#include <lib/InsPng.h>

#include <stdio.h>
#include <stdlib.h>
#include <setjmp.h>
#include <string.h>

#include <zlib.h>
#include <png.h>
#include <pngstruct.h>
#include <pnginfo.h>

typedef struct Struct_MemPng
{
    UInt08 *data;
    Int32 size;
    Int32 offset;
} MemPng;

static void callback_ReadMemPng(png_structp ptrPng, png_bytep data, png_size_t length)
{
    MemPng *mPngSrc = (MemPng*)ptrPng->io_ptr;
    if(mPngSrc == NULL)
    {
        png_error(ptrPng, "not mem png source define");
    }
    else if(mPngSrc->offset + length <= mPngSrc->size)
    {
        memcpy(data, mPngSrc->data+mPngSrc->offset, length);
        mPngSrc->offset += length;
    }
    else
    {
        png_error(ptrPng, "more mem png data is needed");
    }
}

/*RGB888 only*/
Bool LoadPngFromMem(void *mem, UInt32 memSz, Int32 *width, Int32 *height, UInt32 *format, void **bmp, UInt32 bmpSize)
{
    Int32 i, j, w, h, type;
    UInt32 fmt;
    MemPng mSrc =
    {
        .data = mem,
        .size = memSz,
        .offset = 0
    };
    UInt08 *buff;
#define GL_RGB  0x1907
#define GL_RGBA 0x1908

    png_structp ptrPng = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
    if(ptrPng == 0)return INS_FALSE;

    png_infop ptrInfo = png_create_info_struct(ptrPng);
    if(ptrInfo == 0)
    {
        png_destroy_read_struct(&ptrPng, 0, 0);
        return INS_FALSE;
    }

    if(setjmp(png_jmpbuf(ptrPng)))
    {
        png_destroy_read_struct(&ptrPng, 0, 0);
        return INS_FALSE;
    }

    png_set_read_fn(ptrPng, &mSrc, callback_ReadMemPng);
    png_read_png(ptrPng, ptrInfo, PNG_TRANSFORM_EXPAND, 0);

    w = ptrInfo->width;
    h = ptrInfo->height;
//    depth = ptrInfo->pixel_depth;
    png_bytep *PtrRow = png_get_rows(ptrPng, ptrInfo);
    type = ptrInfo->color_type;

    switch(type)
    {
    case PNG_COLOR_TYPE_RGB:
        if(bmp[0] != NULL && bmpSize > 0)
        {
            if(w*h*3 > bmpSize)
            {
                png_destroy_read_struct(&ptrPng, 0, 0);
                return INS_FALSE;
            }
        }
        else if(bmp[0] == NULL)
        {
            bmp[0] = malloc(w*h*3);
        }
        else
        {
            png_destroy_read_struct(&ptrPng, 0, 0);
            return INS_FALSE;
        }
        buff = bmp[0];
        fmt = GL_RGB;
        for(i = 0; i < h; i++)
        {
            for(j = 0; j < w; j++)
            {
                buff[3*((h-1-i)*w+j)+0] = PtrRow[i][3*j+0];
                buff[3*((h-1-i)*w+j)+1] = PtrRow[i][3*j+1];
                buff[3*((h-1-i)*w+j)+2] = PtrRow[i][3*j+2];
            }
        }
        break;
    case PNG_COLOR_TYPE_RGBA:
        if(bmp[0] != NULL && bmpSize > 0)
        {
            if(w*h*4 > bmpSize)
            {
                png_destroy_read_struct(&ptrPng, 0, 0);
                return INS_FALSE;
            }
        }
        else if(bmp[0] == NULL)
        {
            bmp[0] = malloc(w*h*4);
        }
        else
        {
            png_destroy_read_struct(&ptrPng, 0, 0);
            return INS_FALSE;
        }
        buff = bmp[0];
        fmt = GL_RGBA;
        for(i = 0; i < h; i++)
        {
            for(j = 0; j < w; j++)
            {
                buff[4*((h-1-i)*w+j)+0] = PtrRow[i][4*j+0];
                buff[4*((h-1-i)*w+j)+1] = PtrRow[i][4*j+1];
                buff[4*((h-1-i)*w+j)+2] = PtrRow[i][4*j+2];
                buff[4*((h-1-i)*w+j)+3] = PtrRow[i][4*j+3];
            }
        }
        break;
    default:
        png_destroy_read_struct(&ptrPng, 0, 0);
        return INS_FALSE;
    }

    *width = w;
    *height = h;
    *format = fmt;

    return INS_TRUE;
}