/*      _______   __   __   __   ______   __   __   _______   __   __
 *     / _____/\ / /\ / /\ / /\ / ____/\ / /\ / /\ / ___  /\ /  |\/ /\
 *    / /\____\// / // / // / // /\___\// /_// / // /\_/ / // , |/ / /
 *   / / /__   / / // / // / // / /    / ___  / // ___  / // /| ' / /
 *  / /_// /\ / /_// / // / // /_/_   / / // / // /\_/ / // / |  / /
 * /______/ //______/ //_/ //_____/\ /_/ //_/ //_/ //_/ //_/ /|_/ /
 * \______\/ \______\/ \_\/ \_____\/ \_\/ \_\/ \_\/ \_\/ \_\/ \_\/
 *
 * Copyright (c) 2004 - 2008 Olof Naessén and Per Larsson
 *
 *
 * Per Larsson a.k.a finalman
 * Olof Naessén a.k.a jansem/yakslem
 *
 * Visit: http://guichan.sourceforge.net
 *
 * License: (BSD)
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of Guichan nor the names of its contributors may
 *    be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * For comments regarding functions please see the header file.
 */

#include "guichan/sdl/sdlgraphics.hpp"

#include "guichan/exception.hpp"
#include "guichan/font.hpp"
#include "guichan/image.hpp"
#include "guichan/sdl/sdlimage.hpp"
#include "guichan/sdl/sdlpixel.hpp"

#include "debug.h"

// For some reason an old version of MSVC did not like std::abs,
// so we added this macro.
#ifndef ABS
#define ABS(x) ((x)<0?-(x):(x))
#endif

namespace gcn
{

    SDLGraphics::SDLGraphics() :
        mTarget(nullptr),
        mAlpha(false)
    {
    }

    void SDLGraphics::_beginDraw()
    {
        Rectangle area;
        area.x = 0;
        area.y = 0;
        area.width = mTarget->w;
        area.height = mTarget->h;
        pushClipArea(area);
    }

    void SDLGraphics::_endDraw()
    {
        popClipArea();
    }

    void SDLGraphics::setTarget(SDL_Surface* target)
    {
        mTarget = target;
    }

    bool SDLGraphics::pushClipArea(Rectangle area)
    {
        SDL_Rect rect;
        bool result = Graphics::pushClipArea(area);

        const ClipRectangle& carea = mClipStack.top();
        rect.x = carea.x;
        rect.y = carea.y;
        rect.w = carea.width;
        rect.h = carea.height;

        SDL_SetClipRect(mTarget, &rect);

        return result;
    }

    void SDLGraphics::popClipArea()
    {
        Graphics::popClipArea();

        if (mClipStack.empty())
            return;

        const ClipRectangle& carea = mClipStack.top();
        SDL_Rect rect;
        rect.x = carea.x;
        rect.y = carea.y;
        rect.w = carea.width;
        rect.h = carea.height;

        SDL_SetClipRect(mTarget, &rect);
    }

    SDL_Surface* SDLGraphics::getTarget() const
    {
        return mTarget;
    }

    void SDLGraphics::drawImage(const Image* image,
                                int srcX,
                                int srcY,
                                int dstX,
                                int dstY,
                                int width,
                                int height)
    {
        if (mClipStack.empty())
        {
            throw GCN_EXCEPTION("Clip stack is empty, perhaps you called a "
                "draw funtion outside of _beginDraw() and _endDraw()?");
        }

        const ClipRectangle& top = mClipStack.top();

        SDL_Rect src;
        SDL_Rect dst;
        src.x = srcX;
        src.y = srcY;
        src.w = width;
        src.h = height;
        dst.x = dstX + top.xOffset;
        dst.y = dstY + top.yOffset;

        const SDLImage* srcImage = dynamic_cast<const SDLImage*>(image);

        if (!srcImage)
        {
            throw GCN_EXCEPTION("Trying to draw an image of unknown format,"
                " must be an SDLImage.");
        }

        SDL_BlitSurface(srcImage->getSurface(), &src, mTarget, &dst);
    }

    void SDLGraphics::fillRectangle(const Rectangle& rectangle)
    {
        if (mClipStack.empty())
        {
            throw GCN_EXCEPTION("Clip stack is empty, perhaps you called a "
                "draw funtion outside of _beginDraw() and _endDraw()?");
        }

        const ClipRectangle& top = mClipStack.top();

        Rectangle area = rectangle;
        area.x += top.xOffset;
        area.y += top.yOffset;

        if (!area.isIntersecting(top))
            return;

        if (mAlpha)
        {
            int x1 = area.x > top.x ? area.x : top.x;
            int y1 = area.y > top.y ? area.y : top.y;
            int x2 = area.x + area.width < top.x + top.width ?
                area.x + area.width : top.x + top.width;
            int y2 = area.y + area.height < top.y + top.height ?
                area.y + area.height : top.y + top.height;
            int x, y;

            SDL_LockSurface(mTarget);
            for (y = y1; y < y2; y++)
            {
                for (x = x1; x < x2; x++)
                    SDLputPixelAlpha(mTarget, x, y, mColor);
            }
            SDL_UnlockSurface(mTarget);
        }
        else
        {
            SDL_Rect rect;
            rect.x = area.x;
            rect.y = area.y;
            rect.w = area.width;
            rect.h = area.height;

            Uint32 color = SDL_MapRGBA(mTarget->format,
                                       mColor.r,
                                       mColor.g,
                                       mColor.b,
                                       mColor.a);
            SDL_FillRect(mTarget, &rect, color);
        }
    }

    void SDLGraphics::drawPoint(int x, int y)
    {
        if (mClipStack.empty())
        {
            throw GCN_EXCEPTION("Clip stack is empty, perhaps you called a "
                "draw funtion outside of _beginDraw() and _endDraw()?");
        }

        const ClipRectangle& top = mClipStack.top();

        x += top.xOffset;
        y += top.yOffset;

        if (!top.isPointInRect(x, y))
            return;

        if (mAlpha)
            SDLputPixelAlpha(mTarget, x, y, mColor);
        else
            SDLputPixel(mTarget, x, y, mColor);
    }

    void SDLGraphics::drawHLine(int x1, int y, int x2)
    {
        if (mClipStack.empty())
        {
            throw GCN_EXCEPTION("Clip stack is empty, perhaps you called a "
                "draw funtion outside of _beginDraw() and _endDraw()?");
        }

        const ClipRectangle& top = mClipStack.top();

        x1 += top.xOffset;
        y += top.yOffset;
        x2 += top.xOffset;

        if (y < top.y || y >= top.y + top.height)
            return;

        if (x1 > x2)
        {
            x1 ^= x2;
            x2 ^= x1;
            x1 ^= x2;
        }

        if (top.x > x1)
        {
            if (top.x > x2)
                return;

            x1 = top.x;
        }

        if (top.x + top.width <= x2)
        {
            if (top.x + top.width <= x1)
                return;

            x2 = top.x + top.width -1;
        }

        int bpp = mTarget->format->BytesPerPixel;

        SDL_LockSurface(mTarget);

        Uint8 *p = (Uint8 *)mTarget->pixels + y * mTarget->pitch + x1 * bpp;

        Uint32 pixel = SDL_MapRGB(mTarget->format,
                                  mColor.r,
                                  mColor.g,
                                  mColor.b);
        switch(bpp)
        {
            case 1:
                for (; x1 <= x2; ++x1)
                    *(p++) = pixel;
                break;

            case 2:
            {
                Uint16* q = (Uint16*)p;
                for (; x1 <= x2; ++x1)
                    *(q++) = pixel;
                break;
            }

            case 3:
                if (SDL_BYTEORDER == SDL_BIG_ENDIAN)
                {
                    for (; x1 <= x2; ++x1)
                    {
                        p[0] = (pixel >> 16) & 0xff;
                        p[1] = (pixel >> 8) & 0xff;
                        p[2] = pixel & 0xff;
                        p += 3;
                    }
                }
                else
                {
                    for (; x1 <= x2; ++x1)
                    {
                        p[0] = pixel & 0xff;
                        p[1] = (pixel >> 8) & 0xff;
                        p[2] = (pixel >> 16) & 0xff;
                        p += 3;
                    }
                }
                break;

            case 4:
            {
                Uint32* q = (Uint32*)p;
                for (; x1 <= x2; ++x1)
                {
                    if (mAlpha)
                    {
                        *q = SDLAlpha32(pixel, *q, mColor.a);
                        q++;
                    }
                    else
                    {
                        *(q++) = pixel;
                    }
                }
                break;
            }
            default:
                break;
        } // end switch

        SDL_UnlockSurface(mTarget);
    }

    void SDLGraphics::drawVLine(int x, int y1, int y2)
    {
        if (mClipStack.empty())
        {
            throw GCN_EXCEPTION("Clip stack is empty, perhaps you called a "
                "draw funtion outside of _beginDraw() and _endDraw()?");
        }

        const ClipRectangle& top = mClipStack.top();

        x += top.xOffset;
        y1 += top.yOffset;
        y2 += top.yOffset;

        if (x < top.x || x >= top.x + top.width)
            return;

        if (y1 > y2)
        {
            y1 ^= y2;
            y2 ^= y1;
            y1 ^= y2;
        }

        if (top.y > y1)
        {
            if (top.y > y2)
                return;

            y1 = top.y;
        }

        if (top.y + top.height <= y2)
        {
            if (top.y + top.height <= y1)
                return;

            y2 = top.y + top.height - 1;
        }

        int bpp = mTarget->format->BytesPerPixel;

        SDL_LockSurface(mTarget);

        Uint8 *p = (Uint8 *)mTarget->pixels + y1 * mTarget->pitch + x * bpp;

        Uint32 pixel = SDL_MapRGB(mTarget->format, mColor.r,
            mColor.g, mColor.b);

        switch(bpp)
        {
            case 1:
                for (; y1 <= y2; ++y1)
                {
                    *p = pixel;
                    p += mTarget->pitch;
                }
                break;

            case 2:
                for (; y1 <= y2; ++y1)
                {
                    *(Uint16*)p = pixel;
                    p += mTarget->pitch;
                }
                break;

            case 3:
                if (SDL_BYTEORDER == SDL_BIG_ENDIAN)
                {
                    for (; y1 <= y2; ++y1)
                    {
                        p[0] = (pixel >> 16) & 0xff;
                        p[1] = (pixel >> 8) & 0xff;
                        p[2] = pixel & 0xff;
                        p += mTarget->pitch;
                    }
                }
                else
                {
                    for (; y1 <= y2; ++y1)
                    {
                        p[0] = pixel & 0xff;
                        p[1] = (pixel >> 8) & 0xff;
                        p[2] = (pixel >> 16) & 0xff;
                        p += mTarget->pitch;
                    }
                }
                break;

            case 4:
                for (; y1 <= y2; ++y1)
                {
                    if (mAlpha)
                        *(Uint32*)p = SDLAlpha32(pixel, *(Uint32*)p, mColor.a);
                    else
                        *(Uint32*)p = pixel;
                    p += mTarget->pitch;
                }
                break;

            default:
                break;
        } // end switch

        SDL_UnlockSurface(mTarget);
    }

    void SDLGraphics::drawRectangle(const Rectangle& rectangle)
    {
        int x1 = rectangle.x;
        int x2 = rectangle.x + rectangle.width - 1;
        int y1 = rectangle.y;
        int y2 = rectangle.y + rectangle.height - 1;

        drawHLine(x1, y1, x2);
        drawHLine(x1, y2, x2);

        drawVLine(x1, y1, y2);
        drawVLine(x2, y1, y2);
    }

    void SDLGraphics::drawLine(int x1, int y1, int x2, int y2)
    {
        if (x1 == x2)
        {
            drawVLine(x1, y1, y2);
            return;
        }
        if (y1 == y2)
        {
            drawHLine(x1, y1, x2);
            return;
        }

        if (mClipStack.empty())
        {
            throw GCN_EXCEPTION("Clip stack is empty, perhaps you called a "
                "draw funtion outside of _beginDraw() and _endDraw()?");
        }

        const ClipRectangle& top = mClipStack.top();

        x1 += top.xOffset;
        y1 += top.yOffset;
        x2 += top.xOffset;
        y2 += top.yOffset;

        // Draw a line with Bresenham

        int dx = ABS(x2 - x1);
        int dy = ABS(y2 - y1);

        if (dx > dy)
        {
            if (x1 > x2)
            {
                // swap x1, x2
                x1 ^= x2;
                x2 ^= x1;
                x1 ^= x2;

                // swap y1, y2
                y1 ^= y2;
                y2 ^= y1;
                y1 ^= y2;
            }

            if (y1 < y2)
            {
                int y = y1;
                int p = 0;

                for (int x = x1; x <= x2; x++)
                {
                    if (top.isPointInRect(x, y))
                    {
                        if (mAlpha)
                            SDLputPixelAlpha(mTarget, x, y, mColor);
                        else
                            SDLputPixel(mTarget, x, y, mColor);
                    }

                    p += dy;

                    if (p * 2 >= dx)
                    {
                        y++;
                        p -= dx;
                    }
                }
            }
            else
            {
                int y = y1;
                int p = 0;

                for (int x = x1; x <= x2; x++)
                {
                    if (top.isPointInRect(x, y))
                    {
                        if (mAlpha)
                            SDLputPixelAlpha(mTarget, x, y, mColor);
                        else
                            SDLputPixel(mTarget, x, y, mColor);
                    }

                    p += dy;

                    if (p * 2 >= dx)
                    {
                        y--;
                        p -= dx;
                    }
                }
            }
        }
        else
        {
            if (y1 > y2)
            {
                // swap y1, y2
                y1 ^= y2;
                y2 ^= y1;
                y1 ^= y2;

                // swap x1, x2
                x1 ^= x2;
                x2 ^= x1;
                x1 ^= x2;
            }

            if (x1 < x2)
            {
                int x = x1;
                int p = 0;

                for (int y = y1; y <= y2; y++)
                {
                    if (top.isPointInRect(x, y))
                    {
                        if (mAlpha)
                            SDLputPixelAlpha(mTarget, x, y, mColor);
                        else
                            SDLputPixel(mTarget, x, y, mColor);
                    }

                    p += dx;

                    if (p * 2 >= dy)
                    {
                        x++;
                        p -= dy;
                    }
                }
            }
            else
            {
                int x = x1;
                int p = 0;

                for (int y = y1; y <= y2; y++)
                {
                    if (top.isPointInRect(x, y))
                    {
                        if (mAlpha)
                            SDLputPixelAlpha(mTarget, x, y, mColor);
                        else
                            SDLputPixel(mTarget, x, y, mColor);
                    }

                    p += dx;

                    if (p * 2 >= dy)
                    {
                        x--;
                        p -= dy;
                    }
                }
            }
        }
    }

    void SDLGraphics::setColor(const Color& color)
    {
        mColor = color;

        mAlpha = color.a != 255;
    }

    const Color& SDLGraphics::getColor() const
    {
        return mColor;
    }

    void SDLGraphics::drawSDLSurface(SDL_Surface* surface,
                                     SDL_Rect source,
                                     SDL_Rect destination)
    {
        if (mClipStack.empty())
        {
            throw GCN_EXCEPTION("Clip stack is empty, perhaps you called a "
                "draw funtion outside of _beginDraw() and _endDraw()?");
        }

        const ClipRectangle& top = mClipStack.top();

        destination.x += top.xOffset;
        destination.y += top.yOffset;

        SDL_BlitSurface(surface, &source, mTarget, &destination);
    }
}
