/*
 * *      wattscope.c  ... PC code for a wattmeter with scope and datalogger
 * *
 * *      Copyright (C) 2012 Jiri Pittner <jiri@pittnerovi.com>
 * *
 * *      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 3 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, see <http://www.gnu.org/licenses/>.
 * *
 * *
 * */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>

void xerror(error_text)
char error_text[];
{

        fprintf(stderr,"wattscope: %s\n",error_text);
        exit(10);
}




int main(int argc, char **argv)
{
char line[1024];

int plotx=1; //time by default
int iploty=0;
int nploty=1;
int *ploty=malloc(nploty*sizeof(int));
ploty[0]=3; //true power

while((--argc>0)&&((*++argv)[0]=='-')){
if(argc>0) switch ((*argv)[1]){
  case 'x': if(--argc <0) xerror("missing format after option -x");
                sscanf(*++argv,"%d",&plotx);
                break;
  case 'y': if(--argc <0) xerror("missing format after option -y");
		++iploty;
		if(iploty > nploty) {ploty=realloc(ploty,iploty*sizeof(int)); nploty=iploty;}
                sscanf(*++argv,"%d",ploty+iploty-1);
                break;
  default : xerror("unknown option");
  }
}

if(argc!=0)  xerror("wrong command line");



int mode=0;
FILE *f,*g,*l,*h;
l=fopen("/tmp/wattscope.log","w");
if(!l) {perror("cannot fopen /tmp/wattscope.log for w\n");exit(1);}
f=fopen("/tmp/wattscope.tmp","w");
if(!f) {perror("cannot fopen /tmp/wattscope.tmp for w\n");exit(1);}
g=popen("gnuplot","w");
if(!g) {perror("cannot popen gnuplot for w\n");exit(1);}
h=popen("gnuplot","w");
if(!h) {perror("cannot popen gnuplot for w\n");exit(1);}

setlinebuf(l);
setlinebuf(g);
setlinebuf(h);

fprintf(h,"set xlabel 'Time'\n");
fprintf(h,"set autoscale y\n");
fprintf(h,"set grid\n");

fprintf(g,"set xlabel 'Time'\n");
fprintf(g,"set ylabel 'Volts'\n");
fprintf(g,"set y2label 'Ampers'\n");
fprintf(g,"set grid\n");
fprintf(g,"set format y2 \"%%.3f\"\n");
fprintf(g,"set autoscale y\n");
fprintf(g,"set autoscale y2\n");
fprintf(g,"set y2tics nomirror tc lt 3\n");
fprintf(g,"set xrange [0:0.02]\n");


int first=1;
int nline=0;
while(fgets(line,1024,stdin))
	{
	if(mode==0)
		{ 
		if(!strncmp(line,"Time =",6)) 
			{
			nline=0;
			fprintf(l,"\n");
			fprintf(h,"plot ");
			int i;
			for(i=0; i<nploty; ++i)
				{
				fprintf(h,"%s\"/tmp/wattscope.log\" using %d:%d with lines",(i>0?", ":""),plotx, ploty[i]);
				}
			fprintf(h,"\n");
			}
		char *p = strchr(line, '=');
		if(p)
			{
			double x=0;
			sscanf(p+1,"%lf",&x);
			fprintf(l,"%g ",x);
			}
		}
	if(!strncmp(line,"BEGIN SAMPLE POINTS",19)) 
		{
		if(ftruncate(fileno(f),0)) perror("cannot ftruncate");
		mode=1;
		continue;
		}
	if(!strncmp(line,"END SAMPLE POINTS",17))
                {
		fflush(f);
		usleep(50000);
                mode=0;
		if(first)
			{
			first=0;
			fprintf(g,"plot \"/tmp/wattscope.tmp\" using 1:2 axes x1y1 title 'Voltage' with lines, \"/tmp/wattscope.tmp\" using 3:4 axes x1y2  title 'Current' with lines, \"/tmp/wattscope.tmp\" using 5:6 axes x1y1  title 'Power' with lines\n");
			}
		else
			{
			fprintf(g,"replot\n");
			}
                continue;
                }
	fputs(line,mode==0?stdout:f); 
	}
fclose(f);
pclose(g);
return 0;
}