#include <sys/socket.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <stdio.h>
#include <time.h>
#include <err.h>

#include "tunnel.h"
#include "macro.h"
#include "utils.h"

static time_t since;

static void tunnel_daemon_atexit(void)
{
	unlink(TUNNEL_SOCK_PATH);
}

static void sighandler(int signo __unused)
{
	exit(EXIT_FAILURE);
}

static char **parse_args(char *buf, int len)
{
	char **args = NULL;

	while (len) {
		addv(&args, buf);

		char *p = memchr(buf, '\0', len);
		if (!p)
			break;

		len -= p - buf + 1;
		buf = p + 1;
	}

	return args;
}

static void echo(FILE *fp, char **args)
{
	for (int n = 0; args[n]; n++)
		fprintf(fp, "%s%s", n ? " " : "", args[n]);
}

static void tunnel_daemon_loop(int sock)
{
	bool alive = true;

	while (alive) {
		char msg[1024];
		int len;

		int fd = accept(sock, NULL, NULL);
		if (fd < 0) {
			warn("accept");
			continue;
		}

		len = read(fd, msg, sizeof(msg) - 1);
		if (len < 0) {
			warn("read");
			close(fd);
			continue;
		}

		if (! len) {
			close(fd);
			continue;
		}

		msg[len] = '\0';

		char **args = parse_args(msg, len);

		let (fp, fdopen(fd, "w"), fclose) {
			char *cmd = *args;

			if (strequal(cmd, "echo"))
				echo(fp, args + 1);
			else if (strequal(cmd, "hello"))
				fprintf(fp, "hello from %d", getpid());
			else if (strequal(cmd, "alive"))
				fprintf(fp, "since %s", ctime(&since));
			else if (strequal(cmd, "stop")) {
				fprintf(fp, "ok");
				alive = false;
			} else
				fprintf(fp, "what do you want?");
		}

		free(args);
	}
}

bool tunnel_daemon(int sock)
{
	switch (fork()) {
	case -1:
		warn("fork");
		return false;
	case 0:
		break;
	default:
		return true;
	}

	if (setsid() < 0)
		err(EXIT_FAILURE, "setsid");

	chdir("/");

	struct sigaction sa = {
		.sa_handler = sighandler
	};

	sigaction(SIGTERM, &sa, NULL);
	sigaction(SIGINT, &sa, NULL);

#if 0
	int fd = open("/dev/null", O_RDWR);
	if (fd < 0)
		err(EXIT_FAILURE, "open /dev/null");

	dup2(fd, STDIN_FILENO);
	dup2(fd, STDOUT_FILENO);
	dup2(fd, STDERR_FILENO);

	if (fd > 2)
		close(fd);
#endif

	time(&since);

	atexit(tunnel_daemon_atexit);

	tunnel_daemon_loop(sock);

	exit(EXIT_SUCCESS);

	return true;
}