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/*
 * Copyright 2015 Agapsys Tecnologia Ltda-ME.
 *
 * 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 com.agapsys.jpa;

import com.agapsys.jpa.WhereClauseBuilder.QueryParameter;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import javax.persistence.EntityManager;

public abstract class AbstractFindBuilder extends AbstractQueryBuilder {
	// CLASS SCOPE =============================================================
	private static final String DEFAULT_PARAM_PREFIX = "f";
	// =========================================================================
	
	// INSTANCE SCOPE ==========================================================
	private final WhereClauseBuilder whereBuilder = new WhereClauseBuilder(DEFAULT_PARAM_PREFIX);

	
	public AbstractFindBuilder(Class entityClass) {
		super(entityClass);
	}
	
	public AbstractFindBuilder(Class entityClass, String alias) {
		super(entityClass, alias);
	}
	
	public AbstractFindBuilder(boolean distinct, Class entityClass) {
		super(distinct, entityClass);
	}
	
	public AbstractFindBuilder(boolean distinct, Class entityClass, String alias) {
		super(distinct, entityClass, alias);
	}
	
	
	private String getFieldName(String field) {
		if (field == null || field.trim().isEmpty())
			throw new IllegalArgumentException("Null/Empty field");
		
		return String.format("%s.%s", getAlias(), field);
	}
	
	
	protected AbstractFindBuilder by(String field, Object...values) {
		return by(field, FindOperator.EQUALS, values);
	}
	
	protected AbstractFindBuilder by(String field, FindOperator operator, Object...values) {
		whereBuilder.initialCondition(getFieldName(field), operator, values);
		return this;
	}
	
	protected AbstractFindBuilder by(String literal, QueryParameter...parameters) {
		whereBuilder.initialCondition(literal, parameters);
		return this;
	}
	
	
	protected AbstractFindBuilder and(String field, Object...values) {
		return and(field, FindOperator.EQUALS, values);
	}	
	
	protected AbstractFindBuilder and(String field, FindOperator operator, Object...values) {
		whereBuilder.and(getFieldName(field), operator, values);
		return this;
	}
	
	protected AbstractFindBuilder and(String literal, QueryParameter...parameters) {
		whereBuilder.and(literal, parameters);
		return this;
	}
	
	
	protected AbstractFindBuilder or(String field, Object...values) {
		return or(field, FindOperator.EQUALS, values);
	}
	
	protected AbstractFindBuilder or(String field, FindOperator operator, Object...values) {
		whereBuilder.or(getFieldName(field), operator, values);
		return this;
	}
	
	protected AbstractFindBuilder or(String literal, QueryParameter...parameters) {
		whereBuilder.or(literal, parameters);
		return this;
	}
	
		
	protected AbstractFindBuilder beginAndGroup() {
		whereBuilder.beginAndGroup();
		return this;
	}
	
	protected AbstractFindBuilder beginOrGroup() {
		whereBuilder.beginOrGroup();
		return this;
	}
	
	protected AbstractFindBuilder closeGroup() {
		whereBuilder.closeGroup();
		return this;
	}
	
	
	@Override
	protected AbstractFindBuilder offset(Integer offset) {
		return (AbstractFindBuilder) super.offset(offset);
	}

	@Override
	protected AbstractFindBuilder maxResults(Integer maxResults) {
		return (AbstractFindBuilder) super.maxResults(maxResults);
	}

	@Override
	protected AbstractFindBuilder orderBy(String ordering) {
		return (AbstractFindBuilder) super.orderBy(ordering);
	}
	
	@Override
	protected String getWhereClause() {
		if (whereBuilder == null)
			return null;
		
		return whereBuilder.build();
	}

	@Override
	protected Map getValues() {
		if (whereBuilder == null)
			return new LinkedHashMap<>();
		
		return whereBuilder.getValues();
	}
	

	protected List find(EntityManager entityManager) {
		return  (List) super.select(entityManager);
	}
	
	protected T findFirst(EntityManager entityManager) {
		Integer previousMaxResults = getMaxResults();
		
		setLocked(false); // <-- allows attribute change
		maxResults(1);		
		
		List results = (List) find(entityManager);

		maxResults(previousMaxResults);
		setLocked(true); // <-- restores locking state
		
		setLocked(true);
		
		if (results.isEmpty())
			return null;
		else
			return results.get(0);
	}
	// =========================================================================
}