/***
    Copyright (C) 2021 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: EncoderNSL.cpp
    Date: 2021-8-19
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "../Locale.hpp"
#include "Encoding.hpp"
#include "EncoderNSL.hpp"

namespace Aurora::Locale::Encoding
{
    static AuStreamReadWrittenPair_t Win32ConvertCpAToCPB(AuUInt32 cpA, AuUInt32 cpB, const void *in, AuUInt32 inLength, void *cpBlob, AuUInt32 cpLen)
    {
    #if defined(AU_HAS_MSFT_NATIONALLANGSUPPORT)
        if (!in)
        {
            return {};
        }
        // Get the UTF-16 character count of the cpA string in/inLength
        auto chars = MultiByteToWideChar(cpA, 0, (LPCCH)in, inLength, NULL, 0);

        if (!chars)
        {
            return {};
        }
        
        // Allocate a temp utf-16/widechar string buffer
        auto ret = _new wchar_t[chars];
        if (!ret)
        {
            return {};
        }

        // Convert the cpA buffer to UTF-16
        MultiByteToWideChar(cpA, 0, (LPCCH)in, inLength, ret, chars);

        // convert the shortened string with invalid surrogates back into a cpA length
        AuUInt32 cpLength;
        if (!cpBlob)
        {
            cpLength = WideCharToMultiByte(cpB, 0, ret, chars, NULL, NULL, NULL, NULL);
        }
        else
        {
            cpLength = WideCharToMultiByte(cpB, 0, ret, chars, (LPSTR)cpBlob, cpLen, NULL, NULL);
        }
        
        delete[] ret;
        return {inLength, cpLength};
    #else
        return {};
    #endif
    }
    
    AuStreamReadWrittenPair_t Win32ConvertFromCPToUTF8(AuUInt32 cp, const void *in, AuUInt length, void *utf8, AuUInt32 utf8Len)
    {
    #if !defined(AU_HAS_MSFT_NATIONALLANGSUPPORT)
        return {};
    #else
        return Win32ConvertCpAToCPB(cp, CP_UTF8, in, length, utf8, utf8Len);
    #endif
    }

    AuStreamReadWrittenPair_t Win32ConvertFromUTF8ToCp(AuUInt32 cp, const void *utf8, AuUInt utf8Length, void *cpBlob, AuUInt32 cpLen)
    {
    #if !defined(AU_HAS_MSFT_NATIONALLANGSUPPORT)
        return {};
    #else 
        return Win32ConvertCpAToCPB(CP_UTF8, cp, utf8, utf8Length, cpBlob, cpLen);
    #endif
    }

    AuStreamReadWrittenPair_t Win32ConvertFromUTF16ToUTF8(const void *in, AuUInt32 inLength, void *utf8, AuUInt32 utf8Len)
    {
    #if defined(AU_HAS_MSFT_NATIONALLANGSUPPORT)
        if (!in)
        {
            return {};
        }

        auto pWideChars = (const wchar_t *)in;
       
        AuUInt32 cpLength;
        if (!utf8)
        {
            auto cpLength = WideCharToMultiByte(CP_UTF8, 0, (const wchar_t *)in, inLength / sizeof(wchar_t), NULL, NULL, NULL, NULL);
            return {inLength, cpLength};
        }
        else
        {
            cpLength = WideCharToMultiByte(CP_UTF8, 0, (const wchar_t *)in, inLength / sizeof(wchar_t), (LPSTR)utf8, utf8Len, NULL, NULL);
            return {inLength, cpLength};
        }

    #else
        return {};
    #endif
    }

    AuStreamReadWrittenPair_t Win32ConvertFromUTF8ToUTF16(const void *in, AuUInt32 inLength, void *utf16, AuUInt32 utf16Len)
    {
    #if defined(AU_HAS_MSFT_NATIONALLANGSUPPORT)
        if (!in)
        {
            return {};
        }
    
        // Get the UTF-16 character count of the cpA string in/inLength
        auto chars = MultiByteToWideChar(CP_UTF8, 0, (LPCCH)in, inLength, NULL, 0);
        
        if (!chars)
        {
            return {};
        }
        
        if (chars > utf16Len)
        {
            if (!utf16)
            {
                return {0, utf16Len};
            }
            else
            {
                return {};
            }
        }

        // Convert the CP_UTF8 buffer to UTF-16
        MultiByteToWideChar(CP_UTF8, 0, (LPCCH)in, inLength, (LPWSTR)utf16, chars);

        // convert the shortened string with invalid surrogates back into a CP_UTF8 length
        AuUInt32 read = inLength;
    #if 0
        if (slowPath)
    #endif
        {
            read = WideCharToMultiByte(CP_UTF8, 0, (LPWSTR)utf16, chars, NULL, 0, NULL, NULL);
        }

        return {read, chars * sizeof(wchar_t)};
    #else
        return {};
    #endif
    }

    AuStreamReadWrittenPair_t Win32CPToUTF8(ECodePage page, const void *in, AuUInt length, void *utf8, AuUInt32 utf8Max)
    { 
        AuStreamReadWrittenPair_t  ret {};

    #if defined(AU_HAS_MSFT_NATIONALLANGSUPPORT)
        switch (page)
        {
        default:
        case ECodePage::eUnsupported:
            return {};
        case ECodePage::e18030:
            ret = Win32ConvertFromUTF8ToCp(CP_CHINESE, in, length, utf8, utf8Max);
            break;
        case ECodePage::eSysUnk:
            ret = Win32ConvertFromCPToUTF8(CP_ACP, in, length, utf8, utf8Max);
            break;
        case ECodePage::eLatin1:
            ret = Win32ConvertFromCPToUTF8(CP_LATIN_1, in, length, utf8, utf8Max);
            break;
        case ECodePage::eUTF7:
            ret = Win32ConvertFromCPToUTF8(CP_UTF7, in, length, utf8, utf8Max);
            break;
        case ECodePage::e2312:
            ret = Win32ConvertFromCPToUTF8(CP_2312_LIMITED_GBK, in, length, utf8, utf8Max);
            break;
        case ECodePage::eGBK: 
            ret = Win32ConvertFromCPToUTF8(CP_2312_LIMITED_GBK, in, length, utf8, utf8Max);
            break;
        case ECodePage::eSJIS:
            ret = Win32ConvertFromCPToUTF8(CP_SHIFTJIS, in, length, utf8, utf8Max);
            break;
        case ECodePage::eUTF16:
            ret = Win32ConvertFromUTF16ToUTF8(in, length, utf8, utf8Max);
            break;
        }
    #endif

        return ret;
    }

    AuStreamReadWrittenPair_t Win32UTF8ToCp(ECodePage page, const void *utf8, AuUInt32 utf8Length, void *cp, AuUInt32 cpLen)
    {
        AuStreamReadWrittenPair_t ret {};
        
    #if defined(AU_HAS_MSFT_NATIONALLANGSUPPORT)
        switch (page)
        {
        default:
        case ECodePage::eUnsupported:
            return {};
        case ECodePage::eSysUnk:
            ret = Win32ConvertFromUTF8ToCp(CP_ACP, utf8, utf8Length, cp, cpLen);
            break;
        case ECodePage::eUTF7:
            ret = Win32ConvertFromUTF8ToCp(CP_UTF7, utf8, utf8Length, cp, cpLen);
            break;
        case ECodePage::eLatin1:
            ret = Win32ConvertFromUTF8ToCp(CP_LATIN_1, utf8, utf8Length, cp, cpLen);
            break;
        case ECodePage::e18030:
            ret = Win32ConvertFromUTF8ToCp(CP_CHINESE, utf8, utf8Length, cp, cpLen);
            break;
        case ECodePage::eSJIS:
            ret = Win32ConvertFromUTF8ToCp(CP_SHIFTJIS, utf8, utf8Length, cp, cpLen);
            break;
        case ECodePage::e2312:
        case ECodePage::eGBK: 
            ret = Win32ConvertFromUTF8ToCp(CP_2312_LIMITED_GBK, utf8, utf8Length, cp, cpLen);
            break;
        case ECodePage::eUTF16:
            ret = Win32ConvertFromUTF8ToUTF16(utf8, utf8Length, cp, cpLen);
            break;
        }

    #endif
        return ret;
    }
}