/*
 * 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
 *
 *      https://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.text.DateFormat;
import java.text.NumberFormat;
import java.text.ParseException;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

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.
 */
public class GenericTypeValidator implements Serializable {

    private static final Log LOG = LogFactory.getLog(GenericTypeValidator.class);
    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(final String value) {
        if (value == null) {
            return null;
        }
        try {
            return Byte.valueOf(value);
        } catch (final 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(final String value, final Locale locale) {
        Byte result = null;
        if (value != null) {
            final ParsePosition pos = new ParsePosition(0);
            final Number num = getIntegerOnlyFormat(locale).parse(value, pos);
            // parseIntegerOnly only stops at the decimal separator, so a fractional value written with a negative
            // exponent and no decimal point (for example "15E-1" for 1.5) is consumed in full and returned as a
            // Double; byteValue() would floor it. NumberFormat returns a Long only for a non-fractional value in
            // long range, so guard on that before the byte range check, matching formatLong.
            if (pos.getIndex() == value.length() && num instanceof Long) {
                final long longValue = (Long) num;
                if (longValue >= Byte.MIN_VALUE && longValue <= Byte.MAX_VALUE) {
                    result = Byte.valueOf((byte) longValue);
                }
            }
        }
        return result;
    }

    /**
     * Checks if the field is a valid credit card number.
     *
     * <p>
     * Reference Sean M. Burke's <a href="https://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(final String value) {
        return GenericValidator.isCreditCard(value) ? Long.valueOf(value) : null;
    }

    /**
     * Checks if the field is a valid date.
     *
     * <p>
     * The {@link Locale} is used with {@link DateFormat}. The {@link java.text.DateFormat#setLenient(boolean)} method is set to {@code false} 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(final String value, final Locale locale) {
        Date date = null;
        if (value == null) {
            return null;
        }
        try {
            // Get the formatters to check against
            final DateFormat formatterShort = DateFormat.getDateInstance(DateFormat.SHORT, Validator.toLocale(locale));
            final DateFormat formatterDefault = DateFormat.getDateInstance(DateFormat.DEFAULT, Validator.toLocale(locale));
            // Turn off lenient parsing
            formatterShort.setLenient(false);
            formatterDefault.setLenient(false);
            // Firstly, try with the short form
            try {
                date = formatterShort.parse(value);
            } catch (final ParseException e) {
                // Fall back on the default one
                date = formatterDefault.parse(value);
            }
        } catch (final ParseException e) {
            // Bad date, so LOG and return null
            if (LOG.isDebugEnabled()) {
                LOG.debug("Date parse failed value=[" + value + "], " + "locale=[" + locale + "] " + e);
            }
        }
        return date;
    }

    /**
     * Checks if the field is a valid date.
     *
     * <p>
     * The pattern is used with {@link SimpleDateFormat}. 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 {@link java.text.SimpleDateFormat#setLenient(boolean)} method is set to
     * {@code false} for all.
     * </p>
     *
     * @param value       The value validation is being performed on.
     * @param datePattern The pattern passed to {@link SimpleDateFormat}.
     * @param strict      Whether or not to have an exact match of the datePattern.
     * @return The converted Date value.
     */
    public static Date formatDate(final String value, final String datePattern, final boolean strict) {
        if (value == null || datePattern == null || datePattern.isEmpty()) {
            return null;
        }
        final SimpleDateFormat formatter = new SimpleDateFormat(datePattern);
        formatter.setLenient(false);
        final ParsePosition pos = new ParsePosition(0);
        Date date = formatter.parse(value, pos);
        // parse(String, ParsePosition) stops at the first unparsable character instead of failing, so a strict
        // match must also confirm the whole value was consumed; otherwise trailing text such as the 'f' in
        // "11/11/199f" is dropped and the truncated date validates.
        if (date != null && strict && (pos.getIndex() < value.length() || datePattern.length() != value.length())) {
            date = null;
        }
        return date;
    }

    /**
     * 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(final String value) {
        if (value == null) {
            return null;
        }
        try {
            return Double.valueOf(value);
        } catch (final 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(final String value, final Locale locale) {
        Double result = null;
        if (value != null) {
            final ParsePosition pos = new ParsePosition(0);
            final Number num = getNumberFormat(locale).parse(value, pos);
            // If there was no error and we used the whole string
            if (pos.getErrorIndex() == -1 && pos.getIndex() == value.length() && num.doubleValue() >= Double.MAX_VALUE * -1
                    && num.doubleValue() <= Double.MAX_VALUE) {
                result = Double.valueOf(num.doubleValue());
            }
        }
        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(final String value) {
        if (value == null) {
            return null;
        }
        try {
            return Float.valueOf(value);
        } catch (final 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(final String value, final Locale locale) {
        Float result = null;
        if (value != null) {
            final ParsePosition pos = new ParsePosition(0);
            final Number num = getNumberFormat(locale).parse(value, pos);
            // If there was no error and we used the whole string
            if (pos.getErrorIndex() == -1 && pos.getIndex() == value.length() && num.doubleValue() >= Float.MAX_VALUE * -1
                    && num.doubleValue() <= Float.MAX_VALUE) {
                result = Float.valueOf(num.floatValue());
            }
        }
        return result;
    }

    /**
     * Checks if the value can safely be converted to an int primitive.
     *
     * @param value The value validation is being performed on.
     * @return The converted Integer value.
     */
    public static Integer formatInt(final String value) {
        if (value == null) {
            return null;
        }
        try {
            return Integer.valueOf(value);
        } catch (final 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(final String value, final Locale locale) {
        Integer result = null;
        if (value != null) {
            final NumberFormat formatter = getIntegerOnlyFormat(locale);
            final ParsePosition pos = new ParsePosition(0);
            final Number num = formatter.parse(value, pos);
            // parseIntegerOnly only stops at the decimal separator, so a fractional value written with a negative
            // exponent and no decimal point (for example "15E-1" for 1.5) is consumed in full and returned as a
            // Double; intValue() would floor it. NumberFormat returns a Long only for a non-fractional value in
            // long range, so guard on that before the int range check, matching formatLong.
            if (pos.getIndex() == value.length() && num instanceof Long) {
                final long longValue = (Long) num;
                if (longValue >= Integer.MIN_VALUE && longValue <= Integer.MAX_VALUE) {
                    result = Integer.valueOf((int) longValue);
                }
            }
        }
        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(final String value) {
        if (value == null) {
            return null;
        }
        try {
            return Long.valueOf(value);
        } catch (final 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(final String value, final Locale locale) {
        Long result = null;
        if (value != null) {
            final NumberFormat formatter = getIntegerOnlyFormat(locale);
            final ParsePosition pos = new ParsePosition(0);
            final Number num = formatter.parse(value, pos);
            // If we used the whole string and the value fits in a long.
            // NumberFormat returns a Long only when the value fits in a long;
            // out-of-range input is returned as a Double, so a doubleValue()
            // range check cannot be used here (Long.MAX_VALUE is not exactly
            // representable as a double and would let 2^63 through). A failed
            // parse returns null, so the instanceof check also covers it and
            // the pos.getErrorIndex() test is no longer needed.
            if (pos.getIndex() == value.length() && num instanceof Long) {
                result = (Long) num;
            }
        }
        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(final String value) {
        if (value == null) {
            return null;
        }
        try {
            return Short.valueOf(value);
        } catch (final 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)
     * @return The converted Short value.
     */
    public static Short formatShort(final String value, final Locale locale) {
        Short result = null;
        if (value != null) {
            final NumberFormat formatter = getIntegerOnlyFormat(locale);
            final ParsePosition pos = new ParsePosition(0);
            final Number num = formatter.parse(value, pos);
            // parseIntegerOnly only stops at the decimal separator, so a fractional value written with a negative
            // exponent and no decimal point (for example "15E-1" for 1.5) is consumed in full and returned as a
            // Double; shortValue() would floor it. NumberFormat returns a Long only for a non-fractional value in
            // long range, so guard on that before the short range check, matching formatLong.
            if (pos.getIndex() == value.length() && num instanceof Long) {
                final long longValue = (Long) num;
                if (longValue >= Short.MIN_VALUE && longValue <= Short.MAX_VALUE) {
                    result = Short.valueOf((short) longValue);
                }
            }
        }
        return result;
    }

    private static NumberFormat getIntegerOnlyFormat(final Locale locale) {
        final NumberFormat formatter = NumberFormat.getNumberInstance(Validator.toLocale(locale));
        formatter.setParseIntegerOnly(true);
        return formatter;
    }

    private static NumberFormat getNumberFormat(final Locale locale) {
        return NumberFormat.getInstance(Validator.toLocale(locale));
    }

    /**
     * Constructs a new instance.
     *
     * @deprecated Will be private in the next major version.
     */
    @Deprecated
    public GenericTypeValidator() {
        // empty
    }
}