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/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file:

 *

 * Copyright (c) 2008-2012, Stephen Colebourne & Michael Nascimento Santos

 *

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 *  * Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

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 *  * Neither the name of JSR-310 nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

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 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

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 */

package java.time.format;

import java.text.DecimalFormatSymbols;

import java.util.Collections;

import java.util.HashSet;

import java.util.Locale;

import java.util.Objects;

import java.util.Set;

import java.util.concurrent.ConcurrentHashMap;

import java.util.concurrent.ConcurrentMap;

/**

 * Localized decimal style used in date and time formatting.

 * <p>

 * A significant part of dealing with dates and times is the localization.

 * This class acts as a central point for accessing the information.

 *

 * @implSpec

 * This class is immutable and thread-safe.

 *

 * @since 1.8

 */

public final class DecimalStyle {

    /**

     * The standard set of non-localized decimal style symbols.

     * <p>

     * This uses standard ASCII characters for zero, positive, negative and a dot for the decimal point.

     */

    public static final DecimalStyle STANDARD = new DecimalStyle('0', '+', '-', '.');

    /**

     * The cache of DecimalStyle instances.

     */

    private static final ConcurrentMap<Locale, DecimalStyle> CACHE = new ConcurrentHashMap<>(16, 0.75f, 2);

    /**

     * The zero digit.

     */

    private final char zeroDigit;

    /**

     * The positive sign.

     */

    private final char positiveSign;

    /**

     * The negative sign.

     */

    private final char negativeSign;

    /**

     * The decimal separator.

     */

    private final char decimalSeparator;

    //-----------------------------------------------------------------------

    /**

     * Lists all the locales that are supported.

     * <p>

     * The locale 'en_US' will always be present.

     *

     * @return a Set of Locales for which localization is supported

     */

    public static Set<Locale> getAvailableLocales() {

        Locale[] l = DecimalFormatSymbols.getAvailableLocales();

        Set<Locale> locales = new HashSet<>(l.length);

        Collections.addAll(locales, l);

        return locales;

    }

    /**

     * Obtains the DecimalStyle for the default

     * {@link java.util.Locale.Category#FORMAT FORMAT} locale.

     * <p>

     * This method provides access to locale sensitive decimal style symbols.

     * <p>

     * This is equivalent to calling

     * {@link #of(Locale)

     *     of(Locale.getDefault(Locale.Category.FORMAT))}.

     *

     * @see java.util.Locale.Category#FORMAT

     */

    public static DecimalStyle ofDefaultLocale() {

        return of(Locale.getDefault(Locale.Category.FORMAT));

    }

    /**

     * Obtains the DecimalStyle for the specified locale.

     * <p>

     * This method provides access to locale sensitive decimal style symbols.

     *

     * @param locale  the locale, not null

     */

    public static DecimalStyle of(Locale locale) {

        Objects.requireNonNull(locale, "locale");

        DecimalStyle info = CACHE.get(locale);

        if (info == null) {

            info = create(locale);

            CACHE.putIfAbsent(locale, info);

            info = CACHE.get(locale);

        }

        return info;

    }

    private static DecimalStyle create(Locale locale) {

        DecimalFormatSymbols oldSymbols = DecimalFormatSymbols.getInstance(locale);

        char zeroDigit = oldSymbols.getZeroDigit();

        char positiveSign = '+';

        char negativeSign = oldSymbols.getMinusSign();

        char decimalSeparator = oldSymbols.getDecimalSeparator();

        if (zeroDigit == '0' && negativeSign == '-' && decimalSeparator == '.') {

            return STANDARD;

        }

        return new DecimalStyle(zeroDigit, positiveSign, negativeSign, decimalSeparator);

    }

    //-----------------------------------------------------------------------

    /**

     * Restricted constructor.

     *

     * @param zeroChar  the character to use for the digit of zero

     * @param positiveSignChar  the character to use for the positive sign

     * @param negativeSignChar  the character to use for the negative sign

     * @param decimalPointChar  the character to use for the decimal point

     */

    private DecimalStyle(char zeroChar, char positiveSignChar, char negativeSignChar, char decimalPointChar) {

        this.zeroDigit = zeroChar;

        this.positiveSign = positiveSignChar;

        this.negativeSign = negativeSignChar;

        this.decimalSeparator = decimalPointChar;

    }

    //-----------------------------------------------------------------------

    /**

     * Gets the character that represents zero.

     * <p>

     * The character used to represent digits may vary by culture.

     * This method specifies the zero character to use, which implies the characters for one to nine.

     *

     * @return the character for zero

     */

    public char getZeroDigit() {

        return zeroDigit;

    }

    /**

     * Returns a copy of the info with a new character that represents zero.

     * <p>

     * The character used to represent digits may vary by culture.

     * This method specifies the zero character to use, which implies the characters for one to nine.

     *

     * @param zeroDigit  the character for zero

     * @return  a copy with a new character that represents zero, not null

     */

    public DecimalStyle withZeroDigit(char zeroDigit) {

        if (zeroDigit == this.zeroDigit) {

            return this;

        }

        return new DecimalStyle(zeroDigit, positiveSign, negativeSign, decimalSeparator);

    }

    //-----------------------------------------------------------------------

    /**

     * Gets the character that represents the positive sign.

     * <p>

     * The character used to represent a positive number may vary by culture.

     * This method specifies the character to use.

     *

     * @return the character for the positive sign

     */

    public char getPositiveSign() {

        return positiveSign;

    }

    /**

     * Returns a copy of the info with a new character that represents the positive sign.

     * <p>

     * The character used to represent a positive number may vary by culture.

     * This method specifies the character to use.

     *

     * @param positiveSign  the character for the positive sign

     * @return  a copy with a new character that represents the positive sign, not null

     */

    public DecimalStyle withPositiveSign(char positiveSign) {

        if (positiveSign == this.positiveSign) {

            return this;

        }

        return new DecimalStyle(zeroDigit, positiveSign, negativeSign, decimalSeparator);

    }

    //-----------------------------------------------------------------------

    /**

     * Gets the character that represents the negative sign.

     * <p>

     * The character used to represent a negative number may vary by culture.

     * This method specifies the character to use.

     *

     * @return the character for the negative sign

     */

    public char getNegativeSign() {

        return negativeSign;

    }

    /**

     * Returns a copy of the info with a new character that represents the negative sign.

     * <p>

     * The character used to represent a negative number may vary by culture.

     * This method specifies the character to use.

     *

     * @param negativeSign  the character for the negative sign

     * @return  a copy with a new character that represents the negative sign, not null

     */

    public DecimalStyle withNegativeSign(char negativeSign) {

        if (negativeSign == this.negativeSign) {

            return this;

        }

        return new DecimalStyle(zeroDigit, positiveSign, negativeSign, decimalSeparator);

    }

    //-----------------------------------------------------------------------

    /**

     * Gets the character that represents the decimal point.

     * <p>

     * The character used to represent a decimal point may vary by culture.

     * This method specifies the character to use.

     *

     * @return the character for the decimal point

     */

    public char getDecimalSeparator() {

        return decimalSeparator;

    }

    /**

     * Returns a copy of the info with a new character that represents the decimal point.

     * <p>

     * The character used to represent a decimal point may vary by culture.

     * This method specifies the character to use.

     *

     * @param decimalSeparator  the character for the decimal point

     * @return  a copy with a new character that represents the decimal point, not null

     */

    public DecimalStyle withDecimalSeparator(char decimalSeparator) {

        if (decimalSeparator == this.decimalSeparator) {

            return this;

        }

        return new DecimalStyle(zeroDigit, positiveSign, negativeSign, decimalSeparator);

    }

    //-----------------------------------------------------------------------

    /**

     * Checks whether the character is a digit, based on the currently set zero character.

     *

     * @param ch  the character to check

     * @return the value, 0 to 9, of the character, or -1 if not a digit

     */

    int convertToDigit(char ch) {

        int val = ch - zeroDigit;

        return (val >= 0 && val <= 9) ? val : -1;

    }

    /**

     * Converts the input numeric text to the internationalized form using the zero character.

     *

     * @param numericText  the text, consisting of digits 0 to 9, to convert, not null

     * @return the internationalized text, not null

     */

    String convertNumberToI18N(String numericText) {

        if (zeroDigit == '0') {

            return numericText;

        }

        int diff = zeroDigit - '0';

        char[] array = numericText.toCharArray();

        for (int i = 0; i < array.length; i++) {

            array[i] = (char) (array[i] + diff);

        }

        return new String(array);

    }

    //-----------------------------------------------------------------------

    /**

     *

     * @param obj  the object to check, null returns false

     * @return true if this is equal to the other date

     */

    @Override

    public boolean equals(Object obj) {

        if (this == obj) {

            return true;

        }

        if (obj instanceof DecimalStyle) {

            DecimalStyle other = (DecimalStyle) obj;

            return (zeroDigit == other.zeroDigit && positiveSign == other.positiveSign &&

                    negativeSign == other.negativeSign && decimalSeparator == other.decimalSeparator);

        }

        return false;

    }

    /**

     * A hash code for this DecimalStyle.

     *

     * @return a suitable hash code

     */

    @Override

    public int hashCode() {

        return zeroDigit + positiveSign + negativeSign + decimalSeparator;

    }

    //-----------------------------------------------------------------------

    /**

     * Returns a string describing this DecimalStyle.

     *

     * @return a string description, not null

     */

    @Override

    public String toString() {

        return "DecimalStyle[" + zeroDigit + positiveSign + negativeSign + decimalSeparator + "]";

    }

}