/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * 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
 * 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 org.apache.commons.validator;

import java.io.Serializable;
import java.util.Date;
import java.util.Locale;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.text.NumberFormat;
import java.text.ParseException;
import java.text.ParsePosition;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 *  This class contains basic methods for performing validations that return the
 *  correctly typed class based on the validation performed.
 *
 * @version $Revision: 1227719 $ $Date: 2012-01-05 12:45:51 -0500 (Thu, 05 Jan 2012) $
 */
public class GenericTypeValidator implements Serializable {

    private static final long serialVersionUID = 5487162314134261703L;

    /**
     *  Checks if the value can safely be converted to a byte primitive.
     *
     *@param  value  The value validation is being performed on.
     *@return the converted Byte value.
     */
    public static Byte formatByte(String value) {
        if (value == null) {
            return null;
        }

        try {
            return new Byte(value);
        } catch (NumberFormatException e) {
            return null;
        }

    }

    /**
     *  Checks if the value can safely be converted to a byte primitive.
     *
     *@param  value   The value validation is being performed on.
     *@param  locale  The locale to use to parse the number (system default if
     *      null)
     *@return the converted Byte value.
     */
    public static Byte formatByte(String value, Locale locale) {
        Byte result = null;

        if (value != null) {
            NumberFormat formatter = null;
            if (locale != null) {
                formatter = NumberFormat.getNumberInstance(locale);
            } else {
                formatter = NumberFormat.getNumberInstance(Locale.getDefault());
            }
            formatter.setParseIntegerOnly(true);
            ParsePosition pos = new ParsePosition(0);
            Number num = formatter.parse(value, pos);

            // If there was no error      and we used the whole string
            if (pos.getErrorIndex() == -1 && pos.getIndex() == value.length()) {
                if (num.doubleValue() >= Byte.MIN_VALUE &&
                    num.doubleValue() <= Byte.MAX_VALUE) {
                    result = new Byte(num.byteValue());
                }
            }
        }

        return result;
    }

    /**
     *  Checks if the value can safely be converted to a short primitive.
     *
     *@param  value  The value validation is being performed on.
     *@return the converted Short value.
     */
    public static Short formatShort(String value) {
        if (value == null) {
            return null;
        }

        try {
            return new Short(value);
        } catch (NumberFormatException e) {
            return null;
        }

    }

    /**
     *  Checks if the value can safely be converted to a short primitive.
     *
     *@param  value   The value validation is being performed on.
     *@param  locale  The locale to use to parse the number (system default if
     *      null)vv
     *@return the converted Short value.
     */
    public static Short formatShort(String value, Locale locale) {
        Short result = null;

        if (value != null) {
            NumberFormat formatter = null;
            if (locale != null) {
                formatter = NumberFormat.getNumberInstance(locale);
            } else {
                formatter = NumberFormat.getNumberInstance(Locale.getDefault());
            }
            formatter.setParseIntegerOnly(true);
            ParsePosition pos = new ParsePosition(0);
            Number num = formatter.parse(value, pos);

            // If there was no error      and we used the whole string
            if (pos.getErrorIndex() == -1 && pos.getIndex() == value.length()) {
                if (num.doubleValue() >= Short.MIN_VALUE &&
                    num.doubleValue() <= Short.MAX_VALUE) {
                    result = new Short(num.shortValue());
                }
            }
        }

        return result;
    }

    /**
     *  Checks if the value can safely be converted to a int primitive.
     *
     *@param  value  The value validation is being performed on.
     *@return the converted Integer value.
     */
    public static Integer formatInt(String value) {
        if (value == null) {
            return null;
        }

        try {
            return new Integer(value);
        } catch (NumberFormatException e) {
            return null;
        }

    }

    /**
     *  Checks if the value can safely be converted to an int primitive.
     *
     *@param  value   The value validation is being performed on.
     *@param  locale  The locale to use to parse the number (system default if
     *      null)
     *@return the converted Integer value.
     */
    public static Integer formatInt(String value, Locale locale) {
        Integer result = null;

        if (value != null) {
            NumberFormat formatter = null;
            if (locale != null) {
                formatter = NumberFormat.getNumberInstance(locale);
            } else {
                formatter = NumberFormat.getNumberInstance(Locale.getDefault());
            }
            formatter.setParseIntegerOnly(true);
            ParsePosition pos = new ParsePosition(0);
            Number num = formatter.parse(value, pos);

            // If there was no error      and we used the whole string
            if (pos.getErrorIndex() == -1 && pos.getIndex() == value.length()) {
                if (num.doubleValue() >= Integer.MIN_VALUE &&
                    num.doubleValue() <= Integer.MAX_VALUE) {
                    result = new Integer(num.intValue());
                }
            }
        }

        return result;
    }

    /**
     *  Checks if the value can safely be converted to a long primitive.
     *
     *@param  value  The value validation is being performed on.
     *@return the converted Long value.
     */
    public static Long formatLong(String value) {
        if (value == null) {
            return null;
        }

        try {
            return new Long(value);
        } catch (NumberFormatException e) {
            return null;
        }

    }

    /**
     *  Checks if the value can safely be converted to a long primitive.
     *
     *@param  value   The value validation is being performed on.
     *@param  locale  The locale to use to parse the number (system default if
     *      null)
     *@return the converted Long value.
     */
    public static Long formatLong(String value, Locale locale) {
        Long result = null;

        if (value != null) {
            NumberFormat formatter = null;
            if (locale != null) {
                formatter = NumberFormat.getNumberInstance(locale);
            } else {
                formatter = NumberFormat.getNumberInstance(Locale.getDefault());
            }
            formatter.setParseIntegerOnly(true);
            ParsePosition pos = new ParsePosition(0);
            Number num = formatter.parse(value, pos);

            // If there was no error      and we used the whole string
            if (pos.getErrorIndex() == -1 && pos.getIndex() == value.length()) {
                if (num.doubleValue() >= Long.MIN_VALUE &&
                    num.doubleValue() <= Long.MAX_VALUE) {
                    result = new Long(num.longValue());
                }
            }
        }

        return result;
    }

    /**
     *  Checks if the value can safely be converted to a float primitive.
     *
     *@param  value  The value validation is being performed on.
     *@return the converted Float value.
     */
    public static Float formatFloat(String value) {
        if (value == null) {
            return null;
        }

        try {
            return new Float(value);
        } catch (NumberFormatException e) {
            return null;
        }

    }

    /**
     *  Checks if the value can safely be converted to a float primitive.
     *
     *@param  value   The value validation is being performed on.
     *@param  locale  The locale to use to parse the number (system default if
     *      null)
     *@return the converted Float value.
     */
    public static Float formatFloat(String value, Locale locale) {
        Float result = null;

        if (value != null) {
            NumberFormat formatter = null;
            if (locale != null) {
                formatter = NumberFormat.getInstance(locale);
            } else {
                formatter = NumberFormat.getInstance(Locale.getDefault());
            }
            ParsePosition pos = new ParsePosition(0);
            Number num = formatter.parse(value, pos);

            // If there was no error      and we used the whole string
            if (pos.getErrorIndex() == -1 && pos.getIndex() == value.length()) {
                if (num.doubleValue() >= (Float.MAX_VALUE * -1) &&
                    num.doubleValue() <= Float.MAX_VALUE) {
                    result = new Float(num.floatValue());
                }
            }
        }

        return result;
    }

    /**
     *  Checks if the value can safely be converted to a double primitive.
     *
     *@param  value  The value validation is being performed on.
     *@return the converted Double value.
     */
    public static Double formatDouble(String value) {
        if (value == null) {
            return null;
        }

        try {
            return new Double(value);
        } catch (NumberFormatException e) {
            return null;
        }

    }

    /**
     *  Checks if the value can safely be converted to a double primitive.
     *
     *@param  value   The value validation is being performed on.
     *@param  locale  The locale to use to parse the number (system default if
     *      null)
     *@return the converted Double value.
     */
    public static Double formatDouble(String value, Locale locale) {
        Double result = null;

        if (value != null) {
            NumberFormat formatter = null;
            if (locale != null) {
                formatter = NumberFormat.getInstance(locale);
            } else {
                formatter = NumberFormat.getInstance(Locale.getDefault());
            }
            ParsePosition pos = new ParsePosition(0);
            Number num = formatter.parse(value, pos);

            // If there was no error      and we used the whole string
            if (pos.getErrorIndex() == -1 && pos.getIndex() == value.length()) {
                if (num.doubleValue() >= (Double.MAX_VALUE * -1) &&
                    num.doubleValue() <= Double.MAX_VALUE) {
                    result = new Double(num.doubleValue());
                }
            }
        }

        return result;
    }

    /**
     *  <p>
     *
     *  Checks if the field is a valid date. The <code>Locale</code> is used
     *  with <code>java.text.DateFormat</code>. The setLenient method is set to
     *  <code>false</code> for all.</p>
     *
     *@param  value   The value validation is being performed on.
     *@param  locale  The Locale to use to parse the date (system default if
     *      null)
     *@return the converted Date value.
     */
    public static Date formatDate(String value, Locale locale) {
        Date date = null;

        if (value == null) {
            return null;
        }

        try {
            // Get the formatters to check against
            DateFormat formatterShort = null;
            DateFormat formatterDefault = null;
            if (locale != null) {
                formatterShort =
                   DateFormat.getDateInstance(DateFormat.SHORT, locale);
                formatterDefault =
                   DateFormat.getDateInstance(DateFormat.DEFAULT, locale);
            } else {
                formatterShort =
                    DateFormat.getDateInstance(
                    DateFormat.SHORT,
                    Locale.getDefault());
                formatterDefault =
                   DateFormat.getDateInstance(
                   DateFormat.DEFAULT,
                   Locale.getDefault());
            }

            // Turn off lenient parsing
            formatterShort.setLenient(false);
            formatterDefault.setLenient(false);

            // Firstly, try with the short form
            try {
               date = formatterShort.parse(value);
            } catch (ParseException e) {
               // Fall back on the default one
               date = formatterDefault.parse(value);
            }
        } catch (ParseException e) {
            // Bad date, so log and return null
            Log log = LogFactory.getLog(GenericTypeValidator.class);
            if (log.isDebugEnabled()) {
                log.debug("Date parse failed value=[" + value  + "], " +
                                           "locale=[" + locale + "] "  + e);
            }
        }

        return date;
    }

    /**
     *  <p>
     *  Checks if the field is a valid date. The pattern is used with <code>java.text.SimpleDateFormat</code>
     *  . If strict is true, then the length will be checked so '2/12/1999' will
     *  not pass validation with the format 'MM/dd/yyyy' because the month isn't
     *  two digits. The setLenient method is set to <code>false</code> for all.
     *  </p>
     *
     *@param  value        The value validation is being performed on.
     *@param  datePattern  The pattern passed to <code>SimpleDateFormat</code>.
     *@param  strict       Whether or not to have an exact match of the
     *      datePattern.
     *@return the converted Date value.
     */
    public static Date formatDate(String value, String datePattern, boolean strict) {
        Date date = null;

        if (value == null
             || datePattern == null
             || datePattern.length() == 0) {
            return null;
        }

        try {
            SimpleDateFormat formatter = new SimpleDateFormat(datePattern);
            formatter.setLenient(false);

            date = formatter.parse(value);

            if (strict) {
                if (datePattern.length() != value.length()) {
                    date = null;
                }
            }
        } catch (ParseException e) {
            // Bad date so return null
            Log log = LogFactory.getLog(GenericTypeValidator.class);
            if (log.isDebugEnabled()) {
                log.debug("Date parse failed value=[" + value       + "], " +
                                          "pattern=[" + datePattern + "], " +
                                           "strict=[" + strict      + "] "  + e);
            }
        }

        return date;
    }

    /**
     *  <p>
     *  Checks if the field is a valid credit card number.</p> <p>
     *
     *  Reference Sean M. Burke's <a href="http://www.ling.nwu.edu/~sburke/pub/luhn_lib.pl">
     *  script</a> .</p>
     *
     *@param  value  The value validation is being performed on.
     *@return the converted Credit Card number.
     */
    public static Long formatCreditCard(String value) {
        return GenericValidator.isCreditCard(value) ? new Long(value) : null;
    }

}