/*
 * Here we implement our handling of SIP INVITE method.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <syslog.h>
#include <unistd.h>
#include "../libsip/parse.h"
#include "../libsip/uas_basic.h"
#include "../libsip/out_msg.h"

void
handle_sip_invite(req, ess, sin)
	struct sip_pkt_rx *req;
	struct uas_parse_hdrs *ess;
	struct sockaddr_in *sin;
{
	char uri_user[13], *called_nanp;
	struct sip_msg_out resp;
	int rc;

	/* check for existing Call-ID will go here */
	/* extract called number from Request-URI */
	rc = user_from_sip_uri(req->req_uri, uri_user, 12);
	if (rc < 0) {
not_nanp:	start_response_out_msg(&resp,
			"416 Request-URI is not a NANP number");
error_resp:	rc = add_resp_basic_headers(&resp, ess, req->req_method);
		if (rc < 0) {
			syslog(LOG_ERR,
				"INVITE error response length exceeded");
			return;
		}
		out_msg_finish(&resp);
		sip_tx_packet(&resp, sin);
			return;
	}
	if (uri_user[0] == '+') {
		if (grok_number_string(uri_user+1, 0) != 11 ||
		    uri_user[1] != '1')
			goto not_nanp;
		called_nanp = uri_user + 2;
	} else switch (grok_number_string(uri_user)) {
	case 10:
		called_nanp = uri_user;
		break;
	case 11:
		if (uri_user[0] != '1')
			goto not_nanp;
		called_nanp = uri_user + 1;
		break;
	default:
		goto not_nanp;
	}
	if (!is_nanp_valid_prefix(called_nanp))
		goto not_nanp;
	/* it is valid NANP - but is it one of ours? */
	refresh_number_db();
	if (!is_nanp_locally_owned(called_nanp)) {
		start_response_out_msg(&resp,
			"404 Called number does not belong here");
		goto error_resp;
	}
	/*
	 * Remaining checks to be implemented:
	 * Require and Supported headers
	 * SDP message body
	 */
}