#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdbool.h>
#include <sys/inotify.h>
#include <dirent.h>
#include <errno.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <inttypes.h>

#include "main.h"
#include "uring.h"
#include "config-parser.h"
#include "server.h"
#include "server-config.h"
#include "server-config-options.h"

static void
scfg_dns_cb(struct dns_async *dns, bool (*server_cb)(struct server *, struct saddr *))
{
	struct server *server;
	struct sockaddr_in *in4;
	struct sockaddr_in6 *in6;
	struct saddr *saddr;
	struct addrinfo *results = NULL, *ai;
	int r;

	assert_return(dns && dns->priv && server_cb);

	server = dns->priv;
	debug(DBG_DNS, "called, dns: %p, name: %s, server: %p, server->name: %s",
	      dns, dns->name, server, server->name);

	r = gai_error(&dns->gcb);
	if (r == EAI_INPROGRESS) {
		/* This shouldn't happen, assume we'll get called again */
		error("called with request in progress");
		return;
	} else if (r == EAI_CANCELED) {
		/* The server must be in the process of going away */
		goto out;
	} else if (r < 0) {
		error("DNS lookup of %s:%s failed: %s",
		      dns->name, dns->port, gai_strerror(r));
		goto out;
	}

	results = dns->gcb.ar_result;

	for (ai = results; ai; ai = ai->ai_next) {
		saddr = zmalloc(sizeof(*saddr));
		if (!saddr) {
			error("DNS lookup of %s:%s failed: %m", dns->name, dns->port);
			goto out;
		}

		switch (ai->ai_family) {
		case AF_INET:
			in4 = (struct sockaddr_in *)ai->ai_addr;
			saddr_set_ipv4(saddr, in4->sin_addr.s_addr, in4->sin_port);
			server_cb(server, saddr);
			break;

		case AF_INET6:
			in6 = (struct sockaddr_in6 *)ai->ai_addr;
			saddr_set_ipv6(saddr, &in6->sin6_addr, in6->sin6_port);
			server_cb(server, saddr);
			break;

		default:
			error("getaddrinfo(%s:%s): unknown address family (%i)",
			      dns->name, dns->port, ai->ai_family);
			xfree(saddr);
			break;
		}
	}

out:
	freeaddrinfo(results);
	list_del(&dns->list);
	xfree(dns);
	uring_task_put(&server->task);
	server_commit(server);
}

static void
scfg_local_dns_cb(struct dns_async *dns)
{
	assert_return(dns);

	scfg_dns_cb(dns, server_add_local);
}

static void
scfg_remote_dns_cb(struct dns_async *dns)
{
	assert_return(dns);

	scfg_dns_cb(dns, server_add_remote);
}

static void
scfg_rcon_dns_cb(struct dns_async *dns)
{
	assert_return(dns);

	scfg_dns_cb(dns, server_add_rcon);
}

static bool
handle_dns(struct server *server, const char *type,
	   struct cfg_value *value, dns_cb_t *async_cb,
	   bool (*sync_cb)(struct server *, struct saddr *))
{
	struct saddr *saddr, *tmp;
	struct dns_async *dns;

	assert_return(server && type && value && async_cb && sync_cb, false);

	switch (value->type) {
	case CFG_VAL_TYPE_ADDRS:
		debug(DBG_DNS, "%s: got immediate addrs", type);

		list_for_each_entry_safe(saddr, tmp, &value->saddrs, list) {
			list_del(&saddr->list);
			sync_cb(server, saddr);
		}
		return true;

	case CFG_VAL_TYPE_ASYNC_ADDRS:
		debug(DBG_DNS, "%s: doing async lookup of DNS record: %p",
		      type, value->dns_async);

		dns = value->dns_async;
		dns->cb = async_cb;
		dns->priv = server;
		list_add(&dns->list, &server->dnslookups);
		uring_task_get(&server->task);
		return true;

	default:
		return false;
	}
}

static void
scfg_parse(struct server *server)
{
	char *pos;

	assert_return(server);

	pos = server->tbuf.buf;

	if (!config_parse_header(SERVER_CFG_HEADER, &pos)) {
		verbose("%s: missing/invalid header", server->name);
		return;
	}

	while (true) {
		int key;
		const char *keyname;
		struct cfg_value value;

		if (!config_parse_line(server->name, &pos, scfg_key_map,
				       &key, &keyname, &value, true))
			break;

		if (key == SCFG_KEY_INVALID)
			break;

		debug(DBG_CFG, "%s: key %s", server->name, keyname);

		switch (key) {

		case SCFG_KEY_TYPE:
			if (streq(value.str, "proxy")) {
				if (!server_set_type(server, SERVER_TYPE_PROXY))
					return;
			} else if (streq(value.str, "announce")) {
				if (!server_set_type(server, SERVER_TYPE_ANNOUNCE))
					return;
			}
			break;

		case SCFG_KEY_NAME:
			if (!server_set_pretty_name(server, value.str))
				return;
			break;

		case SCFG_KEY_PORT:
			if (!server_set_port(server, value.uint16))
				return;
			break;

		case SCFG_KEY_LOCAL:
			if (!handle_dns(server, "local", &value,
					scfg_local_dns_cb, server_add_local))
				return;
			break;

		case SCFG_KEY_REMOTE:
			if (!handle_dns(server, "remote", &value,
					scfg_remote_dns_cb, server_add_remote))
				return;
			break;

		case SCFG_KEY_IDLE_TIMEOUT:
			if (!server_set_idle_timeout(server, value.uint16))
				return;
			break;

		case SCFG_KEY_STOP_METHOD:
			if (streq(value.str, "exec")) {
				if (server_set_stop_method(server, SERVER_STOP_METHOD_EXEC))
					break;
			} else if (streq(value.str, "rcon")) {
				if (server_set_stop_method(server, SERVER_STOP_METHOD_RCON))
					break;
			} else if (streq(value.str, "systemd")) {
				if (server_set_stop_method(server, SERVER_STOP_METHOD_SYSTEMD))
					break;
			}
			return;

		case SCFG_KEY_START_METHOD:
			if (streq(value.str, "exec")) {
				if (server_set_start_method(server, SERVER_START_METHOD_EXEC))
					break;
			} else if (streq(value.str, "systemd")) {
				if (server_set_start_method(server, SERVER_START_METHOD_SYSTEMD))
					break;
			}
			return;

		case SCFG_KEY_STOP_EXEC:
			if (!server_set_stop_exec(server, value.str))
				return;
			break;

		case SCFG_KEY_START_EXEC:
			if (!server_set_start_exec(server, value.str))
				return;
			break;

		case SCFG_KEY_RCON:
			if (!handle_dns(server, "rcon", &value,
					scfg_rcon_dns_cb, server_add_rcon))
				return;
			break;

		case SCFG_KEY_RCON_PASSWORD:
			if (!server_set_rcon_password(server, value.str))
				return;
			break;

		case SCFG_KEY_SYSTEMD_SERVICE:
			if (!server_set_systemd_service(server, value.str))
				return;
			break;

		case SCFG_KEY_INVALID:
		default:
			break;
		}
	}
}

static void
scfg_read_cb(struct uring_task *task, int res)
{
	struct server *server = container_of(task, struct server, task);

	assert_return(task);
	assert_task_alive(DBG_CFG, task);

	if (res <= 0) {
		error("error reading config file for %s: %s",
		      server->name, strerror(-res));
		server_delete(server);
	}

	debug(DBG_CFG, "%s: parsing cfg (%i bytes)", server->name, res);
	uring_task_close_fd(&server->task);
	scfg_parse(server);
	server_commit(server);
}

static void 
scfg_open_cb(struct uring_task *task, int res)
{
	struct server *server = container_of(task, struct server, task);

	assert_return(task);
	assert_task_alive(DBG_CFG, task);

	if (res < 0) {
		error("open(%s) failed: %s", server->name, strerror(-res));
		server_delete(server);
		return;
	}

	debug(DBG_CFG, "reading server cfg %s (fd %i)", server->name, res);
	uring_task_set_fd(&server->task, res);
	uring_tbuf_read_until_eof(&server->task, scfg_read_cb);
}

struct server_cfg_monitor {
	struct uring_task task;
	char buf[4096] _alignas_(struct inotify_event);
};

static void
scfgm_free(struct uring_task *task)
{
	struct server_cfg_monitor *scfgm = container_of(task,
							struct server_cfg_monitor,
							task);

	assert_return(task);

	debug(DBG_CFG, "called");
	xfree(scfgm);
	cfg->server_cfg_monitor = NULL;
}

static void
inotify_event_dump(const struct inotify_event *event)
{
	assert_return(event);

	debug(DBG_CFG, "inotify event:");
	debug(DBG_CFG, " * WD     : %i", event->wd);
	debug(DBG_CFG, " * Cookie : %" PRIu32, event->cookie);
	debug(DBG_CFG, " * Length : %" PRIu32, event->len);
	debug(DBG_CFG, " * Name   : %s", event->name);
	debug(DBG_CFG, " * Mask   : %" PRIu32, event->mask);
	if (event->mask & IN_ACCESS)
		debug(DBG_CFG, "\tIN_ACCESS");
	else if(event->mask & IN_MODIFY)
		debug(DBG_CFG, "\tIN_MODIFY");
	else if(event->mask & IN_ATTRIB)
		debug(DBG_CFG, "\tIN_ATTRIB");
	else if(event->mask & IN_CLOSE_WRITE)
		debug(DBG_CFG, "\tIN_CLOSE_WRITE");
	else if(event->mask & IN_CLOSE_NOWRITE)
		debug(DBG_CFG, "\tIN_CLOSE_NOWRITE");
	else if(event->mask & IN_OPEN)
		debug(DBG_CFG, "\tIN_OPEN");
	else if(event->mask & IN_MOVED_FROM)
		debug(DBG_CFG, "\tIN_MOVED_FROM");
	else if(event->mask & IN_MOVED_TO)
		debug(DBG_CFG, "\tIN_MOVED_TO");
	else if(event->mask & IN_CREATE)
		debug(DBG_CFG, "\tIN_CREATE");
	else if(event->mask & IN_DELETE)
		debug(DBG_CFG, "\tIN_DELETE");
	else if(event->mask & IN_DELETE_SELF)
		debug(DBG_CFG, "\tIN_DELETE_SELF");
	else if(event->mask & IN_MOVE_SELF)
		debug(DBG_CFG, "\tIN_MOVE_SELF");
	else if(event->mask & IN_UNMOUNT)
		debug(DBG_CFG, "\tIN_UNMOUNT");
	else if(event->mask & IN_Q_OVERFLOW)
		debug(DBG_CFG, "\tIN_Q_OVERFLOW");
	else if(event->mask & IN_IGNORED)
		debug(DBG_CFG, "\tIN_IGNORED");
}

static void
inotify_cb(struct uring_task *task, int res)
{
	struct server_cfg_monitor *scfgm = container_of(task,
							struct server_cfg_monitor,
							task);
	const struct inotify_event *event;
	char *ptr;
	struct server *server;

	assert_return(task);
	assert_task_alive(DBG_CFG, task);

	if (res <= 0) {
		error("inotify_read: %i", res);
		return;
	}

	for (ptr = scfgm->buf; ptr < scfgm->buf + res; ptr += sizeof(struct inotify_event) + event->len) {
		event = (const struct inotify_event *)ptr;

		if (debug_enabled(DBG_CFG))
			inotify_event_dump(event);

		if (event->mask & (IN_IGNORED | IN_MOVE_SELF | IN_DELETE_SELF | IN_UNMOUNT))
			die("configuration directory gone, exiting");

		if (event->mask & IN_Q_OVERFLOW) {
			error("inotify queue overflow");
			continue;
		}

		if (!is_valid_server_config_filename(NULL, event->name))
			continue;

		if (event->mask & (IN_MOVED_FROM | IN_DELETE))
			server_delete_by_name(event->name);
		else if (event->mask & (IN_MOVED_TO | IN_CREATE | IN_CLOSE_WRITE)) {
			server = server_new(event->name);
			verbose("New server config file detected: %s", server->name);
			uring_openat(&server->task, server->name, scfg_open_cb);
		} else
			error("inotify: unknown event: 0x%08x", event->mask);
	}

	uring_read(&scfgm->task, scfgm->buf, sizeof(scfgm->buf), inotify_cb);
}

void
server_cfg_monitor_refdump()
{
	assert_return_silent(cfg->server_cfg_monitor);

	uring_task_refdump(&cfg->server_cfg_monitor->task);
}

void
server_cfg_monitor_delete()
{
	assert_return(cfg->server_cfg_monitor);

	debug(DBG_CFG, "closing fd %i", cfg->server_cfg_monitor->task.fd);
	uring_task_destroy(&cfg->server_cfg_monitor->task);
	cfg->server_cfg_monitor = NULL;
}

void
server_cfg_monitor_init()
{
	int ifd;
	int iwd;
	struct server_cfg_monitor *scfgm;
	DIR *dir;
	struct dirent *dent;
	struct server *server;

	assert_return(!cfg->server_cfg_monitor);

	scfgm = zmalloc(sizeof(*scfgm));
	if (!scfgm)
		die("malloc: %m");

	ifd = inotify_init1(IN_CLOEXEC);
	if (ifd < 0)
		die("inotify_init1: %m");

	/* ln = IN_CREATE, cp/vi/mv = IN_CREATE, IN_OPEN, IN_CLOSE_WRITE */
	iwd = inotify_add_watch(ifd, ".",
				IN_CLOSE_WRITE | IN_DELETE | IN_CREATE |
				IN_DELETE_SELF | IN_MOVE_SELF | IN_MOVED_TO |
				IN_MOVED_FROM | IN_DONT_FOLLOW |
				IN_EXCL_UNLINK | IN_ONLYDIR );
	if (iwd < 0)
		die("inotify_add_watch: %m");

	uring_task_init(&scfgm->task, "server-config-monitor", uring_parent(), scfgm_free);
	uring_task_set_fd(&scfgm->task, ifd);
	cfg->server_cfg_monitor = scfgm;
	uring_read(&scfgm->task, scfgm->buf, sizeof(scfgm->buf), inotify_cb);

	dir = opendir(".");
	if (!dir)
		die("opendir(%s): %m", cfg->cfg_dir);

	while ((dent = readdir(dir)) != NULL) {
		if (!is_valid_server_config_filename(dent, NULL))
			continue;

		server = server_new(dent->d_name);
		if (server)
			uring_openat(&server->task, server->name, scfg_open_cb);
	}

	closedir(dir);
}