/*
    * Copyright 2001-2008 The Apache Software Foundation.
    * 
    * 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 org.apache.juddi.query;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  import javax.persistence.EntityManager;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.juddi.config.Constants;
  import org.apache.juddi.query.util.DynamicQuery;
  import org.apache.juddi.query.util.FindQualifiers;
  import org.apache.juddi.query.util.KeyedRefTModelComparator;
  import org.uddi.api_v3.CategoryBag;
  import org.uddi.api_v3.KeyedReference;
  
  /**
   * Returns the list of "entity" keys possessing the keyedReferences in the passed category bag.
   * Output is restricted by list of "entity" keys passed in.  If null, all entities are searched.
   * Output is produced by building the appropriate JPA query based on input and find qualifiers.
   * 
   * NOTES:
   * 1) Categories are grouped with a logical AND by default.
   * 2) Concerning when the categories are AND'd together - the only way this can be done with a single query was to create a self-join for 
   *    each category.  If there are a lot of categories, the performance could suffer.
   *    TODO:  Test performance with multiple AND'd categories.  If too slow, look to process this query in multiple steps.
   * 3) The "orLikeKeys" qualifier complicates matters.  The "like" keys are OR'd together and these groups of "like" keys are AND'd together.
   *    As with "andAllKeys", self-joins are created but only one for each group of "like" keys.  If none of the keyedReferences passed are alike then this
   *    will reduce to an "andAllKeys" query.  If all are alike, then this will query will exhibit the behavior of OR'ing all keys.
   * 
   * @author <a href="mailto:jfaath@apache.org">Jeff Faath</a>
   */
  public class FindEntityByCategoryQuery extends EntityQuery {
  	
  	@SuppressWarnings("unused")
  	private final static Log log = LogFactory.getLog(FindEntityByCategoryQuery.class);
  
  	private static final String ENTITY_KEYEDREFERENCE = "KeyedReference";
  	private static final String ALIAS_KEYEDREFERENCE = buildAlias(ENTITY_KEYEDREFERENCE);
  	private static final String FIELD_CATEGORYBAG = "categoryBag";
  	
  	protected String entityName;
  	protected String entityAlias;
  	protected String keyName;
  	protected String entityField;
  	protected String entityNameChild;
  	protected String entityAliasChild;
  	protected String selectSQL;
  	protected String signaturePresent;
  
  	public FindEntityByCategoryQuery(String entityName, String entityAlias, String keyName,
  			String entityField, String entityNameChild, String signaturePresent) {
  		this.entityName = entityName;
  		this.entityAlias = entityAlias;
  		this.keyName = keyName;
  		this.entityField = entityField;
  		this.entityNameChild = entityNameChild;
  		this.entityAliasChild = buildAlias(entityNameChild);
  		this.signaturePresent = signaturePresent;
  		
  		StringBuffer sql = new StringBuffer(200);
  		sql.append("select distinct " + entityAlias + "." + keyName + " from " + entityName + " " + entityAlias + " , " + entityNameChild + " " + entityAliasChild + " ");
  		selectSQL = sql.toString();
  	}
  	
  	public String getEntityName() {
  		return entityName;
  	}
  
  	public String getEntityAlias() {
  		return entityAlias;
  	}
  
  	public String getKeyName() {
  		return keyName;
  	}
  
  	public String getEntityField() {
  		return entityField;
  	}
  
 	public String getEntityNameChild() {
 		return entityNameChild;
 	}
 	
 	public String getEntityAliasChild() {
 		return entityAliasChild;
 	}
 	
 	public String getSelectSQL() {
 		return selectSQL;
 	}
 	
 	public String getSignaturePresent() {
 		return signaturePresent;
 	}
 
 	public void setSignaturePresent(String signaturePresent) {
 		this.signaturePresent = signaturePresent;
 	}
 	
 	public List<Object> select(EntityManager em, FindQualifiers fq, CategoryBag categoryBag, List<Object> keysIn, DynamicQuery.Parameter... restrictions) {
 		// If keysIn is not null and empty, then search is over.
 		if ((keysIn != null) && (keysIn.size() == 0))
 			return keysIn;
 		
 		if (categoryBag == null)
 			return keysIn;
 		
 		List<KeyedReference> categories = categoryBag.getKeyedReference();
 		if (categories == null || categories.size() == 0)
 			return keysIn;
 		
 		List<KeyedReference> keyedRefs = new ArrayList<KeyedReference>(0);
 		for (KeyedReference elem : categories) {
 			if (elem instanceof KeyedReference)
 				keyedRefs.add((KeyedReference)elem);
 		}
 		if (keyedRefs.isEmpty())
 			return keysIn;		
 		
 		DynamicQuery dynamicQry = new DynamicQuery(selectSQL);
 		appendConditions(dynamicQry, fq, keyedRefs);
 		if (restrictions != null && restrictions.length > 0)
 			dynamicQry.AND().pad().appendGroupedAnd(restrictions);
 
 		return getQueryResult(em, dynamicQry, keysIn, entityAlias + "." + keyName);
 	}
 	
 	
 	/*
 	 * Appends the conditions to the query based on the keyedReference list.  With the default or when "orAllKeys" is passed, the keyedReferences are autonomous and are
 	 * all AND'd or OR'd respectively.  However, "orLikeKeys" requires special treatment.  The goal is to create the conditions in this format:
 	 * 
 	 * (likeKey1 = X or likeKey1 = Y) and (likeKey2 = A or likeKey2 = B or likeKey2 = C) 
 	 * 
 	 * ie. the "like" KeyedReferences are OR'd and the groups of "like" KeyedReferences are AND'd with each other.
 	 */
 	public void appendConditions(DynamicQuery qry, FindQualifiers fq, List<KeyedReference> keyedRefs) {
 		
 		// Append the necessary tables (two will always be added connecting the entity to its category table and then the category table to the keyed references).
 		appendJoinTables(qry, fq, keyedRefs);
 		qry.AND().pad().openParen().pad();
 		
 		String predicate = DynamicQuery.PREDICATE_EQUALS;
 		if (fq.isApproximateMatch()) {
 			predicate = DynamicQuery.PREDICATE_LIKE;
 		}
 		
 		// Sorting the collection by tModel Key
 		Collections.sort(keyedRefs, new KeyedRefTModelComparator());
 
 		String prevTModelKey = null;
 		int count = 0;
 		int tblCount = -1;
 		for(KeyedReference keyedRef : keyedRefs) {
 			String tmodelKey = keyedRef.getTModelKey();
 			String keyValue = keyedRef.getKeyValue();
 			String keyName = keyedRef.getKeyName();
 			
 			if (fq.isApproximateMatch()) {
 				// JUDDI-235: wildcards are provided by user (only commenting in case a new interpretation arises)
 				//keyValue = keyValue.endsWith(DynamicQuery.WILDCARD)?keyValue:keyValue + DynamicQuery.WILDCARD;
 				//keyName = keyName.endsWith(DynamicQuery.WILDCARD)?keyName:keyName + DynamicQuery.WILDCARD;
 			}
 
 			// Either opening up (and AND'ing) a new "group" of like keys or simply appending an "or".  If this is not "orLikeKeys", then just need to increment
 			// the table count.
 			if (fq.isOrLikeKeys()) {
 				if (count == 0) {
 					qry.openParen().pad();
 					tblCount++;
 				}
 				else {
 					if (!tmodelKey.equals(prevTModelKey)) {
 						qry.closeParen().pad().AND().pad().openParen().pad();
 						tblCount++;
 					}
 					else
 						qry.OR().pad();
 				}
 			}
 			else
 				tblCount++;
 			
 			String keyValueTerm = (fq.isOrAllKeys()?ALIAS_KEYEDREFERENCE + "0":ALIAS_KEYEDREFERENCE + tblCount) + ".keyValue";
 			String keyNameTerm = (fq.isOrAllKeys()?ALIAS_KEYEDREFERENCE + "0":ALIAS_KEYEDREFERENCE + tblCount) + ".keyName";
 			String tmodelKeyTerm = (fq.isOrAllKeys()?ALIAS_KEYEDREFERENCE + "0":ALIAS_KEYEDREFERENCE + tblCount) + ".tmodelKeyRef";
 			if (fq.isCaseInsensitiveMatch()) {
 				keyValueTerm = "upper(" + keyValueTerm + ")";
 				keyValue = keyValue.toUpperCase();
 				
 				keyNameTerm = "upper(" + keyNameTerm + ")";
 				keyName = keyName.toUpperCase();
 			}
 			
 			
 			// According to specification, if the "general keyword" tmodel is used, then the keyName must be part of the query.
 			if (Constants.GENERAL_KEYWORD_TMODEL.equalsIgnoreCase(tmodelKey)) {
 				qry.appendGroupedAnd(new DynamicQuery.Parameter(tmodelKeyTerm, tmodelKey, DynamicQuery.PREDICATE_EQUALS),
 									 new DynamicQuery.Parameter(keyValueTerm, keyValue, predicate),
 									 new DynamicQuery.Parameter(keyNameTerm, keyName, predicate));
 			}
 			else {
 				qry.appendGroupedAnd(new DynamicQuery.Parameter(tmodelKeyTerm, tmodelKey, DynamicQuery.PREDICATE_EQUALS),
 									 new DynamicQuery.Parameter(keyValueTerm, keyValue, predicate));
 				
 			}
 			
 			if (count + 1 < keyedRefs.size()) {
 				if (fq.isOrAllKeys())
 					qry.OR().pad();
 				else if (fq.isOrLikeKeys()) {
 				}
 				else
 					qry.AND().pad();
 			}
 			
 			// The "orLikeKeys" will always leave an unclosed parenthesis.  This will close it.
 			if (fq.isOrLikeKeys() && (count + 1 == keyedRefs.size()))
 				qry.closeParen().pad();
 
 			prevTModelKey = tmodelKey;
 			count++;
 		}
 		qry.closeParen().pad();
 		
 	}
 
 	
 	
 	/*
 	 * Appends the necessary join table for the child entity and additional tables for when keys are AND'd.  When "orLikeKeys" is used, 
 	 * we only need an extra table for each distinct tmodelKey.
 	 */
 	public void appendJoinTables(DynamicQuery qry, FindQualifiers fq, List<KeyedReference> keyedRefs) {
 		
 		if (keyedRefs != null && keyedRefs.size() > 0) {
 			// Sorting the collection by tModel Key
 			Collections.sort(keyedRefs, new KeyedRefTModelComparator());
 
 			StringBuffer thetaJoins = new StringBuffer(200);
 			int tblCount = 0;
 			int count = 0;
 			String curTModelKey = null;
 			String prevTModelKey = null;
 			for(KeyedReference kr : keyedRefs) {
 				curTModelKey = kr.getTModelKey();
 				if (count != 0) {
 					if (!fq.isOrAllKeys()) {
 						if (fq.isOrLikeKeys() && curTModelKey.equals(prevTModelKey)) {
 							// Do nothing
 						}
 						else {
 							tblCount++;
 							qry.comma().pad().append(ENTITY_KEYEDREFERENCE + " " + ALIAS_KEYEDREFERENCE + tblCount).pad();
 							thetaJoins.append(ALIAS_KEYEDREFERENCE + (tblCount - 1) + "." + FIELD_CATEGORYBAG + ".id = " + ALIAS_KEYEDREFERENCE + tblCount + "." + FIELD_CATEGORYBAG + ".id ");
 							thetaJoins.append(DynamicQuery.OPERATOR_AND + " ");
 						}
 					}
 
 				}
 				else {
 					qry.comma().pad().append(ENTITY_KEYEDREFERENCE + " " + ALIAS_KEYEDREFERENCE + tblCount).pad();
 					thetaJoins.append(entityAliasChild + ".id = " + ALIAS_KEYEDREFERENCE + tblCount + "." + FIELD_CATEGORYBAG + ".id ");
 					thetaJoins.append(DynamicQuery.OPERATOR_AND + " ");
 				}
 				prevTModelKey = curTModelKey;
 				count++;
 			}
 			
 			qry.WHERE().pad().openParen().pad();
 			
 			// Appending the middling entity-specific category table condition
 			qry.append(entityAlias + "." + keyName + " = " + entityAliasChild + "." + entityField + "." + KEY_NAME).pad();
 			qry.AND().pad();
 
 			String thetaJoinsStr = thetaJoins.toString();
 			if (thetaJoinsStr.endsWith(DynamicQuery.OPERATOR_AND + " "))
 				thetaJoinsStr = thetaJoinsStr.substring(0, thetaJoinsStr.length() - (DynamicQuery.OPERATOR_AND + " ").length());
 			qry.append(thetaJoinsStr);
 
 			qry.closeParen().pad();
 			if (fq!=null && fq.isSignaturePresent()) {
 				qry.AND().pad().openParen().pad().append(getSignaturePresent()).pad().closeParen().pad();
 			}
 		}
 	}
 	
 }