#include <nds.h>
#include "NtftFont.h"

NtftFont::NtftFont(const void* data)
{
    const ntft_header_t* font = (const ntft_header_t*)data;
    _font.header = font;
    _font.characterInfo = (const ntft_cinfo_t*)((u32)font + font->charInfoOffset);
    _font.glyphData = (const ntft_gdata_t*)((u32)font + font->glyphDataOffset);
}

void NtftFont::MeasureString(const char* text, int& width, int& height) const
{
    width = 0;
    height = _font.characterInfo->characterHeight;
    int tmpwidth = 0;
    unsigned char c = *text++;
    while (c != 0)
    {
        int end = 0;
        if (c == '\n')
        {
            if (width < tmpwidth)
                width = tmpwidth;
            tmpwidth = 0;
            height += _font.characterInfo->characterHeight + 1;
        }
        else
        {
            if ((tmpwidth + _font.characterInfo->characters[c].characterBeginOffset) >= 0)
                tmpwidth += _font.characterInfo->characters[c].characterBeginOffset;
            tmpwidth += _font.characterInfo->characters[c].characterWidth;
            end = _font.characterInfo->characters[c].characterEndOffset;
        }
        c = *text++;
        if (c != 0)
            tmpwidth += end;
    }
    if (width < tmpwidth)
        width = tmpwidth;
}

void NtftFont::CreateStringData(const char* text, u8* dst, int stride) const
{
    // todo: maybe support alignment
    // int width;
    // int height;
    // GetStringSize(text, width, height);
    int xpos = 0;
    int ypos = 0;
    bool nodraw = false;
    unsigned char c = *text++;
    while (c != 0)
    {
        if (c == '\n')
        {
            xpos = 0;
            ypos += _font.characterInfo->characterHeight + 1;
            nodraw = false;
        }
        else
        {
            if ((xpos + _font.characterInfo->characters[c].characterBeginOffset) >= 0)
                xpos += _font.characterInfo->characters[c].characterBeginOffset;
            if (xpos + (int)_font.characterInfo->characters[c].characterWidth > stride)
                nodraw = true;
            if (!nodraw)
            {
                u8* glyph = (uint8_t*)&_font.glyphData->glyphData[_font.characterInfo->characters[c].glyphDataOffset];
                u8* dst_ptr = dst + ypos * stride + xpos;
				int w = _font.characterInfo->characters[c].characterWidth;
				int h = _font.characterInfo->characterHeight;
                for (int y = 0; y < h; y++)
                {
                    for (int x = 0; x < w; x++)
                    {
                        u8 data = *glyph++;
                        int oldval = *dst_ptr;
                        int newval = oldval + data;
                        if (newval > 255)
                            newval = 255;
                        *dst_ptr++ = newval;
                    }
                    dst_ptr -= _font.characterInfo->characters[c].characterWidth;
                    dst_ptr += stride;
                }
                xpos += _font.characterInfo->characters[c].characterWidth;
                xpos += _font.characterInfo->characters[c].characterEndOffset;
            }
        }
        c = *text++;
    }
}