/*********************************************************************
 *
 *      Copyright (C) 2002 Andrew Khan
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ***************************************************************************/

package org.xbib.datastructures.xslx.jxl.biff.formula;

import java.util.Stack;
import org.xbib.datastructures.xslx.jxl.WorkbookSettings;
import org.xbib.datastructures.xslx.jxl.biff.IntegerHelper;
import org.xbib.datastructures.xslx.jxl.common.Logger;

/**
 * A built in function in a formula.  These functions take a variable
 * number of arguments, such as a range (eg. SUM etc)
 */
class VariableArgFunction extends Operator implements ParsedThing {
    /**
     * The logger
     */
    private static final Logger logger = Logger.getLogger(VariableArgFunction.class);

    /**
     * The function
     */
    private Function function;

    /**
     * The number of arguments
     */
    private int arguments;

    /**
     * Flag which indicates whether this was initialized from the client
     * api or from an excel sheet
     */
    private final boolean readFromSheet;

    /**
     * The workbooks settings
     */
    private final WorkbookSettings settings;

    /**
     * Constructor
     */
    public VariableArgFunction(WorkbookSettings ws) {
        readFromSheet = true;
        settings = ws;
    }

    /**
     * Constructor used when parsing a function from a string
     *
     * @param f the function
     * @param a the number of arguments
     */
    public VariableArgFunction(Function f, int a, WorkbookSettings ws) {
        function = f;
        arguments = a;
        readFromSheet = false;
        settings = ws;
    }

    /**
     * Reads the ptg data from the array starting at the specified position
     *
     * @param data the RPN array
     * @param pos  the current position in the array, excluding the ptg identifier
     * @return the number of bytes read
     * @throws FormulaException
     */
    public int read(byte[] data, int pos) throws FormulaException {
        arguments = data[pos];
        int index = IntegerHelper.getInt(data[pos + 1], data[pos + 2]);
        function = Function.getFunction(index);

        if (function == Function.UNKNOWN) {
            throw new FormulaException(FormulaException.UNRECOGNIZED_FUNCTION,
                    index);
        }

        return 3;
    }

    /**
     * Gets the operands for this operator from the stack
     */
    public void getOperands(Stack s) {
        // parameters are in the correct order, god damn them
        ParseItem[] items = new ParseItem[arguments];

        for (int i = arguments - 1; i >= 0; i--) {
            ParseItem pi = (ParseItem) s.pop();

            items[i] = pi;
        }

        for (int i = 0; i < arguments; i++) {
            add(items[i]);
        }
    }

    public void getString(StringBuffer buf) {
        buf.append(function.getName(settings));
        buf.append('(');

        if (arguments > 0) {
            ParseItem[] operands = getOperands();
            if (readFromSheet) {
                // arguments are in the same order they were specified
                operands[0].getString(buf);

                for (int i = 1; i < arguments; i++) {
                    buf.append(',');
                    operands[i].getString(buf);
                }
            } else {
                // arguments are stored in the reverse order to which they
                // were specified, so iterate through them backwards
                operands[arguments - 1].getString(buf);

                for (int i = arguments - 2; i >= 0; i--) {
                    buf.append(',');
                    operands[i].getString(buf);
                }
            }
        }

        buf.append(')');
    }

    /**
     * Adjusts all the relative cell references in this formula by the
     * amount specified.  Used when copying formulas
     *
     * @param colAdjust the amount to add on to each relative cell reference
     * @param rowAdjust the amount to add on to each relative row reference
     */
    public void adjustRelativeCellReferences(int colAdjust, int rowAdjust) {
        ParseItem[] operands = getOperands();

        for (int i = 0; i < operands.length; i++) {
            operands[i].adjustRelativeCellReferences(colAdjust, rowAdjust);
        }
    }

    /**
     * Called when a column is inserted on the specified sheet.  Tells
     * the formula  parser to update all of its cell references beyond this
     * column
     *
     * @param sheetIndex   the sheet on which the column was inserted
     * @param col          the column number which was inserted
     * @param currentSheet TRUE if this formula is on the sheet in which the
     *                     column was inserted, FALSE otherwise
     */
    void columnInserted(int sheetIndex, int col, boolean currentSheet) {
        ParseItem[] operands = getOperands();
        for (int i = 0; i < operands.length; i++) {
            operands[i].columnInserted(sheetIndex, col, currentSheet);
        }
    }

    /**
     * Called when a column is inserted on the specified sheet.  Tells
     * the formula  parser to update all of its cell references beyond this
     * column
     *
     * @param sheetIndex   the sheet on which the column was removed
     * @param col          the column number which was removed
     * @param currentSheet TRUE if this formula is on the sheet in which the
     *                     column was inserted, FALSE otherwise
     */
    void columnRemoved(int sheetIndex, int col, boolean currentSheet) {
        ParseItem[] operands = getOperands();
        for (int i = 0; i < operands.length; i++) {
            operands[i].columnRemoved(sheetIndex, col, currentSheet);
        }
    }

    /**
     * Called when a column is inserted on the specified sheet.  Tells
     * the formula  parser to update all of its cell references beyond this
     * column
     *
     * @param sheetIndex   the sheet on which the row was inserted
     * @param row          the row number which was inserted
     * @param currentSheet TRUE if this formula is on the sheet in which the
     *                     column was inserted, FALSE otherwise
     */
    void rowInserted(int sheetIndex, int row, boolean currentSheet) {
        ParseItem[] operands = getOperands();
        for (int i = 0; i < operands.length; i++) {
            operands[i].rowInserted(sheetIndex, row, currentSheet);
        }
    }

    /**
     * Called when a column is inserted on the specified sheet.  Tells
     * the formula  parser to update all of its cell references beyond this
     * column
     *
     * @param sheetIndex   the sheet on which the row was removed
     * @param row          the row number which was removed
     * @param currentSheet TRUE if this formula is on the sheet in which the
     *                     column was inserted, FALSE otherwise
     */
    void rowRemoved(int sheetIndex, int row, boolean currentSheet) {
        ParseItem[] operands = getOperands();
        for (int i = 0; i < operands.length; i++) {
            operands[i].rowRemoved(sheetIndex, row, currentSheet);
        }
    }

    /**
     * If this formula was on an imported sheet, check that
     * cell references to another sheet are warned appropriately
     * Does nothing, as operators don't have cell references
     */
    void handleImportedCellReferences() {
        ParseItem[] operands = getOperands();
        for (int i = 0; i < operands.length; i++) {
            operands[i].handleImportedCellReferences();
        }
    }

    /**
     * Gets the underlying function
     */
    Function getFunction() {
        return function;
    }

    /**
     * Gets the token representation of this item in RPN
     *
     * @return the bytes applicable to this formula
     */
    byte[] getBytes() {
        handleSpecialCases();

        // Get the data for the operands - in the correct order
        ParseItem[] operands = getOperands();
        byte[] data = new byte[0];

        for (int i = 0; i < operands.length; i++) {
            byte[] opdata = operands[i].getBytes();

            // Grow the array
            byte[] newdata = new byte[data.length + opdata.length];
            System.arraycopy(data, 0, newdata, 0, data.length);
            System.arraycopy(opdata, 0, newdata, data.length, opdata.length);
            data = newdata;
        }

        // Add on the operator byte
        byte[] newdata = new byte[data.length + 4];
        System.arraycopy(data, 0, newdata, 0, data.length);
        newdata[data.length] = !useAlternateCode() ?
                Token.FUNCTIONVARARG.getCode() : Token.FUNCTIONVARARG.getCode2();
        newdata[data.length + 1] = (byte) arguments;
        IntegerHelper.getTwoBytes(function.getCode(), newdata, data.length + 2);

        return newdata;
    }

    /**
     * Gets the precedence for this operator.  Operator precedents run from
     * 1 to 5, one being the highest, 5 being the lowest
     *
     * @return the operator precedence
     */
    int getPrecedence() {
        return 3;
    }

    /**
     * Handles functions which form a special case
     */
    private void handleSpecialCases() {
        // Handle the array functions.  Tell all the Area records to
        // use their alternative token code
        if (function == Function.SUMPRODUCT) {
            // Get the data for the operands - in reverse order
            ParseItem[] operands = getOperands();

            for (int i = operands.length - 1; i >= 0; i--) {
                if (operands[i] instanceof Area) {
                    operands[i].setAlternateCode();
                }
            }
        }
    }
}
 

