/* ITU-T Q.77x TCAP / CCO - Component CoOrdinator
 * 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 <stdint.h>
#include <errno.h>

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

#include "tcap.h"

#if 0
int tcap_tc_invoke_req(uint32_t dialogue_id, uint8_t op_class, int8_t inv_id,
			int8_t *linked_id, struct OPERATION *op,
			uint8_t *param, uint32_t param_len, uint32_t timeout)
{
	struct tcap_dialogue *td;

	/* resolve or allocate the dialogue for this ID */
	td = tcap_dialg_by_dialg_id(dialogue_id);
	if (!td)
		td = tcap_dialg_alloc(dialogue_id);
	if (!td)
		return -ENOMEM;

	return tcap_cha_tc_invoke_req(td, op_class, inv_id, linked_id, op, param, param_len, timeout);
}
#endif

/* Gernerate Parameter_t; copy data from original buffer */
static Parameter_t *gen_param(const void *ctx, uint8_t *param, uint32_t param_len)
{
	Parameter_t *p = talloc_zero(ctx, Parameter_t);
	uint8_t *_param;

	if (!p)
		return NULL;

	/* make our local copy of the parameter data */
	_param = talloc_size(p, param_len);
	if (!_param) {
		talloc_free(p);
		return NULL;
	}
	memcpy(_param, param, param_len);

	/* Note: Parameter_t == ANY_t == OCTET_STRING_t */ 
	/* initialize Parameter structure and link it with invocation */
	ANY_fromBuf((OCTET_STRING_t *)p, _param, param_len);

	return p;
};

/* TC-INVOKE.req (TCU -> CHA) */
/*   
 * linked_id	not referenced after call, caller needs to free it
 * op		not referenced after call, caller needs to free it
 * param	not referenced after call, caller needs to free it
 */
int tcap_cha_tc_invoke_req(struct tcap_dialogue *td, uint8_t op_class, int8_t inv_id,
			   int8_t *linked_id, struct OPERATION *op,
			   uint8_t *param, uint32_t param_len, uint32_t timeout)
{
	/* allocate new Invocation State Machine, link it with dialogue */
	struct tcap_invocation *ti = tcap_ism_alloc(td, inv_id);
	struct Component *comp;
	struct Invoke *inv;

	if (!ti)
		return -ENOMEM;

	ti->inv_timeout = timeout;

	if (linked_id) {
		ti->_linked_id = *linked_id;
		ti->linked_id = &ti->_linked_id;
	}

	ti->op_class = op_class;

	/* Allocate a new component structure */
	comp = talloc_zero(td, struct Component);
	if (!comp)
		return -ENOMEM;
	comp->present = Component_PR_invoke;

	/* Assemble INV component */
	inv = &comp->choice.invoke;
	inv->invokeID = ti->invoke_id;
	if (ti->linked_id) {
		InvokeIdType_t *lid = talloc_zero(inv, InvokeIdType_t);
		*lid = *ti->linked_id;
		inv->linkedID = lid;
	}
	memcpy(&inv->opCode, op, sizeof(inv->opCode));
	if (param && param_len)
		inv->parameter = gen_param(comp, param, param_len);

	/* Make component available for this Dialogue ID */
	tcap_dialg_comp_add(td, comp);

	return 0;
}

/* TC-U-CANCEL.req (TCU -> CHA) */
int tcap_cha_tc_cancel_req(struct tcap_dialogue *td, int8_t inv_id)
{
	struct tcap_invocation *ti = tcap_ism_lookup(td, inv_id);

	if (!ti || ti->state != TCAP_IS_IDLE)
		return -EINVAL;

	/* FIXME: Iterate over Component list of this dialogue
	 * and evict any INVOKE component */

	tcap_ism_terminate(ti);

	return 0;
}

/* Dialogue Terminated (CHA <- DHA) */
int tcap_cha_dialg_term(struct tcap_dialogue *td)
{
	struct tcap_invocation *ti, *ti2;

	/* FIXME: Discard components awaiting transmission */

	/* Any ISM alive for this dialogue ID? */
	llist_for_each_entry_safe(ti, ti2, &td->ism_list, list) {
		/* Terminate ISM CCO -> ISM */
		tcap_ism_terminate(ti);
	}
}


/* TC-RESULT-NL / TC-RESULT-L req (TCL -> CHA) */
int tcap_cha_tc_result_req(struct tcap_dialogue *td, int8_t inv_id, int last,
			     struct OPERATION *op, uint8_t *param, uint32_t param_len)
{
	struct tcap_invocation *ti = tcap_ism_lookup(td, inv_id);
	struct Component *comp;
	struct ReturnResult *res;
	struct resultretres *retres;

	if (!ti)
		return -ENOENT;

	/* Allocate a new component structure */
	comp = talloc_zero(td, struct Component);
	if (!comp)
		return -ENOMEM;

	/* Assemble requested component */
	if (last) {
		comp->present = Component_PR_returnResultLast;
		res = &comp->choice.returnResultLast;
	} else {
		comp->present = Component_PR_returnResultNotLast;
		res = &comp->choice.returnResultNotLast;
	}
	res->invokeID = ti->invoke_id;
	retres = talloc_zero(comp, struct resultretres);
	res->resultretres = retres;
	memcpy(&retres->opCode, op, sizeof(retres->opCode));
	if (param && param_len)
		retres->parameter = gen_param(comp, param, param_len);

	/* Mark component available for this dialogue ID */
	tcap_dialg_comp_add(td, comp);

	return 0;
}

/* TC-U-ERROR request TCL -> CHA */
int tcap_cha_tc_u_error_req(struct tcap_dialogue *td, int8_t inv_id,
			    ErrorCode_t *err, uint8_t *param,
			    uint32_t param_len)
{
	struct tcap_invocation *ti = tcap_ism_lookup(td, inv_id);
	struct Component *comp;

	if (!ti)
		return -ENOENT;

	comp = talloc_zero(td, struct Component);
	if (!comp)
		return -ENOMEM;

	/* Assemble requested component */
	comp->present = Component_PR_returnError;

	if (err)
		memcpy(&comp->choice.returnError.errorCode, err, sizeof(*err));

	if (param && param_len)
		comp->choice.returnError.parameter =
					gen_param(comp, param, param_len);

	/* Mark component available for this dialogue ID */
	tcap_dialg_comp_add(td, comp);

	return 0;
}

/* TC-U-REJECT.req (TCU -> CHA) */
int tcap_cha_tc_u_rej_req(struct tcap_dialogue *td, int8_t *invoke_id,
			  enum problem_PR problem, long problem_code)
{
	struct tcap_invocation *ti;
	struct Component *comp = talloc_zero(td, struct Component);
	struct Reject *rej;
	INTEGER_t *err_code_int = NULL;

	if (!comp)
		return -ENOMEM;

	/* Assemble reject component */
	comp->present = Component_PR_reject;
	rej = &comp->choice.reject;
	if (invoke_id) {
		rej->invokeIDRej.present = invokeIDRej_PR_derivable;
		rej->invokeIDRej.choice.derivable = *invoke_id;
	} else
		rej->invokeIDRej.present = invokeIDRej_PR_not_derivable;

	rej->problem.present = problem;
	switch (problem) {
	case problem_PR_generalProblem:
		err_code_int = &rej->problem.choice.generalProblem;
		break;
	case problem_PR_invokeProblem:
		err_code_int = &rej->problem.choice.invokeProblem;
		break;
	case problem_PR_returnResultProblem:
		err_code_int = &rej->problem.choice.returnResultProblem;
		break;
	case problem_PR_returnErrorProblem:
		err_code_int = &rej->problem.choice.returnErrorProblem;
		break;
	case problem_PR_NOTHING:
	default:
		break;
	}

	if (err_code_int)
		asn_long2INTEGER(err_code_int, problem_code);

	/* Problem type invoke? */
	if (problem == problem_PR_returnResultProblem ||
	    problem == problem_PR_returnErrorProblem) {
		/* Terminate ISM (CCO -> ISM) */
		tcap_ism_terminate(ti);
	}

	/* Mark component available for this dialogue ID */
	tcap_dialg_comp_add(td, comp);

	return 0;
}

/* Components (CHA <- DHA) */
int tcap_cha_proc_components(struct tcap_dialogue *td, struct ComponentPortion *comp_por)
{
	struct tcap_invocation *ti;
	int rc;
	unsigned int i;

	/* Iterate over list of components as part of comp_por */
	for (i = 0; i < comp_por->list.count; i++) {
		/* Extract next component */
		struct Component *comp = comp_por->list.array[i];
		int is_last_component = i+1 == comp_por->list.count ? 1 : 0;
		/* Check syntax error and proceed with 5, 3 or 4 */

		switch (comp->present) {
		case Component_PR_invoke:
			ti = tcap_ism_alloc(td, comp->choice.invoke.invokeID);
			if (comp->choice.invoke.linkedID) {
				/* Linked to ISM not in sent state? Proceed with 6 */
				ti->_linked_id = *comp->choice.invoke.linkedID;
				ti->linked_id = &ti->_linked_id;
			}
			/* TC-INVOKE.ind (TCU <- CHA) */
			rc = tcap_tcu_tc_invoke_ind(ti, &comp->choice.invoke.opCode,
						    comp->choice.invoke.parameter,
						    is_last_component);
			break;
		case Component_PR_returnResultNotLast:
			ti = tcap_ism_lookup(td, comp->choice.returnResultNotLast.invokeID);
			/* ISM active? */
			/* RR-NL.recv CCO -> ISM */
			rc = tcap_ism_rr_nl_recv(ti, &comp->choice.returnResultNotLast,
						 is_last_component);
			break;
		case Component_PR_returnResultLast:
			ti = tcap_ism_lookup(td, comp->choice.returnResultLast.invokeID);
			/* ISM active? */
			/* RR-L.recv CCO -> ISM */
			rc = tcap_ism_rr_l_recv(ti, &comp->choice.returnResultLast,
						is_last_component);
			break;
		case Component_PR_returnError:
			ti = tcap_ism_lookup(td, comp->choice.returnError.invokeID);
			/* ISM active? */
			/* RE.recv CCO -> ISM */
			rc = tcap_ism_re_recv(ti, &comp->choice.returnError,
						is_last_component);
			break;
		case Component_PR_reject:
			/* TC-R-REJECT or TC-U-REJECT.ind (TCU <- CHA) */
			rc = tcap_tcu_tc_r_rej_ind(ti, &ti->invoke_id, 0 /* FIXME problem */,
						   is_last_component);
			break;
		case Component_PR_NOTHING:
			break;
		}
	}
}

/* Generate REJ component (CCO <- ISM) */
int tcap_cco_gen_rej(struct tcap_invocation *ti)
{
	/* FIXME: Assemble REJ component */
	/* TC-L-REJ.ind (TCU <- CHA) */
	return tcap_tcu_tc_l_rej_ind(ti, &ti->invoke_id, 0 /* FIXME problem */);
}

/* Return list of pending components for given dialogue */
ComponentPortion_t *tcap_cha_req_components(struct tcap_dialogue *td)
{
	ComponentPortion_t *cp = td->pend_comp;
	Component_t *comp;
	struct tcap_invocation *ti;
	unsigned int i;

	/* iterate over list of components, find INV components and call
	 * tcap_ism_op_sent() */
	for (i = 0; i < cp->list.count; i++) {
		comp = cp->list.array[i];
		if (comp->present != Component_PR_invoke)
			continue;
		ti = tcap_ism_lookup(td, comp->choice.invoke.invokeID);
		if (!ti)
			continue;
		tcap_ism_op_sent(ti);
	}

	td->pend_comp = NULL;

	return cp;
}