/*******************************************************************************
 * Copyright 2017 Bstek
 *
 * 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.bstek.ureport.expression.function.page;

import com.bstek.ureport.Utils;
import com.bstek.ureport.build.Context;
import com.bstek.ureport.expression.model.data.ExpressionData;
import com.bstek.ureport.expression.model.data.ObjectListExpressionData;
import com.bstek.ureport.model.Cell;

import java.math.BigDecimal;
import java.util.List;

/**
 * @author Jacky.gao
 * @since 2017年5月5日
 */
public class PageAvgFunction extends PageFunction {

    @Override
    public Object execute(List<ExpressionData<?>> dataList, Context context, Cell currentCell) {
        if (dataList == null) {
            return 0;
        }
        int size = 0;
        BigDecimal total = new BigDecimal(0);
        for (ExpressionData<?> exprData : dataList) {
            if (exprData instanceof ObjectListExpressionData) {
                ObjectListExpressionData listExpr = (ObjectListExpressionData) exprData;
                List<?> list = listExpr.getData();
                for (Object obj : list) {
                    if (obj == null) {
                        continue;
                    }
                    BigDecimal bigData = Utils.toBigDecimal(obj);
                    total = total.add(bigData);
                    size++;
                }
            }
        }
        return total.divide(new BigDecimal(size), 8, BigDecimal.ROUND_HALF_UP);
    }

    @Override
    public String name() {
        return "pavg";
    }
}
