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/*
 * @test
 * @bug 8035133
 * @summary Checks that the tags matching the range with quality weight q=0
 *          e.g. en;q=0 must be elimited and must not be the part of output
 * @run junit MatchEmptyWeightCorrectly
 */

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.stream.Stream;

import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.MethodSource;

import static org.junit.jupiter.api.Assertions.assertEquals;

public class MatchEmptyWeightCorrectly {

    // Ensure weights with 'q=0' work as expected during lookup
    @ParameterizedTest
    @MethodSource("lookupProvider")
    public void lookupTest(String ranges, String tags,
            String expectedLocale) {

        List<Locale.LanguageRange> priorityList = Locale.LanguageRange
                .parse(ranges);
        List<Locale> localeList = generateLocales(tags);
        Locale loc = Locale.lookup(priorityList, localeList);
        String actualLocale = loc.toLanguageTag();
        assertEquals(expectedLocale, actualLocale);
    }

    private static Stream<Arguments> lookupProvider() {
        return Stream.of(
                // checking Locale.lookup with de-ch;q=0
                Arguments.of("en;q=0.1, *-ch;q=0.5, de-ch;q=0",
                        "de-ch, en, fr-ch", "fr-CH"),
                // checking Locale.lookup with *;q=0 '*' should be ignored in lookup
                Arguments.of("en;q=0.1, *-ch;q=0.5, *;q=0",
                        "de-ch, en, fr-ch", "de-CH")
        );
    }

    // Ensure weights with 'q=0' work as expected during filtering
    @ParameterizedTest
    @MethodSource("filterProvider")
    public void filterTest(String ranges, String tags,
            String expectedLocales) {

        List<Locale.LanguageRange> priorityList = Locale.LanguageRange
                .parse(ranges);
        List<Locale> localeList = generateLocales(tags);
        String actualLocales = getLocalesAsString(
                Locale.filter(priorityList, localeList));
        assertEquals(expectedLocales, actualLocales);
    }

    private static Stream<Arguments> filterProvider() {
        return Stream.of(
                // checking Locale.filter with fr-ch;q=0 in BASIC_FILTERING
                Arguments.of("en;q=0.1, fr-ch;q=0.0, de-ch;q=0.5",
                        "de-ch, en, fr-ch", "de-CH, en"),
                // checking Locale.filter with *;q=0 in BASIC_FILTERING
                Arguments.of("de-ch;q=0.6, *;q=0", "de-ch, fr-ch", ""),
                // checking Locale.filter with *;q=0 in BASIC_FILTERING
                Arguments.of("de-ch;q=0.6, de;q=0", "de-ch", ""),
                // checking Locale.filter with *;q=0.6, en;q=0 in BASIC_FILTERING
                Arguments.of("*;q=0.6, en;q=0", "de-ch, hi-in, en", "de-CH, hi-IN"),
                // checking Locale.filter with de-ch;q=0 in EXTENDED_FILTERING
                Arguments.of("en;q=0.1, *-ch;q=0.5, de-ch;q=0",
                        "de-ch, en, fr-ch", "fr-CH, en"),
                /* checking Locale.filter with *-ch;q=0 in EXTENDED_FILTERING which
                 * must make filter to return "" empty or no match
                 */
                Arguments.of("de-ch;q=0.5, *-ch;q=0", "de-ch, fr-ch", ""),
                /* checking Locale.filter with *;q=0 in EXTENDED_FILTERING which
                 * must make filter to return "" empty or no match
                 */
                Arguments.of("*-ch;q=0.5, *;q=0", "de-ch, fr-ch", ""),
                /* checking Locale.filter with *;q=0.6, *-Latn;q=0 in
                 * EXTENDED_FILTERING
                 */
                Arguments.of("*;q=0.6, *-Latn;q=0", "de-ch, hi-in, en-Latn",
                        "de-CH, hi-IN")
        );
    }

    private static List<Locale> generateLocales(String tags) {
        if (tags == null) {
            return null;
        }

        List<Locale> localeList = new ArrayList<>();
        if (tags.equals("")) {
            return localeList;
        }
        String[] t = tags.split(", ");
        for (String tag : t) {
            localeList.add(Locale.forLanguageTag(tag));
        }
        return localeList;
    }

    private static String getLocalesAsString(List<Locale> locales) {
        StringBuilder sb = new StringBuilder();

        Iterator<Locale> itr = locales.iterator();
        if (itr.hasNext()) {
            sb.append(itr.next().toLanguageTag());
        }
        while (itr.hasNext()) {
            sb.append(", ");
            sb.append(itr.next().toLanguageTag());
        }

        return sb.toString().trim();
    }
}