// © 2017 and later: Unicode, Inc. and others.

// License & terms of use: http://www.unicode.org/copyright.html

#include "unicode/utypes.h"

#if !UCONFIG_NO_FORMATTING

#include "unicode/ustring.h"

#include "unicode/ures.h"

#include "cstring.h"

#include "charstr.h"

#include "resource.h"

#include "number_compact.h"

#include "number_microprops.h"

#include "uresimp.h"

using namespace icu;

using namespace icu::number;

using namespace icu::number::impl;

namespace {

// A dummy object used when a "0" compact decimal entry is encountered. This is necessary

// in order to prevent falling back to root. Object equality ("==") is intended.

const char16_t *USE_FALLBACK = u"<USE FALLBACK>";

/** Produces a string like "NumberElements/latn/patternsShort/decimalFormat". */

void getResourceBundleKey(const char *nsName, CompactStyle compactStyle, CompactType compactType,

                                 CharString &sb, UErrorCode &status) {

    sb.clear();

    sb.append("NumberElements/", status);

    sb.append(nsName, status);

    sb.append(compactStyle == CompactStyle::UNUM_SHORT ? "/patternsShort" : "/patternsLong", status);

    sb.append(compactType == CompactType::TYPE_DECIMAL ? "/decimalFormat" : "/currencyFormat", status);

}

int32_t getIndex(int32_t magnitude, StandardPlural::Form plural) {

    return magnitude * StandardPlural::COUNT + plural;

}

int32_t countZeros(const char16_t *patternString, int32_t patternLength) {

    // NOTE: This strategy for computing the number of zeros is a hack for efficiency.

    // It could break if there are any 0s that aren't part of the main pattern.

    int32_t numZeros = 0;

    for (int32_t i = 0; i < patternLength; i++) {

        if (patternString[i] == u'0') {

            numZeros++;

        } else if (numZeros > 0) {

            break; // zeros should always be contiguous

        }

    }

    return numZeros;

}

} // namespace

// NOTE: patterns and multipliers both get zero-initialized.

CompactData::CompactData() : patterns(), multipliers(), largestMagnitude(0), isEmpty(true) {

}

void CompactData::populate(const Locale &locale, const char *nsName, CompactStyle compactStyle,

                           CompactType compactType, UErrorCode &status) {

    CompactDataSink sink(*this);

    LocalUResourceBundlePointer rb(ures_open(nullptr, locale.getName(), &status));

    if (U_FAILURE(status)) { return; }

    bool nsIsLatn = strcmp(nsName, "latn") == 0;

    bool compactIsShort = compactStyle == CompactStyle::UNUM_SHORT;

    // Fall back to latn numbering system and/or short compact style.

    CharString resourceKey;

    getResourceBundleKey(nsName, compactStyle, compactType, resourceKey, status);

    UErrorCode localStatus = U_ZERO_ERROR;

    ures_getAllItemsWithFallback(rb.getAlias(), resourceKey.data(), sink, localStatus);

    if (isEmpty && !nsIsLatn) {

        getResourceBundleKey("latn", compactStyle, compactType, resourceKey, status);

        localStatus = U_ZERO_ERROR;

        ures_getAllItemsWithFallback(rb.getAlias(), resourceKey.data(), sink, localStatus);

    }

    if (isEmpty && !compactIsShort) {

        getResourceBundleKey(nsName, CompactStyle::UNUM_SHORT, compactType, resourceKey, status);

        localStatus = U_ZERO_ERROR;

        ures_getAllItemsWithFallback(rb.getAlias(), resourceKey.data(), sink, localStatus);

    }

    if (isEmpty && !nsIsLatn && !compactIsShort) {

        getResourceBundleKey("latn", CompactStyle::UNUM_SHORT, compactType, resourceKey, status);

        localStatus = U_ZERO_ERROR;

        ures_getAllItemsWithFallback(rb.getAlias(), resourceKey.data(), sink, localStatus);

    }

    // The last fallback should be guaranteed to return data.

    if (isEmpty) {

        status = U_INTERNAL_PROGRAM_ERROR;

    }

}

int32_t CompactData::getMultiplier(int32_t magnitude) const {

    if (magnitude < 0) {

        return 0;

    }

    if (magnitude > largestMagnitude) {

        magnitude = largestMagnitude;

    }

    return multipliers[magnitude];

}

const char16_t *CompactData::getPattern(

        int32_t magnitude,

        const PluralRules *rules,

        const DecimalQuantity &dq) const {

    if (magnitude < 0) {

        return nullptr;

    }

    if (magnitude > largestMagnitude) {

        magnitude = largestMagnitude;

    }

    const char16_t *patternString = nullptr;

    if (dq.hasIntegerValue()) {

        int64_t i = dq.toLong(true);

        if (i == 0) {

            patternString = patterns[getIndex(magnitude, StandardPlural::Form::EQ_0)];

        } else if (i == 1) {

            patternString = patterns[getIndex(magnitude, StandardPlural::Form::EQ_1)];

        }

        if (patternString != nullptr) {

            return patternString;

        }

    }

    StandardPlural::Form plural = utils::getStandardPlural(rules, dq);

    patternString = patterns[getIndex(magnitude, plural)];

    if (patternString == nullptr && plural != StandardPlural::OTHER) {

        // Fall back to "other" plural variant

        patternString = patterns[getIndex(magnitude, StandardPlural::OTHER)];

    }

    if (patternString == USE_FALLBACK) { // == is intended

        // Return null if USE_FALLBACK is present

        patternString = nullptr;

    }

    return patternString;

}

void CompactData::getUniquePatterns(UVector &output, UErrorCode &status) const {

    U_ASSERT(output.isEmpty());

    // NOTE: In C++, this is done more manually with a UVector.

    // In Java, we can take advantage of JDK HashSet.

    for (const auto* pattern : patterns) {

        if (pattern == nullptr || pattern == USE_FALLBACK) {

            continue;

        }

        // Insert pattern into the UVector if the UVector does not already contain the pattern.

        // Search the UVector from the end since identical patterns are likely to be adjacent.

        for (int32_t i = output.size() - 1; i >= 0; i--) {

            if (u_strcmp(pattern, static_cast<const char16_t *>(output[i])) == 0) {

                goto continue_outer;

            }

        }

        // The string was not found; add it to the UVector.

        // Note: must cast off const from pattern to store it in a UVector, which expects (void *)

        output.addElement(const_cast<char16_t *>(pattern), status);

        continue_outer:

        continue;

    }

}

void CompactData::CompactDataSink::put(const char *key, ResourceValue &value, UBool /*noFallback*/,

                                       UErrorCode &status) {

    // traverse into the table of powers of ten

    ResourceTable powersOfTenTable = value.getTable(status);

    if (U_FAILURE(status)) { return; }

    for (int i3 = 0; powersOfTenTable.getKeyAndValue(i3, key, value); ++i3) {

        // Assumes that the keys are always of the form "10000" where the magnitude is the

        // length of the key minus one.  We only support magnitudes less than COMPACT_MAX_DIGITS;

        // ignore entries that have greater magnitude.

        auto magnitude = static_cast<int8_t> (strlen(key) - 1);

        U_ASSERT(magnitude < COMPACT_MAX_DIGITS); // debug assert

        if (magnitude >= COMPACT_MAX_DIGITS) { // skip in production

            continue;

        }

        int8_t multiplier = data.multipliers[magnitude];

        // Iterate over the plural variants ("one", "other", etc)

        ResourceTable pluralVariantsTable = value.getTable(status);

        if (U_FAILURE(status)) { return; }

        for (int i4 = 0; pluralVariantsTable.getKeyAndValue(i4, key, value); ++i4) {

            // Skip this magnitude/plural if we already have it from a child locale.

            // Note: This also skips USE_FALLBACK entries.

            StandardPlural::Form plural = StandardPlural::fromString(key, status);

            if (U_FAILURE(status)) { return; }

            if (data.patterns[getIndex(magnitude, plural)] != nullptr) {

                continue;

            }

            // The value "0" means that we need to use the default pattern and not fall back

            // to parent locales. Example locale where this is relevant: 'it'.

            int32_t patternLength;

            const char16_t *patternString = value.getString(patternLength, status);

            if (U_FAILURE(status)) { return; }

            if (u_strcmp(patternString, u"0") == 0) {

                patternString = USE_FALLBACK;

                patternLength = 0;

            }

            // Save the pattern string. We will parse it lazily.

            data.patterns[getIndex(magnitude, plural)] = patternString;

            // If necessary, compute the multiplier: the difference between the magnitude

            // and the number of zeros in the pattern.

            if (multiplier == 0) {

                int32_t numZeros = countZeros(patternString, patternLength);

                if (numZeros > 0) { // numZeros==0 in certain cases, like Somali "Kun"

                    multiplier = static_cast<int8_t> (numZeros - magnitude - 1);

                }

            }

        }

        // Save the multiplier.

        if (data.multipliers[magnitude] == 0) {

            data.multipliers[magnitude] = multiplier;

            if (magnitude > data.largestMagnitude) {

                data.largestMagnitude = magnitude;

            }

            data.isEmpty = false;

        } else {

            U_ASSERT(data.multipliers[magnitude] == multiplier);

        }

    }

}

///////////////////////////////////////////////////////////

/// END OF CompactData.java; BEGIN CompactNotation.java ///

///////////////////////////////////////////////////////////

CompactHandler::CompactHandler(

        CompactStyle compactStyle,

        const Locale &locale,

        const char *nsName,

        CompactType compactType,

        const PluralRules *rules,

        MutablePatternModifier *buildReference,

        bool safe,

        const MicroPropsGenerator *parent,

        UErrorCode &status)

        : rules(rules), parent(parent), safe(safe) {

    data.populate(locale, nsName, compactStyle, compactType, status);

    if (safe) {

        // Safe code path

        precomputeAllModifiers(*buildReference, status);

    } else {

        // Unsafe code path

        // Store the MutablePatternModifier reference.

        unsafePatternModifier = buildReference;

    }

}

CompactHandler::~CompactHandler() {

    for (int32_t i = 0; i < precomputedModsLength; i++) {

        delete precomputedMods[i].mod;

    }

}

void CompactHandler::precomputeAllModifiers(MutablePatternModifier &buildReference, UErrorCode &status) {

    if (U_FAILURE(status)) { return; }

    // Initial capacity of 12 for 0K, 00K, 000K, ...M, ...B, and ...T

    UVector allPatterns(12, status);

    if (U_FAILURE(status)) { return; }

    data.getUniquePatterns(allPatterns, status);

    if (U_FAILURE(status)) { return; }

    // C++ only: ensure that precomputedMods has room.

    precomputedModsLength = allPatterns.size();

    if (precomputedMods.getCapacity() < precomputedModsLength) {

        precomputedMods.resize(allPatterns.size(), status);

        if (U_FAILURE(status)) { return; }

    }

    for (int32_t i = 0; i < precomputedModsLength; i++) {

        const auto* patternString = static_cast<const char16_t*>(allPatterns[i]);

        UnicodeString hello(patternString);

        CompactModInfo &info = precomputedMods[i];

        ParsedPatternInfo patternInfo;

        PatternParser::parseToPatternInfo(UnicodeString(patternString), patternInfo, status);

        if (U_FAILURE(status)) { return; }

        buildReference.setPatternInfo(&patternInfo, {UFIELD_CATEGORY_NUMBER, UNUM_COMPACT_FIELD});

        info.mod = buildReference.createImmutable(status);

        if (U_FAILURE(status)) { return; }

        info.patternString = patternString;

    }

}

void CompactHandler::processQuantity(DecimalQuantity &quantity, MicroProps &micros,

                                     UErrorCode &status) const {

    parent->processQuantity(quantity, micros, status);

    if (U_FAILURE(status)) { return; }

    // Treat zero, NaN, and infinity as if they had magnitude 0

    int32_t magnitude;

    int32_t multiplier = 0;

    if (quantity.isZeroish()) {

        magnitude = 0;

        micros.rounder.apply(quantity, status);

    } else {

        // TODO: Revisit chooseMultiplierAndApply

        multiplier = micros.rounder.chooseMultiplierAndApply(quantity, data, status);

        magnitude = quantity.isZeroish() ? 0 : quantity.getMagnitude();

        magnitude -= multiplier;

    }

    const char16_t *patternString = data.getPattern(magnitude, rules, quantity);

    if (patternString == nullptr) {

        // Use the default (non-compact) modifier.

        // No need to take any action.

    } else if (safe) {

        // Safe code path.

        // Java uses a hash set here for O(1) lookup.  C++ uses a linear search.

        // TODO: Benchmark this and maybe change to a binary search or hash table.

        int32_t i = 0;

        for (; i < precomputedModsLength; i++) {

            const CompactModInfo &info = precomputedMods[i];

            if (u_strcmp(patternString, info.patternString) == 0) {

                info.mod->applyToMicros(micros, quantity, status);

                break;

            }

        }

        // It should be guaranteed that we found the entry.

        U_ASSERT(i < precomputedModsLength);

    } else {

        // Unsafe code path.

        // Overwrite the PatternInfo in the existing modMiddle.

        // C++ Note: Use unsafePatternInfo for proper lifecycle.

        ParsedPatternInfo &patternInfo = const_cast<CompactHandler *>(this)->unsafePatternInfo;

        PatternParser::parseToPatternInfo(UnicodeString(patternString), patternInfo, status);

        unsafePatternModifier->setPatternInfo(

            &unsafePatternInfo,

            {UFIELD_CATEGORY_NUMBER, UNUM_COMPACT_FIELD});

        unsafePatternModifier->setNumberProperties(quantity.signum(), StandardPlural::Form::COUNT);

        micros.modMiddle = unsafePatternModifier;

    }

    // Change the exponent only after we select appropriate plural form

    // for formatting purposes so that we preserve expected formatted

    // string behavior.

    quantity.adjustExponent(-1 * multiplier);

    // We already performed rounding. Do not perform it again.

    micros.rounder = RoundingImpl::passThrough();

}

#endif /* #if !UCONFIG_NO_FORMATTING */