// © 2019 and later: Unicode, Inc. and others.

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

#include <optional>

#include <string_view>

#include <utility>

#include "bytesinkutil.h"  // StringByteSink<CharString>

#include "charstr.h"

#include "cstring.h"

#include "fixedstring.h"

#include "ulocimp.h"

#include "unicode/localebuilder.h"

#include "unicode/locid.h"

namespace {

inline bool UPRV_ISDIGIT(char c) { return c >= '0' && c <= '9'; }

inline bool UPRV_ISALPHANUM(char c) { return uprv_isASCIILetter(c) || UPRV_ISDIGIT(c); }

constexpr const char* kAttributeKey = "attribute";

bool _isExtensionSubtags(char key, const char* s, int32_t len) {

    switch (uprv_tolower(key)) {

        case 'u':

            return ultag_isUnicodeExtensionSubtags(s, len);

        case 't':

            return ultag_isTransformedExtensionSubtags(s, len);

        case 'x':

            return ultag_isPrivateuseValueSubtags(s, len);

        default:

            return ultag_isExtensionSubtags(s, len);

    }

}

}  // namespace

U_NAMESPACE_BEGIN

LocaleBuilder::LocaleBuilder() : UObject(), status_(U_ZERO_ERROR), language_(),

    script_(), region_(), variant_(nullptr), extensions_(nullptr)

{

    language_[0] = 0;

    script_[0] = 0;

    region_[0] = 0;

}

LocaleBuilder::~LocaleBuilder()

{

    delete variant_;

    delete extensions_;

}

LocaleBuilder& LocaleBuilder::setLocale(const Locale& locale)

{

    clear();

    setLanguage(locale.getLanguage());

    setScript(locale.getScript());

    setRegion(locale.getCountry());

    setVariant(locale.getVariant());

    extensions_ = locale.clone();

    if (extensions_ == nullptr) {

        status_ = U_MEMORY_ALLOCATION_ERROR;

    }

    return *this;

}

LocaleBuilder& LocaleBuilder::setLanguageTag(StringPiece tag)

{

    Locale l = Locale::forLanguageTag(tag, status_);

    if (U_FAILURE(status_)) { return *this; }

    // Because setLocale will reset status_ we need to return

    // first if we have error in forLanguageTag.

    setLocale(l);

    return *this;

}

namespace {

void setField(StringPiece input, char* dest, UErrorCode& errorCode,

              bool (*test)(const char*, int32_t)) {

    if (U_FAILURE(errorCode)) { return; }

    if (input.empty()) {

        dest[0] = '\0';

    } else if (test(input.data(), input.length())) {

        uprv_memcpy(dest, input.data(), input.length());

        dest[input.length()] = '\0';

    } else {

        errorCode = U_ILLEGAL_ARGUMENT_ERROR;

    }

}

}  // namespace

LocaleBuilder& LocaleBuilder::setLanguage(StringPiece language)

{

    setField(language, language_, status_, &ultag_isLanguageSubtag);

    return *this;

}

LocaleBuilder& LocaleBuilder::setScript(StringPiece script)

{

    setField(script, script_, status_, &ultag_isScriptSubtag);

    return *this;

}

LocaleBuilder& LocaleBuilder::setRegion(StringPiece region)

{

    setField(region, region_, status_, &ultag_isRegionSubtag);

    return *this;

}

namespace {

void transform(char* data, int32_t len) {

    for (int32_t i = 0; i < len; i++, data++) {

        if (*data == '_') {

            *data = '-';

        } else {

            *data = uprv_tolower(*data);

        }

    }

}

}  // namespace

LocaleBuilder& LocaleBuilder::setVariant(StringPiece variant)

{

    if (U_FAILURE(status_)) { return *this; }

    if (variant.empty()) {

        delete variant_;

        variant_ = nullptr;

        return *this;

    }

    FixedString* new_variant = new FixedString(variant);

    if (new_variant == nullptr || new_variant->isEmpty()) {

        status_ = U_MEMORY_ALLOCATION_ERROR;

        return *this;

    }

    transform(new_variant->getAlias(), variant.length());

    if (!ultag_isVariantSubtags(new_variant->data(), variant.length())) {

        delete new_variant;

        status_ = U_ILLEGAL_ARGUMENT_ERROR;

        return *this;

    }

    delete variant_;

    variant_ = new_variant;

    return *this;

}

namespace {

bool

_isKeywordValue(const char* key, const char* value, int32_t value_len)

{

    if (key[1] == '\0') {

        // one char key

        return (UPRV_ISALPHANUM(uprv_tolower(key[0])) &&

                _isExtensionSubtags(key[0], value, value_len));

    } else if (uprv_strcmp(key, kAttributeKey) == 0) {

        // unicode attributes

        return ultag_isUnicodeLocaleAttributes(value, value_len);

    }

    // otherwise: unicode extension value

    // We need to convert from legacy key/value to unicode

    // key/value

    std::optional<std::string_view> unicode_locale_key = ulocimp_toBcpKeyWithFallback(key);

    std::optional<std::string_view> unicode_locale_type = ulocimp_toBcpTypeWithFallback(key, value);

    return unicode_locale_key.has_value() &&

           unicode_locale_type.has_value() &&

           ultag_isUnicodeLocaleKey(unicode_locale_key->data(),

                                    static_cast<int32_t>(unicode_locale_key->size())) &&

           ultag_isUnicodeLocaleType(unicode_locale_type->data(),

                                     static_cast<int32_t>(unicode_locale_type->size()));

}

void

_copyExtensions(const Locale& from, icu::StringEnumeration *keywords,

                Locale& to, bool validate, UErrorCode& errorCode)

{

    if (U_FAILURE(errorCode)) { return; }

    LocalPointer<icu::StringEnumeration> ownedKeywords;

    if (keywords == nullptr) {

        ownedKeywords.adoptInstead(from.createKeywords(errorCode));

        if (U_FAILURE(errorCode) || ownedKeywords.isNull()) { return; }

        keywords = ownedKeywords.getAlias();

    }

    const char* key;

    while ((key = keywords->next(nullptr, errorCode)) != nullptr) {

        auto value = from.getKeywordValue<CharString>(key, errorCode);

        if (U_FAILURE(errorCode)) { return; }

        if (uprv_strcmp(key, kAttributeKey) == 0) {

            transform(value.data(), value.length());

        }

        if (validate &&

            !_isKeywordValue(key, value.data(), value.length())) {

            errorCode = U_ILLEGAL_ARGUMENT_ERROR;

            return;

        }

        to.setKeywordValue(key, value.data(), errorCode);

        if (U_FAILURE(errorCode)) { return; }

    }

}

void

_clearUAttributesAndKeyType(Locale& locale, UErrorCode& errorCode)

{

    if (U_FAILURE(errorCode)) { return; }

    // Clear Unicode attributes

    locale.setKeywordValue(kAttributeKey, "", errorCode);

    // Clear all Unicode keyword values

    LocalPointer<icu::StringEnumeration> iter(locale.createUnicodeKeywords(errorCode));

    if (U_FAILURE(errorCode) || iter.isNull()) { return; }

    const char* key;

    while ((key = iter->next(nullptr, errorCode)) != nullptr) {

        locale.setUnicodeKeywordValue(key, nullptr, errorCode);

    }

}

void

_setUnicodeExtensions(Locale& locale, const CharString& value, UErrorCode& errorCode)

{

    if (U_FAILURE(errorCode)) { return; }

    // Add the unicode extensions to extensions_

    CharString locale_str("und-u-", errorCode);

    locale_str.append(value, errorCode);

    _copyExtensions(

        Locale::forLanguageTag(locale_str.data(), errorCode), nullptr,

        locale, false, errorCode);

}

}  // namespace

LocaleBuilder& LocaleBuilder::setExtension(char key, StringPiece value)

{

    if (U_FAILURE(status_)) { return *this; }

    if (!UPRV_ISALPHANUM(key)) {

        status_ = U_ILLEGAL_ARGUMENT_ERROR;

        return *this;

    }

    CharString value_str(value, status_);

    if (U_FAILURE(status_)) { return *this; }

    transform(value_str.data(), value_str.length());

    if (!value_str.isEmpty() &&

            !_isExtensionSubtags(key, value_str.data(), value_str.length())) {

        status_ = U_ILLEGAL_ARGUMENT_ERROR;

        return *this;

    }

    if (extensions_ == nullptr) {

        extensions_ = Locale::getRoot().clone();

        if (extensions_ == nullptr) {

            status_ = U_MEMORY_ALLOCATION_ERROR;

            return *this;

        }

    }

    if (uprv_tolower(key) != 'u') {

        // for t, x and others extension.

        extensions_->setKeywordValue(StringPiece(&key, 1), value_str.data(),

                                     status_);

        return *this;

    }

    _clearUAttributesAndKeyType(*extensions_, status_);

    if (U_FAILURE(status_)) { return *this; }

    if (!value.empty()) {

        _setUnicodeExtensions(*extensions_, value_str, status_);

    }

    return *this;

}

LocaleBuilder& LocaleBuilder::setUnicodeLocaleKeyword(

      StringPiece key, StringPiece type)

{

    if (U_FAILURE(status_)) { return *this; }

    if (!ultag_isUnicodeLocaleKey(key.data(), key.length()) ||

            (!type.empty() &&

                 !ultag_isUnicodeLocaleType(type.data(), type.length()))) {

      status_ = U_ILLEGAL_ARGUMENT_ERROR;

      return *this;

    }

    if (extensions_ == nullptr) {

        extensions_ = Locale::getRoot().clone();

        if (extensions_ == nullptr) {

            status_ = U_MEMORY_ALLOCATION_ERROR;

            return *this;

        }

    }

    extensions_->setUnicodeKeywordValue(key, type, status_);

    return *this;

}

LocaleBuilder& LocaleBuilder::addUnicodeLocaleAttribute(

    StringPiece value)

{

    CharString value_str(value, status_);

    if (U_FAILURE(status_)) { return *this; }

    transform(value_str.data(), value_str.length());

    if (!ultag_isUnicodeLocaleAttribute(value_str.data(), value_str.length())) {

        status_ = U_ILLEGAL_ARGUMENT_ERROR;

        return *this;

    }

    if (extensions_ == nullptr) {

        extensions_ = Locale::getRoot().clone();

        if (extensions_ == nullptr) {

            status_ = U_MEMORY_ALLOCATION_ERROR;

            return *this;

        }

        extensions_->setKeywordValue(kAttributeKey, value_str.data(), status_);

        return *this;

    }

    UErrorCode localErrorCode = U_ZERO_ERROR;

    auto attributes = extensions_->getKeywordValue<CharString>(kAttributeKey, localErrorCode);

    if (U_FAILURE(localErrorCode)) {

        CharString new_attributes(value_str.data(), status_);

        // No attributes, set the attribute.

        extensions_->setKeywordValue(kAttributeKey, new_attributes.data(), status_);

        return *this;

    }

    transform(attributes.data(),attributes.length());

    const char* start = attributes.data();

    const char* limit = attributes.data() + attributes.length();

    CharString new_attributes;

    bool inserted = false;

    while (start < limit) {

        if (!inserted) {

            int cmp = uprv_strcmp(start, value_str.data());

            if (cmp == 0) { return *this; }  // Found it in attributes: Just return

            if (cmp > 0) {

                if (!new_attributes.isEmpty()) new_attributes.append('_', status_);

                new_attributes.append(value_str.data(), status_);

                inserted = true;

            }

        }

        if (!new_attributes.isEmpty()) {

            new_attributes.append('_', status_);

        }

        new_attributes.append(start, status_);

        start += uprv_strlen(start) + 1;

    }

    if (!inserted) {

        if (!new_attributes.isEmpty()) {

            new_attributes.append('_', status_);

        }

        new_attributes.append(value_str.data(), status_);

    }

    // Not yet in the attributes, set the attribute.

    extensions_->setKeywordValue(kAttributeKey, new_attributes.data(), status_);

    return *this;

}

LocaleBuilder& LocaleBuilder::removeUnicodeLocaleAttribute(

    StringPiece value)

{

    CharString value_str(value, status_);

    if (U_FAILURE(status_)) { return *this; }

    transform(value_str.data(), value_str.length());

    if (!ultag_isUnicodeLocaleAttribute(value_str.data(), value_str.length())) {

        status_ = U_ILLEGAL_ARGUMENT_ERROR;

        return *this;

    }

    if (extensions_ == nullptr) { return *this; }

    UErrorCode localErrorCode = U_ZERO_ERROR;

    auto attributes = extensions_->getKeywordValue<CharString>(kAttributeKey, localErrorCode);

    // get failure, just return

    if (U_FAILURE(localErrorCode)) { return *this; }

    // Do not have any attributes, just return.

    if (attributes.isEmpty()) { return *this; }

    char* p = attributes.data();

    // Replace null terminiator in place for _ and - so later

    // we can use uprv_strcmp to compare.

    for (int32_t i = 0; i < attributes.length(); i++, p++) {

        *p = (*p == '_' || *p == '-') ? '\0' : uprv_tolower(*p);

    }

    const char* start = attributes.data();

    const char* limit = attributes.data() + attributes.length();

    CharString new_attributes;

    bool found = false;

    while (start < limit) {

        if (uprv_strcmp(start, value_str.data()) == 0) {

            found = true;

        } else {

            if (!new_attributes.isEmpty()) {

                new_attributes.append('_', status_);

            }

            new_attributes.append(start, status_);

        }

        start += uprv_strlen(start) + 1;

    }

    // Found the value in attributes, set the attribute.

    if (found) {

        extensions_->setKeywordValue(kAttributeKey, new_attributes.data(), status_);

    }

    return *this;

}

LocaleBuilder& LocaleBuilder::clear()

{

    status_ = U_ZERO_ERROR;

    language_[0] = 0;

    script_[0] = 0;

    region_[0] = 0;

    delete variant_;

    variant_ = nullptr;

    clearExtensions();

    return *this;

}

LocaleBuilder& LocaleBuilder::clearExtensions()

{

    delete extensions_;

    extensions_ = nullptr;

    return *this;

}

Locale makeBogusLocale() {

  Locale bogus;

  bogus.setToBogus();

  return bogus;

}

void LocaleBuilder::copyExtensionsFrom(const Locale& src, UErrorCode& errorCode)

{

    if (U_FAILURE(errorCode)) { return; }

    LocalPointer<icu::StringEnumeration> keywords(src.createKeywords(errorCode));

    if (U_FAILURE(errorCode) || keywords.isNull() || keywords->count(errorCode) == 0) {

        // Error, or no extensions to copy.

        return;

    }

    if (extensions_ == nullptr) {

        extensions_ = Locale::getRoot().clone();

        if (extensions_ == nullptr) {

            status_ = U_MEMORY_ALLOCATION_ERROR;

            return;

        }

    }

    _copyExtensions(src, keywords.getAlias(), *extensions_, false, errorCode);

}

Locale LocaleBuilder::build(UErrorCode& errorCode)

{

    if (U_FAILURE(errorCode)) {

        return makeBogusLocale();

    }

    if (U_FAILURE(status_)) {

        errorCode = status_;

        return makeBogusLocale();

    }

    CharString locale_str(language_, errorCode);

    if (uprv_strlen(script_) > 0) {

        locale_str.append('-', errorCode).append(StringPiece(script_), errorCode);

    }

    if (uprv_strlen(region_) > 0) {

        locale_str.append('-', errorCode).append(StringPiece(region_), errorCode);

    }

    if (variant_ != nullptr) {

        locale_str.append('-', errorCode).append(StringPiece(variant_->data()), errorCode);

    }

    if (U_FAILURE(errorCode)) {

        return makeBogusLocale();

    }

    Locale product(locale_str.data());

    if (extensions_ != nullptr) {

        _copyExtensions(*extensions_, nullptr, product, true, errorCode);

    }

    if (U_FAILURE(errorCode)) {

        return makeBogusLocale();

    }

    return product;

}

UBool LocaleBuilder::copyErrorTo(UErrorCode &outErrorCode) const {

    if (U_FAILURE(outErrorCode)) {

        // Do not overwrite the older error code

        return true;

    }

    outErrorCode = status_;

    return U_FAILURE(outErrorCode);

}

U_NAMESPACE_END