auditEvent = userPreferences.getAuditEvent();
  		}
  		
  		if(auditEvent == null) { // default to CURRENT_VIEW
  			auditEvent = AuditEvent.CURRENT_VIEW;
  		}
  					
  	    AuditEventContextHolder.getContext().setAuditEvent(auditEvent);
  		userPreferences.setAuditEvent(auditEvent);
  	    
  		return true;
      }
  }