/*
 * Copyright (C) 2014 The Android Open Source Project
 * Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package java.util;

import java.io.Serializable;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

import libcore.icu.ICU;

// BEGIN Android-changed: Removed docs about superseding runtime currency data.
// Doing so via a properties file is not supported on Android.
/**
 * Represents a currency. Currencies are identified by their ISO 4217 currency
 * codes. Visit the <a href="http://www.iso.org/iso/home/standards/currency_codes.htm">
 * ISO web site</a> for more information.
 * <p>
 * The class is designed so that there's never more than one
 * <code>Currency</code> instance for any given currency. Therefore, there's
 * no public constructor. You obtain a <code>Currency</code> instance using
 * the <code>getInstance</code> methods.
 *
 * @since 1.4
 */
// END Android-changed: Removed docs about superseding runtime currency data.
public final class Currency implements Serializable {

    private static final long serialVersionUID = -158308464356906721L;

    /**
     * ISO 4217 currency code for this currency.
     *
     * @serial
     */
    private final String currencyCode;

    // BEGIN Android-changed: Use ICU.
    // We do not keep track of defaultFractionDigits and numericCode separately.
    /*
    /**
     * Default fraction digits for this currency.
     * Set from currency data tables.
     *
    transient private final int defaultFractionDigits;

    /**
     * ISO 4217 numeric code for this currency.
     * Set from currency data tables.
     *
    transient private final int numericCode;
    */
    private transient final android.icu.util.Currency icuCurrency;
    // END Android-changed: Use ICU.


    // class data: instance map

    private static ConcurrentMap<String, Currency> instances = new ConcurrentHashMap<>(7);
    private static HashSet<Currency> available;

    // BEGIN Android-removed: Use ICU.
    // We don't need any of these static fields nor the static initializer.
    /*
    // Class data: currency data obtained from currency.data file.
    // Purpose:
    // - determine valid country codes
    // - determine valid currency codes
    // - map country codes to currency codes
    // - obtain default fraction digits for currency codes
    //
    // sc = special case; dfd = default fraction digits
    // Simple countries are those where the country code is a prefix of the
    // currency code, and there are no known plans to change the currency.
    //
    // table formats:
    // - mainTable:
    //   - maps country code to 32-bit int
    //   - 26*26 entries, corresponding to [A-Z]*[A-Z]
    //   - \u007F -> not valid country
    //   - bits 20-31: unused
    //   - bits 10-19: numeric code (0 to 1023)
    //   - bit 9: 1 - special case, bits 0-4 indicate which one
    //            0 - simple country, bits 0-4 indicate final char of currency code
    //   - bits 5-8: fraction digits for simple countries, 0 for special cases
    //   - bits 0-4: final char for currency code for simple country, or ID of special case
    // - special case IDs:
    //   - 0: country has no currency
    //   - other: index into sc* arrays + 1
    // - scCutOverTimes: cut-over time in millis as returned by
    //   System.currentTimeMillis for special case countries that are changing
    //   currencies; Long.MAX_VALUE for countries that are not changing currencies
    // - scOldCurrencies: old currencies for special case countries
    // - scNewCurrencies: new currencies for special case countries that are
    //   changing currencies; null for others
    // - scOldCurrenciesDFD: default fraction digits for old currencies
    // - scNewCurrenciesDFD: default fraction digits for new currencies, 0 for
    //   countries that are not changing currencies
    // - otherCurrencies: concatenation of all currency codes that are not the
    //   main currency of a simple country, separated by "-"
    // - otherCurrenciesDFD: decimal format digits for currencies in otherCurrencies, same order

    static int formatVersion;
    static int dataVersion;
    static int[] mainTable;
    static long[] scCutOverTimes;
    static String[] scOldCurrencies;
    static String[] scNewCurrencies;
    static int[] scOldCurrenciesDFD;
    static int[] scNewCurrenciesDFD;
    static int[] scOldCurrenciesNumericCode;
    static int[] scNewCurrenciesNumericCode;
    static String otherCurrencies;
    static int[] otherCurrenciesDFD;
    static int[] otherCurrenciesNumericCode;

    // handy constants - must match definitions in GenerateCurrencyData
    // magic number
    private static final int MAGIC_NUMBER = 0x43757244;
    // number of characters from A to Z
    private static final int A_TO_Z = ('Z' - 'A') + 1;
    // entry for invalid country codes
    private static final int INVALID_COUNTRY_ENTRY = 0x0000007F;
    // entry for countries without currency
    private static final int COUNTRY_WITHOUT_CURRENCY_ENTRY = 0x00000200;
    // mask for simple case country entries
    private static final int SIMPLE_CASE_COUNTRY_MASK = 0x00000000;
    // mask for simple case country entry final character
    private static final int SIMPLE_CASE_COUNTRY_FINAL_CHAR_MASK = 0x0000001F;
    // mask for simple case country entry default currency digits
    private static final int SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_MASK = 0x000001E0;
    // shift count for simple case country entry default currency digits
    private static final int SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_SHIFT = 5;
    // maximum number for simple case country entry default currency digits
    private static final int SIMPLE_CASE_COUNTRY_MAX_DEFAULT_DIGITS = 9;
    // mask for special case country entries
    private static final int SPECIAL_CASE_COUNTRY_MASK = 0x00000200;
    // mask for special case country index
    private static final int SPECIAL_CASE_COUNTRY_INDEX_MASK = 0x0000001F;
    // delta from entry index component in main table to index into special case tables
    private static final int SPECIAL_CASE_COUNTRY_INDEX_DELTA = 1;
    // mask for distinguishing simple and special case countries
    private static final int COUNTRY_TYPE_MASK = SIMPLE_CASE_COUNTRY_MASK | SPECIAL_CASE_COUNTRY_MASK;
    // mask for the numeric code of the currency
    private static final int NUMERIC_CODE_MASK = 0x000FFC00;
    // shift count for the numeric code of the currency
    private static final int NUMERIC_CODE_SHIFT = 10;

    // Currency data format version
    private static final int VALID_FORMAT_VERSION = 2;

    static {
        AccessController.doPrivileged(new PrivilegedAction<Void>() {
            @Override
            public Void run() {
                String homeDir = System.getProperty("java.home");
                try {
                    String dataFile = homeDir + File.separator +
                            "lib" + File.separator + "currency.data";
                    try (DataInputStream dis = new DataInputStream(
                             new BufferedInputStream(
                             new FileInputStream(dataFile)))) {
                        if (dis.readInt() != MAGIC_NUMBER) {
                            throw new InternalError("Currency data is possibly corrupted");
                        }
                        formatVersion = dis.readInt();
                        if (formatVersion != VALID_FORMAT_VERSION) {
                            throw new InternalError("Currency data format is incorrect");
                        }
                        dataVersion = dis.readInt();
                        mainTable = readIntArray(dis, A_TO_Z * A_TO_Z);
                        int scCount = dis.readInt();
                        scCutOverTimes = readLongArray(dis, scCount);
                        scOldCurrencies = readStringArray(dis, scCount);
                        scNewCurrencies = readStringArray(dis, scCount);
                        scOldCurrenciesDFD = readIntArray(dis, scCount);
                        scNewCurrenciesDFD = readIntArray(dis, scCount);
                        scOldCurrenciesNumericCode = readIntArray(dis, scCount);
                        scNewCurrenciesNumericCode = readIntArray(dis, scCount);
                        int ocCount = dis.readInt();
                        otherCurrencies = dis.readUTF();
                        otherCurrenciesDFD = readIntArray(dis, ocCount);
                        otherCurrenciesNumericCode = readIntArray(dis, ocCount);
                    }
                } catch (IOException e) {
                    throw new InternalError(e);
                }

                // look for the properties file for overrides
                String propsFile = System.getProperty("java.util.currency.data");
                if (propsFile == null) {
                    propsFile = homeDir + File.separator + "lib" +
                        File.separator + "currency.properties";
                }
                try {
                    File propFile = new File(propsFile);
                    if (propFile.exists()) {
                        Properties props = new Properties();
                        try (FileReader fr = new FileReader(propFile)) {
                            props.load(fr);
                        }
                        Set<String> keys = props.stringPropertyNames();
                        Pattern propertiesPattern =
                            Pattern.compile("([A-Z]{3})\\s*,\\s*(\\d{3})\\s*,\\s*" +
                                "(\\d+)\\s*,?\\s*(\\d{4}-\\d{2}-\\d{2}T\\d{2}:" +
                                "\\d{2}:\\d{2})?");
                        for (String key : keys) {
                           replaceCurrencyData(propertiesPattern,
                               key.toUpperCase(Locale.ROOT),
                               props.getProperty(key).toUpperCase(Locale.ROOT));
                        }
                    }
                } catch (IOException e) {
                    info("currency.properties is ignored because of an IOException", e);
                }
                return null;
            }
        });
    }

    /**
     * Constants for retrieving localized names from the name providers.
     *
    private static final int SYMBOL = 0;
    private static final int DISPLAYNAME = 1;
    */
    // END Android-removed: Use ICU.

    /**
     * Constructs a <code>Currency</code> instance. The constructor is private
     * so that we can insure that there's never more than one instance for a
     * given currency.
     */
    // BEGIN Android-changed: Use ICU.
    // We do not keep track of defaultFractionDigits and numericCode separately.
    /*
    private Currency(String currencyCode, int defaultFractionDigits, int numericCode) {
        this.currencyCode = currencyCode;
        this.defaultFractionDigits = defaultFractionDigits;
        this.numericCode = numericCode;
    }
    */
    private Currency(android.icu.util.Currency icuCurrency) {
        this.icuCurrency = icuCurrency;
        this.currencyCode = icuCurrency.getCurrencyCode();
    }
    // END Android-changed: Use ICU.

    /**
     * Returns the <code>Currency</code> instance for the given currency code.
     *
     * @param currencyCode the ISO 4217 code of the currency
     * @return the <code>Currency</code> instance for the given currency code
     * @exception NullPointerException if <code>currencyCode</code> is null
     * @exception IllegalArgumentException if <code>currencyCode</code> is not
     * a supported ISO 4217 code.
     */
    public static Currency getInstance(String currencyCode) {
        // BEGIN Android-changed: Use ICU.
        // Upstream uses a private static helper method, implemented differently.
        Currency instance = instances.get(currencyCode);
        if (instance != null) {
            return instance;
        }
        android.icu.util.Currency icuInstance =
                  android.icu.util.Currency.getInstance(currencyCode);
        if (icuInstance == null) {
            return null;
        }
        Currency currencyVal = new Currency(icuInstance);
        // END Android-changed: Use ICU.
        instance = instances.putIfAbsent(currencyCode, currencyVal);
        return (instance != null ? instance : currencyVal);
    }

    /**
     * Returns the <code>Currency</code> instance for the country of the
     * given locale. The language and variant components of the locale
     * are ignored. The result may vary over time, as countries change their
     * currencies. For example, for the original member countries of the
     * European Monetary Union, the method returns the old national currencies
     * until December 31, 2001, and the Euro from January 1, 2002, local time
     * of the respective countries.
     * <p>
     * The method returns <code>null</code> for territories that don't
     * have a currency, such as Antarctica.
     *
     * @param locale the locale for whose country a <code>Currency</code>
     * instance is needed
     * @return the <code>Currency</code> instance for the country of the given
     * locale, or {@code null}
     * @exception NullPointerException if <code>locale</code> or its country
     * code is {@code null}
     * @exception IllegalArgumentException if the country of the given {@code locale}
     * is not a supported ISO 3166 country code.
     */
    public static Currency getInstance(Locale locale) {
        String country = locale.getCountry();
        if (country == null) {
            throw new NullPointerException();
        }

        // BEGIN Android-changed: Use ICU.
        /*
        if (country.length() != 2) {
            throw new IllegalArgumentException();
        }

        char char1 = country.charAt(0);
        char char2 = country.charAt(1);
        int tableEntry = getMainTableEntry(char1, char2);
        if ((tableEntry & COUNTRY_TYPE_MASK) == SIMPLE_CASE_COUNTRY_MASK
                    && tableEntry != INVALID_COUNTRY_ENTRY) {
            char finalChar = (char) ((tableEntry & SIMPLE_CASE_COUNTRY_FINAL_CHAR_MASK) + 'A');
            int defaultFractionDigits = (tableEntry & SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_MASK) >> SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_SHIFT;
            int numericCode = (tableEntry & NUMERIC_CODE_MASK) >> NUMERIC_CODE_SHIFT;
            StringBuilder sb = new StringBuilder(country);
            sb.append(finalChar);
            return getInstance(sb.toString(), defaultFractionDigits, numericCode);
        } else {
            // special cases
            if (tableEntry == INVALID_COUNTRY_ENTRY) {
                throw new IllegalArgumentException();
            }
            if (tableEntry == COUNTRY_WITHOUT_CURRENCY_ENTRY) {
                return null;
            } else {
                int index = (tableEntry & SPECIAL_CASE_COUNTRY_INDEX_MASK) - SPECIAL_CASE_COUNTRY_INDEX_DELTA;
                if (scCutOverTimes[index] == Long.MAX_VALUE || System.currentTimeMillis() < scCutOverTimes[index]) {
                    return getInstance(scOldCurrencies[index], scOldCurrenciesDFD[index],
                        scOldCurrenciesNumericCode[index]);
                } else {
                    return getInstance(scNewCurrencies[index], scNewCurrenciesDFD[index],
                        scNewCurrenciesNumericCode[index]);
                }
            }
        }
        */
        android.icu.util.Currency icuInstance =
                android.icu.util.Currency.getInstance(locale);
        // Unknown historical reason to append variant to country code. The API documentation
        // does not mention the effect of locale variant. The actual effect here is throwing
        // IllegalArgumentException because the code like FR_EURO is not a valid country code.
        String variant = locale.getVariant();
        if (!variant.isEmpty() && (variant.equals("EURO") || variant.equals("HK") ||
                variant.equals("PREEURO"))) {
            country = country + "_" + variant;
        }
        if (!ICU.isIsoCountry(country)) {
            // Throws IllegalArgumentException as required by the API documentation.
            throw new IllegalArgumentException("Unsupported ISO 3166 country: " + locale);
        }
        String currencyCode = ICU.getCurrencyCode(country);
        if (currencyCode == null || icuInstance == null ||
                icuInstance.getCurrencyCode().equals("XXX")) { // XXX is not a real currency.
            return null;
        }
        return getInstance(currencyCode);
        // END Android-changed: Use ICU.
    }

    /**
     * Gets the set of available currencies.  The returned set of currencies
     * contains all of the available currencies, which may include currencies
     * that represent obsolete ISO 4217 codes.  The set can be modified
     * without affecting the available currencies in the runtime.
     *
     * @return the set of available currencies.  If there is no currency
     *    available in the runtime, the returned set is empty.
     * @since 1.7
     */
    public static Set<Currency> getAvailableCurrencies() {
        synchronized(Currency.class) {
            if (available == null) {
                // BEGIN Android-changed: Use ICU.
                /*
                available = new HashSet<>(256);

                // Add simple currencies first
                for (char c1 = 'A'; c1 <= 'Z'; c1 ++) {
                    for (char c2 = 'A'; c2 <= 'Z'; c2 ++) {
                        int tableEntry = getMainTableEntry(c1, c2);
                        if ((tableEntry & COUNTRY_TYPE_MASK) == SIMPLE_CASE_COUNTRY_MASK
                             && tableEntry != INVALID_COUNTRY_ENTRY) {
                            char finalChar = (char) ((tableEntry & SIMPLE_CASE_COUNTRY_FINAL_CHAR_MASK) + 'A');
                            int defaultFractionDigits = (tableEntry & SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_MASK) >> SIMPLE_CASE_COUNTRY_DEFAULT_DIGITS_SHIFT;
                            int numericCode = (tableEntry & NUMERIC_CODE_MASK) >> NUMERIC_CODE_SHIFT;
                            StringBuilder sb = new StringBuilder();
                            sb.append(c1);
                            sb.append(c2);
                            sb.append(finalChar);
                            available.add(getInstance(sb.toString(), defaultFractionDigits, numericCode));
                        }
                    }
                }

                // Now add other currencies
                StringTokenizer st = new StringTokenizer(otherCurrencies, "-");
                while (st.hasMoreElements()) {
                    available.add(getInstance((String)st.nextElement()));
                }
                */
                available = new HashSet<>();
                Set<android.icu.util.Currency> icuAvailableCurrencies
                        = android.icu.util.Currency.getAvailableCurrencies();
                for (android.icu.util.Currency icuCurrency : icuAvailableCurrencies) {
                    Currency currency = getInstance(icuCurrency.getCurrencyCode());
                    if (currency == null) {
                        currency = new Currency(icuCurrency);
                        instances.put(currency.currencyCode, currency);
                    }
                    available.add(currency);
                }
                // END Android-changed: Use ICU.
            }
        }

        @SuppressWarnings("unchecked")
        Set<Currency> result = (Set<Currency>) available.clone();
        return result;
    }

    /**
     * Gets the ISO 4217 currency code of this currency.
     *
     * @return the ISO 4217 currency code of this currency.
     */
    public String getCurrencyCode() {
        return currencyCode;
    }

    /**
     * Gets the symbol of this currency for the default
     * {@link Locale.Category#DISPLAY DISPLAY} locale.
     * For example, for the US Dollar, the symbol is "$" if the default
     * locale is the US, while for other locales it may be "US$". If no
     * symbol can be determined, the ISO 4217 currency code is returned.
     * <p>
     * This is equivalent to calling
     * {@link #getSymbol(Locale)
     *     getSymbol(Locale.getDefault(Locale.Category.DISPLAY))}.
     *
     * @return the symbol of this currency for the default
     *     {@link Locale.Category#DISPLAY DISPLAY} locale
     */
    public String getSymbol() {
        return getSymbol(Locale.getDefault(Locale.Category.DISPLAY));
    }

    /**
     * Gets the symbol of this currency for the specified locale.
     * For example, for the US Dollar, the symbol is "$" if the specified
     * locale is the US, while for other locales it may be "US$". If no
     * symbol can be determined, the ISO 4217 currency code is returned.
     *
     * @param locale the locale for which a display name for this currency is
     * needed
     * @return the symbol of this currency for the specified locale
     * @exception NullPointerException if <code>locale</code> is null
     */
    public String getSymbol(Locale locale) {
        // BEGIN Android-changed: Use ICU.
        /*
        LocaleServiceProviderPool pool =
            LocaleServiceProviderPool.getPool(CurrencyNameProvider.class);
        String symbol = pool.getLocalizedObject(
                                CurrencyNameGetter.INSTANCE,
                                locale, currencyCode, SYMBOL);
        if (symbol != null) {
            return symbol;
        }

        // use currency code as symbol of last resort
        return currencyCode;
        */
        if (locale == null) {
            throw new NullPointerException("locale == null");
        }
        return icuCurrency.getSymbol(locale);
        // END Android-changed: Use ICU.
    }

    /**
     * Gets the default number of fraction digits used with this currency.
     * For example, the default number of fraction digits for the Euro is 2,
     * while for the Japanese Yen it's 0.
     * In the case of pseudo-currencies, such as IMF Special Drawing Rights,
     * -1 is returned.
     *
     * @return the default number of fraction digits used with this currency
     */
    public int getDefaultFractionDigits() {
        // BEGIN Android-changed: Use ICU.
        // return defaultFractionDigits;
        if (icuCurrency.getCurrencyCode().equals("XXX")) {
            return -1;
        }
        return icuCurrency.getDefaultFractionDigits();
        // END Android-changed: Use ICU.
    }

    /**
     * Returns the ISO 4217 numeric code of this currency.
     *
     * @return the ISO 4217 numeric code of this currency
     * @since 1.7
     */
    public int getNumericCode() {
        // Android-changed: Use ICU.
        // return numericCode;
        return icuCurrency.getNumericCode();
    }

    /**
     * Gets the name that is suitable for displaying this currency for
     * the default {@link Locale.Category#DISPLAY DISPLAY} locale.
     * If there is no suitable display name found
     * for the default locale, the ISO 4217 currency code is returned.
     * <p>
     * This is equivalent to calling
     * {@link #getDisplayName(Locale)
     *     getDisplayName(Locale.getDefault(Locale.Category.DISPLAY))}.
     *
     * @return the display name of this currency for the default
     *     {@link Locale.Category#DISPLAY DISPLAY} locale
     * @since 1.7
     */
    public String getDisplayName() {
        return getDisplayName(Locale.getDefault(Locale.Category.DISPLAY));
    }

    /**
     * Gets the name that is suitable for displaying this currency for
     * the specified locale.  If there is no suitable display name found
     * for the specified locale, the ISO 4217 currency code is returned.
     *
     * @param locale the locale for which a display name for this currency is
     * needed
     * @return the display name of this currency for the specified locale
     * @exception NullPointerException if <code>locale</code> is null
     * @since 1.7
     */
    public String getDisplayName(Locale locale) {
        // Android-changed: Use ICU.
        /*
        LocaleServiceProviderPool pool =
            LocaleServiceProviderPool.getPool(CurrencyNameProvider.class);
        String result = pool.getLocalizedObject(
                                CurrencyNameGetter.INSTANCE,
                                locale, currencyCode, DISPLAYNAME);
        if (result != null) {
            return result;
        }

        // use currency code as symbol of last resort
        return currencyCode;
        */
        return icuCurrency.getDisplayName(Objects.requireNonNull(locale));
    }

    /**
     * Returns the ISO 4217 currency code of this currency.
     *
     * @return the ISO 4217 currency code of this currency
     */
    @Override
    public String toString() {
        // Android-changed: Use ICU.
        // return currencyCode;
        return icuCurrency.toString();
    }

    /**
     * Resolves instances being deserialized to a single instance per currency.
     */
    private Object readResolve() {
        return getInstance(currencyCode);
    }

    // Android-removed: Use ICU.
    // Removed a bunch of private helper methods that are unused on Android.
}