# A response to send over HTTP
class HttpResponse
	serialize

	# HTTP protocol version
	var http_version = "HTTP/1.0" is writable

	# Status code of this response (200, 404, etc.)
	var status_code: Int is writable

	# Return the message associated to `status_code`
	fun status_message: nullable String do return http_status_codes[status_code]

	# Headers of this response as a `Map`
	var header = new HashMap[String, String]

	# Body of this response
	var body: Writable = "" is writable

	# Files appended after `body`
	var files = new Array[String]

	# Finalize this response before sending it over HTTP
	fun finalize
	do
		# Set the content length if not already set
		if not header.keys.has("Content-Length") then
			# Size of the body
			var len
			var body = self.body
			if body isa Text then
				len = body.byte_length
			else if body isa Bytes then
				len = body.length
			else
				# We need the length, but there is no length in a writable.
				# So just render it as a bytes then measure :/
				body = body.write_to_bytes
				len = body.length
				# Keep the body as bytes since we have it
				self.body = body
			end

			# Size of included files
			for path in files do
				# TODO handle these error cases elsewhere, an error here will result in an invalid response
				if not path.file_exists then
					print_error "File does not exists at '{path}'"
					continue
				end

				var stat = path.file_stat
				if stat == null then
					print_error "Failed to stat file at '{path}'"
					continue
				end

				len += stat.size
			end

			# Set header
			header["Content-Length"] = len.to_s
		end

		# Set server ID
		if not header.keys.has("Server") then header["Server"] = "nitcorn"
	end

	# Get this reponse as a string according to HTTP protocol
	fun render: Writable
	do
		finalize

		var buf = new Template
		buf.add("{http_version} {status_code} {status_message or else ""}\r\n")
		for key, value in header do
			buf.add("{key}: {value}\r\n")
		end
		buf.add("\r\n")
		buf.add body
		return buf
	end
end