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   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
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       http://www.apache.org/licenses/LICENSE-2.0

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   distributed under the License is distributed on an "AS IS" BASIS,
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package org.apache.poi.ss.formula.functions;

import org.apache.poi.ss.formula.TwoDEval;
import org.apache.poi.ss.formula.eval.ErrorEval;
import org.apache.poi.ss.formula.eval.MissingArgEval;
import org.apache.poi.ss.formula.eval.NumberEval;
import org.apache.poi.ss.formula.eval.ValueEval;
import org.apache.poi.ss.formula.functions.CountUtils.I_MatchPredicate;
import org.apache.poi.ss.formula.functions.CountUtils.I_MatchAreaPredicate;

Counts the number of cells that contain numeric data within
 the list of arguments.
Excel Syntax
COUNT(value1,value2,...)
Value1, value2, ...   are 1 to 30 arguments representing the values or ranges to be counted.
TODO: Check this properly matches excel on edge cases
 like formula cells, error cells etc
/**
 * Counts the number of cells that contain numeric data within
 *  the list of arguments.
 *
 * Excel Syntax
 * COUNT(value1,value2,...)
 * Value1, value2, ...   are 1 to 30 arguments representing the values or ranges to be counted.
 *
 * TODO: Check this properly matches excel on edge cases
 *  like formula cells, error cells etc
 */
public final class Count implements Function {
    private final I_MatchPredicate _predicate;

    public Count(){
        _predicate = defaultPredicate;
    }

    private Count(I_MatchPredicate criteriaPredicate){
        _predicate = criteriaPredicate;
    }

	public ValueEval evaluate(ValueEval[] args, int srcCellRow, int srcCellCol) {
		int nArgs = args.length;
		if (nArgs < 1) {
			// too few arguments
			return ErrorEval.VALUE_INVALID;
		}

		if (nArgs > 30) {
			// too many arguments
			return ErrorEval.VALUE_INVALID;
		}

		int temp = 0;

		for(int i=0; i<nArgs; i++) {
			temp += CountUtils.countArg(args[i], _predicate);

		}
		return new NumberEval(temp);
	}

	private static final I_MatchPredicate defaultPredicate = new I_MatchPredicate() {

		public boolean matches(ValueEval valueEval) {

			if(valueEval instanceof NumberEval) {
				// only numbers are counted
				return true;
			}
			if(valueEval == MissingArgEval.instance) {
				// oh yeah, and missing arguments
				return true;
			}

			// error values and string values not counted
			return false;
		}
	};

    
matches hidden rows but not subtotals
/**
     * matches hidden rows but not subtotals
     */
    private static final I_MatchPredicate subtotalPredicate = new I_MatchAreaPredicate() {
        public boolean matches(ValueEval valueEval) {
            return defaultPredicate.matches(valueEval);
        }

        
don't count cells that are subtotals
/**
         * don't count cells that are subtotals
         */
        public boolean matches(TwoDEval areEval, int rowIndex, int columnIndex) {
            return !areEval.isSubTotal(rowIndex, columnIndex);
        }
    };

    
matches nither hidden rows or subtotals
/**
     * matches nither hidden rows or subtotals
     */
    private static final I_MatchPredicate subtotalVisibleOnlyPredicate = new I_MatchAreaPredicate() {
        public boolean matches(ValueEval valueEval) {
            return defaultPredicate.matches(valueEval);
        }
        
        
don't count cells that are subtotals
/**
         * don't count cells that are subtotals
         */
        public boolean matches(TwoDEval areEval, int rowIndex, int columnIndex) {
            return !areEval.isSubTotal(rowIndex, columnIndex) && !areEval.isRowHidden(rowIndex);
        }
    };
    
    
 Create an instance of Count to use in Subtotal 

    If there are other subtotals within argument refs (or nested subtotals),
    these nested subtotals are ignored to avoid double counting.

Params:
includeHiddenRows – true to include hidden rows in the aggregate, false to skip them
Returns:
function
 @see Subtotal/**
     *  Create an instance of Count to use in {@link Subtotal}
     * <p>
     *     If there are other subtotals within argument refs (or nested subtotals),
     *     these nested subtotals are ignored to avoid double counting.
     * </p>
     * @param includeHiddenRows true to include hidden rows in the aggregate, false to skip them
     * @return function
     *
     *  @see Subtotal
     */
    public static Count subtotalInstance(boolean includeHiddenRows) {
        return new Count(includeHiddenRows ? subtotalPredicate : subtotalVisibleOnlyPredicate);
    }
}