// © 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 "charstr.h"

#include "uassert.h"

#include "unicode/numberformatter.h"

#include "number_types.h"

#include "number_decimalquantity.h"

#include "double-conversion.h"

#include "number_roundingutils.h"

#include "number_skeletons.h"

#include "putilimp.h"

#include "string_segment.h"

using namespace icu;

using namespace icu::number;

using namespace icu::number::impl;

using double_conversion::DoubleToStringConverter;

using icu::StringSegment;

void number::impl::parseIncrementOption(const StringSegment &segment,

                                        Precision &outPrecision,

                                        UErrorCode &status) {

    // Need to do char <-> UChar conversion...

    U_ASSERT(U_SUCCESS(status));

    CharString buffer;

    SKELETON_UCHAR_TO_CHAR(buffer, segment.toTempUnicodeString(), 0, segment.length(), status);

    // Utilize DecimalQuantity/decNumber to parse this for us.

    DecimalQuantity dq;

    UErrorCode localStatus = U_ZERO_ERROR;

    dq.setToDecNumber({buffer.data(), buffer.length()}, localStatus);

    if (U_FAILURE(localStatus)) {

        // throw new SkeletonSyntaxException("Invalid rounding increment", segment, e);

        status = U_NUMBER_SKELETON_SYNTAX_ERROR;

        return;

    }

    double increment = dq.toDouble();

    // We also need to figure out how many digits. Do a brute force string operation.

    int decimalOffset = 0;

    while (decimalOffset < segment.length() && segment.charAt(decimalOffset) != '.') {

        decimalOffset++;

    }

    if (decimalOffset == segment.length()) {

        outPrecision = Precision::increment(increment);

    } else {

        int32_t fractionLength = segment.length() - decimalOffset - 1;

        outPrecision = Precision::increment(increment).withMinFraction(fractionLength);

    }

}

namespace {

int32_t getRoundingMagnitudeFraction(int maxFrac) {

    if (maxFrac == -1) {

        return INT32_MIN;

    }

    return -maxFrac;

}

int32_t getRoundingMagnitudeSignificant(const DecimalQuantity &value, int maxSig) {

    if (maxSig == -1) {

        return INT32_MIN;

    }

    int magnitude = value.isZeroish() ? 0 : value.getMagnitude();

    return magnitude - maxSig + 1;

}

int32_t getDisplayMagnitudeFraction(int minFrac) {

    if (minFrac == 0) {

        return INT32_MAX;

    }

    return -minFrac;

}

int32_t getDisplayMagnitudeSignificant(const DecimalQuantity &value, int minSig) {

    int magnitude = value.isZeroish() ? 0 : value.getMagnitude();

    return magnitude - minSig + 1;

}

}

MultiplierProducer::~MultiplierProducer() = default;

digits_t roundingutils::doubleFractionLength(double input, int8_t* singleDigit) {

    char buffer[DoubleToStringConverter::kBase10MaximalLength + 1];

    bool sign; // unused; always positive

    int32_t length;

    int32_t point;

    DoubleToStringConverter::DoubleToAscii(

            input,

            DoubleToStringConverter::DtoaMode::SHORTEST,

            0,

            buffer,

            sizeof(buffer),

            &sign,

            &length,

            &point

    );

    if (singleDigit == nullptr) {

        // no-op

    } else if (length == 1) {

        *singleDigit = buffer[0] - '0';

    } else {

        *singleDigit = -1;

    }

    return static_cast<digits_t>(length - point);

}

Precision Precision::unlimited() {

    return Precision(RND_NONE, {});

}

FractionPrecision Precision::integer() {

    return constructFraction(0, 0);

}

FractionPrecision Precision::fixedFraction(int32_t minMaxFractionPlaces) {

    if (minMaxFractionPlaces >= 0 && minMaxFractionPlaces <= kMaxIntFracSig) {

        return constructFraction(minMaxFractionPlaces, minMaxFractionPlaces);

    } else {

        return {U_NUMBER_ARG_OUTOFBOUNDS_ERROR};

    }

}

FractionPrecision Precision::minFraction(int32_t minFractionPlaces) {

    if (minFractionPlaces >= 0 && minFractionPlaces <= kMaxIntFracSig) {

        return constructFraction(minFractionPlaces, -1);

    } else {

        return {U_NUMBER_ARG_OUTOFBOUNDS_ERROR};

    }

}

FractionPrecision Precision::maxFraction(int32_t maxFractionPlaces) {

    if (maxFractionPlaces >= 0 && maxFractionPlaces <= kMaxIntFracSig) {

        return constructFraction(0, maxFractionPlaces);

    } else {

        return {U_NUMBER_ARG_OUTOFBOUNDS_ERROR};

    }

}

FractionPrecision Precision::minMaxFraction(int32_t minFractionPlaces, int32_t maxFractionPlaces) {

    if (minFractionPlaces >= 0 && maxFractionPlaces <= kMaxIntFracSig &&

        minFractionPlaces <= maxFractionPlaces) {

        return constructFraction(minFractionPlaces, maxFractionPlaces);

    } else {

        return {U_NUMBER_ARG_OUTOFBOUNDS_ERROR};

    }

}

Precision Precision::fixedSignificantDigits(int32_t minMaxSignificantDigits) {

    if (minMaxSignificantDigits >= 1 && minMaxSignificantDigits <= kMaxIntFracSig) {

        return constructSignificant(minMaxSignificantDigits, minMaxSignificantDigits);

    } else {

        return {U_NUMBER_ARG_OUTOFBOUNDS_ERROR};

    }

}

Precision Precision::minSignificantDigits(int32_t minSignificantDigits) {

    if (minSignificantDigits >= 1 && minSignificantDigits <= kMaxIntFracSig) {

        return constructSignificant(minSignificantDigits, -1);

    } else {

        return {U_NUMBER_ARG_OUTOFBOUNDS_ERROR};

    }

}

Precision Precision::maxSignificantDigits(int32_t maxSignificantDigits) {

    if (maxSignificantDigits >= 1 && maxSignificantDigits <= kMaxIntFracSig) {

        return constructSignificant(1, maxSignificantDigits);

    } else {

        return {U_NUMBER_ARG_OUTOFBOUNDS_ERROR};

    }

}

Precision Precision::minMaxSignificantDigits(int32_t minSignificantDigits, int32_t maxSignificantDigits) {

    if (minSignificantDigits >= 1 && maxSignificantDigits <= kMaxIntFracSig &&

        minSignificantDigits <= maxSignificantDigits) {

        return constructSignificant(minSignificantDigits, maxSignificantDigits);

    } else {

        return {U_NUMBER_ARG_OUTOFBOUNDS_ERROR};

    }

}

Precision Precision::trailingZeroDisplay(UNumberTrailingZeroDisplay trailingZeroDisplay) const {

    Precision result(*this); // copy constructor

    result.fTrailingZeroDisplay = trailingZeroDisplay;

    return result;

}

IncrementPrecision Precision::increment(double roundingIncrement) {

    if (roundingIncrement > 0.0) {

        return constructIncrement(roundingIncrement, 0);

    } else {

        return {U_NUMBER_ARG_OUTOFBOUNDS_ERROR};

    }

}

CurrencyPrecision Precision::currency(UCurrencyUsage currencyUsage) {

    return constructCurrency(currencyUsage);

}

Precision FractionPrecision::withSignificantDigits(

        int32_t minSignificantDigits,

        int32_t maxSignificantDigits,

        UNumberRoundingPriority priority) const {

    if (fType == RND_ERROR) { return *this; } // no-op in error state

    if (minSignificantDigits >= 1 &&

            maxSignificantDigits >= minSignificantDigits &&

            maxSignificantDigits <= kMaxIntFracSig) {

        return constructFractionSignificant(

            *this,

            minSignificantDigits,

            maxSignificantDigits,

            priority);

    } else {

        return {U_NUMBER_ARG_OUTOFBOUNDS_ERROR};

    }

}

Precision FractionPrecision::withMinDigits(int32_t minSignificantDigits) const {

    if (fType == RND_ERROR) { return *this; } // no-op in error state

    if (minSignificantDigits >= 1 && minSignificantDigits <= kMaxIntFracSig) {

        return constructFractionSignificant(

            *this,

            1,

            minSignificantDigits,

            UNUM_ROUNDING_PRIORITY_RELAXED);

    } else {

        return {U_NUMBER_ARG_OUTOFBOUNDS_ERROR};

    }

}

Precision FractionPrecision::withMaxDigits(int32_t maxSignificantDigits) const {

    if (fType == RND_ERROR) { return *this; } // no-op in error state

    if (maxSignificantDigits >= 1 && maxSignificantDigits <= kMaxIntFracSig) {

        return constructFractionSignificant(*this,

            1,

            maxSignificantDigits,

            UNUM_ROUNDING_PRIORITY_STRICT);

    } else {

        return {U_NUMBER_ARG_OUTOFBOUNDS_ERROR};

    }

}

// Private method on base class

Precision Precision::withCurrency(const CurrencyUnit &currency, UErrorCode &status) const {

    if (fType == RND_ERROR) { return *this; } // no-op in error state

    U_ASSERT(fType == RND_CURRENCY);

    const char16_t *isoCode = currency.getISOCurrency();

    double increment = ucurr_getRoundingIncrementForUsage(isoCode, fUnion.currencyUsage, &status);

    int32_t minMaxFrac = ucurr_getDefaultFractionDigitsForUsage(

            isoCode, fUnion.currencyUsage, &status);

    Precision retval = (increment != 0.0)

        ? static_cast<Precision>(constructIncrement(increment, minMaxFrac))

        : static_cast<Precision>(constructFraction(minMaxFrac, minMaxFrac));

    retval.fTrailingZeroDisplay = fTrailingZeroDisplay;

    return retval;

}

// Public method on CurrencyPrecision subclass

Precision CurrencyPrecision::withCurrency(const CurrencyUnit &currency) const {

    UErrorCode localStatus = U_ZERO_ERROR;

    Precision result = Precision::withCurrency(currency, localStatus);

    if (U_FAILURE(localStatus)) {

        return {localStatus};

    }

    return result;

}

Precision IncrementPrecision::withMinFraction(int32_t minFrac) const {

    if (fType == RND_ERROR) { return *this; } // no-op in error state

    if (minFrac >= 0 && minFrac <= kMaxIntFracSig) {

        return constructIncrement(fUnion.increment.fIncrement, minFrac);

    } else {

        return {U_NUMBER_ARG_OUTOFBOUNDS_ERROR};

    }

}

FractionPrecision Precision::constructFraction(int32_t minFrac, int32_t maxFrac) {

    FractionSignificantSettings settings;

    settings.fMinFrac = static_cast<digits_t>(minFrac);

    settings.fMaxFrac = static_cast<digits_t>(maxFrac);

    settings.fMinSig = -1;

    settings.fMaxSig = -1;

    PrecisionUnion union_;

    union_.fracSig = settings;

    return {RND_FRACTION, union_};

}

Precision Precision::constructSignificant(int32_t minSig, int32_t maxSig) {

    FractionSignificantSettings settings;

    settings.fMinFrac = -1;

    settings.fMaxFrac = -1;

    settings.fMinSig = static_cast<digits_t>(minSig);

    settings.fMaxSig = static_cast<digits_t>(maxSig);

    PrecisionUnion union_;

    union_.fracSig = settings;

    return {RND_SIGNIFICANT, union_};

}

Precision

Precision::constructFractionSignificant(

        const FractionPrecision &base,

        int32_t minSig,

        int32_t maxSig,

        UNumberRoundingPriority priority) {

    FractionSignificantSettings settings = base.fUnion.fracSig;

    settings.fMinSig = static_cast<digits_t>(minSig);

    settings.fMaxSig = static_cast<digits_t>(maxSig);

    settings.fPriority = priority;

    PrecisionUnion union_;

    union_.fracSig = settings;

    return {RND_FRACTION_SIGNIFICANT, union_};

}

IncrementPrecision Precision::constructIncrement(double increment, int32_t minFrac) {

    IncrementSettings settings;

    // Note: For number formatting, fIncrement is used for RND_INCREMENT but not

    // RND_INCREMENT_ONE or RND_INCREMENT_FIVE. However, fIncrement is used in all

    // three when constructing a skeleton.

    settings.fIncrement = increment;

    settings.fMinFrac = static_cast<digits_t>(minFrac);

    // One of the few pre-computed quantities:

    // Note: it is possible for minFrac to be more than maxFrac... (misleading)

    int8_t singleDigit;

    settings.fMaxFrac = roundingutils::doubleFractionLength(increment, &singleDigit);

    PrecisionUnion union_;

    union_.increment = settings;

    if (singleDigit == 1) {

        // NOTE: In C++, we must return the correct value type with the correct union.

        // It would be invalid to return a RND_FRACTION here because the methods on the

        // IncrementPrecision type assume that the union is backed by increment data.

        return {RND_INCREMENT_ONE, union_};

    } else if (singleDigit == 5) {

        return {RND_INCREMENT_FIVE, union_};

    } else {

        return {RND_INCREMENT, union_};

    }

}

CurrencyPrecision Precision::constructCurrency(UCurrencyUsage usage) {

    PrecisionUnion union_;

    union_.currencyUsage = usage;

    return {RND_CURRENCY, union_};

}

RoundingImpl::RoundingImpl(const Precision& precision, UNumberFormatRoundingMode roundingMode,

                           const CurrencyUnit& currency, UErrorCode& status)

        : fPrecision(precision), fRoundingMode(roundingMode), fPassThrough(false) {

    if (precision.fType == Precision::RND_CURRENCY) {

        fPrecision = precision.withCurrency(currency, status);

    }

}

RoundingImpl RoundingImpl::passThrough() {

    return {};

}

bool RoundingImpl::isSignificantDigits() const {

    return fPrecision.fType == Precision::RND_SIGNIFICANT;

}

int32_t

RoundingImpl::chooseMultiplierAndApply(impl::DecimalQuantity &input, const impl::MultiplierProducer &producer,

                                  UErrorCode &status) {

    // Do not call this method with zero, NaN, or infinity.

    U_ASSERT(!input.isZeroish());

    // Perform the first attempt at rounding.

    int magnitude = input.getMagnitude();

    int multiplier = producer.getMultiplier(magnitude);

    input.adjustMagnitude(multiplier);

    apply(input, status);

    // If the number rounded to zero, exit.

    if (input.isZeroish() || U_FAILURE(status)) {

        return multiplier;

    }

    // If the new magnitude after rounding is the same as it was before rounding, then we are done.

    // This case applies to most numbers.

    if (input.getMagnitude() == magnitude + multiplier) {

        return multiplier;

    }

    // If the above case DIDN'T apply, then we have a case like 99.9 -> 100 or 999.9 -> 1000:

    // The number rounded up to the next magnitude. Check if the multiplier changes; if it doesn't,

    // we do not need to make any more adjustments.

    int _multiplier = producer.getMultiplier(magnitude + 1);

    if (multiplier == _multiplier) {

        return multiplier;

    }

    // We have a case like 999.9 -> 1000, where the correct output is "1K", not "1000".

    // Fix the magnitude and re-apply the rounding strategy.

    input.adjustMagnitude(_multiplier - multiplier);

    apply(input, status);

    return _multiplier;

}

/** This is the method that contains the actual rounding logic. */

void RoundingImpl::apply(impl::DecimalQuantity &value, UErrorCode& status) const {

    if (U_FAILURE(status)) {

        return;

    }

    if (fPassThrough) {

        return;

    }

    int32_t resolvedMinFraction = 0;

    switch (fPrecision.fType) {

        case Precision::RND_BOGUS:

        case Precision::RND_ERROR:

            // Errors should be caught before the apply() method is called

            status = U_INTERNAL_PROGRAM_ERROR;

            break;

        case Precision::RND_NONE:

            value.roundToInfinity();

            break;

        case Precision::RND_FRACTION:

            value.roundToMagnitude(

                    getRoundingMagnitudeFraction(fPrecision.fUnion.fracSig.fMaxFrac),

                    fRoundingMode,

                    status);

            resolvedMinFraction =

                    uprv_max(0, -getDisplayMagnitudeFraction(fPrecision.fUnion.fracSig.fMinFrac));

            break;

        case Precision::RND_SIGNIFICANT:

            value.roundToMagnitude(

                    getRoundingMagnitudeSignificant(value, fPrecision.fUnion.fracSig.fMaxSig),

                    fRoundingMode,

                    status);

            resolvedMinFraction =

                    uprv_max(0, -getDisplayMagnitudeSignificant(value, fPrecision.fUnion.fracSig.fMinSig));

            // Make sure that digits are displayed on zero.

            if (value.isZeroish() && fPrecision.fUnion.fracSig.fMinSig > 0) {

                value.setMinInteger(1);

            }

            break;

        case Precision::RND_FRACTION_SIGNIFICANT: {

            int32_t roundingMag1 = getRoundingMagnitudeFraction(fPrecision.fUnion.fracSig.fMaxFrac);

            int32_t roundingMag2 = getRoundingMagnitudeSignificant(value, fPrecision.fUnion.fracSig.fMaxSig);

            int32_t roundingMag;

            if (fPrecision.fUnion.fracSig.fPriority == UNUM_ROUNDING_PRIORITY_RELAXED) {

                roundingMag = uprv_min(roundingMag1, roundingMag2);

            } else {

                roundingMag = uprv_max(roundingMag1, roundingMag2);

            }

            value.roundToMagnitude(roundingMag, fRoundingMode, status);

            int32_t displayMag1 = getDisplayMagnitudeFraction(fPrecision.fUnion.fracSig.fMinFrac);

            int32_t displayMag2 = getDisplayMagnitudeSignificant(value, fPrecision.fUnion.fracSig.fMinSig);

            int32_t displayMag = uprv_min(displayMag1, displayMag2);

            resolvedMinFraction = uprv_max(0, -displayMag);

            break;

        }

        case Precision::RND_INCREMENT:

            value.roundToIncrement(

                    fPrecision.fUnion.increment.fIncrement,

                    fRoundingMode,

                    status);

            resolvedMinFraction = fPrecision.fUnion.increment.fMinFrac;

            break;

        case Precision::RND_INCREMENT_ONE:

            value.roundToMagnitude(

                    -fPrecision.fUnion.increment.fMaxFrac,

                    fRoundingMode,

                    status);

            resolvedMinFraction = fPrecision.fUnion.increment.fMinFrac;

            break;

        case Precision::RND_INCREMENT_FIVE:

            value.roundToNickel(

                    -fPrecision.fUnion.increment.fMaxFrac,

                    fRoundingMode,

                    status);

            resolvedMinFraction = fPrecision.fUnion.increment.fMinFrac;

            break;

        case Precision::RND_CURRENCY:

            // Call .withCurrency() before .apply()!

            UPRV_UNREACHABLE;

        default:

            UPRV_UNREACHABLE;

    }

    if (fPrecision.fTrailingZeroDisplay == UNUM_TRAILING_ZERO_AUTO ||

            // PLURAL_OPERAND_T returns fraction digits as an integer

            value.getPluralOperand(PLURAL_OPERAND_T) != 0) {

        value.setMinFraction(resolvedMinFraction);

    }

}

void RoundingImpl::apply(impl::DecimalQuantity &value, int32_t minInt, UErrorCode /*status*/) {

    // This method is intended for the one specific purpose of helping print "00.000E0".

    // Question: Is it useful to look at trailingZeroDisplay here?

    U_ASSERT(isSignificantDigits());

    U_ASSERT(value.isZeroish());

    value.setMinFraction(fPrecision.fUnion.fracSig.fMinSig - minInt);

}

#endif /* #if !UCONFIG_NO_FORMATTING */