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

#include "main.h"
#include "uring.h"
#include "config.h"
#include "server.h"

static void
eat_whitespace_and_comments(char **pos)
{
	while (true) {
		while (isspace(**pos))
			(*pos)++;

		if (**pos == '#') {
			while (**pos != '\r' && **pos != '\n' && **pos != '\0')
				(*pos)++;
			continue;
		}
		
		return;
	}
}

static char *
get_line(char **pos)
{
	char *begin = *pos;
	char *end;

	while (isspace(*begin))
		begin++;

	if (*begin == '\0')
		return NULL;

	end = begin;
	while (*end != '\n' && *end != '\0')
		end++;

	if (*end == '\0')
		*pos = end;
	else
		*pos = end + 1;

	while (isspace(*end)) {
		*end = '\0';
		end--;
	}

	return begin;
}

static bool
strtosockaddrs(const char *str, struct list_head *list)
{
	char *tmp;
	uint16_t port;
	int r;
	struct sockaddr_in46 *addr;

	if (!str || *str == '\0' || !list)
		return false;
	list_init(list);

	if (*str == '[') {
		/* IPv6, [a:b:c...h]:p or [*]:p */
		str++;
		tmp = strchr(str, ']');
		if (!tmp)
			goto out;
		*tmp = '\0';

		addr = zmalloc(sizeof(*addr));
		if (!addr)
			goto out;
		list_add(&addr->list, list);

		if (!strcmp(str, "*"))
			addr->in6.sin6_addr = in6addr_any;
		else if (inet_pton(AF_INET6, str, &addr->in6.sin6_addr) <= 0)
			goto out;

		tmp++;
		if (*tmp != ':')
			goto out;

		tmp++;
		if (strtou16_strict(tmp, &port) < 0)
			goto out;

		addr->in6.sin6_family = AF_INET6;
		addr->in6.sin6_port = htons(port);
		addr->addrlen = sizeof(addr->in6);

	} else if (*str == '*') {
		/* IPv4, *:p */
		str++;
		if (*str != ':')
			goto out;

		str++;
		if (strtou16_strict(str, &port) < 0)
			goto out;

		addr = zmalloc(sizeof(*addr));
		if (!addr)
			goto out;
		list_add(&addr->list, list);

		addr->in4.sin_family = AF_INET;
		addr->in4.sin_addr.s_addr = INADDR_ANY;
		addr->in4.sin_port = htons(port);
		addr->addrlen = sizeof(addr->in4);

	} else if ((tmp = strchr(str, ':'))) {
		/* IPv4, a.b.c.d:p or IPv4/6 hostname:p */
		fprintf(stderr, "Got an IPv4:port or hostname:port\n");
		*tmp = '\0';
		tmp++;
		if (strtou16_strict(tmp, &port) < 0)
			goto out;

		addr = zmalloc(sizeof(*addr));
		if (!addr)
			goto out;

		if (inet_pton(AF_INET, str, &addr->in4.sin_addr) > 0) {
			fprintf(stderr, "...Got an IPv4:port (0x%p, list 0x%p)\n", addr, &addr->list);
			addr->in4.sin_family = AF_INET;
			addr->in4.sin_port = htons(port);
			addr->addrlen = sizeof(addr->in4);
			list_add(&addr->list, list);
			goto success;
		} else {
			free(addr);
		}

		struct addrinfo hints = {
			.ai_family = AF_UNSPEC,
			.ai_socktype = SOCK_STREAM,
			.ai_protocol = 0,
			.ai_flags = 0,
		};
		struct addrinfo *results, *ai;

		/* FIXME: This is completely synchronous but getaddrinfo_a is not very ergonomic */
		r = getaddrinfo(str, tmp, &hints, &results);
		if (r != 0) {
			fprintf(stderr, "gettaddrinfo(%s): %s\n", str, gai_strerror(r));
			goto out;
		}

		fprintf(stderr, "...Got an hostname:port\n");
		for (ai = results; ai; ai = ai->ai_next) {
			fprintf(stderr, "Got a result from getaddrinfo\n");

			addr = zmalloc(sizeof(*addr));
			if (!addr) {
				freeaddrinfo(results);
				goto out;
			}

			switch (ai->ai_family) {
			case AF_INET: {
				struct sockaddr_in *naddr = (struct sockaddr_in *)ai->ai_addr;

				addr->in4.sin_family = AF_INET;
				addr->in4.sin_addr = naddr->sin_addr;
				addr->in4.sin_port = naddr->sin_port;
				addr->addrlen = sizeof(addr->in4);
				list_add(&addr->list, list);
				break;
			}
			case AF_INET6: {
				struct sockaddr_in6 *naddr = (struct sockaddr_in6 *)ai->ai_addr;

				addr->in6.sin6_family = AF_INET6;
				addr->in6.sin6_addr = naddr->sin6_addr;
				addr->in6.sin6_port = naddr->sin6_port;
				addr->addrlen = sizeof(addr->in6);
				list_add(&addr->list, list);
				break;
			}
			default:
				fprintf(stderr, "  Fam: Unknown (%i)\n", ai->ai_family);
				free(addr);
				continue;
			}
		}

		freeaddrinfo(results);

	} else if (strtou16_strict(tmp, &port) == 0) {
		/* Port */

		addr = zmalloc(sizeof(*addr));
		if (!addr)
			goto out;
		addr->in6.sin6_family = AF_INET6;
		addr->in6.sin6_addr = in6addr_any;
		addr->in6.sin6_port = htons(port);
		addr->addrlen = sizeof(addr->in6);
		list_add(&addr->list, list);

		addr = zmalloc(sizeof(*addr));
		if (!addr)
			goto out;
		addr->in4.sin_family = AF_INET;
		addr->in4.sin_addr.s_addr = INADDR_ANY;
		addr->in4.sin_port = htons(port);
		addr->addrlen = sizeof(addr->in4);
		list_add(&addr->list, list);
	}

success:
	if (list_empty(list)) {
		fprintf(stderr, "Success but empty list!?\n");
		return false;
	} else {
		int i = 0;
		struct list_head *pos;

		list_for_each(pos, list)
			i++;
		fprintf(stderr, "Success, %i entries\n", i);
	}

	return true;

out:
	if (!list_empty(list)) {
		struct sockaddr_in46 *tmpaddr;

		list_for_each_entry_safe(addr, tmpaddr, list, list) {
			list_del(&addr->list);
			free(addr);
		}
	}
	return false;
}

enum scfg_keys {
	SCFG_KEY_TYPE,
	SCFG_KEY_NAME,
	SCFG_KEY_PORT,
	SCFG_KEY_LOCAL,
	SCFG_KEY_REMOTE,
	SCFG_KEY_INVALID
};

enum value_type {
	VAL_TYPE_STRING,
	VAL_TYPE_UINT16,
	VAL_TYPE_ADDR,
	VAL_TYPE_INVALID
};

struct scfg_key_map {
	const char *key_name;
	enum scfg_keys key_value;
	enum value_type value_type;
} scfg_key_map[] = {
	{
		.key_name = "type",
		.key_value = SCFG_KEY_TYPE,
		.value_type = VAL_TYPE_STRING,
	}, {
		.key_name = "name",
		.key_value = SCFG_KEY_NAME,
		.value_type = VAL_TYPE_STRING,
	}, {
		.key_name = "port",
		.key_value = SCFG_KEY_PORT,
		.value_type = VAL_TYPE_UINT16,
	}, {
		.key_name = "local",
		.key_value = SCFG_KEY_LOCAL,
		.value_type = VAL_TYPE_ADDR,
	}, {
		.key_name = "remote",
		.key_value = SCFG_KEY_REMOTE,
		.value_type = VAL_TYPE_ADDR,
	}
};

union cfg_value {
	const char *str;
	uint16_t uint16;
	struct list_head addr_list;
};


static void
line_get_key_value(char *line, enum scfg_keys *rkey, union cfg_value *rvalue)
{
	char *tmp, *key;
	int i;

	*rkey = SCFG_KEY_INVALID;
	if (!line)
		return;

	tmp = line;
	while (isspace(*tmp))
		tmp++;

	if (*tmp == '\0')
		return;

	key = tmp;
	while (*tmp != '\0' && !isspace(*tmp))
		tmp++;

	if (*tmp == '\0')
		return;

	*tmp = '\0';
	tmp++;

	while (isspace(*tmp))
		tmp++;

	if (*tmp != '=')
		return;

	tmp++;
	while (isspace(*tmp))
		tmp++;

	if (*tmp == '\0')
		return;

	for (i = 0; i < ARRAY_SIZE(scfg_key_map); i++) {
		if (strcmp(scfg_key_map[i].key_name, key))
			continue;

		switch (scfg_key_map[i].value_type) {

		case VAL_TYPE_STRING:
			rvalue->str = tmp;
			break;

		case VAL_TYPE_UINT16: {
			uint16_t v;

			if (strtou16_strict(tmp, &v) < 0)
				return;
			rvalue->uint16 = v;
			break;
		}

		case VAL_TYPE_ADDR: {
			if (!strtosockaddrs(tmp, &rvalue->addr_list))
				return;
			if (list_empty(&rvalue->addr_list)) {
				fprintf(stderr, "VAL_TYPE_ADDR with zero list!?\n");
				return;
			} else {
				int i = 0;
				struct list_head *pos;

				list_for_each(pos, &rvalue->addr_list)
					i++;
				fprintf(stderr, "VAL_TYPE_ADDR with list %i entries\n", i);
			}
			break;
		}

		case VAL_TYPE_INVALID:
			/* fall through */
		default:
			return;
		}
		*rkey = scfg_key_map[i].key_value;
		break;
	}
}

static void
scfg_parse(struct cfg *cfg, struct server *scfg)
{
	char *pos = &scfg->buf[0];
	char *line;

	eat_whitespace_and_comments(&pos);

	line = get_line(&pos);
	if (!line) {
		printf("Cfg: premature EOF\n");
		return;
	}

	if (strcmp(line, "[server]")) {
		printf("Invalid line: %s\n", line);
		return;
	}

	while (true) {
		enum scfg_keys key;
		union cfg_value value;

		eat_whitespace_and_comments(&pos);
		line = get_line(&pos);
		printf("Examining line: %s\n", line);
		line_get_key_value(line, &key, &value);
		if (key == SCFG_KEY_INVALID)
			break;
		printf("Got a key-value pair: %i = something\n", key);

		switch (key) {

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

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

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

		case SCFG_KEY_LOCAL: {
			struct sockaddr_in46 *addr, *tmp;

			list_for_each_entry_safe(addr, tmp, &value.addr_list, list) {
				list_del(&addr->list);
				server_add_local(cfg, scfg, addr);
			}
			break;
		}

		case SCFG_KEY_REMOTE: {
			struct sockaddr_in46 *addr, *tmp;

			list_for_each_entry_safe(addr, tmp, &value.addr_list, list) {
				list_del(&addr->list);
				server_add_remote(cfg, scfg, addr);
			}
			break;
		}

		case SCFG_KEY_INVALID:
		default:
			break;
		}
	}

	//printf("Cfg:\n%s\n\n", pos);
}

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

	printf("Asked to parse server cfg %s (bytes %i)\n", scfg->name, res);

	if (res < 0) {
		perrordie("read");
	} else if (res > 0) {
		scfg->len += res;
		if (scfg->len + 1 >= sizeof(scfg->buf)) {
			fprintf(stderr, "Server config too large\n");
			server_delete(cfg, scfg);
			return;
		}

		uring_read(cfg, &scfg->task, scfg->buf + scfg->len, sizeof(scfg->buf) - scfg->len, scfg->len, scfg_read_cb);
		return;
	} else {
		/* EOF */
		scfg->buf[scfg->len] = '\0';
		uring_task_close_fd(cfg, &scfg->task);
		scfg_parse(cfg, scfg);
		server_commit(cfg, scfg);
	}
}

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

	if (res < 0) {
		fprintf(stderr, "Open failed\n");
		server_delete(cfg, scfg);
		return;
	}

	printf("Asked to read server cfg %s (fd %i)\n", scfg->name, res);
	uring_task_set_fd(&scfg->task, res);
	scfg->len = 0;
	uring_read(cfg, &scfg->task, scfg->buf, sizeof(scfg->buf), 0, scfg_read_cb);
}

static bool
scfg_valid_filename(const char *name)
{
	const char *suffix;

	if (!name)
		return false;
	if (name[0] == '\0')
		return false;
	if (name[0] == '.')
		return false;
	if ((suffix = strrchr(name, '.')) == NULL)
		return false;
	if (strcmp(suffix, ".server"))
		return false;

	return true;
}

struct inotify_ev {
	struct uring_task task;
	char buf[4096] __attribute__((aligned(__alignof__(struct inotify_event))));
};

static void
inotify_free(struct uring_task *task)
{
	struct inotify_ev *iev = container_of(task, struct inotify_ev, task);
	struct cfg *cfg = container_of(task->parent, struct cfg, task);

	fprintf(stderr, "%s called\n", __func__);
	if (!iev || !cfg)
		die("%s: iev or cfg is NULL!?\n", __func__);

	free(iev);
	cfg->iev = NULL;
	uring_task_put(cfg, &cfg->task);
}

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

static void
inotify_cb(struct cfg *cfg, struct uring_task *task, int res)
{
	struct inotify_ev *iev = container_of(task, struct inotify_ev, task);
	const struct inotify_event *event;
	char *ptr;
	struct server *scfg;

	fprintf(stderr, "%s: ret is %i (ref %u)\n", __func__, res, task->refcount);

	if (task->dead) {
		fprintf(stderr, "%s: task is dead\n", __func__);
		uring_task_put(cfg, task);
		return;
	}

	if (res <= 0)
		perrordie("inotify_read");

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

		if (debuglvl > 0)
			inotify_event_dump(event);

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

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

		if (!scfg_valid_filename(event->name))
			continue;

		if (event->mask & (IN_MOVED_FROM | IN_DELETE))
			server_delete_by_name(cfg, event->name);
		else if (event->mask & (IN_MOVED_TO | IN_CREATE | IN_CLOSE_WRITE)) {
			scfg = server_new(cfg, event->name);
			uring_openat(cfg, &scfg->task, event->name, scfg_open_cb);
		} else
			error("inotify: weird, unknown event: 0x%08x\n", event->mask);
	}

	uring_read(cfg, &iev->task, iev->buf, sizeof(iev->buf), 0, inotify_cb);
}

void
inotify_refdump(struct inotify_ev *iev)
{
	uring_task_refdump(&iev->task);
}

void
scfg_stop_monitor_dir(struct cfg *cfg)
{
	if (!cfg->iev) {
		fprintf(stderr, "%s called with no iev!\n", __func__);
		return;
	}

	fprintf(stderr, "%s called, closing fd %i\n", __func__, cfg->iev->task.fd);
	uring_cancel(cfg, &cfg->iev->task);
	cfg->iev = NULL;
}

void
scfg_monitor_dir(struct cfg *cfg)
{
	int ifd;
	int iwd;
	struct inotify_ev *iev;

	iev = malloc(sizeof(*iev));
	if (!iev)
		perrordie("malloc");

	ifd = inotify_init1(IN_CLOEXEC);
	if (ifd < 0)
		perrordie("inotify_init1");

	/* 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)
		perrordie("inotify_add_watch");

	uring_task_init(&iev->task, "iev", &cfg->task, inotify_free);
	uring_task_set_fd(&iev->task, ifd);
	cfg->iev = iev;
	uring_read(cfg, &iev->task, iev->buf, sizeof(iev->buf), 0, inotify_cb);
}

void
scfg_read_all(struct cfg *cfg)
{

	DIR *cfgdir;
	struct dirent *dent;
	struct server *scfg;

	cfgdir = opendir(".");
	if (!cfgdir) {
		perror("opendir");
		free(cfg);
		return;
	}

	while ((dent = readdir(cfgdir)) != NULL) {
		char *suffix;

		if (dent->d_name[0] == '.')
			continue;
		if (dent->d_type != DT_REG && dent->d_type != DT_UNKNOWN)
			continue;
		if ((suffix = strrchr(dent->d_name, '.')) == NULL)
			continue;
		if (strcmp(suffix, ".server"))
			continue;

		scfg = server_new(cfg, dent->d_name);
		uring_openat(cfg, &scfg->task, dent->d_name, scfg_open_cb);
	}

	closedir(cfgdir);
}