#include "noit_defines.h"

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <signal.h>
#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif

#include "eventer/eventer.h"
#include "utils/noit_log.h"
#include "utils/noit_hash.h"
#include "noit_listener.h"
#include "noit_console.h"
#include "noit_jlog_listener.h"
#include "noit_module.h"
#include "noit_conf.h"
#include "noit_conf_checks.h"
#include "noit_filters.h"

#define APPNAME "noit"
#define CHILD_WATCHDOG_TIMEOUT 5 /*seconds*/

static char *config_file = ETC_DIR "/" APPNAME ".conf";
static int debug = 0;

void parse_clargs(int argc, char **argv) {
  int c;
  while((c = getopt(argc, argv, "c:d")) != EOF) {
    switch(c) {
      case 'c':
        config_file = strdup(optarg);
        break;
      case 'd':
        debug++;
        break;
      default:
        break;
    }
  }
}

static
int configure_eventer() {
  int rv = 0;
  noit_hash_table *table;
  table = noit_conf_get_hash(NULL, "/" APPNAME "/eventer/config");
  if(table) {
    noit_hash_iter iter = NOIT_HASH_ITER_ZERO;
    const char *key, *value;
    int klen;
    while(noit_hash_next(table, &iter, &key, &klen, (void **)&value)) {
      int subrv;
      if((subrv = eventer_propset(key, value)) != 0)
        rv = subrv;
    }
    noit_hash_destroy(table, free, free);
    free(table);
  }
  return rv;
}

/* Watchdog stuff */
static int *lifeline = NULL;
static unsigned long last_tick_time() {
  static struct timeval lastchange = { 0, 0 };
  static int lastcheck = 0;
  struct timeval now, diff;

  gettimeofday(&now, NULL);
  if(lastcheck != *lifeline) {
    lastcheck = *lifeline;
    memcpy(&lastchange, &now, sizeof(lastchange));
  }
  sub_timeval(now, lastchange, &diff);
  return (unsigned long)diff.tv_sec;
}
static void it_ticks() {
  (*lifeline)++;
}
static void setup_mmap() {
  lifeline = mmap(NULL, sizeof(int), PROT_READ|PROT_WRITE,
                  MAP_SHARED|MAP_ANON, -1, 0);
  if(lifeline == (void *)-1) {
    noitL(noit_error, "Failed to mmap anon for watchdog\n");
    exit(-1);
  }
}

static int watch_over_child(int (*func)()) {
  int child_pid;
  setup_mmap();
  while(1) {
    child_pid = fork();
    if(child_pid == -1) {
      noitL(noit_error, "fork failed: %s\n", strerror(errno));
      exit(-1);
    }
    if(child_pid == 0) {
      /* This sets up things so we start alive */
      it_ticks();
      /* run the program */
      exit(func());
    }
    else {
      int sig = -1, exit_val = -1;
      while(1) {
        unsigned long ltt;
        int status, rv;
        sleep(1); /* Just check child status every second */
        rv = waitpid(child_pid, &status, WNOHANG);
        if(rv == 0) {
          /* Nothing */
        }
        else if (rv == child_pid) {
          /* We died!... we need to relaunch, unless the status was a requested exit (2) */
          sig = WTERMSIG(status);
          exit_val = WEXITSTATUS(status);
          if(sig == SIGINT || sig == SIGQUIT ||
             (sig == 0 && (exit_val == 2 || exit_val < 0))) {
            noitL(noit_error, "noitd shutdown acknowledged.\n");
            exit(0);
          }
          break;
        }
        else {
          noitL(noit_error, "Unexpected return from waitpid: %d\n", rv);
          exit(-1);
        }
        /* Now check out timeout */
        if((ltt = last_tick_time()) > CHILD_WATCHDOG_TIMEOUT) {
          noitL(noit_error,
                "Watchdog timeout (%lu s)... terminating child\n",
                ltt);
          kill(child_pid, SIGKILL);
        }
      }
      noitL(noit_error, "noitd child died [%d/%d], restarting.\n", exit_val, sig);
    }
  }
}

static int watchdog_tick(eventer_t e, int mask, void *unused, struct timeval *now) {
  it_ticks();
  return 0;
}
static int child_main() {
  eventer_t e;

  /* Load our config...
   * to ensure it is current w.r.t. to this child starting */
  if(noit_conf_load(config_file) == -1) {
    noitL(noit_error, "Cannot load config: '%s'\n", config_file);
  }

  /* initialize the eventer */
  if(eventer_init() == -1) {
    noitL(noit_stderr, "Cannot initialize eventer\n");
    exit(-1);
  }

  /* Setup our hearbeat */
  e = eventer_alloc();
  e->mask = EVENTER_RECURRENT;
  e->callback = watchdog_tick;
  eventer_add_recurrent(e);

  /* Initialize all of our listeners */
  noit_console_init();
  noit_jlog_listener_init();

  noit_module_init();
  noit_filters_init();
  noit_poller_init();
  noit_listener_init(APPNAME);

  /* Write our log out, and setup a watchdog to write it out on change. */
  noit_conf_write_log(NULL);
  noit_conf_coalesce_changes(10); /* 10 seconds of no changes before we write */
  noit_conf_watch_and_journal_watchdog(noit_conf_write_log, NULL);

  eventer_loop();
  return 0;
}

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

  parse_clargs(argc, argv);

  /* First initialize logging, so we can log errors */
  noit_log_init();
  noit_log_stream_add_stream(noit_debug, noit_stderr);
  noit_log_stream_add_stream(noit_error, noit_stderr);

  /* Next load the configs */
  noit_conf_init(APPNAME);
  noit_conf_checks_init(APPNAME);
  if(noit_conf_load(config_file) == -1) {
    fprintf(stderr, "Cannot load config: '%s'\n", config_file);
  }

  /* Reinitialize the logging system now that we have a config */
  noit_conf_log_init(APPNAME);
  if(debug)
    noit_debug->enabled = 1;

  /* Lastly, run through all other system inits */
  if(!noit_conf_get_stringbuf(NULL, "/" APPNAME "/eventer/@implementation",
                              conf_str, sizeof(conf_str))) {
    noitL(noit_stderr, "Cannot find '%s' in configuration\n",
          "/" APPNAME "/eventer/@implementation");
    exit(-1);
  }
  if(eventer_choose(conf_str) == -1) {
    noitL(noit_stderr, "Cannot choose eventer %s\n", conf_str);
    exit(-1);
  }
  if(configure_eventer() != 0) {
    noitL(noit_stderr, "Cannot configure eventer\n");
    exit(-1);
  }

  return watch_over_child(child_main);
}