/*****************************************************************************
 * RRDtool 1.0.50  Copyright Tobias Oetiker, 1997 - 2005
 *****************************************************************************
 * rrd_first Return
 *****************************************************************************
 * Initial version by Burton Strauss, ntopSupport.com - 3/2005
 *****************************************************************************/

#include "rrd_tool.h"

time_t
rrd_first(int argc, char **argv)    
{   
    long rra_start,
         timer;
    unsigned long target_rraindex=0;
    time_t then;
    char *endptr;
    FILE *in_file;
    rrd_t rrd;

    while (1){
        static struct option long_options[] =
        {
            {"rraindex", required_argument, 0, 129},
            {0,0,0,0}
        };
        int option_index = 0;
        int opt;
        opt = getopt_long(argc, argv, "", long_options, &option_index);

        if (opt == EOF)
            break;

        switch(opt) {
          case 129:
            target_rraindex=strtol(optarg,&endptr,0);
            if(target_rraindex < 0) {
                rrd_set_error("invalid rraindex number");
                return(-1);
            }
            break;
          case '?':
            rrd_set_error("unknown option '-%c'",optopt);
            return(-1);
        }
    }

    if (optind >= argc){
        rrd_set_error("not enough arguments");
        return -1;       
    }     
 
    if(rrd_open(argv[optind],&in_file,&rrd, RRD_READONLY)==-1){
        rrd_set_error("could not open RRD");
        return(-1);
    }

    if((target_rraindex < 0) || (target_rraindex >= rrd.stat_head->rra_cnt)) {
        rrd_set_error("invalid rraindex number");
        return(-1);
    }

    rra_start = ftell(in_file);    
    fseek(in_file,
          (rra_start +
           (rrd.rra_ptr[target_rraindex].cur_row+1) *
           rrd.stat_head->ds_cnt *
           sizeof(rrd_value_t)),
          SEEK_SET);
    timer = - (rrd.rra_def[target_rraindex].row_cnt-1);
    if (rrd.rra_ptr[target_rraindex].cur_row + 1 > rrd.rra_def[target_rraindex].row_cnt) {
      fseek(in_file,rra_start,SEEK_SET);
    }
    then = (rrd.live_head->last_up -
            rrd.live_head->last_up %
            (rrd.rra_def[target_rraindex].pdp_cnt*rrd.stat_head->pdp_step)) +
           (timer * 
            rrd.rra_def[target_rraindex].pdp_cnt*rrd.stat_head->pdp_step);

    rrd_free(&rrd);
    fclose(in_file);
    return(then);
}