#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdbool.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 != '#') {
			return;

		while (**pos != '\r' && **pos != '\n' && **pos != '\0')
			(*pos)++;
	}
}

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 saddr *saddr;

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

	if (*str == '[') {
		/* IPv6, [a:b:c...h]:p or [*]:p */
		debug(DBG_CFG, "attempting to parse IPv6 addr (%s)\n", str);

		str++;
		tmp = strchr(str, ']');
		if (!tmp)
			goto error;
		*tmp = '\0';

		saddr = zmalloc(sizeof(*saddr));
		if (!saddr)
			goto error;

		/* early list_add to make sure saddr is free():d on error */
		list_add(&saddr->list, list);

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

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

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

		saddr_set_ipv6(saddr, NULL, htons(port));

	} else if (*str == '*') {
		/* IPv4, *:p */
		debug(DBG_CFG, "attempting to parse IPv4 addr (%s)\n", str);

		str++;
		if (*str != ':')
			goto error;

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

		saddr = zmalloc(sizeof(*saddr));
		if (!saddr)
			goto error;

		saddr_set_ipv4(saddr, INADDR_ANY, htons(port));
		list_add(&saddr->list, list);

	} else if ((tmp = strchr(str, ':'))) {
		/* IPv4, a.b.c.d:p or IPv4/6 hostname:p */
		debug(DBG_CFG, "attempting to parse IPv4 addr or hostname (%s)\n", str);

		*tmp = '\0';
		tmp++;
		if (strtou16_strict(tmp, &port) < 0)
			goto error;

		saddr = zmalloc(sizeof(*saddr));
		if (!saddr)
			goto error;

		if (inet_pton(AF_INET, str, &saddr->in4.sin_addr) > 0) {
			debug(DBG_CFG, "got an IPv4:port (%s)\n", str);
			saddr_set_ipv4(saddr, saddr->in4.sin_addr.s_addr, htons(port));
			list_add(&saddr->list, list);
			goto success;
		} else {
			xfree(saddr);
		}

		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) {
			error("getaddrinfo(%s): %s\n", str, gai_strerror(r));
			goto error;
		}

		debug(DBG_CFG, "got a hostname:port (%s)\n", str);
		for (ai = results; ai; ai = ai->ai_next) {
			saddr = zmalloc(sizeof(*saddr));
			if (!saddr) {
				freeaddrinfo(results);
				goto error;
			}

			switch (ai->ai_family) {
			case AF_INET: {
				struct sockaddr_in *in4 = (struct sockaddr_in *)ai->ai_addr;

				saddr_set_ipv4(saddr, in4->sin_addr.s_addr, htons(port));
				list_add(&saddr->list, list);
				break;
			}

			case AF_INET6: {
				struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)ai->ai_addr;

				saddr_set_ipv6(saddr, &in6->sin6_addr, in6->sin6_port);
				list_add(&saddr->list, list);
				break;
			}

			default:
				error("getaddrinfo(%s): unknown address family (%i)\n",
				      str, ai->ai_family);
				xfree(saddr);
				break;
			}
		}

		freeaddrinfo(results);

	} else if (strtou16_strict(tmp, &port) == 0) {
		/* Port */
		debug(DBG_CFG, "attempting to parse a port number (%s)\n", str);

		saddr = zmalloc(sizeof(*saddr));
		if (!saddr)
			goto error;

		saddr_set_ipv6(saddr, &in6addr_any, htons(port));
		list_add(&saddr->list, list);

		saddr = zmalloc(sizeof(*saddr));
		if (!saddr)
			goto error;

		saddr_set_ipv4(saddr, INADDR_ANY, htons(port));
		list_add(&saddr->list, list);

	} else {
		/* Unknown */
		error("unable to parse address: %s\n", str);
		goto error;
	}

success:
	if (list_empty(list)) {
		error("empty address list!?\n");
		return false;
	} else {
		int i = 0;

		list_for_each_entry(saddr, list, list)
			i++;

		debug(DBG_CFG, "parsed to %i addresses\n", i);
	}

	return true;

error:
	if (!list_empty(list)) {
		struct saddr *tmp;

		list_for_each_entry_safe(saddr, tmp, list, list) {
			list_del(&saddr->list);
			xfree(saddr);
		}
	}
	return false;
}

/* Returns true if there's data left to parse in buf */
bool
config_parse_line(struct cfg *cfg, const char *filename, char **buf,
		  struct cfg_key_value_map *kvmap, int *rkey,
		  const char **rkeyname, union cfg_value *rvalue)
{
	char *line, *tmp, *key;
	int i;

	if (!cfg || !buf || !*buf || !kvmap || !rkey || !rkeyname || !rvalue)
		die("%s: invalid parameters", filename);

	eat_whitespace_and_comments(buf);
	line = get_line(buf);
	if (!line)
		return false;

	debug(DBG_CFG, "%s: parsing config line: %s\n", filename, line);

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

	if (*tmp == '\0')
		goto error;

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

	if (*tmp == '\0')
		goto error;

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

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

	if (*tmp != '=')
		goto error;

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

	if (*tmp == '\0')
		goto error;

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

		switch (kvmap[i].value_type) {

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

		case CFG_VAL_TYPE_UINT16: {
			uint16_t v;

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

		case CFG_VAL_TYPE_ADDRS: {
			if (!strtosockaddrs(tmp, &rvalue->saddrs))
				goto error;
			if (list_empty(&rvalue->saddrs)) {
				error("empty address list\n");
				goto error;
			}
			break;
		}

		case CFG_VAL_TYPE_BOOL:
			if (!strcasecmp(tmp, "yes"))
				rvalue->boolean = true;
			else if (!strcasecmp(tmp, "no"))
				rvalue->boolean = false;
			else {
				error("invalid boolean value (%s)\n", tmp);
				goto error;
			}
			break;

		case CFG_VAL_TYPE_INVALID:
			/* fall through */
		default:
			goto error;
		}

		*rkey = kvmap[i].key_value;
		*rkeyname = kvmap[i].key_name;
		return true;
	}

error:
	/* FIXME: the line is already mangled here, a line number would be nice */
	error("%s: invalid config line: %s\n", filename, line);
	*rkey = 0;
	*rkeyname = NULL;
	return true;
}

bool
config_parse_header(struct cfg *cfg, const char *filename, const char *title,
		    char **buf)
{
	char *line;

	if (!cfg || !title || !buf || !*buf)
		return false;

	eat_whitespace_and_comments(buf);

	line = get_line(buf);
	if (!line) {
		error("%s: missing header in configuration file\n", filename);
		return false;
	} else {
		char titlehdr[strlen(title) + 3];

		sprintf(titlehdr, "[%s]", title);
		if (strcmp(line, titlehdr)) {
			error("%s: incorrect header in configuration file\n", filename);
			return false;
		}
	}

	return true;
}