#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <strings.h>
#include <sys/file.h>

extern const char *__progname;

#include "system.h"

#include "profile.h"

static int did_p_r = 0;
static PROFILE *def_profile;
static int lockfd = -1;
static const char *mmdir = 0;
static const char *folder_dir = 0;

static void get_syslock_fd(void)
{
 const char *lockpath;

 if (lockfd >= 0) return;
 lockpath = profile_relative_to(system_get_profile(),"syslock",".syslock",system_mmdir());
 lockfd = open(lockpath,O_RDWR|O_CREAT,0600);
 fcntl(lockfd,F_SETFD,1);
}

const char *system_homedir(void)
{
 const char *home;

 home = getenv("HOME");
 if (home == 0) home = ".";
 return(home);
}

const char *system_mmdir(void)
{
 if (! mmdir) mmdir = profile_relative_to(system_get_profile(),"mmdir",".mm",system_homedir());
 return(mmdir);
}

const char *system_folder_dir(void)
{
 if (! folder_dir) folder_dir = profile_relative_to(system_get_profile(),"folders","mail",system_mmdir());
 return(folder_dir);
}

PROFILE *system_get_profile(void)
{
 if (! did_p_r)
  { def_profile = profile_read(0);
    if (def_profile == 0)
     { fprintf(stderr,"%s: no profile!\n",__progname);
       exit(1);
     }
    profile_set_envoverride(def_profile,1);
    did_p_r = 1;
  }
 return(def_profile);
}

int system_lock(unsigned int how)
{
 int lockop;
 int srv;

 switch (how & (SYS_SHARED|SYS_EXCLUSIVE))
  { case SYS_SHARED:
       lockop = LOCK_SH;
       break;
    case SYS_EXCLUSIVE:
       lockop = LOCK_EX;
       break;
    default:
       errno = EINVAL;
       return(-1);
       break;
  }
 switch (how & (SYS_WAIT|SYS_NOWAIT))
  { case SYS_WAIT:
       break;
    case SYS_NOWAIT:
       lockop |= LOCK_NB;
       break;
    default:
       errno = EINVAL;
       return(-1);
       break;
  }
 get_syslock_fd();
 srv = (lockfd < 0) ? -1 : flock(lockfd,lockop);
 if (srv < 0)
  { if (how & SYS_FAILEXIT)
     { fprintf(stderr,"%s: can't get system lock: %s\n",__progname,strerror(errno));
       exit(1);
     }
    return(-1);
  }
 return(0);
}

void system_unlock(void)
{
 if (lockfd >= 0) flock(lockfd,LOCK_UN);
}