/*********************************************************************************
*                             recordMyDesktop                                    *
**********************************************************************************
*                                                                                *
*             Copyright (C) 2006  John Varouhakis                                *
*                                                                                *
*                                                                                *
*    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           *
*    (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, write to the Free Software                 *
*    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA   *
*                                                                                *
*                                                                                *
*                                                                                *
*    For further information contact me at johnvarouhakis@gmail.com              *
**********************************************************************************/

#include <recordmydesktop.h>

void MakeChecksums(unsigned char *buf,int width,int height,int divisor,unsigned short int *checksums){
    int i,k,j,m;

    for(i=0;i<divisor;i++){
        for(k=0;k<divisor;k++){
            int A=1,B=0;    
            for(j=0;j<height/divisor;j++){
                for(m=0;m<width/divisor;m++){
                    unsigned char cur=buf[i*(width*height/divisor)+j*width+k*width/divisor+m];
                    A+=cur;
                    B+=A+cur;
                }
            }
            A=A%65521;
            B=B%65521;
            checksums[i*divisor+k]=A+B;
        }
    }
}

void *CacheImageBuffer(void *pdata){
    pthread_mutex_t pmut,imut;
    pthread_mutex_init(&pmut,NULL);
    pthread_mutex_init(&imut,NULL);
    yuv_buffer yuv[2];


    unsigned short int  checksums_y[2][256],
                        checksums_u[2][64],
                        checksums_v[2][64];
    int i,current=0,divisor=16,firstrun=1;

    //we want to make sure that each block has a sufficient
    //number of bytes, so that the checksum will wrap
    //around 65521. 
    while(((((ProgData *)pdata)->brwin.rgeom.width*
            ((ProgData *)pdata)->brwin.rgeom.width )
            /pow(divisor,2))
            <=1024){
        divisor/=2;
        if(divisor==2)
            break;
    }


    for(i=0;i<2;i++){
        yuv[i].y_width=((ProgData *)pdata)->enc_data->yuv.y_width;
        yuv[i].y_height=((ProgData *)pdata)->enc_data->yuv.y_height;
        yuv[i].uv_width=((ProgData *)pdata)->enc_data->yuv.uv_width;
        yuv[i].uv_height=((ProgData *)pdata)->enc_data->yuv.uv_height;
        
        yuv[i].y=(unsigned char *)malloc(yuv[i].y_width*yuv[i].y_height);
        yuv[i].u=(unsigned char *)malloc(yuv[i].uv_width*yuv[i].uv_height);
        yuv[i].v=(unsigned char *)malloc(yuv[i].uv_width*yuv[i].uv_height);
    }
    

    while(((ProgData *)pdata)->running){
        pthread_cond_wait(&((ProgData *)pdata)->image_buffer_ready,&imut);
        if(Paused)
            pthread_cond_wait(&((ProgData *)pdata)->pause_cond,&pmut);
        pthread_mutex_lock(&((ProgData *)pdata)->yuv_mutex);

        //rotate buffers
        current=(current)?0:1;
        //copy incoming
        memcpy(yuv[current].y,((ProgData *)pdata)->enc_data->yuv.y,yuv[current].y_width*yuv[current].y_height);
        memcpy(yuv[current].u,((ProgData *)pdata)->enc_data->yuv.u,yuv[current].uv_width*yuv[current].uv_height);
        memcpy(yuv[current].v,((ProgData *)pdata)->enc_data->yuv.v,yuv[current].uv_width*yuv[current].uv_height);
        //release main buffer
        pthread_mutex_unlock(&((ProgData *)pdata)->yuv_mutex);
        //get checksums for new
        MakeChecksums(yuv[current].y,yuv[current].y_width,yuv[current].y_height,divisor,checksums_y[current]);
        MakeChecksums(yuv[current].u,yuv[current].uv_width,yuv[current].uv_height,divisor/2,checksums_u[current]);
        MakeChecksums(yuv[current].v,yuv[current].uv_width,yuv[current].uv_height,divisor/2,checksums_v[current]);

        //find and flush different blocks
        if(firstrun){
            firstrun=0;
            continue;
        }
        else{
            int prev=(current)?0:1;
            int j;
            unsigned short ynum,unum,vnum;
            unsigned char yblocks[256],ublocks[64],vblocks[64];
            ynum=unum=vnum=0;
            for(j=0;j<pow(divisor,2);j++){
                if(checksums_y[current][j]!=checksums_y[prev][j]){
                    ynum++;
                    yblocks[ynum-1]=j;
                }
            }
            for(j=0;j<pow(divisor/2,2);j++){
                if(checksums_u[current][j]!=checksums_u[prev][j]){
                    unum++;
                    ublocks[unum-1]=j;
                }
            }    
            for(j=0;j<pow(divisor/2,2);j++){
                if(checksums_v[current][j]!=checksums_v[prev][j]){
                    vnum++;
                    vblocks[vnum-1]=j;
                }
            }
            ((ProgData *)pdata)->avd+=((ProgData *)pdata)->frametime*2*((ProgData *)pdata)->args.channels;
//             fprintf(stderr,"k %d uk %d vk %d\n ",k,uk,vk);
        }
    }

    //clean up since we're not finished
    for(i=0;i<2;i++){
        free(yuv[i].y);
        free(yuv[i].u);
        free(yuv[i].v);
    }

    pthread_exit(&errno);
}