/*
 * 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.kylin.rest.response;

import java.io.Serializable;

import org.apache.kylin.metadata.cube.model.IndexPlan.UpdateRuleImpact;

import com.fasterxml.jackson.annotation.JsonProperty;

import lombok.AllArgsConstructor;
import lombok.Getter;

@Getter
@AllArgsConstructor
public class DiffRuleBasedIndexResponse implements Serializable {

    private static DiffRuleBasedIndexResponse EMPTY = new DiffRuleBasedIndexResponse("", 0, 0, 0);

    @JsonProperty("index_plan_id")
    private String indexPlanId;

    @JsonProperty("decrease_layouts")
    private Integer decreaseLayouts;

    @JsonProperty("increase_layouts")
    private Integer increaseLayouts;

    @JsonProperty("rollback_layouts")
    private Integer rollbackLayouts;

    public static DiffRuleBasedIndexResponse from(String modelId, UpdateRuleImpact impact) {
        return new DiffRuleBasedIndexResponse(modelId, impact.getDecreaseLayouts().size(),
                impact.getIncreaseLayouts().size(), impact.getRollbackLayouts().size());

    }

    public static DiffRuleBasedIndexResponse combine(DiffRuleBasedIndexResponse batch,
            DiffRuleBasedIndexResponse stream) {
        if (batch.isEmpty()) {
            return stream;
        }
        if (stream.isEmpty()) {
            return batch;
        }
        return new DiffRuleBasedIndexResponse(stream.indexPlanId,
                stream.getDecreaseLayouts() + batch.getDecreaseLayouts(),
                stream.getIncreaseLayouts() + batch.getIncreaseLayouts(),
                stream.getRollbackLayouts() + batch.getRollbackLayouts());
    }

    private boolean isEmpty() {
        return this == EMPTY;
    }

    public static DiffRuleBasedIndexResponse empty() {
        return EMPTY;
    }
}
