/*
 *  The ManaPlus Client
 *  Copyright (C) 2004-2009  The Mana World Development Team
 *  Copyright (C) 2009-2010  The Mana Developers
 *  Copyright (C) 2011-2012  The ManaPlus Developers
 *
 *  This file is part of The ManaPlus Client.
 *
 *  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 2 of the License, or
 *  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/>.
 */

#include "resources/sdlimagehelper.h"

#include "resources/dye.h"
#include "resources/resourcemanager.h"

#include "client.h"
#include "logger.h"
#include "main.h"

#include "utils/stringutils.h"

#include "resources/image.h"

#include <SDL_image.h>
#include <SDL_rotozoom.h>

#include "debug.h"

bool SDLImageHelper::mEnableAlphaCache = false;

Resource *SDLImageHelper::load(SDL_RWops *rw, Dye const &dye)
{
    SDL_Surface *tmpImage = IMG_Load_RW(rw, 1);

    if (!tmpImage)
    {
        logger->log("Error, image load failed: %s", IMG_GetError());
        return nullptr;
    }

    SDL_Surface *surf = nullptr;
    SDL_PixelFormat rgba;
    rgba.palette = nullptr;
    rgba.BitsPerPixel = 32;
    rgba.BytesPerPixel = 4;
    rgba.colorkey = 0;
    rgba.alpha = 255;
    rgba.Rmask = 0xFF000000; rgba.Rloss = 0; rgba.Rshift = 24;
    rgba.Gmask = 0x00FF0000; rgba.Gloss = 0; rgba.Gshift = 16;
    rgba.Bmask = 0x0000FF00; rgba.Bloss = 0; rgba.Bshift = 8;
    rgba.Amask = 0x000000FF; rgba.Aloss = 0; rgba.Ashift = 0;

    surf = SDL_ConvertSurface(tmpImage, &rgba, SDL_SWSURFACE);
    SDL_FreeSurface(tmpImage);

    Uint32 *pixels = static_cast<Uint32 *>(surf->pixels);
    DyePalette *pal = dye.getSPalete();

    if (pal)
    {
        for (Uint32 *p_end = pixels + surf->w * surf->h;
             pixels != p_end; ++pixels)
        {
            Uint8 *p = (Uint8 *)pixels;
            const int alpha = *p & 255;
            if (!alpha)
                continue;
            pal->replaceColor(p + 1);
        }
    }
    else
    {
        for (Uint32 *p_end = pixels + surf->w * surf->h;
             pixels != p_end; ++pixels)
        {
            const Uint32 p = *pixels;
            const int alpha = p & 255;
            if (!alpha)
                continue;
            int v[3];
            v[0] = (p >> 24) & 255;
            v[1] = (p >> 16) & 255;
            v[2] = (p >> 8 ) & 255;
            dye.update(v);
            *pixels = (v[0] << 24) | (v[1] << 16) | (v[2] << 8) | alpha;
        }
    }

    Image *image = load(surf);
    SDL_FreeSurface(surf);
    return image;
}

Image *SDLImageHelper::load(SDL_Surface *tmpImage)
{
    return _SDLload(tmpImage);
}

Image *SDLImageHelper::createTextSurface(SDL_Surface *tmpImage, float alpha)
{
    if (!tmpImage)
        return nullptr;

    Image *img;

    bool hasAlpha = false;
    bool converted = false;

    const int sz = tmpImage->w * tmpImage->h;

    // The alpha channel to be filled with alpha values
    Uint8 *alphaChannel = new Uint8[sz];

    const SDL_PixelFormat * const fmt = tmpImage->format;
    if (fmt->Amask)
    {
        for (int i = 0; i < sz; ++ i)
        {
            Uint32 c = (static_cast<Uint32*>(tmpImage->pixels))[i];

            unsigned v = (c & fmt->Amask) >> fmt->Ashift;
            Uint8 a = (v << fmt->Aloss) + (v >> (8 - (fmt->Aloss << 1)));

            Uint8 a2 = static_cast<Uint8>(static_cast<float>(a) * alpha);

            c &= ~fmt->Amask;
            c |= ((a2 >> fmt->Aloss) << fmt->Ashift & fmt->Amask);
            (static_cast<Uint32*>(tmpImage->pixels))[i] = c;

            if (a != 255)
                hasAlpha = true;

            alphaChannel[i] = a;
        }
    }

    SDL_Surface *image;

    // Convert the surface to the current display format
    if (hasAlpha)
    {
        image = SDL_DisplayFormatAlpha(tmpImage);
    }
    else
    {
        image = SDL_DisplayFormat(tmpImage);

        // We also delete the alpha channel since
        // it's not used.
        delete [] alphaChannel;
        alphaChannel = nullptr;
    }

    if (!image)
    {
        logger->log1("Error: Image convert failed.");
        delete [] alphaChannel;
        return nullptr;
    }

    if (converted)
        SDL_FreeSurface(tmpImage);

    img = new Image(image, hasAlpha, alphaChannel);
    img->mAlpha = alpha;
    return img;
}

SDL_Surface* SDLImageHelper::SDLDuplicateSurface(SDL_Surface* tmpImage)
{
    if (!tmpImage || !tmpImage->format)
        return nullptr;

    return SDL_ConvertSurface(tmpImage, tmpImage->format, SDL_SWSURFACE);
}

Image *SDLImageHelper::_SDLload(SDL_Surface *tmpImage)
{
    if (!tmpImage)
        return nullptr;

    bool hasAlpha = false;
    bool converted = false;

    if (tmpImage->format->BitsPerPixel != 32)
    {
        tmpImage = convertTo32Bit(tmpImage);

        if (!tmpImage)
            return nullptr;
        converted = true;
    }

    const int sz = tmpImage->w * tmpImage->h;

    // The alpha channel to be filled with alpha values
    Uint8 *alphaChannel = new Uint8[sz];

    // Figure out whether the image uses its alpha layer
    if (!tmpImage->format->palette)
    {
        const SDL_PixelFormat * const fmt = tmpImage->format;
        if (fmt->Amask)
        {
            for (int i = 0; i < sz; ++ i)
            {
                unsigned v = ((static_cast<Uint32*>(tmpImage->pixels))[i]
                    & fmt->Amask) >> fmt->Ashift;
                Uint8 a = (v << fmt->Aloss) + (v >> (8 - (fmt->Aloss << 1)));

                if (a != 255)
                    hasAlpha = true;

                alphaChannel[i] = a;
            }
        }
        else
        {
            if (SDL_ALPHA_OPAQUE != 255)
            {
                hasAlpha = true;
                memset(alphaChannel, SDL_ALPHA_OPAQUE, sz);
            }
        }
    }
    else
    {
        if (SDL_ALPHA_OPAQUE != 255)
        {
            hasAlpha = true;
            memset(alphaChannel, SDL_ALPHA_OPAQUE, sz);
        }
    }

    SDL_Surface *image;

    // Convert the surface to the current display format
    if (hasAlpha)
    {
        image = SDL_DisplayFormatAlpha(tmpImage);
    }
    else
    {
        image = SDL_DisplayFormat(tmpImage);

        // We also delete the alpha channel since
        // it's not used.
        delete [] alphaChannel;
        alphaChannel = nullptr;
    }

    if (!image)
    {
        logger->log1("Error: Image convert failed.");
        delete [] alphaChannel;
        return nullptr;
    }

    if (converted)
        SDL_FreeSurface(tmpImage);

    return new Image(image, hasAlpha, alphaChannel);
}

int SDLImageHelper::useOpenGL()
{
    return 0;
}