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#include "qanimationwriter.h"

#include <QFile>

#include <QString>

#include <QPainter>

#include <png.h>

#include <limits.h>

#include <netinet/in.h> // for htonl

#ifdef QT_LINUXBASE

#  include <arpa/inet.h> // for htonl (LSB only)

#endif

QT_BEGIN_NAMESPACE

class QAnimationWriterData

{

public:

    QAnimationWriterData(QIODevice* d) : framerate(1000), dev(d) {}

    void setFrameRate(int d) { framerate = d; }

    virtual ~QAnimationWriterData() { }

    virtual void setImage(const QImage& src)=0;

    virtual bool canCompose() const { return false; }

    virtual void composeImage(const QImage&, const QPoint& ) {}

protected:

    int framerate;

    QIODevice* dev;

};

class QAnimationWriterMNG : public QAnimationWriterData {

    bool first;

    png_structp png_ptr;

    png_infop info_ptr;

public:

    QAnimationWriterMNG(QIODevice* d) : QAnimationWriterData(d)

    {

        first = true;

        begin_png();

    }

    ~QAnimationWriterMNG()

    {

        if (first) {

            // Eh? Not images.

            QImage dummy(1,1,QImage::Format_RGB32);

            setImage(dummy);

        }

        writeMEND();

        end_png();

    }

    void begin_png()

    {

        png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,0,0,0);

        info_ptr = png_create_info_struct(png_ptr);

        png_set_compression_level(png_ptr,9);

        png_set_write_fn(png_ptr, (void*)this, write, 0);

    }

    void end_png()

    {

        png_destroy_write_struct(&png_ptr, &info_ptr);

    }

    static void write( png_structp png_ptr, png_bytep data, png_size_t length)

    {

        QAnimationWriterMNG* that = (QAnimationWriterMNG*)png_get_io_ptr(png_ptr);

        /*uint nw =*/ that->dev->write((const char*)data,length);

    }

    void writePNG(const QImage& image)

    {

#ifndef QT_LINUXBASE

        // LSB disallows accessing the info_ptr directly. LSB's png_set_IHDR sets

        // the channels anyways, so just comment it out for LSB usage

        info_ptr->channels = 4;

#endif

        png_set_sig_bytes(png_ptr, 8); // Pretend we already wrote the sig

        png_set_IHDR(png_ptr, info_ptr, image.width(), image.height(),

                     8, image.hasAlphaChannel()

                     ? PNG_COLOR_TYPE_RGB_ALPHA : PNG_COLOR_TYPE_RGB,

                     0, 0, 0);

        png_write_info(png_ptr, info_ptr);

        if (!image.hasAlphaChannel())

            png_set_filler(png_ptr, 0,

                           QSysInfo::ByteOrder == QSysInfo::BigEndian ?

                           PNG_FILLER_BEFORE : PNG_FILLER_AFTER);

        //if ( QImage::systemByteOrder() == QImage::BigEndian ) {

        //png_set_swap_alpha(png_ptr);

        //}

        if (QSysInfo::ByteOrder == QSysInfo::LittleEndian) {

            png_set_bgr(png_ptr);

        }

        int height = image.height();

        png_bytep *row_pointers = new png_bytep[height];

        for (int i = 0; i < height; ++i)

            row_pointers[i] = (png_bytep)image.scanLine(i);

        png_write_image(png_ptr, row_pointers);

        delete [] row_pointers;

        png_write_end(png_ptr, info_ptr);

        end_png();

        begin_png();

    }

    void writeMHDR(const QSize& size, int framerate)

    {

        dev->write("\212MNG\r\n\032\n", 8);

        struct {

            int width;

            int height;

            int framerate;

            int a,b,c;

            int profile;

        } chunk;

        chunk.width = htonl(size.width());

        chunk.height = htonl(size.height());

        chunk.framerate = htonl(framerate);

        chunk.a=0;

        chunk.b=0;

        chunk.c=0;

        chunk.profile = htonl(0x00000003);

        png_write_chunk(png_ptr, (png_byte*)"MHDR", (png_byte*)&chunk, sizeof(chunk));

    }

    void writeMEND()

    {

        png_write_chunk(png_ptr, (png_byte*)"MEND", 0, 0);

    }

    void writeDEFI(const QPoint& offset, const QSize& /*size*/)

    {

        struct {

            ushort o;

            uchar s;

            uchar concrete;

            int x,y;

            int lc,rc,tc,bc;

        } chunk;

        chunk.o=0;

        chunk.s=0;

        chunk.concrete=1;

        chunk.x=htonl(offset.x());

        chunk.y=htonl(offset.y());

        chunk.lc=0;

        chunk.rc=0;

        chunk.tc=htonl(INT_MAX);

        chunk.bc=htonl(INT_MAX);

        png_write_chunk(png_ptr, (png_byte*)"DEFI", (png_byte*)&chunk, sizeof(chunk));

    }

    void writeFRAM(const QSize& size)

    {

        struct {

            uchar mode;

            uchar n;

            uchar nu;

            uchar d;

            uchar t;

            uchar clip;

            uchar s;

            uchar deltatype;

            uint left;

            uint right;

            uint top;

            uint bottom;

        } chunk;

        chunk.mode=1;

        chunk.n='a';

        chunk.nu=0;

        chunk.d=0;

        chunk.clip=1;

        chunk.t=0;

        chunk.s=0;

        chunk.deltatype=0;

        chunk.left=0;

        chunk.right=htonl(size.width());

        chunk.top=0;

        chunk.bottom=htonl(size.height());

        png_write_chunk(png_ptr, (png_byte*)"FRAM", (png_byte*)&chunk, sizeof(chunk));

    }

    void writeMOVE(const QPoint& offset)

    {

        struct {

            uchar filler[3];

            uchar z[5];

            int x,y;

        } chunk;

        memset(chunk.z,0,5);

        chunk.x=htonl(offset.x());

        chunk.y=htonl(offset.y());

        png_write_chunk(png_ptr, (png_byte*)"MOVE", ((png_byte*)&chunk)+3, sizeof(chunk)-3);

    }

    void setImage(const QImage& src)

    {

        if (first) {

            first = false;

            writeMHDR(src.size(),framerate);

        }

        composeImage(src,QPoint(0,0));

    }

    bool canCompose() const { return true; }

    void composeImage(const QImage& src, const QPoint& offset)

    {

        writeMOVE(offset);

        //writeFRAM(src.size());

        writePNG(src);

    }

};

QAnimationWriter::QAnimationWriter(const QString& filename, const char* format)

{

    if (qstrncmp(format, "MNG", 4)) {

	qWarning("Format \"%s\" not supported, only MNG", format);

	dev = 0;

	d = 0;

    } else {

	QFile *f = new QFile(filename);

	f->open(QIODevice::WriteOnly);

	dev = f;

	d = new QAnimationWriterMNG(dev);

    }

}

bool QAnimationWriter::okay() const

{

    if (!dev)

        return false;

    QFile *file = qobject_cast<QFile*>(dev);

    Q_ASSERT(file);

    return (file->error() == QFile::NoError);

}

QAnimationWriter::~QAnimationWriter()

{

    delete d;

    delete dev;

}

void QAnimationWriter::setFrameRate(int r)

{

    if (d)

        d->setFrameRate(r);

}

void QAnimationWriter::appendFrame(const QImage& frm, const QPoint& offset)

{

    if (!dev)

        return;

    const QImage frame = frm.convertToFormat(QImage::Format_RGB32);

    const int alignx = 1;

    if (prev.isNull() || !d->canCompose()) {

        d->setImage(frame);

    } else {

        bool done;

        int minx, maxx, miny, maxy;

        int w = frame.width();

        int h = frame.height();

        const quint32 *framePtr = reinterpret_cast<const quint32*>(frame.bits());

        const quint32 *prevPtr = reinterpret_cast<const quint32*>(prev.bits());

        const int frameStride = frame.bytesPerLine() / sizeof(quint32);

        const int prevStride = prev.bytesPerLine() / sizeof(quint32);

        // Find left edge of change

        done = false;

        for (minx = 0; minx < w && !done; ++minx) {

            const quint32 *p1 = framePtr + minx;

            const quint32 *p2 = prevPtr + minx + offset.x();

            for (int y = 0; y < h; ++y) {

                if (*p1 != *p2) {

                    done = true;

                    break;

                }

                p1 += frameStride;

                p2 += prevStride;

            }

        }

        --minx;

        // Find right edge of change

        done = false;

        for (maxx = w-1; maxx >= 0 && !done; --maxx) {

            const quint32 *p1 = framePtr + maxx;

            const quint32 *p2 = prevPtr + maxx + offset.x();

            for (int y = 0; y < h; ++y) {

                if (*p1 != *p2) {

                    done = true;

                    break;

                }

                p1 += frameStride;

                p2 += prevStride;

            }

        }

        ++maxx;

        // Find top edge of change

        done = false;

        for (miny = 0; miny < h && !done; ++miny) {

            const quint32 *p1 = framePtr + miny * frameStride;

            const quint32 *p2 = prevPtr + miny * prevStride + offset.x();

            for (int x = 0; x < w; ++x) {

                if (*p1 != *p2) {

                    done = true;

                    break;

                }

                ++p1;

                ++p2;

            }

        }

        --miny;

        // Find right edge of change

        done = false;

        for (maxy = h-1; maxy >= 0 && !done; --maxy) {

            const quint32 *p1 = framePtr + maxy * frameStride;

            const quint32 *p2 = prevPtr + maxy * prevStride + offset.x();

            for (int x = 0; x < w; ++x) {

                if (*p1 != *p2) {

                    done = true;

                    break;

                }

                ++p1;

                ++p2;

            }

        }

        ++maxy;

        if (minx > maxx)

            minx = maxx = 0;

        if (miny > maxy)

            miny = maxy = 0;

        if (alignx > 1) {

            minx -= minx % alignx;

            maxx = maxx - maxx % alignx + alignx - 1;

        }

        int dw = maxx - minx + 1;

        int dh = maxy - miny + 1;

        QImage diff(dw, dh, QImage::Format_ARGB32);

        int x, y;

        for (y = 0; y < dh; ++y) {

            QRgb* li = (QRgb*)frame.scanLine(y+miny)+minx;

            QRgb* lp = (QRgb*)prev.scanLine(y+miny+offset.y())+minx+offset.x();

            QRgb* ld = (QRgb*)diff.scanLine(y);

            if (alignx) {

                for (x = 0; x < dw; x += alignx) {

                    int i;

                    for (i = 0; i < alignx; ++i) {

                        if (li[x+i] != lp[x+i])

                            break;

                    }

                    if (i == alignx) {

                        // All the same

                        for (i = 0; i < alignx; ++i)

                            ld[x+i] = qRgba(0,0,0,0);

                    } else {

                        // Some different

                        for (i = 0; i < alignx; ++i)

                            ld[x+i] = 0xff000000 | li[x+i];

                    }

                }

            } else {

                for (x = 0; x < dw; ++x) {

                    if (li[x] != lp[x])

                        ld[x] = 0xff000000 | li[x];

                    else

                        ld[x] = qRgba(0,0,0,0);

                }

            }

        }

        d->composeImage(diff, QPoint(minx, miny) + offset);

    }

    if (prev.isNull() || (prev.size() == frame.size() && offset == QPoint(0,0))) {

        prev = frame;

    } else {

        QPainter p(&prev);

        p.drawImage(offset.x(), offset.y(), frame, 0, 0,

                    frame.width(), frame.height());

    }

}

void QAnimationWriter::appendFrame(const QImage& frm)

{

    appendFrame(frm, QPoint(0,0));

}

void QAnimationWriter::appendBlankFrame()

{

    QImage i(1,1,QImage::Format_ARGB32);

    i.fill(0);

    d->composeImage(i, QPoint(0,0));

}

QT_END_NAMESPACE