/*
 * Copyright 2003-2005 The Apache Software Foundation
 * Copyright 2005 Stephen McConnell
 *
 * 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 net.dpml.cli.validation;

import java.text.NumberFormat;
import java.text.ParsePosition;

import java.util.List;
import java.util.ListIterator;

import net.dpml.cli.resource.ResourceConstants;
import net.dpml.cli.resource.ResourceHelper;

/**
 * The <code>NumberValidator</code> validates the string argument
 * values are numbers.  If the value is a number, the string value in
 * the {@link java.util.List} of values is replaced with the
 * {@link java.lang.Number} instance.
 *
 * A maximum and minimum value can also be specified using
 * the {@link #setMaximum setMaximum}, and the
 * {@link #setMinimum setMinimum} methods.
 *
 * The following example shows how to limit the valid values
 * for the age attribute to integers less than 100.
 *
 * <pre>
 * ...
 * ArgumentBuilder builder = new ArgumentBuilder();
 * NumberValidator validator = NumberValidator.getIntegerInstance();
 * validator.setMaximum(new Integer(100));
 *
 * Argument age =
 *     builder.withName("age");
 *            .withValidator(validator);
 * </pre>
 *
 * @author <a href="@PUBLISHER-URL@">@PUBLISHER-NAME@</a>
 * @version @PROJECT-VERSION@
 */
public class NumberValidator implements Validator
{
    /** the <code>NumberFormat</code> being used. */
    private NumberFormat m_format;

    /** the lower bound for argument values. */
    private Number m_minimum = null;

    /** the upper bound for argument values */
    private Number m_maximum = null;

    /**
     * Creates a new NumberValidator based on the specified NumberFormat
     * @param format the format of numbers to accept
     */
    public NumberValidator( final NumberFormat format ) 
    {
        setFormat( format );
    }

    /**
     * Returns a <code>NumberValidator</code> for a currency format
     * for the current default locale.
     * @return a <code>NumberValidator</code> for a currency format
     * for the current default locale.
     */
    public static NumberValidator getCurrencyInstance() 
    {
        return new NumberValidator( NumberFormat.getCurrencyInstance() );
    }

    /**
     * Returns a <code>NumberValidator</code> for an integer number format
     * for the current default locale.
     * @return a <code>NumberValidator</code> for an integer number format
     * for the current default locale.
     */
    public static NumberValidator getIntegerInstance()
    {
        final NumberFormat format = NumberFormat.getNumberInstance();
        format.setParseIntegerOnly( true );
        return new NumberValidator( format );
    }

    /**
     * Returns a <code>NumberValidator</code> for a percentage format
     * for the current default locale.
     * @return a <code>NumberValidator</code> for a percentage format
     * for the current default locale.
     */
    public static NumberValidator getPercentInstance() 
    {
        return new NumberValidator( NumberFormat.getPercentInstance() );
    }

    /**
     * Returns a <code>NumberValidator</code> for a general-purpose
     * number format for the current default locale.
     * @return a <code>NumberValidator</code> for a general-purpose
     * number format for the current default locale.
     */
    public static NumberValidator getNumberInstance()
    {
        return new NumberValidator( NumberFormat.getNumberInstance() );
    }

   /**
    * Validate the list of values against the list of permitted values.
    * If a value is valid, replace the string in the <code>values</code>
    * {@link java.util.List} with the {@link java.lang.Number} instance.
    *
    * @param values the list of values to validate 
    * @exception InvalidArgumentException if a value is invalid
    * @see net.dpml.cli.validation.Validator#validate(java.util.List)
    */
    public void validate( final List values ) throws InvalidArgumentException 
    {
        for( final ListIterator i = values.listIterator(); i.hasNext();) 
        {
            final Object next = i.next();
            if( next instanceof Number )
            {
                return;
            }
            final String value = (String) next;
            final ParsePosition pp = new ParsePosition( 0 );
            final Number number = m_format.parse( value, pp );
            if( pp.getIndex() < value.length() )
            {
                throw new InvalidArgumentException( value );
            }
            if(
              ( ( m_minimum != null ) && ( number.doubleValue() < m_minimum.doubleValue() ) ) 
              || ( ( m_maximum != null ) && ( number.doubleValue() > m_maximum.doubleValue() ) )
            ) 
            {
                throw new InvalidArgumentException(
                  ResourceHelper.getResourceHelper().getMessage(
                    ResourceConstants.NUMBERVALIDATOR_NUMBER_OUTOFRANGE,
                    new Object[]{value} ) );
            }
            i.set( number );
        }
    }

    /**
     * Return the format being used to validate argument values against.
     *
     * @return the format being used to validate argument values against.
     */
    public NumberFormat getFormat() 
    {
        return m_format;
    }

    /**
     * Specify the format being used to validate argument values against.
     *
     * @param format the format being used to validate argument values against.
     */
    protected void setFormat( NumberFormat format ) 
    {
        m_format = format;
    }

    /**
     * Return the maximum value allowed for an argument value.
     *
     * @return the maximum value allowed for an argument value.
     */
    public Number getMaximum() 
    {
        return m_maximum;
    }

    /**
     * Specify the maximum value allowed for an argument value.
     *
     * @param maximum the maximum value allowed for an argument value.
     */
    public void setMaximum( Number maximum )
    {
        m_maximum = maximum;
    }

    /**
     * Return the minimum value allowed for an argument value.
     *
     * @return the minimum value allowed for an argument value.
     */
    public Number getMinimum()
    {
        return m_minimum;
    }

    /**
     * Specify the minimum value allowed for an argument value.
     *
     * @param minimum the minimum value allowed for an argument value.
     */
    public void setMinimum( Number minimum )
    {
        m_minimum = minimum;
    }
}