#pragma once

#include <assert.h>
#include <stdio.h>
#include <stdbool.h>
#include <stdarg.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <signal.h>
#include <time.h>

#include "board.h"
#include "mcp.h"

enum exit_reason {
  /* Invalid moves disqualify the player. */
  INVALID_MOVE_0 = 1,
  INVALID_MOVE_1,
  /* Crashes do, too. */
  CRASH_0,
  CRASH_1,
  /* Couldn't execute a player. This is a configuration error. */
  EXEC_FAILED
};

/* Time given to players after softlimit has been exhausted. */
//#define CLEANUP_TIME 1 /* seconds */

static struct rlimit cpu_limit = { RLIM_INFINITY, RLIM_INFINITY };
static struct rlimit mem_limit = { RLIM_INFINITY, RLIM_INFINITY };
static bool debug = false;

static struct player {
  volatile pid_t pid;
  int pipe_from_player;
  int pipe_to_player;

  volatile bool soft_timeout;
  volatile bool hard_timeout;
} player[2];

static struct player * volatile current_player = NULL;

/* Specify seconds = RLIM_INFINITY to disarm timer. */
static void
arm_timer(time_t seconds)
{
  struct itimerval t;

  t.it_interval.tv_sec = 0;
  t.it_interval.tv_usec = 0;
  t.it_value.tv_sec = (seconds == (int)RLIM_INFINITY) ? 0 : seconds;
  t.it_value.tv_usec = 0;

  if (setitimer(ITIMER_REAL, &t, NULL) < 0)
    abort();
}

static void
alarm_handler(int signum, siginfo_t *, void *)
{
  assert(signum == SIGALRM);

  struct player *p = current_player;
  assert(p);

  if (!p->soft_timeout) {
    p->soft_timeout = true;
    kill(p->pid, SIGXCPU);
    arm_timer(static_cast<time_t>(cpu_limit.rlim_max - cpu_limit.rlim_cur));
  } else {
    p->hard_timeout = true;
    kill(p->pid, SIGKILL);
  }
}


static char const *
si_code_str(int si_code)
{
	switch(si_code) {
		case CLD_EXITED: return "exited";
		case CLD_KILLED: return "killed";
		case CLD_DUMPED: return "coredumped";
		case CLD_TRAPPED: return "trapped";
		default: break;
	}
	return "unknown";
}

static char const *
signal_str(int sig)
{
	switch(sig)
	{
#define CASE(x) case x: return #x;
		CASE(SIGHUP); CASE(SIGINT); CASE(SIGILL); CASE(SIGABRT);
		CASE(SIGSEGV); CASE(SIGFPE); CASE(SIGPIPE); CASE(SIGKILL);
		CASE(SIGTERM); CASE(SIGALRM); CASE(SIGUSR1); CASE(SIGUSR2);
		CASE(SIGBUS); CASE(SIGCHLD);
#undef CASE
	}
	return "unknown";
}

static void
child_handler(int signum, siginfo_t *si, void *)
{
	/* For any SIGCHLD code other than STOP/CONT, we print additional info:
	 * si_code contains what happened to the child. If the child was terminated
	 * with a signal (most common case), then si_status additionally contains
	 * the signal that caused termination.
	 */
	if ((si->si_code != CLD_STOPPED) &&
		(si->si_code != CLD_CONTINUED)) {
		// si_status contains the signal that caused the child to terminate
		switch(si->si_status) {
			case SIGKILL:
			case SIGSEGV:
				printf("\n\033[31mCHILD signal: %d ", si->si_status);
				printf("(%s,%s)\033[0m\n", si_code_str(si->si_code), signal_str(si->si_status));
				printf("killing the other one\n");
				for (int i = 0; i < 2; i++) {
					int status;
					kill(player[i].pid, SIGTERM);
					kill(player[i].pid, SIGCONT);
					waitpid(player[i].pid, &status, 0);
				}
				printf("MCP exiting\n");
				exit(1);
				break;
			case SIGTERM:
				printf("\n\033[32mCHILD terminated successfully\033[0m\n");
				break;
			default:
				printf(" HANDLEME!\n");
				break;
		}
	}
}


static void __attribute__((noreturn))
exit_msg(enum exit_reason r, const char *msg, ...)
{
  va_list ap;
  va_start(ap, msg);
  vfprintf(stderr, msg, ap);
  exit(r);
  va_end(ap);
}

static bool
player_move(struct player    *the_player,
            const game_state *state,
            game_move        *move)
{
  bool succ;

  the_player->hard_timeout = false;
  the_player->soft_timeout = false;

  /* Arm timer with softlimit */
  current_player = the_player;
  arm_timer(static_cast<time_t>(cpu_limit.rlim_cur));

  if (kill(the_player->pid, SIGCONT) < 0) return false;

  ssize_t written = serialize_state(the_player->pipe_to_player, state);
  if (the_player->hard_timeout) goto timeout;
  if (written < 0)
    return false;

  succ = deserialize_move(the_player->pipe_from_player, move);
  if (the_player->hard_timeout) goto timeout;
  if (!succ) return false;

  /* Stop player and disarm timer. */
  if (kill(the_player->pid, SIGSTOP) < 0) return false;
  arm_timer(static_cast<time_t>(RLIM_INFINITY));
  current_player = NULL;

  return true;

 timeout:
  fprintf(stderr, "Player timeout!\n");
  return false;
}

static void
print_usage()
{
  fprintf(stderr, "Usage: mcp [-s state_string] [-t soft-player-time] [-m soft-player-mem]\n"
          "           [-T hard-player-time] [-M hard-player-mem]\n"
          "           [-d]\n"
          "           player1 player2\n"
          " state_string - 65 character string representing an initial field state\n"
          "                (this is the string the MCP prints before every move.)\n"
          " player-time  - CPU time per turn in seconds\n"
          " player-mem   - Memory limit per player in megabytes\n"
          " -d           - turn on debugging, program won't exit on invalid move\n");
}


static void
setup_signal_handlers()
{
	/* Ignore SIGPIPE. Accessing dead pipes now returns EPIPE. */
	struct sigaction pact;
	pact.sa_handler = SIG_IGN;
	sigemptyset(&pact.sa_mask);
	pact.sa_restorer = 0;
	pact.sa_sigaction = 0;
	pact.sa_flags = 0;
	if (sigaction(SIGPIPE, &pact, NULL) != 0)
		abort();

	/* Handle SIGALRM. */
	struct sigaction aact;
	aact.sa_handler = 0;
	sigemptyset(&aact.sa_mask);
	aact.sa_restorer = 0;
	aact.sa_sigaction = alarm_handler;
	aact.sa_flags = SA_SIGINFO | SA_RESTART;
	if (sigaction(SIGALRM, &aact, NULL) != 0)
		abort();

	// Catch SIGCHLD
	struct sigaction cact;
	cact.sa_handler = 0;
	sigemptyset(&cact.sa_mask);
	cact.sa_restorer = 0;
	cact.sa_sigaction = child_handler;
	cact.sa_flags = SA_SIGINFO | SA_RESTART /*| SA_NOCLDSTOP*/;
	if (sigaction(SIGCHLD, &cact, NULL) != 0)
		abort();
}


static void getTimeStr(char *timebuf, size_t len)
{
    time_t rawtime;
    struct tm *timeinfo;
    time(&rawtime);
    if (rawtime == (time_t)-1) {
	    perror("time()");
	}
    timeinfo = localtime(&rawtime);
    if (!timeinfo) {
	    perror("localtime()");
	}
    strftime(timebuf, len, "%H:%M:%S", timeinfo);
}