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

#include <wayland-client.h>
#include <wayland-server.h>
#include "ext-idle-notify-v1-protocol.h"

#define LEN(X) (sizeof(X) / sizeof(X[0]))

static struct ext_idle_notifier_v1 *notifier;
static struct wl_compositor *compositor;
static struct wl_display *display;
static struct wl_registry *registry;
static struct wl_seat *seat;
static const struct ext_idle_notification_v1_listener idlelistener;
static const struct wl_registry_listener reglistener;

pid_t cpid;

struct Events {
  uint32_t delay; /* in ms */
  char **idlecmd;
  char **resumecmd;
  struct ext_idle_notification_v1 *notif;
};

#include "config.h"

static void die(const char *fmt, ...);
static void reghandler(void *data, struct wl_registry *registry, uint32_t id,
  const char *interface, uint32_t version);
static void idling(void *data, struct ext_idle_notification_v1 *notif);
static void resuming(void *data, struct ext_idle_notification_v1 *notif);
static void run(char **cmd);

static void
die(const char *fmt, ...)
{
  va_list ap;

  va_start(ap, fmt);
  vfprintf(stderr, fmt, ap);
  va_end(ap);

  if (fmt[0] && fmt[strlen(fmt)-1] == ':') {
    fputc(' ', stderr);
    perror(NULL);
  } else
    fputc('\n', stderr);
  exit(1);
}

static void
reghandler(void *data, struct wl_registry *registry, uint32_t id,
    const char *interface, uint32_t version)
{
  if (strcmp(interface, wl_compositor_interface.name) == 0)
    compositor = wl_registry_bind(registry, id, &wl_compositor_interface, 1);
  else if (strcmp(interface, ext_idle_notifier_v1_interface.name) == 0)
    notifier = wl_registry_bind(registry, id, &ext_idle_notifier_v1_interface, 1);
  else if (strcmp(interface, wl_seat_interface.name) == 0)
    seat = wl_registry_bind(registry, id, &wl_seat_interface, 7);
}

static const struct wl_registry_listener reglistener = {
  .global = reghandler,
};

static void
idling(void *data, struct ext_idle_notification_v1 *notif)
{
  struct Events *event = data;
  run(event->idlecmd);
}

static void
resuming(void *data, struct ext_idle_notification_v1 *notif)
{
  struct Events *event = data;
  run(event->resumecmd);
}

static const struct ext_idle_notification_v1_listener idlelistener = {
  .idled = idling,
  .resumed = resuming,
};

static void
run(char **cmd)
{
  waitpid(-1, NULL, WNOHANG);
  if (killchild && cpid)
    kill(cpid, SIGINT);
  if (cmd && (cpid = fork()) == 0) {
    dup2(STDERR_FILENO, STDOUT_FILENO);
    setsid();
    execvp(cmd[0], cmd);
    die("execvp failed:");
  }
}

int
main(int argc, char *argv[])
{
  int i, c;

  while ((c = getopt(argc, argv, "hv")) != -1) {
    switch (c) {
      case 'v': die("%s-%s", argv[0], VERSION); break;
      case 'h':
      default: die("usage: %s [-hv]", argv[0]); break;
    }
  }

  display = wl_display_connect(NULL);
  if (!display)
    die("%s: failed to connect to wayland display :(", argv[0]);

  registry = wl_display_get_registry(display);
  wl_registry_add_listener(registry, &reglistener, NULL);
  wl_display_roundtrip(display);
  if (!compositor || !notifier || !seat)
    die("%s: compositor doesn't support all necessary protocols", argv[0]);

  /* register all events */
  for (i = 0; i < LEN(events); i++) {
    if (events[i].delay < 0)
      continue;

    events[i].notif = ext_idle_notifier_v1_get_idle_notification(notifier,
      events[i].delay, seat);
    ext_idle_notification_v1_add_listener(events[i].notif, &idlelistener,
      &events[i]);
  }
  wl_display_roundtrip(display);

  while (wl_display_dispatch(display) != -1);

  ext_idle_notifier_v1_destroy(notifier);
  wl_registry_destroy(registry);
  wl_display_destroy(display);
  wl_compositor_destroy(compositor);
}