#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <inttypes.h>
#include <stdarg.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>

#include "rcon-protocol.h"
#include "utils.h"
#include "config-parser.h"
#include "server-config-options.h"

void
__debug(_unused_ enum debug_lvl lvl, const char *fmt, ...)
{
	va_list ap;

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

_noreturn_ void
__die(const char *fmt, ...)
{
	va_list ap;

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

	exit(EXIT_FAILURE);
}

void *
__zmalloc(const char *fn, int line, size_t size)
{
	void *ptr;

	assert_die(!empty_str(fn) && line > 0 && size > 0, "invalid arguments");

	ptr = calloc(1, size);
	if (!ptr)
		die("malloc: %m");
	return ptr;
}

char *
__xstrdup(const char *fn, int line, const char *s)
{
	char *ptr;

	assert_die(!empty_str(fn) && line > 0 && !empty_str(s), "invalid arguments");

	ptr = strdup(s);
	if (!ptr)
		die("strdup: %m");
	return ptr;
}

char *
__xstrndup(const char *fn, int line, const char *s, size_t n)
{
	char *ptr;

	assert_die(!empty_str(fn) && line > 0 && !empty_str(s) && n > 0, "invalid arguments");

	ptr = strndup(s, n);
	if (ptr)
		die("strdup: %m");
	return ptr;
}

void
__xfree(const char *fn, int line, void *ptr)
{
	assert_die(!empty_str(fn) && line > 0, "invalid arguments");

	free(ptr);
}

static void
send_packet(int sfd, const char *buf, size_t len)
{
	size_t off = 0;
	ssize_t r;

	while (true) {
		r = write(sfd, buf + off, len - off);
		if (r < 0) {
			if (errno == EINTR)
				continue;
			else
				die("Failed to write packet: %m");
		}

		off += r;
		if (off == len)
			break;
	}
}

static void
read_packet(int sfd, char *buf, size_t len, int32_t *id, int32_t *type, const char **msg)
{
	size_t off = 0;
	ssize_t r;
	const char *error;

	while (true) {
		r = read(sfd, buf + off, len - off);
		if (r < 0) {
			if (errno == EINTR)
				continue;
			else
				die("Failed to read reply: %m");
		}

		if (r == 0)
			die("Failed, connection closed");

		off += r;
		if (rcon_protocol_packet_complete(buf, off))
			break;

		if (off >= len)
			die("Reply too large %zu and %zu", off, len);
	}

	if (!rcon_protocol_read_packet(buf, off, id, type, msg, &error))
		die("Failed to parse response: %s", error);
}

static void
send_msg(int sfd, char *buf, size_t len, enum rcon_packet_type type,
	 const char *msg, enum rcon_packet_type *rtype, const char **reply)
{
	static uint32_t rcon_packet_id = 1;
	size_t plen;
	int32_t id;

	if (!rcon_protocol_create_packet(buf, len, &plen,
					 rcon_packet_id, type, msg))
		die("Failed to create rcon packet");

	send_packet(sfd, buf, plen);
	read_packet(sfd, buf, len, &id, rtype, reply);

	if (id != rcon_packet_id)
		die("Invalid reply id");

	rcon_packet_id++;
}

static void
send_login(int sfd, const char *password)
{
	char buf[4096];
	int32_t rtype;
	const char *reply;

	send_msg(sfd, buf, sizeof(buf), RCON_PACKET_LOGIN, password, &rtype, &reply);

	if (rtype == RCON_PACKET_LOGIN_OK)
		info("Login ok");
	else if (rtype == RCON_PACKET_LOGIN_FAIL)
		die("Login failure, invalid password?");
	else
		die("Invalid return code: %" PRIi32, rtype);
}

static void
send_cmd(int sfd, const char *cmd)
{
	char buf[4096];
	int32_t rtype;
	const char *reply;

	send_msg(sfd, buf, sizeof(buf), RCON_PACKET_COMMAND, "stop", &rtype, &reply);

	if (rtype == RCON_PACKET_RESPONSE)
		info("Command (%s) sent, reply: %s", cmd, reply);
	else
		die("Invalid return code: %" PRIi32, rtype);
}

static int
connect_any(struct list_head *addrs)
{
	struct saddr *saddr;
	bool connected = false;
	int sfd;

	list_for_each_entry(saddr, addrs, list) {
		sfd = socket(saddr->storage.ss_family, SOCK_STREAM | SOCK_CLOEXEC, 0);
		if (sfd < 0)
			die("socket: %m");

		socket_set_low_latency(sfd, true, true, true);

		if (connect(sfd, (struct sockaddr *)&saddr->storage, saddr->addrlen) < 0) {
			close(sfd);
			continue;
		}

		connected = true;
		break;
	}

	if (!connected)
		die("Failed to connect to remote host");

	return sfd;
}

static void
parse_config(char *buf, const char *filename,
	     const char **password, struct list_head *addrs)
{
	*password = NULL;
	list_init(addrs);

	if (!config_parse_header(SERVER_CFG_HEADER, &buf))
		die("Unable to parse %s: invalid/missing header", filename);

	/* FIXME: this will cause superflous DNS lookups of other cfg entries */
	while (true) {
		int key;
		const char *keyname;
		struct cfg_value value;

		if (!config_parse_line(filename, &buf, scfg_key_map,
				       &key, &keyname, &value, false))
			break;

		switch (key) {
		case SCFG_KEY_RCON:
			list_replace(&value.saddrs, addrs);
			break;
		case SCFG_KEY_RCON_PASSWORD:
			*password = value.str;
			break;
		default:
			continue;
		}

		if (*password && !list_empty(addrs))
			break;
	}

	if (!*password)
		die("rcon password not found in %s", filename);

	if (list_empty(addrs))
		die("rcon address not found in %s", filename);
}

static void
read_file(const char *filename, char *buf, size_t len)
{
	int fd;
	size_t off = 0;
	ssize_t r;

	fd = open(filename, O_RDONLY | O_CLOEXEC);
	if (fd < 0)
		die("Failed to open %s: %m", filename);

	while (true) {
		r = read(fd, buf + off, len - off - 1);
		if (r < 0)
			die("Failed to read %s: %m", filename);
		else if (r == 0)
			break;

		off += r;
		if (off == len)
			die("Failed to read %s: file too large", filename);
	}

	buf[off] = '\0';
	close(fd);
}

int
main(int argc, char **argv)
{
	char buf[4096];
	const char *password;
	const char *filename;
	struct list_head addrs;
	struct saddr *saddr;
	int fd;

	debug_mask = DBG_ERROR | DBG_INFO;

	if (argc != 2)
		die("Usage: minecctl CFGFILE");

	filename = argv[1];

	read_file(filename, buf, sizeof(buf));

	parse_config(buf, filename, &password, &addrs);

	info("Password: %s", password);
	list_for_each_entry(saddr, &addrs, list)
		info("Address: %s", saddr->addrstr);

	fd = connect_any(&addrs);

	send_login(fd, password);

	send_cmd(fd, "stop");

	exit(EXIT_SUCCESS);
}