/****************************************************************************
Copyright (c) 2013      Zynga Inc.

http://www.cocos2d-x.org

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The above copyright notice and this permission notice shall be included in
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
****************************************************************************/

#include "CCTextureCacheEmscripten.h"
#include "platform/CCImage.h"
#include "platform/CCFileUtils.h"
#include <emscripten/emscripten.h>
#include <sstream>

using namespace cocos2d;
using namespace std;

#define MULTILINE(...) #__VA_ARGS__

// Following methods are implemented in TextureCacheEmscripten.js:
extern "C" {
void cocos2dx_newAsyncImageLoader(int textureCache, int callback__ignored);
void cocos2dx_asyncImageLoader_LoadImage(const char *path, TextureCache::AsyncStruct *asyncData);
void cocos2dx_shutdownAsyncImageLoader();
};

extern "C" {
// This C interface is exposed so that the JavaScript in
// TextureCacheEmscripten.js is able to call into these functions.
void TextureCacheEmscripten_addImageAsyncCallBack(TextureCacheEmscripten *tc, TextureCache::AsyncStruct *data, unsigned char *imgData, int width, int height);
void TextureCacheEmscripten_preMultiplyImageRegion( unsigned char *in, int win, int hin, unsigned char *out, int wout, int hout, int xout, int yout);
};

void TextureCacheEmscripten_addImageAsyncCallBack(TextureCacheEmscripten *tc, TextureCache::AsyncStruct *data, unsigned char *imgData, int width, int height)
{
    tc->addImageAsyncCallBack_emscripten(data, imgData, width, height);
}

/**
 * Construct a new TextureCacheEmscripten object. Note that the code in
 * TextureCacheEmscripten.js will be injected into the JavaScript runtime as
 * a side-affect.
 */
TextureCacheEmscripten::TextureCacheEmscripten()
{
    // Add dummy references to these functions so that the compiler will emit
    // code for them prior to this point (which is before when we will call
    // them.
    int deps[] = {
        (int)&TextureCacheEmscripten_addImageAsyncCallBack,
        (int)&TextureCacheEmscripten_preMultiplyImageRegion
    };

    cocos2dx_newAsyncImageLoader((int)this, (int)&deps);
}

/**
 * Destroy this object. Note that this will shutdown the image processing queue
 * (and hence stall anything waiting for those images to finish loading), and
 * unload the classes and objects instantiated in JavaScript to make this class
 * work.
 */
TextureCacheEmscripten::~TextureCacheEmscripten()
{
    cocos2dx_shutdownAsyncImageLoader();
}

/**
 * "Blit" the input image to a particular location on the target image. Output
 * image will be alpha pre-multiplied in the process.
 *
 * @in:     Pointer to input image raw data bytes
 * @win:    Width of input image in pixels
 * @hin:    Height of input image in pixels
 * @out:    Pointer to memory where output image raw pixels should be written
 * @wout:   Width of output image in pixels
 * @hout:   Height of output image in pixels
 * @xout:   x-offset into target image where blitted image should be placed
 * @yout:   y-offset into target image where blitted image should be placed
 */
void TextureCacheEmscripten_preMultiplyImageRegion(
    unsigned char *in, int win, int hin, // Input image, its width and height
    unsigned char *out, int wout, int hout, // Output image, its width and height
    int xout, int yout) // x and y offsets into the output image
{
    int iter = 0;
    for(int j = 0; j < hin; j++)
    {
        for(int i = 0; i < win; i++)
        {
            int inOffset = 4 * (j * win + i);
            int outOffset = 4 * ((j + yout) * wout + (i + xout));

            unsigned char *pin = in + inOffset;
            unsigned int *pout = (unsigned int *) (out + outOffset);

            *pout = CC_RGB_PREMULTIPLY_ALPHA( pin[0], pin[1], pin[2], pin[3] );
        }
    }
}

/**
 * "Private" callback method to load a texture based on the image data
 * generated in TextureCacheEmscripten.js. Exposed here as public so that it
 * can be called from the C wrapper method
 * @TextureCacheEmscripten_addImageAsyncCallBack, above.
 */
void TextureCacheEmscripten::addImageAsyncCallBack_emscripten(AsyncStruct *data, unsigned char *imgData, int width, int height)
{
    const char *filename = data->filename.c_str();

    Image *pImage = new Image();
    pImage->initWithRawData((unsigned char*) imgData, 4 * width * height, width, height, 8, true);

    free(imgData);

    Texture2D *texture = new Texture2D();
    texture->initWithImage(pImage); 

#if CC_ENABLE_CACHE_TEXTURE_DATA
    // cache the texture file name
    VolatileTexture::addImageTexture(texture, filename, Image::kFmtRawData);
#endif

    // cache the texture
    _textures->setObject(texture, filename);
    texture->autorelease();

    Object *target = data->target;
    SEL_CallFuncO selector = data->selector;

    if (target && selector)
    {
        (target->*selector)(texture);
        target->release();
    }

    pImage->release();
    delete data;
}

void TextureCacheEmscripten::addImageAsync(const char *path, Object *target, SEL_CallFuncO selector)
{
    CCAssert(path != NULL, "TextureCache: fileimage MUST not be NULL");    

    Texture2D *texture = NULL;

    // optimization
    std::string pathKey = FileUtils::getInstance()->fullPathForFilename(path);
    texture = (Texture2D*)_textures->objectForKey(pathKey.c_str());

    std::string fullpath = pathKey;
    if (texture != NULL)
    {
        if (target && selector)
        {
            (target->*selector)(texture);
        }
        
        return;
    }

    if (target)
    {
        target->retain();
    }

    // generate async struct
    AsyncStruct *data = new AsyncStruct(fullpath, target, selector);

    // Call into JavaScript code in TextureCacheEmscripten.js to do the rest.
    cocos2dx_asyncImageLoader_LoadImage(data->filename.c_str(), data);

    return;
}