#include <Common/Collator.h>

#pragma GCC diagnostic push
#ifdef __APPLE__
#pragma GCC diagnostic ignored "-Wold-style-cast"
#endif
#include <unicode/ucol.h>
#pragma GCC diagnostic pop

#include <Common/Exception.h>
#include <IO/WriteHelpers.h>
#include <common/Common.h>
#include <Poco/String.h>

Collator::Collator(const std::string & locale_) : locale(Poco::toLower(locale_))
{
    UErrorCode status = U_ZERO_ERROR;

    collator = ucol_open(locale.c_str(), &status);
    if (status != U_ZERO_ERROR)
    {
        ucol_close(collator);
        throw DB::Exception("Unsupported collation locale: " + locale, DB::ErrorCodes::UNSUPPORTED_COLLATION_LOCALE);
    }
}

Collator::~Collator()
{
    ucol_close(collator);
}

int Collator::compare(const char * str1, size_t length1, const char * str2, size_t length2) const
{
    UCharIterator iter1, iter2;
    uiter_setUTF8(&iter1, str1, length1);
    uiter_setUTF8(&iter2, str2, length2);

    UErrorCode status = U_ZERO_ERROR;
    UCollationResult compare_result = ucol_strcollIter(collator, &iter1, &iter2, &status);

    if (status != U_ZERO_ERROR)
        throw DB::Exception("ICU collation comparison failed with error code: " + DB::toString<int>(status),
                            DB::ErrorCodes::COLLATION_COMPARISON_FAILED);

    /** Values of enum UCollationResult are equals to what exactly we need:
     *     UCOL_EQUAL = 0
     *     UCOL_GREATER = 1
     *     UCOL_LESS = -1
     */
    return compare_result;
}

const std::string & Collator::getLocale() const
{
    return locale;
}