/* This file is in the public domain. */

#include <stdlib.h>

#include "ctype.h"

#include "timeint.h"

TIMEINTVL parse_time_interval(const char *s, void (*err)(const char *, ...))
{
 struct {
   char letter;
   unsigned int val;
   int have;
   } specs[]
  = { { 'y' },
#define PTI_SX_Y  0
      { 'm' },
#define PTI_SX_M1 1
      { 'w' },
#define PTI_SX_W  2
      { 'd' },
#define PTI_SX_D  3
      { 'h' },
#define PTI_SX_H  4
      { 'm' },
#define PTI_SX_M2 5
      { 's' } };
#define PTI_SX_S  6
#define PTI_N_SPECS (sizeof(specs)/sizeof(specs[0]))
 int sx;
 unsigned long int ulv;
 unsigned int uv;
 char *e;

 for (sx=PTI_N_SPECS-1;sx>=0;sx--)
  { specs[sx].have = 0;
    specs[sx].val = 0;
  }
 sx = 0;
 while (1)
  { while (*s && UCisspace(*s)) s ++;
    if (! *s) break;
    ulv = strtoul(s,&e,10);
    if (e == s) (*err)("bad number in time interval");
    if (! *e) (*err)("missing unit in time interval");
    uv = ulv;
    if (uv != ulv) (*err)("out-of-range number in time interval");
    while (1)
     { if (sx >= PTI_N_SPECS) (*err)("bad unit `%c' in time interval",*e);
       if (*e == specs[sx].letter) break;
       sx ++;
     }
    specs[sx].have = 1;
    specs[sx].val = uv;
    sx ++;
    s = e + 1;
  }
 if ( specs[PTI_SX_M1].have &&
      !specs[PTI_SX_M2].have &&
      !specs[PTI_SX_W].have &&
      !specs[PTI_SX_D].have &&
      !specs[PTI_SX_H].have )
  { if (specs[PTI_SX_Y].have && !specs[PTI_SX_S].have)
     { /* do nothing, already correct */
     }
    else if (specs[PTI_SX_S].have && !specs[PTI_SX_Y].have)
     { specs[PTI_SX_M2].have = 1;
       specs[PTI_SX_M2].val = specs[PTI_SX_M1].val;
       specs[PTI_SX_M1].have = 0;
       specs[PTI_SX_M1].val = 0;
     }
    else
     { (*err)("ambiguous `m' in time interval");
     }
  }
 return( (specs[PTI_SX_Y ].val * 31556952) +
	 (specs[PTI_SX_M1].val *  2629746) +
	 (specs[PTI_SX_W ].val *   604800) +
	 (specs[PTI_SX_D ].val *    86400) +
	 (specs[PTI_SX_H ].val *     3600) +
	 (specs[PTI_SX_M2].val *       60) +
	 (specs[PTI_SX_S ].val *        1) );
}