#include <utf8proc.h>
#include "hecl/hecl.hpp"

namespace hecl
{
static logvisor::Module Log("hecl-wsconv");

std::string WideToUTF8(std::wstring_view src)
{
    std::string retval;
    retval.reserve(src.length());
    for (wchar_t ch : src)
    {
        utf8proc_uint8_t mb[4];
        utf8proc_ssize_t c = utf8proc_encode_char(utf8proc_int32_t(ch), mb);
        if (c < 0)
        {
            Log.report(logvisor::Warning, "invalid UTF-8 character while encoding");
            return retval;
        }
        retval.append(reinterpret_cast<char*>(mb), c);
    }
    return retval;
}

std::string Char16ToUTF8(std::u16string_view src)
{
    std::string retval;
    retval.reserve(src.length());
    for (char16_t ch : src)
    {
        utf8proc_uint8_t mb[4];
        utf8proc_ssize_t c = utf8proc_encode_char(utf8proc_int32_t(ch), mb);
        if (c < 0)
        {
            Log.report(logvisor::Warning, "invalid UTF-8 character while encoding");
            return retval;
        }
        retval.append(reinterpret_cast<char*>(mb), c);
    }
    return retval;
}

std::wstring UTF8ToWide(std::string_view src)
{
    std::wstring retval;
    retval.reserve(src.length());
    const utf8proc_uint8_t* buf = reinterpret_cast<const utf8proc_uint8_t*>(src.data());
    while (*buf)
    {
        utf8proc_int32_t wc;
        utf8proc_ssize_t len = utf8proc_iterate(buf, -1, &wc);
        if (len < 0)
        {
            Log.report(logvisor::Warning, "invalid UTF-8 character while decoding");
            return retval;
        }
        buf += len;
        retval += wchar_t(wc);
    }
    return retval;
}

std::u16string UTF8ToChar16(std::string_view src)
{
    std::u16string retval;
    retval.reserve(src.length());
    const utf8proc_uint8_t* buf = reinterpret_cast<const utf8proc_uint8_t*>(src.data());
    while (*buf)
    {
        utf8proc_int32_t wc;
        utf8proc_ssize_t len = utf8proc_iterate(buf, -1, &wc);
        if (len < 0)
        {
            Log.report(logvisor::Warning, "invalid UTF-8 character while decoding");
            return retval;
        }
        buf += len;
        retval += char16_t(wc);
    }
    return retval;
}

}