/*
    * 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.util;
  
  import java.util.StringTokenizer;
  import java.util.Vector;
  import java.util.List;
  import javax.persistence.Query;
  import javax.persistence.EntityManager;
  
  /**
   * @author <a href="mailto:jfaath@apache.org">Jeff Faath</a>
   * @author Steve Viens (steve@viens.net)
   */
  public class DynamicQuery {
  	public static final String CLAUSE_WHERE = "where";
  	public static final String CLAUSE_GROUPBY = "group by";
  	public static final String CLAUSE_ORDERBY = "order by";
  	public static final String CLAUSE_HAVING = "having";
  	public static final String OPERATOR_OR = "or";
  	public static final String OPERATOR_AND = "and";
  	public static final String PREDICATE_EQUALS = "=";
  	public static final String PREDICATE_NOTEQUALS = "<>";
  	public static final String PREDICATE_LIKE = "like";
  	public static final String PREDICATE_IN = "in";
  	public static final String PREDICATE_GREATERTHAN = ">";
  	public static final String PREDICATE_LESSTHAN = "<";
  	public static final String SORT_ASC = "asc";
  	public static final String SORT_DESC = "desc";
  	public static final String WILDCARD = "%";
  	
  	private Vector<Object> values = null;
  	private StringBuffer sql = null;
  
  	public DynamicQuery() {
  		this.values = new Vector<Object>();
  		this.sql = new StringBuffer();
  	} 
  
  	public DynamicQuery(String sql) {
  		this.values = new Vector<Object>();
  		this.sql = new StringBuffer(sql);
  	}
  
  	public DynamicQuery append(String sql) {
  		this.sql.append(sql);
  		return this;
  	}
  
  	public DynamicQuery pad() {
  		this.sql.append(" ");
  		return this;
  	}
  	
  	public DynamicQuery openParen() {
  		this.sql.append("(");
  		return this;
  	}
  
  	public DynamicQuery closeParen() {
  		this.sql.append(")");
  		return this;
  	}
  
  	public DynamicQuery param() {
  		this.sql.append("?");
  		return this;
  	}
  	
  	public DynamicQuery comma() {
  		this.sql.append(",");
  		return this;
  	}
  
  	public DynamicQuery AND() {
  		this.sql.append(OPERATOR_AND);
  		return this;
  	}
  	
  	public DynamicQuery OR() {
  		this.sql.append(OPERATOR_OR);
  		return this;
  	}
  
 	public DynamicQuery WHERE() {
 		this.sql.append(CLAUSE_WHERE);
 		return this;
 	}
 
 	public DynamicQuery IN() {
 		this.sql.append(PREDICATE_IN);
 		return this;
 	}
 
 	public DynamicQuery GROUPBY() {
 		this.sql.append(CLAUSE_GROUPBY);
 		return this;
 	}
 
 	public DynamicQuery ORDERBY() {
 		this.sql.append(CLAUSE_ORDERBY);
 		return this;
 	}
 
 	public DynamicQuery HAVING() {
 		this.sql.append(CLAUSE_HAVING);
 		return this;
 	}
 	
 	public DynamicQuery appendGroupedAnd(Parameter... params) {
 		return appendCondition(OPERATOR_AND, params);
 	}
 
 	public DynamicQuery appendGroupedOr(Parameter... params) {
 		return appendCondition(OPERATOR_OR, params);
 	}
 
 	public DynamicQuery appendCondition(String operator, Parameter... params) {
 		if (params == null || operator == null)
 			return this;
 		
 		openParen();
 		for (int i = 0; i < params.length; i++) {
 			if (params[i] != null) {
 				append(params[i].getName()).pad().append(params[i].getPredicate()).pad().param();
 				addValue(params[i].getValue());
 				
 				if (i + 1 < params.length) {
 					pad().append(operator).pad();
 				}
 			}
 		}
 		closeParen().pad();
 		return this;
 		
 	}
 	
 	public DynamicQuery appendInListWithAnd(String term, List<?> list) {
 		if (list == null || list.size() == 0)
 			return this;
 		
 		AND().pad();
 		
 		return appendInList(term, list);
 	}
 	
 	public DynamicQuery appendInList(String term, List<?> list) {
 		if (list == null || list.size() == 0)
 			return this;
 		
 		append(term).pad().IN().pad().openParen().pad();
 		int count = 0;
 		for (Object item : list) {
 			param();
 			addValue(item);
 			
 			if (count + 1 < list.size())
 				comma().pad();
 			
 			count++;
 		}
 		closeParen().pad();
 		return this;
 	}
 
 	public void addValue(Object obj) {
 		this.values.addElement(obj);
 	}
 	
 	public Query buildJPAQuery(EntityManager em) {
 		StringTokenizer tokenizer = new StringTokenizer(sql.toString(),"?");
 		StringBuffer sqlBuffer = new StringBuffer();
 		int numberOfTokens = tokenizer.countTokens();
 		for (int i=1; i<numberOfTokens; i++) {
 			sqlBuffer.append(tokenizer.nextToken() + "?" + i);
 		}
 		if (tokenizer.hasMoreTokens()) sqlBuffer.append(tokenizer.nextToken());
 		Query qry = em.createQuery(sqlBuffer.toString());
 		
 		for (int i = 0; i < values.size(); i++)
 			qry.setParameter(i + 1, values.elementAt(i));
 			
 		return qry;
 	}
 
 	public String toString() { 
 		StringBuffer buffer = new StringBuffer(sql.toString());
 		buffer.append("\n\n");
 	
 		for (int i=0; i<values.size(); i++) {
 			Object obj = values.elementAt(i);
 	  
 			buffer.append(i+1);
 			buffer.append("\t");
 			buffer.append(obj.getClass().getName());
 			buffer.append("\t");
 			buffer.append(obj.toString());
 			buffer.append("\n");
 		}
 	    
 		return buffer.toString();
 	}
 	
 	public static class Parameter {
 		private String name;
 		private Object value;
 		private String predicate;
 		
 		public Parameter(String name, Object value, String predicate) {
 			this.name = name;
 			this.value = value;
 			this.predicate = predicate;
 		}
 
 		public String getName() {
 			return name;
 		}
 		public void setName(String name) {
 			this.name = name;
 		}
 
 		public Object getValue() {
 			return value;
 		}
 		public void setValue(Object value) {
 			this.value = value;
 		}
 
 		public String getPredicate() {
 			return predicate;
 		}
 		public void setPredicate(String predicate) {
 			this.predicate = predicate;
 		}
 
 		
 	}
 }