/*==LICENSE==*

CyanWorlds.com Engine - MMOG client, server and tools
Copyright (C) 2011  Cyan Worlds, Inc.

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

You can contact Cyan Worlds, Inc. by email legal@cyan.com
 or by snail mail at:
      Cyan Worlds, Inc.
      14617 N Newport Hwy
      Mead, WA   99021

*==LICENSE==*/

#include "hsTypes.h"
#include "hsStream.h"
#include "hsExceptions.h"
#include "hsUtils.h"
#include "plPNG.h"
#include "../plGImage/plMipmap.h"

#include <png.h>
#define PNGSIGSIZE 8

//  Custom functions to read and write data from or to an hsStream
//  used by libPNG's respective functions
void pngReadDelegate(png_structp png_ptr, png_bytep png_data, png_size_t length)
{
    hsStream* inStream = (hsStream*)png_get_io_ptr(png_ptr);
    inStream->Read(length, (UInt8*)png_data);
}

void pngWriteDelegate(png_structp png_ptr, png_bytep png_data, png_size_t length)
{
    hsStream* outStream = (hsStream*)png_get_io_ptr(png_ptr);
    outStream->Write(length, (UInt8*)png_data);
}

//// Singleton Instance ///////////////////////////////////////////////////////

plPNG& plPNG::Instance(void)
{
    static plPNG theInstance;
    return theInstance;
}

//// IRead ////////////////////////////////////////////////////////////////////
//  Given an open hsStream, reads the PNG data off of the
//  stream and decodes it into a new plMipmap. The mipmap's buffer ends up
//  being a packed RGBA buffer.
//  Returns a pointer to the new mipmap if successful, NULL otherwise.

plMipmap* plPNG::IRead(hsStream* inStream)
{
    plMipmap* newMipmap = NULL;
    png_structp png_ptr;
    png_infop info_ptr;
    png_infop end_info;

    try {
        //  Check PNG Signature
        png_byte sig[PNGSIGSIZE];
        inStream->Read8Bytes((char*) sig);

        if (!png_sig_cmp(sig, 0, PNGSIGSIZE)) {
            //  Allocate required structs
            png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);

            if (!png_ptr) {
                throw(false);
            }

            info_ptr = png_create_info_struct(png_ptr);

            if (!info_ptr) {
                png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
                throw(false);
            }

            end_info = png_create_info_struct(png_ptr);

            if (!end_info) {
                png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
                throw(false);
            }

            //  Assign delegate function for reading from hsStream
            png_set_read_fn(png_ptr, (png_voidp)inStream, pngReadDelegate);
            //  Get PNG Header information
            png_set_sig_bytes(png_ptr, PNGSIGSIZE);
            png_read_info(png_ptr, info_ptr);
            png_uint_32 imgWidth =  png_get_image_width(png_ptr, info_ptr);
            png_uint_32 imgHeight = png_get_image_height(png_ptr, info_ptr);
            png_uint_32 bitdepth   = png_get_bit_depth(png_ptr, info_ptr);
            png_uint_32 channels   = png_get_channels(png_ptr, info_ptr);
            png_uint_32 color_type = png_get_color_type(png_ptr, info_ptr);

            //  Convert images to RGB color space
            switch (color_type) {
                case PNG_COLOR_TYPE_PALETTE:
                    png_set_palette_to_rgb(png_ptr);
                    channels = 3;
                    break;
                case PNG_COLOR_TYPE_GRAY:

                    if (bitdepth < 8) {
                        png_set_expand_gray_1_2_4_to_8(png_ptr);
                    }

                    bitdepth = 8;
                    break;
            }

            //  Convert transparency (if needed) to a full alpha channel
            if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
                png_set_tRNS_to_alpha(png_ptr);
                channels += 1;
            } else if (channels == 3) {
                // Add an opaque alpha channel if still none exists
                png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
                channels = 4;
            }

            // Invert color byte-order as used by plMipmap for DirectX
            png_set_bgr(png_ptr);
            /// Construct a new mipmap to hold everything
            newMipmap = TRACKED_NEW plMipmap(imgWidth, imgHeight, plMipmap::kARGB32Config, 1, plMipmap::kUncompressed);
            char* destp = (char*)newMipmap->GetImage();
            png_bytep* row_ptrs = TRACKED_NEW png_bytep[imgHeight];
            const unsigned int stride = imgWidth * bitdepth * channels / 8;

            //  Assign row pointers to the appropriate locations in the newly-created Mipmap
            for (size_t i = 0; i < imgHeight; i++) {
                row_ptrs[i] = (png_bytep)destp + (i * stride);
            }

            png_read_image(png_ptr, row_ptrs);
            png_read_end(png_ptr, end_info);
            //  Clean up allocated structs
            png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
            delete [] row_ptrs;
        }
    } catch (...) {
        if (newMipmap != NULL) {
            delete newMipmap;
            newMipmap = NULL;
        }
    }

    return newMipmap;
}

plMipmap* plPNG::ReadFromFile(const char* fileName)
{
    wchar* wFilename = hsStringToWString(fileName);
    plMipmap* retVal = ReadFromFile(wFilename);
    delete [] wFilename;
    return retVal;
}

plMipmap* plPNG::ReadFromFile(const wchar* fileName)
{
    hsUNIXStream in;

    if (!in.Open(fileName, L"rb")) {
        return false;
    }

    plMipmap* ret = IRead(&in);
    in.Close();
    return ret;
}

hsBool plPNG::IWrite(plMipmap* source, hsStream* outStream)
{
    hsBool result = true;

    try {
        //  Allocate required structs
        png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);

        if (!png_ptr) {
            throw(false);
        }

        png_infop info_ptr = png_create_info_struct(png_ptr);

        if (!info_ptr) {
            png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
            throw(false);
        }

        //  Assign delegate function for writing to hsStream
        png_set_write_fn(png_ptr, (png_voidp)outStream, pngWriteDelegate, NULL);
        UInt8 psize = source->GetPixelSize();
        png_set_IHDR(png_ptr, info_ptr, source->GetWidth(), source->GetHeight(), 8, PNG_COLOR_TYPE_RGB_ALPHA,
                     PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
        // Invert color byte-order as used by plMipmap for DirectX
        png_set_bgr(png_ptr);
        // Write out the image metadata
        png_write_info(png_ptr, info_ptr);
        char* srcp = (char*)source->GetImage();
        png_bytep* row_ptrs = TRACKED_NEW png_bytep[source->GetHeight()];
        const unsigned int stride = source->GetWidth() * source->GetPixelSize() / 8;

        //  Assign row pointers to the appropriate locations in the newly-created Mipmap
        for (size_t i = 0; i < source->GetHeight(); i++) {
            row_ptrs[i] = (png_bytep)srcp + (i * stride);
        }

        png_write_image(png_ptr, row_ptrs);
        png_write_end(png_ptr, info_ptr);
        //  Clean up allocated structs
        png_destroy_write_struct(&png_ptr, &info_ptr);
        delete [] row_ptrs;
    } catch (...) {
        result = false;
    }

    return result;
}

hsBool plPNG::WriteToFile(const char* fileName, plMipmap* sourceData)
{
    wchar* wFilename = hsStringToWString(fileName);
    hsBool retVal = WriteToFile(wFilename, sourceData);
    delete [] wFilename;
    return retVal;
}

hsBool plPNG::WriteToFile(const wchar* fileName, plMipmap* sourceData)
{
    hsUNIXStream out;

    if (!out.Open(fileName, L"wb")) {
        return false;
    }

    hsBool ret = IWrite(sourceData, &out);
    out.Close();
    return ret;
}