# Factory to listen on sockets and create new `Connection`
class ConnectionFactory

	# The `NativeEventBase` for the dispatch loop of this factory
	var event_base: NativeEventBase

	# Accept a connection on `listener`
	#
	# By default, it creates a new NativeBufferEvent and calls `spawn_connection`.
	fun accept_connection(listener: ConnectionListener, fd: Int, addrin: Pointer, socklen: Int)
	do
		var base = listener.base
		var bev = new NativeBufferEvent.socket(base, fd, bev_opt_close_on_free)

		# Human representation of remote client address
		var addr_len = 46 # Longest possible IPv6 address + null byte
		var addr_buf = new CString(addr_len)
		addr_buf = addrin_to_address(addrin, addr_buf, addr_len)
		var addr = if addr_buf.address_is_null then
				"Unknown address"
			else addr_buf.to_s

		var conn = spawn_connection(bev, addr)
		bev.enable ev_read|ev_write
		bev.setcb conn
	end

	# Create a new `Connection` object for `buffer_event`
	fun spawn_connection(buffer_event: NativeBufferEvent, address: String): Connection
	do
		return new Connection(buffer_event)
	end

	# Listen on the TCP socket at `address`:`port` for new connections
	#
	# On new connections, libevent callbacks `spawn_connection`.
	fun bind_tcp(address: String, port: Int): nullable ConnectionListener
	do
		var listener = new ConnectionListener.bind_tcp(
			event_base, address.to_cstring, port, self)

		if listener.address_is_null then
			print_error "libevent warning: Opening {address}:{port} failed, " +
				evutil_socket_error_to_string(evutil_socket_error).to_s
			return null
		end

		return listener
	end

	# Listen on a UNIX domain socket for new connections
	#
	# On new connections, libevent callbacks `spawn_connection`.
	fun bind_unix(path: String): nullable ConnectionListener
	do
		# Delete the socket if it already exists
		var stat = path.file_stat
		if stat != null and stat.is_sock then path.file_delete

		var listener = new ConnectionListener.bind_unix(
			event_base, path.to_cstring, self)

		if listener.address_is_null then
			print_error "libevent warning: Opening UNIX domain socket {path} failed, " +
				evutil_socket_error_to_string(evutil_socket_error).to_s
			return null
		end

		return listener
	end

	# Put a human readable string representation of `address` into `buf`
	private fun addrin_to_address(address: Pointer, buf: CString, buf_len: Int): CString `{
		struct sockaddr *addrin = (struct sockaddr*)address;

		if (addrin->sa_family == AF_INET) {
			struct in_addr *src = &((struct sockaddr_in*)addrin)->sin_addr;
			return (char *)inet_ntop(addrin->sa_family, src, buf, buf_len);
		}
		else if (addrin->sa_family == AF_INET6) {
			struct in6_addr *src = &((struct sockaddr_in6*)addrin)->sin6_addr;
			return (char *)inet_ntop(addrin->sa_family, src, buf, buf_len);
		}
		else if (addrin->sa_family == AF_UNIX) {
			struct sockaddr_un *src = (struct sockaddr_un*)addrin;
			char *path = src->sun_path;
			if (path == NULL) return "Unnamed UNIX domain socket";
			if (path[0] == '\0') return "Abstract UNIX domain socket";
			return path;
		}

		return NULL;
	`}
end