#include "jpeg_img.h"

#include <iostream>
#include <jpeglib.h>
#include <jerror.h>

Image decompressJpegImage(const unsigned char* buffer, size_t size)
{
    struct jpeg_decompress_struct info; //for our jpeg info
    struct jpeg_error_mgr err; //the error handler

    info.err = jpeg_std_error( &err );
    jpeg_create_decompress( &info ); //fills info structure

    jpeg_mem_src(&info, buffer, size);
    if(jpeg_read_header(&info, true) !=  JPEG_HEADER_OK)
        std::cerr<<"Could not read jpeg header";

    jpeg_start_decompress( &info );

    Image image;

    image.width = info.output_width;
    image.height = info.output_height;
    image.channels = info.num_components; // 3 = RGB, 4 = RGBA

    // read RGB(A) scanlines one at a time into jdata[]
    image.data = std::shared_ptr<unsigned char>(new unsigned char[image.size()]);
    unsigned char* rowptr;
    while(info.output_scanline < image.height)
    {
        rowptr = image.data.get() + info.output_scanline * image.width * image.channels;
        jpeg_read_scanlines( &info, &rowptr, 1 );
    }

    jpeg_finish_decompress( &info );

    return image;
}

Image decompressJpegImage(FILE *file)
{
    struct jpeg_decompress_struct info; //for our jpeg info
    struct jpeg_error_mgr err; //the error handler

    info.err = jpeg_std_error( &err );
    jpeg_create_decompress( &info ); //fills info structure

    jpeg_stdio_src( &info, file );
    jpeg_read_header( &info, true );

    jpeg_start_decompress( &info );

    Image image;

    image.width = info.output_width;
    image.height = info.output_height;
    image.channels = info.num_components; // 3 = RGB, 4 = RGBA

    // read RGB(A) scanlines one at a time into jdata[]
    image.data = std::shared_ptr<unsigned char>(new unsigned char[image.size()]);
    unsigned char* rowptr;
    while ( info.output_scanline < image.height )
    {
        rowptr = image.data.get() + info.output_scanline * image.width * image.channels;
        jpeg_read_scanlines( &info, &rowptr, 1 );
    }

    jpeg_finish_decompress( &info );

    fclose( file );

    return image;
}

void compressJpegImage(FILE *file, Image *image)
{
    struct jpeg_compress_struct info;
    struct jpeg_error_mgr err;

    info.err = jpeg_std_error( &err );

    jpeg_create_compress(&info);
    jpeg_stdio_dest(&info, file);

    /* Setting the parameters of the output file here */
    info.image_width = image->width;
    info.image_height= image->height;
    info.input_components = image->channels;
    info.in_color_space = JCS_RGB;

    jpeg_set_defaults( &info );
    /* Now do the compression .. */
    jpeg_start_compress( &info, TRUE );
    unsigned char* rowptr;
    while ( info.next_scanline < image->height )
    {
        rowptr = image->data.get() + info.next_scanline * image->width * image->channels;
        jpeg_write_scanlines( &info, &rowptr, 1 );
    }

    jpeg_finish_compress( &info );

    jpeg_destroy_compress( &info );
}