/* ITU-T Q.77x TCAP / ISM - Invocation State Machine,
 * part of CHA (ComponentHAndling), part of CSL (Component Sub-Layer) */

/* (C) 2010 by Harald Welte <laforge@gnumonks.org>
 * (C) 2010 by On-Waves
 *
 * All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation; either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#include <errno.h>

#include <osmocore/talloc.h>
#include <osmocore/msgb.h>

#include "tcap.h"

static void tcap_ism_set_state(struct tcap_invocation *ti, enum tcap_invocation_state st)
{
	printf("Invocation %d old_state=%s, new_state=%s\n", ti->invoke_id,
		tcap_inv_state_name(ti->state), tcap_inv_state_name(st));
	ti->state = st;
}

struct tcap_invocation *tcap_ism_lookup(struct tcap_dialogue *td, int8_t invoke_id)
{
	struct tcap_invocation *ti;
	llist_for_each_entry(ti, &td->ism_list, list) {
		if (ti->invoke_id == invoke_id)
			return ti;
	}
	return NULL;
}

struct tcap_invocation *tcap_ism_alloc(struct tcap_dialogue *td, int8_t invoke_id)
{
	struct tcap_invocation *ti = talloc_zero(td, struct tcap_invocation);
	if (!ti)
		return NULL;
	ti->invoke_id = invoke_id;
	ti->linked_id = NULL;
	ti->dialogue = td;
	tcap_ism_set_state(ti, TCAP_IS_IDLE);

	llist_add_tail(&ti->list, &td->ism_list);

	return ti;
}

void tcap_ism_free(struct tcap_invocation *ti)
{
	llist_del(&ti->list);
	talloc_free(ti);
}

/* Invocation timer expiry */
static void tcap_ism_inv_timer_exp(void *_ti)
{
	struct tcap_invocation *ti = _ti;

	fprintf(stdout, "ISM Invoke Timer expired for InvokeID=%d\n", ti->invoke_id);

	switch (ti->state) {
	case TCAP_IS_OP_SENT_CL1:
	case TCAP_IS_OP_SENT_CL2:
	case TCAP_IS_OP_SENT_CL3:
	case TCAP_IS_OP_SENT_CL4:
		/* TC-L-CANCEL.ind (TCU <- CHA) */
		tcap_ism_set_state(ti, TCAP_IS_INVALID);
		tcap_ism_free(ti);
		break;
	default:
		break;
	}
}

/* Reject timer expiry */
static void tcap_ism_rej_timer_exp(void *_ti)
{
	struct tcap_invocation *ti = _ti;

	fprintf(stdout, "ISM Reject Timer expired for InvokeID=%d\n", ti->invoke_id);

	if (ti->state != TCAP_IS_WAIT_REJECT)
		return;

	tcap_ism_set_state(ti, TCAP_IS_INVALID);
	tcap_ism_free(ti);
}

/* Operation sent (CCO -> ISM) */
int tcap_ism_op_sent(struct tcap_invocation *ti)
{
	/* Start invocation timer */
	ti->inv_timer.cb = tcap_ism_inv_timer_exp;
	ti->inv_timer.data = ti;
	bsc_schedule_timer(&ti->inv_timer, ti->inv_timeout, 0);

	switch (ti->op_class) {
	case 1:
		tcap_ism_set_state(ti, TCAP_IS_OP_SENT_CL1);
		break;
	case 2:
		tcap_ism_set_state(ti, TCAP_IS_OP_SENT_CL2);
		break;
	case 3:
		tcap_ism_set_state(ti, TCAP_IS_OP_SENT_CL3);
		break;
	case 4:
		tcap_ism_set_state(ti, TCAP_IS_OP_SENT_CL4);
		break;
	default:
		return -EINVAL;
	}
}

/* RR-L received (CCO -> ISM) */
int tcap_ism_rr_l_recv(struct tcap_invocation *ti, struct ReturnResult *res,
			int last_component)
{
	int rc = 0;
	OPERATION_t *opCode = NULL;
	Parameter_t *param = NULL;

	if (res->resultretres) {
		opCode = &res->resultretres->opCode;
		param = res->resultretres->parameter;
	}

	switch (ti->state) {
	case TCAP_IS_OP_SENT_CL1:
	case TCAP_IS_OP_SENT_CL3:
		/* TC-RESULT-L.ind (TCU <- CHA) */
		rc = tcap_tcu_result_l_ind(ti, opCode, param, last_component);
		/* Stop invocation timer */
		bsc_del_timer(&ti->inv_timer);
		/* Start reject timer */
		ti->rej_timer.cb = tcap_ism_rej_timer_exp;
		ti->rej_timer.data = ti;
		bsc_schedule_timer(&ti->rej_timer, ti->rej_timeout, 0);
		tcap_ism_set_state(ti, TCAP_IS_WAIT_REJECT);
		break;
	case TCAP_IS_OP_SENT_CL2:
	case TCAP_IS_OP_SENT_CL4:
		/* Generate RJ component (CCO <- ISM) */
		rc = tcap_cco_gen_rej(ti);
		/* Stop invocation timer */
		bsc_del_timer(&ti->inv_timer);
		tcap_ism_set_state(ti, TCAP_IS_INVALID);
		tcap_ism_free(ti);
		break;
	}
}

/* RE received (CCO -> ISM) */
int tcap_ism_re_recv(struct tcap_invocation *ti, struct ReturnError *re,
			int last_component)
{
	switch (ti->state) {
	case TCAP_IS_OP_SENT_CL1:
	case TCAP_IS_OP_SENT_CL2:
		/* TC-U-ERROR.ind (TCU <- CHA) */
		/* Stop invocation timer */
		bsc_del_timer(&ti->inv_timer);
		/* Start reject timer */
		ti->rej_timer.cb = tcap_ism_rej_timer_exp;
		ti->rej_timer.data = ti;
		bsc_schedule_timer(&ti->rej_timer, ti->rej_timeout, 0);
		tcap_ism_set_state(ti, TCAP_IS_WAIT_REJECT);
		break;
	case TCAP_IS_OP_SENT_CL3:
	case TCAP_IS_OP_SENT_CL4:
		tcap_ism_set_state(ti, TCAP_IS_INVALID);
		tcap_ism_free(ti);
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

/* RR-NL received (CCO -> ISM) */
int tcap_ism_rr_nl_recv(struct tcap_invocation *ti, struct ReturnResult *res,
			int last_component)
{
	int rc = 0;
	OPERATION_t *opCode = NULL;
	Parameter_t *param = NULL;

	if (res->resultretres) {
		opCode = &res->resultretres->opCode;
		param = res->resultretres->parameter;
	}

	switch (ti->state) {
	case TCAP_IS_OP_SENT_CL1:
	case TCAP_IS_OP_SENT_CL3:
		/* TC-RESULT-NL.ind (TCU <- CHA) */
		rc = tcap_tcu_result_nl_ind(ti, opCode, param, last_component);
		/* stay in SENT_CL1 state */
		break;
	case TCAP_IS_OP_SENT_CL2:
	case TCAP_IS_OP_SENT_CL4:
		/* Generate RJ component (CCO <- ISM) */
		rc = tcap_cco_gen_rej(ti);
		/* Stop invocation timer */
		bsc_del_timer(&ti->inv_timer);
		tcap_ism_set_state(ti, TCAP_IS_INVALID);
		tcap_ism_free(ti);
		break;
	default:	
		return -EINVAL;
	}

	return rc;
}

/* Terminate (CCO -> ISM) */
int tcap_ism_terminate(struct tcap_invocation *ti)
{
	switch (ti->state) {
	case TCAP_IS_OP_SENT_CL1:
	case TCAP_IS_OP_SENT_CL2:
	case TCAP_IS_OP_SENT_CL3:
	case TCAP_IS_OP_SENT_CL4:
	case TCAP_IS_WAIT_REJECT:
		break;
	default:
		return -EINVAL;
	}

	/* Stop invoation timer */
	bsc_del_timer(&ti->inv_timer);

	tcap_ism_set_state(ti, TCAP_IS_INVALID);
	tcap_ism_free(ti);

	return 0;
}