/*

 *  Copyright 2009-present, Stephen Colebourne

 *

 *  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 org.joda.money;

import java.io.BufferedReader;

import java.io.FileNotFoundException;

import java.io.InputStreamReader;

import java.util.ArrayList;

import java.util.List;

import java.util.regex.Pattern;

/**

 * Provider for available currencies using a file.

 * <p>

 * This reads currencies from various files.

 * Firstly it reads the mandatory resource named {@code /org/joda/money/CurencyData.csv}.

 * Then it reads the mandatory resource named {@code /org/joda/money/CountryData.csv}.

 * These files are located in the joda-money jar file.

 * <p>

 * Then it reads optional resources named {@code META-INF/org/joda/money/CurencyDataExtension.csv}.

 * Then it reads optional resources named {@code META-INF/org/joda/money/CountryDataExtension.csv}.

 * These will be read using {@link ClassLoader#getResources(String)}.

 * These files may augment or replace data from the first two files.

 */

    /** Regex format for the money csv line. */

    private static final Pattern CURRENCY_REGEX_LINE = Pattern.compile("([A-Z]{3}),(-1|[0-9]{1,3}),(-1|[0-9]|[1-2][0-9]|30) *(#.*)?");

    /** Regex format for the country csv line. */

    private static final Pattern COUNTRY_REGEX_LINE = Pattern.compile("([A-Z]{2}),([A-Z]{3}) *(#.*)?");

    /**

     * Registers all the currencies known by this provider.

     *

     * @throws Exception if an error occurs

     */

    @Override

    protected void registerCurrencies() throws Exception {

        parseCurrencies(loadFromFile("/org/joda/money/CurrencyData.csv"));

        parseCountries(loadFromFile("/org/joda/money/CountryData.csv"));

        parseCurrencies(loadFromFiles("META-INF/org/joda/money/CurrencyDataExtension.csv"));

        parseCountries(loadFromFiles("META-INF/org/joda/money/CountryDataExtension.csv"));

    }

    // loads a file

    private List<String> loadFromFile(String fileName) throws Exception {

        try (var in = getClass().getResourceAsStream(fileName)) {

            if (in == null) {

                throw new FileNotFoundException("Data file " + fileName + " not found");

            }

            try (var reader = new BufferedReader(new InputStreamReader(in, "UTF-8"))) {

                String line;

                List<String> content = new ArrayList<>();

                while ((line = reader.readLine()) != null) {

                    content.add(line);

                }

                return content;

            }

        }

    }

    // loads a file

    private List<String> loadFromFiles(String fileName) throws Exception {

        List<String> content = new ArrayList<>();

        var en = getClass().getClassLoader().getResources(fileName);

        while (en.hasMoreElements()) {

            var url = en.nextElement();

            try (var in = url.openStream()) {

                try (var reader = new BufferedReader(new InputStreamReader(in, "UTF-8"))) {

                    String line;

                    while ((line = reader.readLine()) != null) {

                        content.add(line);

                    }

                }

            }

        }

        return content;

    }

    // parse the currencies

    private void parseCurrencies(List<String> content) throws Exception {

        for (String line : content) {

            var matcher = CURRENCY_REGEX_LINE.matcher(line);

            if (matcher.matches()) {

                var currencyCode = matcher.group(1);

                var numericCode = Integer.parseInt(matcher.group(2));

                var digits = Integer.parseInt(matcher.group(3));

                registerCurrency(currencyCode, numericCode, digits);

            }

        }

    }

    // parse the countries

    private void parseCountries(List<String> content) throws Exception {

        for (String line : content) {

            var matcher = COUNTRY_REGEX_LINE.matcher(line);

            if (matcher.matches()) {

                var countryCode = matcher.group(1);

                var currencyCode = matcher.group(2);

                registerCountry(countryCode, currencyCode);

            }

        }

    }

}