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 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.ofbiz.entity.condition;

import java.sql.Timestamp;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import org.apache.ofbiz.base.util.UtilDateTime;
import org.apache.ofbiz.entity.Delegator;
import org.apache.ofbiz.entity.GenericModelException;
import org.apache.ofbiz.entity.config.model.Datasource;
import org.apache.ofbiz.entity.model.ModelEntity;

/**
 * Date-range condition. 
 *
 */
@SuppressWarnings("serial")
public final class EntityDateFilterCondition extends EntityCondition {

    protected final String fromDateName;
    protected final String thruDateName;

    public EntityDateFilterCondition(String fromDateName, String thruDateName) {
        this.fromDateName = fromDateName;
        this.thruDateName = thruDateName;
    }

    @Override
    public boolean isEmpty() {
        return false;
    }

    @Override
    public String makeWhereString(ModelEntity modelEntity, List<EntityConditionParam> entityConditionParams, Datasource datasourceInfo) {
        EntityCondition condition = makeCondition();
        return condition.makeWhereString(modelEntity, entityConditionParams, datasourceInfo);
    }

    @Override
    public void checkCondition(ModelEntity modelEntity) throws GenericModelException {
        EntityCondition condition = makeCondition();
        condition.checkCondition(modelEntity);
    }

    @Override
    public boolean mapMatches(Delegator delegator, Map<String, ? extends Object> map) {
        EntityCondition condition = makeCondition();
        return condition.mapMatches(delegator, map);
    }

    @Override
    public boolean equals(Object obj) {
        if (!(obj instanceof EntityDateFilterCondition)) return false;
        EntityDateFilterCondition other = (EntityDateFilterCondition) obj;
        return equals(fromDateName, other.fromDateName) && equals(thruDateName, other.thruDateName);
    }

    @Override
    public int hashCode() {
        return hashCode(fromDateName) ^ hashCode(thruDateName);
    }

    @Override
    public void visit(EntityConditionVisitor visitor) {
        visitor.acceptEntityDateFilterCondition(this);
    }

    @Override
    public void accept(EntityConditionVisitor visitor) {
        visitor.acceptEntityDateFilterCondition(this);
    }

    @Override
    public EntityCondition freeze() {
        return this;
    }

    protected EntityCondition makeCondition() {
        return makeCondition(UtilDateTime.nowTimestamp(), fromDateName, thruDateName);
    }

    public static EntityExpr makeCondition(Timestamp moment, String fromDateName, String thruDateName) {
        return EntityCondition.makeCondition(
            EntityCondition.makeCondition(
                EntityCondition.makeCondition(thruDateName, EntityOperator.EQUALS, null),
                EntityOperator.OR,
                EntityCondition.makeCondition(thruDateName, EntityOperator.GREATER_THAN, moment)
           ),
            EntityOperator.AND,
            EntityCondition.makeCondition(
                EntityCondition.makeCondition(fromDateName, EntityOperator.EQUALS, null),
                EntityOperator.OR,
                EntityCondition.makeCondition(fromDateName, EntityOperator.LESS_THAN_EQUAL_TO, moment)
           )
      );
    }

    /**
     * Creates an EntityCondition representing a date range filter query to be used against 
     * entities that themselves represent a date range.  When used the resulting entities 
     * will meet at least one of the following criteria:
     * - fromDate is equal to or after rangeStart but before rangeEnd
     * - thruDate is equal to or after rangeStart but before rangeEnd
     * - fromDate is null and thruDate is equal to or after rangeStart
     * - thruDate is null and fromDate is before rangeEnd
     * - fromDate is null and thruDate is null
     * 
     * @param rangeStart    The start of the range to filter against
     * @param rangeEnd      The end of the range to filter against
     * @param fromDateName  The name of the field containing the entity's "fromDate"
     * @param thruDateName  The name of the field containing the entity's "thruDate"
     * @return EntityCondition representing the date range filter
     */
    public static EntityCondition makeRangeCondition(Timestamp rangeStart, Timestamp rangeEnd, String fromDateName, String thruDateName) {
        List<EntityCondition> criteria = new LinkedList<EntityCondition>();
        // fromDate is equal to or after rangeStart but before rangeEnd
        criteria.add(
                EntityCondition.makeCondition(
                        EntityCondition.makeCondition(fromDateName, EntityOperator.GREATER_THAN_EQUAL_TO, rangeStart),
                        EntityOperator.AND,
                        EntityCondition.makeCondition(fromDateName, EntityOperator.LESS_THAN, rangeEnd)
                )
        );
        // thruDate is equal to or after rangeStart but before rangeEnd
        criteria.add(
                EntityCondition.makeCondition(
                        EntityCondition.makeCondition(thruDateName, EntityOperator.GREATER_THAN_EQUAL_TO, rangeStart),
                        EntityOperator.AND,
                        EntityCondition.makeCondition(thruDateName, EntityOperator.LESS_THAN, rangeEnd)
                )
        );
        // fromDate is null and thruDate is equal to or after rangeStart
        criteria.add(
                EntityCondition.makeCondition(
                        EntityCondition.makeCondition(fromDateName, EntityOperator.EQUALS, null),
                        EntityOperator.AND,
                        EntityCondition.makeCondition(thruDateName, EntityOperator.GREATER_THAN_EQUAL_TO, rangeStart)
                )
        );
        // thruDate is null and fromDate is before rangeEnd
        criteria.add(
                EntityCondition.makeCondition(
                        EntityCondition.makeCondition(thruDateName, EntityOperator.EQUALS, null),
                        EntityOperator.AND,
                        EntityCondition.makeCondition(fromDateName, EntityOperator.LESS_THAN, rangeEnd)
                )
        );
        // fromDate is null and thruDate is null
        criteria.add(
                EntityCondition.makeCondition(
                        EntityCondition.makeCondition(thruDateName, EntityOperator.EQUALS, null),
                        EntityOperator.AND,
                        EntityCondition.makeCondition(fromDateName, EntityOperator.EQUALS, null)
                )
        );
        // require at least one of the above to be true
        return EntityCondition.makeCondition(criteria, EntityOperator.OR);
    }
}