#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <signal.h>

#define MAX_SIGNALS 32

#define print(fmt, ...) fprintf(stderr, "test_program: "fmt, ##__VA_ARGS__)

_Bool do_raise = 0;
int raise_signal;   
_Bool do_Com_Error = 0;
_Bool recursive = 0;

enum { DEFAULT = 0, CATCH, IGNORE };
int handle[MAX_SIGNALS] = {0};
_Bool handle_any = 0;

_Bool verbose = 0;

static int read_args(int argc, char **argv)
{
	for (int i = 1; i < argc; i++) {
		if (!strcmp(argv[i], "--raise")) {
			if (i + 1 >= argc)
				goto needs_argument;

			do_raise = 1;
			raise_signal = atoi(argv[i + 1]);
			i++;
		} else if (!strcmp(argv[i], "--Com_Error")) {
			do_Com_Error = 1;
		} else if (!strcmp(argv[i], "--recursive")) {
			recursive = 1;
		} else if (!strcmp(argv[i], "--catch") ||
		           !strcmp(argv[i], "--ignore")) {
			int sig;

			if (i + 1 >= argc)
				goto needs_argument;

			sig = atoi(argv[i + 1]);
			if (sig < 0 || sig >= MAX_SIGNALS) {
				print("invalid argument for --catch/--ignore: %i\n",
				      sig);
				return 1;
			}

			if (!strcmp(argv[i], "--catch"))
				handle[sig] = CATCH;
			else
				handle[sig] = IGNORE;

			handle_any = 1;
			i++;
		} else if (!strcmp(argv[i], "--ignore")) {
			
		} else if (!strcmp(argv[i], "--verbose")) {
			verbose = 1;
		} else {
			print("invalid option '%s'\n", argv[i]);
			return 1;
		}

		continue;
	needs_argument:
		print("option '%s' needs an argument\n", argv[i]);
		return 1;
	}

	if (do_Com_Error && do_raise) {
		print("--raise and --Com_Error are mutually exclusive.\n");
		return 1;
	}

	return 0;
}

_Noreturn void graceful_exit(void)
{
	print("Graceful exit.\n");
	exit(0);
}

void signal_catcher(int sig)
{
	print("Caught signal %i.\n", sig);

	if (recursive) {
		if (verbose)
			print("Raising signal %i from within the handler.\n",
			      raise_signal);
		raise(raise_signal);
	}

	graceful_exit();
}

_Noreturn void Com_Error(int type, const char *str)
{
	print("Com_Error: %s\n", str);

	if (recursive)
		Com_Error(666, "Error while erroring");

	graceful_exit();
}

int main(int argc, char **argv)
{
	int rv;

	rv = read_args(argc, argv);
	if (rv)
		return rv;

	for (int i = 0; i < MAX_SIGNALS; i++) {
		void (*fun)(int);

		switch (handle[i]) {
		case DEFAULT:
			continue;

		case CATCH:
			fun = signal_catcher;
			if (verbose)
				print("Signal %i will be caught.\n", i);
			break;

		case IGNORE:
			fun = SIG_IGN;
			if (verbose)
				print("Signal %i will be ignored.\n", i);
			break;
		}

		if (signal(i, fun) == SIG_ERR) {
			print("For signal %i: ", i);
			perror("signal");
			return 1;
		}
	}

	if (do_raise) {
		print("Raising signal %i.\n", raise_signal);
		raise(raise_signal);
	}

	if (do_Com_Error)
		Com_Error(123, "Some error string");

	print("Reached the end of main().\n");
	graceful_exit();
}