/*
    * Copyright 2007 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
    *
   * 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 org.kuali.rice.kew.engine.node;
  
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  import org.apache.commons.lang.StringUtils;
  import org.kuali.rice.kew.actionrequest.ActionRequestFactory;
  import org.kuali.rice.kew.actionrequest.ActionRequestValue;
  import org.kuali.rice.kew.api.rule.Rule;
  import org.kuali.rice.kew.engine.RouteContext;
  import org.kuali.rice.kew.engine.RouteHelper;
  import org.kuali.rice.kew.exception.RouteManagerException;
  import org.kuali.rice.kew.exception.WorkflowException;
  import org.kuali.rice.kew.routeheader.DocumentRouteHeaderValue;
  import org.kuali.rice.kew.rule.FlexRM;
  import org.kuali.rice.kew.rule.KRAMetaRuleEngine;
  import org.kuali.rice.kew.rule.RuleExpressionResult;
  import org.kuali.rice.kew.service.KEWServiceLocator;
  import org.kuali.rice.kew.util.Utilities;
  
  
  /**
   * Node that implements a KRAMetaRule, with multiple request/response phases
   *
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class KRAMetaRuleNode extends IteratedRequestActivationNode {
  	private static String SUPPRESS_POLICY_ERRORS_KEY = "_suppressPolicyErrorsRequestActivationNode";
  
  	protected List<ActionRequestValue> generateUninitializedRequests(ActionRequestFactory arFactory, RouteContext context, RuleExpressionResult result) throws WorkflowException {
  		FlexRM flexRM = new FlexRM();
  		flexRM.makeActionRequests(arFactory, result.getResponsibilities(), context, Rule.Builder.create(result.getRule().getDefinition()).build(), context.getDocument(), null, null);
  		return new ArrayList<ActionRequestValue>(arFactory.getRequestGraphs());
  	}
  
  	protected List<ActionRequestValue> initializeRequests(List<ActionRequestValue> requests, RouteContext context) {
  		// RequestNode.getNewActionRequests
  		List<ActionRequestValue> newRequests = new ArrayList<ActionRequestValue>();
  		for (Iterator iterator = requests.iterator(); iterator.hasNext();) {
  			ActionRequestValue actionRequest = (ActionRequestValue) iterator.next();
  			actionRequest = KEWServiceLocator.getActionRequestService().initializeActionRequestGraph(actionRequest, context.getDocument(), context.getNodeInstance());
  			saveActionRequest(context, actionRequest);
  			newRequests.add(actionRequest);
  		}
  		return newRequests;
  	}
  
  	@Override
  	protected boolean generateNewRequests(boolean initial, RouteContext context, RouteHelper routeHelper)
  	throws WorkflowException, Exception {
  		RouteNodeInstance nodeInstance = context.getNodeInstance();
  		RouteNode nodeDef = nodeInstance.getRouteNode();
  
  		// get the expression
  		Map<String, String> cfg = Utilities.getKeyValueCollectionAsMap(nodeDef.getConfigParams());
  		String expression = cfg.get("expression");
  		if (StringUtils.isEmpty(expression)) {
  			throw new WorkflowException("No meta-rule expression supplied in node " + nodeDef);
  		}
  		KRAMetaRuleEngine engine = new KRAMetaRuleEngine(expression);
  
  		// get the current statement
  		int curStatement = getCurStatement(nodeInstance);
  
  		engine.setCurStatement(curStatement);
  
  		if (engine.isDone()) {
  			return false;
  		}
  
  		// generate next round of action requests
  		RuleExpressionResult result = engine.processSingleStatement(context);
  		if (!result.isSuccess()) {
  			return false;
  		}
  
  		boolean suppressPolicyErrors = isSupressingPolicyErrors(context);
  		boolean pastFinalApprover = isPastFinalApprover(context.getDocument(), nodeInstance);
  
  		// actionRequests.addAll(makeActionRequests(context, rule, routeHeader, null, null));
 		// copied from parts of FlexRM and RequestsNode
 		ActionRequestFactory arFactory = new ActionRequestFactory(context.getDocument(), context.getNodeInstance());
 		List<ActionRequestValue> requests = generateUninitializedRequests(arFactory, context, result);
 		requests = initializeRequests(requests, context);
 		// RequestNode
 		if ((requests.isEmpty()) && nodeDef.getMandatoryRouteInd().booleanValue() && ! suppressPolicyErrors) {
 			LOG.warn("no requests generated for mandatory route - " + nodeDef.getRouteNodeName());
 			throw new RouteManagerException("No requests generated for mandatory route " + nodeDef.getRouteNodeName() + ":" + nodeDef.getRouteMethodName(), context);
 		}
 		// determine if we have any approve requests for FinalApprover checks
 		boolean hasApproveRequest = false;
 		for (Iterator iter = requests.iterator(); iter.hasNext();) {
 			ActionRequestValue actionRequest = (ActionRequestValue) iter.next();
 			hasApproveRequest = actionRequest.isApproveOrCompleteRequest() || hasApproveRequest;
 		}
 		// if final approver route level and no approve request send to exception routing
 		if (nodeDef.getFinalApprovalInd().booleanValue()) {
 			// we must have an approve request generated if final approver level.
 			if (!hasApproveRequest && ! suppressPolicyErrors) {
 				throw new RuntimeException("No Approve Request generated after final approver");
 			}
 		} else if (pastFinalApprover) {
 			// we can't allow generation of approve requests after final approver. This guys going to exception routing.
 			if (hasApproveRequest && ! suppressPolicyErrors) {
 				throw new RuntimeException("Approve Request generated after final approver");
 			}
 		}
 
 		// increment to next statement
 		nodeInstance.getNodeState("stmt").setValue(String.valueOf(curStatement + 1));
 		return !requests.isEmpty();
 	}
 
 	/**
 	 * @param nodeInstance the current node instance under execution
 	 * @return the meta-rule statement this node instance should process
 	 */
 	protected static int getCurStatement(RouteNodeInstance nodeInstance) {
 		int statement = 0;
 		NodeState nodeState = nodeInstance.getNodeState("stmt");
 		if (nodeState == null) {
 			nodeState = new NodeState();
 			nodeState.setKey("stmt");
 			nodeState.setNodeInstance(nodeInstance);
 			nodeInstance.addNodeState(nodeState);
 		}
 		if (StringUtils.isEmpty(nodeState.getValue())) {
 			nodeState.setValue("0");
 		} else {
 			statement = Integer.parseInt(nodeState.getValue());
 		}
 		return statement;
 	}
 
 	@Override
 	protected RequestFulfillmentCriteria getRequestFulfillmentCriteria(RouteContext routeContext) {
 		return super.getRequestFulfillmentCriteria(routeContext);
 	}
 
 
 	// -- copied from request node; a lot of this action request evaluating code should probably go into helper classes or factored into a common subclass
 
 	/**
 	 * The method will get a key value which can be used for comparison purposes. If the node instance has a primary key value, it will be returned. However, if the node instance has not been saved to the database (i.e. during a simulation) this method will return the node instance passed in.
 	 */
 	private Object getKey(RouteNodeInstance nodeInstance) {
 		String id = nodeInstance.getRouteNodeInstanceId();
 		return (id != null ? (Object) id : (Object) nodeInstance);
 	}
 
 	/**
 	 * Checks if the document has past the final approver node by walking backward through the previous node instances.
 	 * Ignores any previous nodes that have been "revoked".
 	 */
 	private boolean isPastFinalApprover(DocumentRouteHeaderValue document, RouteNodeInstance nodeInstance) {
 		FinalApproverContext context = new FinalApproverContext();
 		List revokedNodeInstances = KEWServiceLocator.getRouteNodeService().getRevokedNodeInstances(document);
 		Set revokedNodeInstanceIds = new HashSet();
 		for (Iterator iterator = revokedNodeInstances.iterator(); iterator.hasNext(); ) {
 			RouteNodeInstance revokedNodeInstance = (RouteNodeInstance) iterator.next();
 			revokedNodeInstanceIds.add(revokedNodeInstance.getRouteNodeInstanceId());
 		}
 		isPastFinalApprover(nodeInstance.getPreviousNodeInstances(), context, revokedNodeInstanceIds);
 		return context.isPast;
 	}
 
 	private void isPastFinalApprover(List previousNodeInstances, FinalApproverContext context, Set revokedNodeInstanceIds) {
 		if (previousNodeInstances != null && !previousNodeInstances.isEmpty()) {
 			for (Iterator iterator = previousNodeInstances.iterator(); iterator.hasNext();) {
 				if (context.isPast) {
 					return;
 				}
 				RouteNodeInstance nodeInstance = (RouteNodeInstance) iterator.next();
 				if (context.inspected.contains(getKey(nodeInstance))) {
 					continue;
 				} else {
 					context.inspected.add(getKey(nodeInstance));
 				}
 				if (Boolean.TRUE.equals(nodeInstance.getRouteNode().getFinalApprovalInd())) {
 					// if the node instance has been revoked (by a Return To Previous action for example)
 					// then we don't want to consider that node when we determine if we are past final
 					// approval or not
 					if (!revokedNodeInstanceIds.contains(nodeInstance.getRouteNodeInstanceId())) {
 						context.isPast = true;
 					}
 					return;
 				}
 				isPastFinalApprover(nodeInstance.getPreviousNodeInstances(), context, revokedNodeInstanceIds);
 			}
 		}
 	}
 	public static boolean isSupressingPolicyErrors(RouteContext routeContext) {
 		Boolean suppressPolicyErrors = (Boolean)routeContext.getParameters().get(SUPPRESS_POLICY_ERRORS_KEY);
 		if (suppressPolicyErrors == null || ! suppressPolicyErrors) {
 			return false;
 		}
 		return true;
 	}
 
 	private class FinalApproverContext {
 		public Set inspected = new HashSet();
 		public boolean isPast = false;
 	}
 
 }