// © 2018 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
package com.ibm.icu.dev.test.number;

import java.math.BigDecimal;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Locale;
import java.util.Map;
import java.util.Set;

import org.junit.Test;

import com.ibm.icu.dev.test.TestFmwk;
import com.ibm.icu.dev.test.format.FormattedValueTest;
import com.ibm.icu.impl.ICUData;
import com.ibm.icu.impl.ICUResourceBundle;
import com.ibm.icu.impl.UResource;
import com.ibm.icu.number.FormattedNumberRange;
import com.ibm.icu.number.LocalizedNumberFormatter;
import com.ibm.icu.number.LocalizedNumberRangeFormatter;
import com.ibm.icu.number.Notation;
import com.ibm.icu.number.NumberFormatter;
import com.ibm.icu.number.NumberFormatter.UnitWidth;
import com.ibm.icu.number.NumberRangeFormatter;
import com.ibm.icu.number.NumberRangeFormatter.RangeCollapse;
import com.ibm.icu.number.NumberRangeFormatter.RangeIdentityFallback;
import com.ibm.icu.number.Precision;
import com.ibm.icu.number.UnlocalizedNumberFormatter;
import com.ibm.icu.number.UnlocalizedNumberRangeFormatter;
import com.ibm.icu.text.NumberFormat;
import com.ibm.icu.text.NumberingSystem;
import com.ibm.icu.util.Currency;
import com.ibm.icu.util.MeasureUnit;
import com.ibm.icu.util.ULocale;
import com.ibm.icu.util.UResourceBundle;

/**
 * @author sffc
 *
 */
public class NumberRangeFormatterTest extends TestFmwk {

    private static final Currency USD = Currency.getInstance("USD");
    private static final Currency CHF = Currency.getInstance("CHF");
    private static final Currency GBP = Currency.getInstance("GBP");
    private static final Currency PTE = Currency.getInstance("PTE");

    @Test
    public void testSanity() {
        LocalizedNumberRangeFormatter lnrf1 = NumberRangeFormatter.withLocale(ULocale.US);
        LocalizedNumberRangeFormatter lnrf2 = NumberRangeFormatter.with().locale(ULocale.US);
        LocalizedNumberRangeFormatter lnrf3 = NumberRangeFormatter.withLocale(Locale.US);
        LocalizedNumberRangeFormatter lnrf4 = NumberRangeFormatter.with().locale(Locale.US);
        assertEquals("Formatters should be equal 1", lnrf1, lnrf2);
        assertEquals("Formatters should be equal 2", lnrf2, lnrf3);
        assertEquals("Formatters should be equal 3", lnrf3, lnrf4);
        assertEquals("Formatters should have same behavior 1", lnrf1.formatRange(4, 6), lnrf2.formatRange(4, 6));
        assertEquals("Formatters should have same behavior 2", lnrf2.formatRange(4, 6), lnrf3.formatRange(4, 6));
        assertEquals("Formatters should have same behavior 3", lnrf3.formatRange(4, 6), lnrf4.formatRange(4, 6));
    }

    @Test
    public void testBasic() {
        assertFormatRange(
            "Basic",
            NumberRangeFormatter.with(),
            new ULocale("en-us"),
            "1–5",
            "~5",
            "~5",
            "0–3",
            "~0",
            "3–3,000",
            "3,000–5,000",
            "4,999–5,001",
            "~5,000",
            "5,000–5,000,000");

        assertFormatRange(
            "Basic with units",
            NumberRangeFormatter.with()
                .numberFormatterBoth(NumberFormatter.with().unit(MeasureUnit.METER)),
            new ULocale("en-us"),
            "1–5 m",
            "~5 m",
            "~5 m",
            "0–3 m",
            "~0 m",
            "3–3,000 m",
            "3,000–5,000 m",
            "4,999–5,001 m",
            "~5,000 m",
            "5,000–5,000,000 m");

        assertFormatRange(
            "Basic with different units",
            NumberRangeFormatter.with()
                .numberFormatterFirst(NumberFormatter.with().unit(MeasureUnit.METER))
                .numberFormatterSecond(NumberFormatter.with().unit(MeasureUnit.KILOMETER)),
            new ULocale("en-us"),
            "1 m – 5 km",
            "5 m – 5 km",
            "5 m – 5 km",
            "0 m – 3 km",
            "0 m – 0 km",
            "3 m – 3,000 km",
            "3,000 m – 5,000 km",
            "4,999 m – 5,001 km",
            "5,000 m – 5,000 km",
            "5,000 m – 5,000,000 km");

        assertFormatRange(
            "Basic long unit",
            NumberRangeFormatter.with()
                .numberFormatterBoth(NumberFormatter.with().unit(MeasureUnit.METER).unitWidth(UnitWidth.FULL_NAME)),
            new ULocale("en-us"),
            "1–5 meters",
            "~5 meters",
            "~5 meters",
            "0–3 meters",
            "~0 meters",
            "3–3,000 meters",
            "3,000–5,000 meters",
            "4,999–5,001 meters",
            "~5,000 meters",
            "5,000–5,000,000 meters");

        assertFormatRange(
            "Non-English locale and unit",
            NumberRangeFormatter.with()
                .numberFormatterBoth(NumberFormatter.with().unit(MeasureUnit.FAHRENHEIT).unitWidth(UnitWidth.FULL_NAME)),
            new ULocale("fr-FR"),
            "1–5\u00A0degrés Fahrenheit",
            "≃5\u00A0degrés Fahrenheit",
            "≃5\u00A0degrés Fahrenheit",
            "0–3\u00A0degrés Fahrenheit",
            "≃0\u00A0degré Fahrenheit",
            "3–3\u202F000\u00A0degrés Fahrenheit",
            "3\u202F000–5\u202F000\u00A0degrés Fahrenheit",
            "4\u202F999–5\u202F001\u00A0degrés Fahrenheit",
            "≃5\u202F000\u00A0degrés Fahrenheit",
            "5\u202F000–5\u202F000\u202F000\u00A0degrés Fahrenheit");

        assertFormatRange(
            "Locale with custom range separator",
            NumberRangeFormatter.with(),
            new ULocale("ja"),
            "1～5",
            "約5",
            "約5",
            "0～3",
            "約0",
            "3～3,000",
            "3,000～5,000",
            "4,999～5,001",
            "約5,000",
            "5,000～5,000,000");

        assertFormatRange(
            "Locale that already has spaces around range separator",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.NONE)
                .numberFormatterBoth(NumberFormatter.with().unit(MeasureUnit.KELVIN)),
            new ULocale("hr"),
            "1 K – 5 K",
            "~5 K",
            "~5 K",
            "0 K – 3 K",
            "~0 K",
            "3 K – 3.000 K",
            "3.000 K – 5.000 K",
            "4.999 K – 5.001 K",
            "~5.000 K",
            "5.000 K – 5.000.000 K");

        assertFormatRange(
            "Locale with custom numbering system and no plural ranges data",
            NumberRangeFormatter.with(),
            new ULocale("shn@numbers=beng"),
            // 012459 = ০১৩৪৫৯
            "১–৫",
            "~৫",
            "~৫",
            "০–৩",
            "~০",
            "৩–৩,০০০",
            "৩,০০০–৫,০০০",
            "৪,৯৯৯–৫,০০১",
            "~৫,০০০",
            "৫,০০০–৫,০০০,০০০");

        assertFormatRange(
            "Portuguese currency",
            NumberRangeFormatter.with()
                .numberFormatterBoth(NumberFormatter.with().unit(PTE)),
            new ULocale("pt-PT"),
            "1$00 - 5$00 \u200B",
            "~5$00 \u200B",
            "~5$00 \u200B",
            "0$00 - 3$00 \u200B",
            "~0$00 \u200B",
            "3$00 - 3000$00 \u200B",
            "3000$00 - 5000$00 \u200B",
            "4999$00 - 5001$00 \u200B",
            "~5000$00 \u200B",
            "5000$00 - 5,000,000$00 \u200B");
    }

    @Test
    public void testCollapse() {
        assertFormatRange(
            "Default collapse on currency (default rounding)",
            NumberRangeFormatter.with()
                .numberFormatterBoth(NumberFormatter.with().unit(USD)),
            new ULocale("en-us"),
            "$1.00 – $5.00",
            "~$5.00",
            "~$5.00",
            "$0.00 – $3.00",
            "~$0.00",
            "$3.00 – $3,000.00",
            "$3,000.00 – $5,000.00",
            "$4,999.00 – $5,001.00",
            "~$5,000.00",
            "$5,000.00 – $5,000,000.00");

        assertFormatRange(
            "Default collapse on currency",
            NumberRangeFormatter.with()
                .numberFormatterBoth(NumberFormatter.with().unit(USD).precision(Precision.integer())),
            new ULocale("en-us"),
            "$1 – $5",
            "~$5",
            "~$5",
            "$0 – $3",
            "~$0",
            "$3 – $3,000",
            "$3,000 – $5,000",
            "$4,999 – $5,001",
            "~$5,000",
            "$5,000 – $5,000,000");

        assertFormatRange(
            "No collapse on currency",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.NONE)
                .numberFormatterBoth(NumberFormatter.with().unit(USD).precision(Precision.integer())),
            new ULocale("en-us"),
            "$1 – $5",
            "~$5",
            "~$5",
            "$0 – $3",
            "~$0",
            "$3 – $3,000",
            "$3,000 – $5,000",
            "$4,999 – $5,001",
            "~$5,000",
            "$5,000 – $5,000,000");

        assertFormatRange(
            "Unit collapse on currency",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.UNIT)
                .numberFormatterBoth(NumberFormatter.with().unit(USD).precision(Precision.integer())),
            new ULocale("en-us"),
            "$1–5",
            "~$5",
            "~$5",
            "$0–3",
            "~$0",
            "$3–3,000",
            "$3,000–5,000",
            "$4,999–5,001",
            "~$5,000",
            "$5,000–5,000,000");

        assertFormatRange(
            "All collapse on currency",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.ALL)
                .numberFormatterBoth(NumberFormatter.with().unit(USD).precision(Precision.integer())),
            new ULocale("en-us"),
            "$1–5",
            "~$5",
            "~$5",
            "$0–3",
            "~$0",
            "$3–3,000",
            "$3,000–5,000",
            "$4,999–5,001",
            "~$5,000",
            "$5,000–5,000,000");

        assertFormatRange(
            "Default collapse on currency ISO code",
            NumberRangeFormatter.with()
                .numberFormatterBoth(NumberFormatter.with()
                    .unit(GBP)
                    .unitWidth(UnitWidth.ISO_CODE)
                    .precision(Precision.integer())),
            new ULocale("en-us"),
            "GBP 1–5",
            "~GBP 5",  // TODO: Fix this at some point
            "~GBP 5",
            "GBP 0–3",
            "~GBP 0",
            "GBP 3–3,000",
            "GBP 3,000–5,000",
            "GBP 4,999–5,001",
            "~GBP 5,000",
            "GBP 5,000–5,000,000");

        assertFormatRange(
            "No collapse on currency ISO code",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.NONE)
                .numberFormatterBoth(NumberFormatter.with()
                    .unit(GBP)
                    .unitWidth(UnitWidth.ISO_CODE)
                    .precision(Precision.integer())),
            new ULocale("en-us"),
            "GBP 1 – GBP 5",
            "~GBP 5",  // TODO: Fix this at some point
            "~GBP 5",
            "GBP 0 – GBP 3",
            "~GBP 0",
            "GBP 3 – GBP 3,000",
            "GBP 3,000 – GBP 5,000",
            "GBP 4,999 – GBP 5,001",
            "~GBP 5,000",
            "GBP 5,000 – GBP 5,000,000");

        assertFormatRange(
            "Unit collapse on currency ISO code",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.UNIT)
                .numberFormatterBoth(NumberFormatter.with()
                    .unit(GBP)
                    .unitWidth(UnitWidth.ISO_CODE)
                    .precision(Precision.integer())),
            new ULocale("en-us"),
            "GBP 1–5",
            "~GBP 5",  // TODO: Fix this at some point
            "~GBP 5",
            "GBP 0–3",
            "~GBP 0",
            "GBP 3–3,000",
            "GBP 3,000–5,000",
            "GBP 4,999–5,001",
            "~GBP 5,000",
            "GBP 5,000–5,000,000");

        assertFormatRange(
            "All collapse on currency ISO code",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.ALL)
                .numberFormatterBoth(NumberFormatter.with()
                    .unit(GBP)
                    .unitWidth(UnitWidth.ISO_CODE)
                    .precision(Precision.integer())),
            new ULocale("en-us"),
            "GBP 1–5",
            "~GBP 5",  // TODO: Fix this at some point
            "~GBP 5",
            "GBP 0–3",
            "~GBP 0",
            "GBP 3–3,000",
            "GBP 3,000–5,000",
            "GBP 4,999–5,001",
            "~GBP 5,000",
            "GBP 5,000–5,000,000");

        // Default collapse on measurement unit is in testBasic()

        assertFormatRange(
            "No collapse on measurement unit",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.NONE)
                .numberFormatterBoth(NumberFormatter.with().unit(MeasureUnit.METER)),
            new ULocale("en-us"),
            "1 m – 5 m",
            "~5 m",
            "~5 m",
            "0 m – 3 m",
            "~0 m",
            "3 m – 3,000 m",
            "3,000 m – 5,000 m",
            "4,999 m – 5,001 m",
            "~5,000 m",
            "5,000 m – 5,000,000 m");

        assertFormatRange(
            "Unit collapse on measurement unit",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.UNIT)
                .numberFormatterBoth(NumberFormatter.with().unit(MeasureUnit.METER)),
            new ULocale("en-us"),
            "1–5 m",
            "~5 m",
            "~5 m",
            "0–3 m",
            "~0 m",
            "3–3,000 m",
            "3,000–5,000 m",
            "4,999–5,001 m",
            "~5,000 m",
            "5,000–5,000,000 m");

        assertFormatRange(
            "All collapse on measurement unit",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.ALL)
                .numberFormatterBoth(NumberFormatter.with().unit(MeasureUnit.METER)),
            new ULocale("en-us"),
            "1–5 m",
            "~5 m",
            "~5 m",
            "0–3 m",
            "~0 m",
            "3–3,000 m",
            "3,000–5,000 m",
            "4,999–5,001 m",
            "~5,000 m",
            "5,000–5,000,000 m");

        assertFormatRange(
            "Default collapse, long-form compact notation",
            NumberRangeFormatter.with()
                .numberFormatterBoth(NumberFormatter.with().notation(Notation.compactLong())),
            new ULocale("de-CH"),
            "1–5",
            "≈5",
            "≈5",
            "0–3",
            "≈0",
            "3–3 Tausend",
            "3–5 Tausend",
            "≈5 Tausend",
            "≈5 Tausend",
            "5 Tausend – 5 Millionen");

        assertFormatRange(
            "Unit collapse, long-form compact notation",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.UNIT)
                .numberFormatterBoth(NumberFormatter.with().notation(Notation.compactLong())),
                new ULocale("de-CH"),
            "1–5",
            "≈5",
            "≈5",
            "0–3",
            "≈0",
            "3–3 Tausend",
            "3 Tausend – 5 Tausend",
            "≈5 Tausend",
            "≈5 Tausend",
            "5 Tausend – 5 Millionen");

        assertFormatRange(
            "Default collapse on measurement unit with compact-short notation",
            NumberRangeFormatter.with()
                .numberFormatterBoth(NumberFormatter.with().notation(Notation.compactShort()).unit(MeasureUnit.METER)),
            new ULocale("en-us"),
            "1–5 m",
            "~5 m",
            "~5 m",
            "0–3 m",
            "~0 m",
            "3–3K m",
            "3K – 5K m",
            "~5K m",
            "~5K m",
            "5K – 5M m");

        assertFormatRange(
            "No collapse on measurement unit with compact-short notation",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.NONE)
                .numberFormatterBoth(NumberFormatter.with().notation(Notation.compactShort()).unit(MeasureUnit.METER)),
            new ULocale("en-us"),
            "1 m – 5 m",
            "~5 m",
            "~5 m",
            "0 m – 3 m",
            "~0 m",
            "3 m – 3K m",
            "3K m – 5K m",
            "~5K m",
            "~5K m",
            "5K m – 5M m");

        assertFormatRange(
            "Unit collapse on measurement unit with compact-short notation",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.UNIT)
                .numberFormatterBoth(NumberFormatter.with().notation(Notation.compactShort()).unit(MeasureUnit.METER)),
            new ULocale("en-us"),
            "1–5 m",
            "~5 m",
            "~5 m",
            "0–3 m",
            "~0 m",
            "3–3K m",
            "3K – 5K m",
            "~5K m",
            "~5K m",
            "5K – 5M m");

        assertFormatRange(
            "All collapse on measurement unit with compact-short notation",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.ALL)
                .numberFormatterBoth(NumberFormatter.with().notation(Notation.compactShort()).unit(MeasureUnit.METER)),
            new ULocale("en-us"),
            "1–5 m",
            "~5 m",
            "~5 m",
            "0–3 m",
            "~0 m",
            "3–3K m",
            "3–5K m",  // this one is the key use case for ALL
            "~5K m",
            "~5K m",
            "5K – 5M m");

        assertFormatRange(
            "No collapse on scientific notation",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.NONE)
                .numberFormatterBoth(NumberFormatter.with().notation(Notation.scientific())),
            new ULocale("en-us"),
            "1E0 – 5E0",
            "~5E0",
            "~5E0",
            "0E0 – 3E0",
            "~0E0",
            "3E0 – 3E3",
            "3E3 – 5E3",
            "4.999E3 – 5.001E3",
            "~5E3",
            "5E3 – 5E6");

        assertFormatRange(
            "All collapse on scientific notation",
            NumberRangeFormatter.with()
                .collapse(RangeCollapse.ALL)
                .numberFormatterBoth(NumberFormatter.with().notation(Notation.scientific())),
            new ULocale("en-us"),
            "1–5E0",
            "~5E0",
            "~5E0",
            "0–3E0",
            "~0E0",
            "3E0 – 3E3",
            "3–5E3",
            "4.999–5.001E3",
            "~5E3",
            "5E3 – 5E6");

        // TODO: Test compact currency?
        // The code is not smart enough to differentiate the notation from the unit.
    }

    @Test
    public void testIdentity() {
        assertFormatRange(
            "Identity fallback Range",
            NumberRangeFormatter.with().identityFallback(RangeIdentityFallback.RANGE),
            new ULocale("en-us"),
            "1–5",
            "5–5",
            "5–5",
            "0–3",
            "0–0",
            "3–3,000",
            "3,000–5,000",
            "4,999–5,001",
            "5,000–5,000",
            "5,000–5,000,000");

        assertFormatRange(
            "Identity fallback Approximately or Single Value",
            NumberRangeFormatter.with().identityFallback(RangeIdentityFallback.APPROXIMATELY_OR_SINGLE_VALUE),
            new ULocale("en-us"),
            "1–5",
            "~5",
            "5",
            "0–3",
            "0",
            "3–3,000",
            "3,000–5,000",
            "4,999–5,001",
            "5,000",
            "5,000–5,000,000");

        assertFormatRange(
            "Identity fallback  Single Value",
            NumberRangeFormatter.with().identityFallback(RangeIdentityFallback.SINGLE_VALUE),
            new ULocale("en-us"),
            "1–5",
            "5",
            "5",
            "0–3",
            "0",
            "3–3,000",
            "3,000–5,000",
            "4,999–5,001",
            "5,000",
            "5,000–5,000,000");

        assertFormatRange(
            "Identity fallback Approximately or Single Value with compact notation",
            NumberRangeFormatter.with()
                .identityFallback(RangeIdentityFallback.APPROXIMATELY_OR_SINGLE_VALUE)
                .numberFormatterBoth(NumberFormatter.with().notation(Notation.compactShort())),
            new ULocale("en-us"),
            "1–5",
            "~5",
            "5",
            "0–3",
            "0",
            "3–3K",
            "3K – 5K",
            "~5K",
            "5K",
            "5K – 5M");

        assertFormatRange(
            "Approximately in middle of unit string",
            NumberRangeFormatter.with().numberFormatterBoth(
                NumberFormatter.with().unit(MeasureUnit.FAHRENHEIT).unitWidth(UnitWidth.FULL_NAME)),
            new ULocale("zh-Hant"),
            "華氏 1-5 度",
            "華氏 ~5 度",
            "華氏 ~5 度",
            "華氏 0-3 度",
            "華氏 ~0 度",
            "華氏 3-3,000 度",
            "華氏 3,000-5,000 度",
            "華氏 4,999-5,001 度",
            "華氏 ~5,000 度",
            "華氏 5,000-5,000,000 度");
    }

    @Test
    public void testDifferentFormatters() {
        assertFormatRange(
            "Different rounding rules",
            NumberRangeFormatter.with()
                .numberFormatterFirst(NumberFormatter.with().precision(Precision.integer()))
                .numberFormatterSecond(NumberFormatter.with().precision(Precision.fixedSignificantDigits(2))),
            new ULocale("en-us"),
            "1–5.0",
            "5–5.0",
            "5–5.0",
            "0–3.0",
            "0–0.0",
            "3–3,000",
            "3,000–5,000",
            "4,999–5,000",
            "5,000–5,000",  // TODO: Should this one be ~5,000?
            "5,000–5,000,000");
    }

    @Test
    public void test21397_UnsetNull() {
        assertFormatRange(
            "Unset identity fallback",
            NumberRangeFormatter.with()
                .identityFallback(RangeIdentityFallback.RANGE)
                .identityFallback(null),
            new ULocale("en-us"),
            "1–5",
            "~5",
            "~5",
            "0–3",
            "~0",
            "3–3,000",
            "3,000–5,000",
            "4,999–5,001",
            "~5,000",
            "5,000–5,000,000");
    }

    @Test
    public void testNaNInfinity() {
        LocalizedNumberRangeFormatter lnf = NumberRangeFormatter.withLocale(ULocale.ENGLISH);
        FormattedNumberRange result1 = lnf.formatRange(Double.NEGATIVE_INFINITY, 0);
        FormattedNumberRange result2 = lnf.formatRange(0, Double.POSITIVE_INFINITY);
        FormattedNumberRange result3 = lnf.formatRange(Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY);
        FormattedNumberRange result4 = lnf.formatRange(Double.NaN, 0);
        FormattedNumberRange result5 = lnf.formatRange(0, Double.NaN);
        FormattedNumberRange result6 = lnf.formatRange(Double.NaN, Double.NaN);

        assertEquals("0 - inf", "-∞ – 0", result1.toString());
        assertEquals("-inf - 0", "0–∞", result2.toString());
        assertEquals("-inf - inf", "-∞ – ∞", result3.toString());
        assertEquals("NaN - 0", "NaN–0", result4.toString());
        assertEquals("0 - NaN", "0–NaN", result5.toString());
        assertEquals("NaN - NaN", "~NaN", result6.toString());
    }

    @Test
    public void testPlurals() {
        // Locale sl has interesting plural forms:
        // GBP{
        //     one{"britanski funt"}
        //     two{"britanska funta"}
        //     few{"britanski funti"}
        //     other{"britanskih funtov"}
        // }
        ULocale locale = new ULocale("sl");

        UnlocalizedNumberFormatter unf = NumberFormatter.with()
            .unit(GBP)
            .unitWidth(UnitWidth.FULL_NAME)
            .precision(Precision.integer());
        LocalizedNumberFormatter lnf = unf.locale(locale);

        // For comparison, run the non-range version of the formatter
        assertEquals(Integer.toString(1), "1 britanski funt", lnf.format(1).toString());
        assertEquals(Integer.toString(2), "2 britanska funta", lnf.format(2).toString());
        assertEquals(Integer.toString(3), "3 britanski funti", lnf.format(3).toString());
        assertEquals(Integer.toString(5), "5 britanskih funtov", lnf.format(5).toString());

        LocalizedNumberRangeFormatter lnrf = NumberRangeFormatter.with()
            .numberFormatterBoth(unf)
            .identityFallback(RangeIdentityFallback.RANGE)
            .locale(locale);

        Object[][] cases = new Object[][] {
            {1, 1, "1–1 britanski funti"}, // one + one -> few
            {1, 2, "1–2 britanska funta"}, // one + two -> two
            {1, 3, "1–3 britanski funti"}, // one + few -> few
            {1, 5, "1–5 britanskih funtov"}, // one + other -> other
            {2, 1, "2–1 britanski funti"}, // two + one -> few
            {2, 2, "2–2 britanska funta"}, // two + two -> two
            {2, 3, "2–3 britanski funti"}, // two + few -> few
            {2, 5, "2–5 britanskih funtov"}, // two + other -> other
            {3, 1, "3–1 britanski funti"}, // few + one -> few
            {3, 2, "3–2 britanska funta"}, // few + two -> two
            {3, 3, "3–3 britanski funti"}, // few + few -> few
            {3, 5, "3–5 britanskih funtov"}, // few + other -> other
            {5, 1, "5–1 britanski funti"}, // other + one -> few
            {5, 2, "5–2 britanska funta"}, // other + two -> two
            {5, 3, "5–3 britanski funti"}, // other + few -> few
            {5, 5, "5–5 britanskih funtov"}, // other + other -> other
        };
        for (Object[] cas : cases) {
            int first = (Integer) cas[0];
            int second = (Integer) cas[1];
            String expected = (String) cas[2];
            String message = Integer.toString(first) + " " + Integer.toString(second);
            String actual = lnrf.formatRange(first, second).toString();
            assertEquals(message, expected, actual);
        }
    }

    @Test
    public void testFieldPositions() {
        {
            String message = "Field position test 1";
            String expectedString = "3K – 5K m";
            FormattedNumberRange fmtd = assertFormattedRangeEquals(
                    message,
                    NumberRangeFormatter.with()
                        .numberFormatterBoth(NumberFormatter.with()
                            .unit(MeasureUnit.METER)
                            .notation(Notation.compactShort()))
                        .locale(ULocale.US),
                    3000,
                    5000,
                    expectedString);
            Object[][] expectedFieldPositions = new Object[][]{
                    {NumberRangeFormatter.SpanField.NUMBER_RANGE_SPAN, 0, 2, 0},
                    {NumberFormat.Field.INTEGER, 0, 1},
                    {NumberFormat.Field.COMPACT, 1, 2},
                    {NumberRangeFormatter.SpanField.NUMBER_RANGE_SPAN, 5, 7, 1},
                    {NumberFormat.Field.INTEGER, 5, 6},
                    {NumberFormat.Field.COMPACT, 6, 7},
                    {NumberFormat.Field.MEASURE_UNIT, 8, 9}};
            FormattedValueTest.checkFormattedValue(message, fmtd, expectedString, expectedFieldPositions);
        }

        {
            String message = "Field position test 2";
            String expectedString = "87,654,321–98,765,432";
            FormattedNumberRange fmtd = assertFormattedRangeEquals(
                    message,
                    NumberRangeFormatter.withLocale(ULocale.US),
                    87654321,
                    98765432,
                    expectedString);
            Object[][] expectedFieldPositions = new Object[][]{
                    {NumberRangeFormatter.SpanField.NUMBER_RANGE_SPAN, 0, 10, 0},
                    {NumberFormat.Field.GROUPING_SEPARATOR, 2, 3},
                    {NumberFormat.Field.GROUPING_SEPARATOR, 6, 7},
                    {NumberFormat.Field.INTEGER, 0, 10},
                    {NumberRangeFormatter.SpanField.NUMBER_RANGE_SPAN, 11, 21, 1},
                    {NumberFormat.Field.GROUPING_SEPARATOR, 13, 14},
                    {NumberFormat.Field.GROUPING_SEPARATOR, 17, 18},
                    {NumberFormat.Field.INTEGER, 11, 21}};
            FormattedValueTest.checkFormattedValue(message, fmtd, expectedString, expectedFieldPositions);
        }

        {
            String message = "Field position with approximately sign";
            String expectedString = "~-100";
            FormattedNumberRange fmtd = assertFormattedRangeEquals(
                    message,
                    NumberRangeFormatter.withLocale(ULocale.US),
                    -100,
                    -100,
                    expectedString);
            Object[][] expectedFieldPositions = new Object[][]{
                    {NumberFormat.Field.APPROXIMATELY_SIGN, 0, 1},
                    {NumberFormat.Field.SIGN, 1, 2},
                    {NumberFormat.Field.INTEGER, 2, 5}};
            FormattedValueTest.checkFormattedValue(message, fmtd, expectedString, expectedFieldPositions);
        }
    }

    static final String[] allNSNames = NumberingSystem.getAvailableNames();

    private class RangePatternSink extends UResource.Sink {
        Map<String,String> rangePatterns = new HashMap<>();
        Map<String,String> approxPatterns = new HashMap<>();

        // NumberElements{ latn{ miscPatterns{ range{"{0}-{1}"} } } }
        @Override
        public void put(UResource.Key key, UResource.Value value, boolean noFallback) {
            UResource.Table numberElementsTable = value.getTable();
            for (int i = 0; numberElementsTable.getKeyAndValue(i, key, value); ++i) {
                String nsName = key.toString();
                if (Arrays.binarySearch(allNSNames, nsName) < 0) {
                    continue;
                }
                UResource.Table nsTable = value.getTable();
                for (int j = 0; nsTable.getKeyAndValue(j, key, value); ++j) {
                    if (!key.contentEquals("miscPatterns") || value.getType()!=UResourceBundle.TABLE) {
                        // now miscPatterns might have an alias; for now skip alias instead of following
                        continue;
                    }
                    UResource.Table miscTable = value.getTable();
                    for (int k = 0; miscTable.getKeyAndValue(k, key, value); ++k) {
                        if (key.contentEquals("range") && !rangePatterns.containsKey(nsName)) {
                            rangePatterns.put(nsName, value.getString());
                        }
                        if (key.contentEquals("approximately") && !approxPatterns.containsKey(nsName)) {
                            approxPatterns.put(nsName, value.getString());
                        }
                    }
                }
            }
        }

        public void checkAndReset(ULocale locale) {
            // NOTE: If this test ever starts failing, there might not need to
            // be any changes made to NumberRangeFormatter.  Please add a new
            // test demonstrating how different numbering systems in the same
            // locale produce different results in NumberRangeFormatter, and
            // then you can disable or delete this test.
            // Additional context: ICU-20144

            Set<String> allRangePatterns = new HashSet<>();
            allRangePatterns.addAll(rangePatterns.values());
            assertEquals("Should have only one unique range pattern: " + locale + ": " + rangePatterns,
                    1, allRangePatterns.size());

            Set<String> allApproxPatterns = new HashSet<>();
            allApproxPatterns.addAll(approxPatterns.values());
            assertEquals("Should have only one unique approximately pattern: " + locale + ": " + approxPatterns,
                    1, allApproxPatterns.size());

            rangePatterns.clear();
            approxPatterns.clear();
        }
    }

    @Test
    public void testNumberingSystemRangeData() {
        RangePatternSink sink = new RangePatternSink();
        for (ULocale locale : ULocale.getAvailableLocales()) {
            ICUResourceBundle resource = (ICUResourceBundle)
                    UResourceBundle.getBundleInstance(ICUData.ICU_BASE_NAME, locale);
            resource.getAllItemsWithFallback("NumberElements", sink);
            sink.checkAndReset(locale);
        }
    }

    @Test
    public void test21684_Performance() {
        LocalizedNumberRangeFormatter lnf = NumberRangeFormatter.withLocale(ULocale.ENGLISH);
        // The following two lines of code should finish quickly.
        lnf.formatRange(new BigDecimal("-1e99999"), new BigDecimal("0"));
        lnf.formatRange(new BigDecimal("0"), new BigDecimal("1e99999"));
    }

    @Test
    public void test21358_SignPosition() {
        // de-CH has currency pattern "¤ #,##0.00;¤-#,##0.00"
        assertFormatRange(
            "Approximately sign position with spacing from pattern",
            NumberRangeFormatter.with()
                .numberFormatterBoth(NumberFormatter.with().unit(CHF)),
            ULocale.forLanguageTag("de-CH"),
            "CHF 1.00–5.00",
            "CHF≈5.00",
            "CHF≈5.00",
            "CHF 0.00–3.00",
            "CHF≈0.00",
            "CHF 3.00–3’000.00",
            "CHF 3’000.00–5’000.00",
            "CHF 4’999.00–5’001.00",
            "CHF≈5’000.00",
            "CHF 5’000.00–5’000’000.00");

        // TODO(ICU-21420): Move the sign to the inside of the number
        assertFormatRange(
            "Approximately sign position with currency spacing",
            NumberRangeFormatter.with()
                .numberFormatterBoth(NumberFormatter.with().unit(CHF)),
            ULocale.forLanguageTag("en-US"),
            "CHF 1.00–5.00",
            "~CHF 5.00",
            "~CHF 5.00",
            "CHF 0.00–3.00",
            "~CHF 0.00",
            "CHF 3.00–3,000.00",
            "CHF 3,000.00–5,000.00",
            "CHF 4,999.00–5,001.00",
            "~CHF 5,000.00",
            "CHF 5,000.00–5,000,000.00");

        {
            LocalizedNumberRangeFormatter lnrf = NumberRangeFormatter
                .withLocale(ULocale.forLanguageTag("de-CH"));
            String actual = lnrf.formatRange(-2, 3).toString();
            assertEquals("Negative to positive range", "-2 – 3", actual);
        }

        {
            LocalizedNumberRangeFormatter lnrf = NumberRangeFormatter
                .withLocale(ULocale.forLanguageTag("de-CH"))
                .numberFormatterBoth(NumberFormatter.forSkeleton("%"));
            String actual = lnrf.formatRange(-2, 3).toString();
            assertEquals("Negative to positive percent", "-2% – 3%", actual);
        }

        {
            // TODO(CLDR-14111): Add spacing between range separator and sign
            LocalizedNumberRangeFormatter lnrf = NumberRangeFormatter
                .withLocale(ULocale.forLanguageTag("de-CH"));
            String actual = lnrf.formatRange(2, -3).toString();
            assertEquals("Positive to negative range", "2–-3", actual);
        }

        {
            LocalizedNumberRangeFormatter lnrf = NumberRangeFormatter
                .withLocale(ULocale.forLanguageTag("de-CH"))
                .numberFormatterBoth(NumberFormatter.forSkeleton("%"));
            String actual = lnrf.formatRange(2, -3).toString();
            assertEquals("Positive to negative percent", "2% – -3%", actual);
        }
    }

    @Test
    public void testCreateLNRFFromNumberingSystemInSkeleton() {
        {
            LocalizedNumberRangeFormatter lnrf = NumberRangeFormatter
                .withLocale(ULocale.forLanguageTag("en"))
                .numberFormatterBoth(NumberFormatter.forSkeleton(
                    ".### rounding-mode-half-up"));
            String actual = lnrf.formatRange(1, 234).toString();
            assertEquals("default numbering system", "1–234", actual);
        }
        {
            LocalizedNumberRangeFormatter lnrf = NumberRangeFormatter
                .withLocale(ULocale.forLanguageTag("th"))
                .numberFormatterBoth(NumberFormatter.forSkeleton(
                    ".### rounding-mode-half-up numbering-system/thai"));
            String actual = lnrf.formatRange(1, 234).toString();
            assertEquals("Thai numbering system", "๑-๒๓๔", actual);
        }
        {
            LocalizedNumberRangeFormatter lnrf = NumberRangeFormatter
                .withLocale(ULocale.forLanguageTag("en"))
                .numberFormatterBoth(NumberFormatter.forSkeleton(
                    ".### rounding-mode-half-up numbering-system/arab"));
            String actual = lnrf.formatRange(1, 234).toString();
            assertEquals("Arabic numbering system", "١–٢٣٤", actual);
        }
        {
            LocalizedNumberRangeFormatter lnrf = NumberRangeFormatter
                .withLocale(ULocale.forLanguageTag("en"))
                .numberFormatterFirst(NumberFormatter.forSkeleton("numbering-system/arab"))
                .numberFormatterSecond(NumberFormatter.forSkeleton("numbering-system/arab"));
            String actual = lnrf.formatRange(1, 234).toString();
            assertEquals("Double Arabic numbering system", "١–٢٣٤", actual);
        }
    }

    @Test(expected = IllegalArgumentException.class)
    public void testCreateLNRFFromNumberingSystemInSkeletonError() {
        LocalizedNumberRangeFormatter lnrf = NumberRangeFormatter
            .withLocale(ULocale.forLanguageTag("en"))
            .numberFormatterFirst(NumberFormatter.forSkeleton("numbering-system/arab"))
            .numberFormatterSecond(NumberFormatter.forSkeleton("numbering-system/latn"));
        // Note: The error is not thrown until `formatRange` because this is where the
        // formatter object gets built.
        lnrf.formatRange(1, 234);
    }

    static void assertFormatRange(
            String message,
            UnlocalizedNumberRangeFormatter f,
            ULocale locale,
            String expected_10_50,
            String expected_49_51,
            String expected_50_50,
            String expected_00_30,
            String expected_00_00,
            String expected_30_3K,
            String expected_30K_50K,
            String expected_49K_51K,
            String expected_50K_50K,
            String expected_50K_50M) {
        LocalizedNumberRangeFormatter l = f.locale(locale);
        assertFormattedRangeEquals(message, l, 1, 5, expected_10_50);
        assertFormattedRangeEquals(message, l, 4.9999999, 5.0000001, expected_49_51);
        assertFormattedRangeEquals(message, l, 5, 5, expected_50_50);
        assertFormattedRangeEquals(message, l, 0, 3, expected_00_30);
        assertFormattedRangeEquals(message, l, 0, 0, expected_00_00);
        assertFormattedRangeEquals(message, l, 3, 3000, expected_30_3K);
        assertFormattedRangeEquals(message, l, 3000, 5000, expected_30K_50K);
        assertFormattedRangeEquals(message, l, 4999, 5001, expected_49K_51K);
        assertFormattedRangeEquals(message, l, 5000, 5000, expected_50K_50K);
        assertFormattedRangeEquals(message, l, 5e3, 5e6, expected_50K_50M);
    }

    private static FormattedNumberRange assertFormattedRangeEquals(String message, LocalizedNumberRangeFormatter l, Number first,
            Number second, String expected) {
        FormattedNumberRange fnr = l.formatRange(first, second);
        String actual = fnr.toString();
        assertEquals(message + ": " + first + ", " + second, expected, actual);
        return fnr;
    }

}