use io;
use os;
use fmt;
use strconv;

export type version = (uint, uint);

// Stores state related to an HTTP response.
export type response = struct {
	// HTTP protocol version (major, minor)
	version: version,
	// The HTTP status for this request as an integer.
	status: uint,
	// The HTTP status reason phrase.
	reason: str,
	// The HTTP headers provided by the server.
	header: header,
	// The response body, if any.
	body: nullable *io::stream,
};

// Frees state associated with an HTTP [[response]]. If the response has a
// non-null body, the user must call [[io::close]] prior to calling this
// function.
export fn response_finish(resp: *response) void = {
	header_free(&resp.header);
	free(resp.reason);
	free(resp.body);
};

export fn response_write(
	rw: io::handle,
	status: uint,
	body: (void | io::handle),
	header: (str, str)...
) (void | io::error) = {
	fmt::fprintfln(rw, "HTTP/1.1 {} {}", status, status_reason(status))?;

	let header = header_dup(&header);
	defer header_free(&header);

	match (body) {
	case void => void;
	case let body: io::handle =>
		match (io::tell(body)) {
		case io::error => void;
		case let off: io::off =>
			header_add(&header, "Content-Length", strconv::i64tos(off));
			io::seek(body, 0, io::whence::SET)!;
			body = &io::limitreader(body, off: size);
		};
	};

	write_header(rw, &header)?;

	fmt::fprintln(rw)!;

	match (body) {
	case void => void;
	case let body: io::handle =>
		io::copy(rw, body)!;
	};
};