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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 java.util.Arrays;

import junit.framework.AssertionFailedError;
import junit.framework.TestCase;

import org.apache.poi.ss.formula.eval.AreaEval;
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.WorkbookEvaluator;
import org.apache.poi.ss.util.CellRangeAddress;

/**
 * Tests for the INDEX() function.</p>
 *
 * This class contains just a few specific cases that directly invoke {@link Index},
 * with minimum overhead.<br/>
 * Another test: {@link TestIndexFunctionFromSpreadsheet} operates from a higher level
 * and has far greater coverage of input permutations.<br/>
 *
 * @author Josh Micich
 */
public final class TestIndex extends TestCase {

	private static final Index FUNC_INST = new Index();
	private static final double[] TEST_VALUES0 = {
			1, 2,
			3, 4,
			5, 6,
			7, 8,
			9, 10,
			11, 12,
	};

	/**
	 * For the case when the first argument to INDEX() is an area reference
	 */
	public void testEvaluateAreaReference() {

		double[] values = TEST_VALUES0;
		confirmAreaEval("C1:D6", values, 4, 1, 7);
		confirmAreaEval("C1:D6", values, 6, 2, 12);
		confirmAreaEval("C1:D6", values, 3, 1, 5);

		// now treat same data as 3 columns, 4 rows
		confirmAreaEval("C10:E13", values, 2, 2, 5);
		confirmAreaEval("C10:E13", values, 4, 1, 10);
	}

	/**
	 * @param areaRefString in Excel notation e.g. 'D2:E97'
	 * @param dValues array of evaluated values for the area reference
	 * @param rowNum 1-based
	 * @param colNum 1-based, pass -1 to signify argument not present
	 */
	private static void confirmAreaEval(String areaRefString, double[] dValues,
			int rowNum, int colNum, double expectedResult) {
		ValueEval[] values = new ValueEval[dValues.length];
		for (int i = 0; i < values.length; i++) {
			values[i] = new NumberEval(dValues[i]);
		}
		AreaEval arg0 = EvalFactory.createAreaEval(areaRefString, values);

		ValueEval[] args;
		if (colNum > 0) {
			args = new ValueEval[] { arg0, new NumberEval(rowNum), new NumberEval(colNum), };
		} else {
			args = new ValueEval[] { arg0, new NumberEval(rowNum), };
		}

		double actual = invokeAndDereference(args);
		assertEquals(expectedResult, actual, 0D);
	}

	private static double invokeAndDereference(ValueEval[] args) {
		ValueEval ve = FUNC_INST.evaluate(args, -1, -1);
		ve = WorkbookEvaluator.dereferenceResult(ve, -1, -1);
		assertEquals(NumberEval.class, ve.getClass());
		return ((NumberEval)ve).getNumberValue();
	}

	/**
	 * Tests expressions like "INDEX(A1:C1,,2)".<br/>
	 * This problem was found while fixing bug 47048 and is observable up to svn r773441.
	 */
	public void testMissingArg() {
		ValueEval[] values = {
				new NumberEval(25.0),
				new NumberEval(26.0),
				new NumberEval(28.0),
		};
		AreaEval arg0 = EvalFactory.createAreaEval("A10:C10", values);
		ValueEval[] args = new ValueEval[] { arg0, MissingArgEval.instance, new NumberEval(2), };
		ValueEval actualResult;
		try {
			actualResult = FUNC_INST.evaluate(args, -1, -1);
		} catch (RuntimeException e) {
			if (e.getMessage().equals("Unexpected arg eval type (org.apache.poi.hssf.record.formula.eval.MissingArgEval")) {
				throw new AssertionFailedError("Identified bug 47048b - INDEX() should support missing-arg");
			}
			throw e;
		}
		// result should be an area eval "B10:B10"
		AreaEval ae = confirmAreaEval("B10:B10", actualResult);
		actualResult = ae.getValue(0, 0);
		assertEquals(NumberEval.class, actualResult.getClass());
		assertEquals(26.0, ((NumberEval)actualResult).getNumberValue(), 0.0);
	}

	/**
	 * When the argument to INDEX is a reference, the result should be a reference
	 * A formula like "OFFSET(INDEX(A1:B2,2,1),1,1,1,1)" should return the value of cell B3.
	 * This works because the INDEX() function returns a reference to A2 (not the value of A2)
	 */
	public void testReferenceResult() {
		ValueEval[] values = new ValueEval[4];
		Arrays.fill(values, NumberEval.ZERO);
		AreaEval arg0 = EvalFactory.createAreaEval("A1:B2", values);
		ValueEval[] args = new ValueEval[] { arg0, new NumberEval(2), new NumberEval(1), };
		ValueEval ve = FUNC_INST.evaluate(args, -1, -1);
		confirmAreaEval("A2:A2", ve);
	}

	/**
	 * Confirms that the result is an area ref with the specified coordinates
	 * @return <tt>ve</tt> cast to {@link AreaEval} if it is valid
	 */
	private static AreaEval confirmAreaEval(String refText, ValueEval ve) {
		CellRangeAddress cra = CellRangeAddress.valueOf(refText);
		assertTrue(ve instanceof AreaEval);
		AreaEval ae = (AreaEval) ve;
		assertEquals(cra.getFirstRow(), ae.getFirstRow());
		assertEquals(cra.getFirstColumn(), ae.getFirstColumn());
		assertEquals(cra.getLastRow(), ae.getLastRow());
		assertEquals(cra.getLastColumn(), ae.getLastColumn());
		return ae;
	}
}