<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.

function scorm_seq_exit_action_rules($seq,$userid) {
    $sco = $seq->currentactivity;
    $ancestors = scorm_get_ancestors($sco);
    $exittarget = null;
    foreach (array_reverse($ancestors) as $ancestor) {
        if (scorm_seq_rules_check($ancestor,'exit') != null) {
            $exittarget = $ancestor;
            break;
        }
    }
    if ($exittarget != null) {
        $commons = array_slice($ancestors,0,scorm_find_common_ancestor($ancestors,$exittarget));

        /// Terminate Descendent Attempts Process
        if ($commons) {
            foreach ($commons as $ancestor) {

                scorm_seq_end_attempt($ancestor,$userid,$seq->attempt);
                $seq->currentactivity = $ancestor;
            }
        }
    }
    return $seq;
}

function scorm_seq_post_cond_rules($seq,$userid) {
    $sco = $seq->currentactivity;
    if (!$seq->suspended) {
        if ($action = scorm_seq_rules_check($sco,'post') != null) {
            switch($action) {
                case 'retry':
                case 'continue':
                case 'previous':
                    $seq->sequencing = $action;
                break;
                case 'exitparent':
                case 'exitall':
                    $seq->termination = $action;
                break;
                case 'retryall':
                    $seq->termination = 'exitall';
                    $seq->sequencing = 'retry';
                break;
            }
        }
    }
    return $seq;
}


function scorm_seq_evaluate_rollupcond($sco,$conditioncombination,$rollupruleconds,$userid){
    $bag = Array();
    $con = "";
    $val = false;
    $unk = false;
    foreach($rollupruleconds as $rolluprulecond){

        $condit = scorm_evaluate_condition($rolluprulecond,$sco,$userid);

        if($rolluprulecond->operator=='not'){// If operator is not, negate the condition
            if ($rolluprulecond->cond != 'unknown'){
                if ($condit){
                    $condit = false;
                }
                else{
                    $condit = true;
                }
            }
            else{
                $condit = 'unknown';
            }
            array_push($childrenbag,$condit);
        }

    }
    if (empty($bag)){
        return 'unknown';
    }
    else{
        $i = 0;
        foreach ($bag as $b){

             if ($rolluprulecond->conditioncombination == 'all'){

                 $val = true;
                 if($b == 'unknown'){
                     $unk = true;
                 }
                 if($b === false){
                     return false;
                 }
             }

             else{

                $val = false;

                if($b == 'unknown'){
                     $unk = true;
                }
                if($b === true){
                    return true;
                }
             }


        }
    }
    if ($unk){
        return 'unknown';
    }
    return $val;

}


function scorm_seq_check_child ($sco, $action, $userid){
    global $DB;

    $included = false;
    $sco=scorm_get_sco($sco->id);
    $r = $DB->get_record('scorm_scoes_track', array('scoid'=>$sco->id,'userid'=>$userid,'element'=>'activityattemptcount'));
    if ($action == 'satisfied' || $action == 'notsatisfied'){
      if (!$sco->rollupobjectivesatisfied){
        $included = true;
        if (($action == 'satisfied' && $sco->requiredforsatisfied == 'ifnotsuspended') || ($action == 'notsatisfied' && $sco->requiredfornotsatisfied == 'ifnotsuspended')){

            if (!scorm_seq_is('activityprogressstatus',$sco->id,$userid) || ((($r->value)>0)&& !scorm_seq_is('suspended',$sco->id,$userid))){
                $included = false;
            }

        }
        else{
            if (($action == 'satisfied' && $sco->requiredforsatisfied == 'ifattempted') || ($action == 'notsatisfied' && $sco->requiredfornotsatisfied == 'ifattempted')){
                if (!scorm_seq_is('activityprogressstatus',$sco->id,$userid) || (($r->value) == 0)){
                    $included = false;
                }
            }
            else{
                if (($action == 'satisfied' && $sco->requiredforsatisfied == 'ifnotskipped') || ($action == 'notsatisfied' && $sco->requiredfornotsatisfied == 'ifnotskipped')){
                    $rulch = scorm_seq_rules_check($sco, 'skip');
                    if ($rulch != null){
                        $included = false;
                    }
                }
            }
        }
      }
    }
    if ($action == 'completed' || $action == 'incomplete'){
        if (!$sco->rollupprogresscompletion){
            $included = true;

            if (($action == 'completed' && $sco->requiredforcompleted == 'ifnotsuspended') || ($action == 'incomplete' && $sco->requiredforincomplete == 'ifnotsuspended')){

                if (!scorm_seq_is('activityprogressstatus',$sco->id,$userid) || ( (($r->value)>0)&& !scorm_seq_is('suspended',$sco->id,$userid))){
                    $included = false;
                }

            }
            else{

                if (($action == 'completed' && $sco->requiredforcompleted == 'ifattempted') || ($action == 'incomplete' && $sco->requiredforincomplete == 'ifattempted')){
                    if (!scorm_seq_is('activityprogressstatus',$sco->id,$userid) || (($r->value)==0)){
                        $included = false;
                    }

                }
                else{
                    if (($action == 'completed' && $sco->requiredforsatisfied == 'ifnotskipped') || ($action == 'incomplete' && $sco->requiredfornotsatisfied == 'ifnotskipped')){
                        $rulch = scorm_seq_rules_check($sco, 'skip');
                        if ($rulch != null){
                            $included = false;
                        }
                    }
                }


            }

        }
    }
    return $included;


}
function scorm_seq_sequencing ($scoid,$userid,$seq) {

    switch ($seq->sequencing) {

        case 'start':
            $seq = scorm_seq_start_sequencing($scoid,$userid,$seq); //We'll see the parameters we have to send, this should update delivery and end
            $seq->sequencing = true;


            break;

        case 'resumeall':
            $seq = scorm_seq_resume_all_sequencing($scoid,$userid,$seq); //We'll see the parameters we have to send, this should update delivery and end
            $seq->sequencing = true;


            break;

        case 'exit':
             $seq = scorm_seq_exit_sequencing($scoid,$userid,$seq); //We'll see the parameters we have to send, this should update delivery and end
            $seq->sequencing = true;


            break;

        case 'retry':
            $seq = scorm_seq_retry_sequencing($scoid,$userid,$seq); //We'll see the parameters we have to send, this should update delivery and end
            $seq->sequencing = true;


            break;

        case 'previous':
            $seq = scorm_seq_previous_sequencing($scoid,$userid,$seq);// We'll see the parameters we have to send, this should update delivery and end
            $seq->sequencing = true;


            break;

        case 'choice':
            $seq = scorm_seq_choice_sequencing($scoid,$userid,$seq);// We'll see the parameters we have to send, this should update delivery and end
             $seq->sequencing = true;


            break;

    }

    if ($seq->exception != null){
        $seq->sequencing = false;
        return $seq;
    }

    $seq->sequencing= true;
    return $seq;
}


function scorm_seq_start_sequencing($scoid,$userid,$seq){
    global $DB;

    if (!empty($seq->currentactivity)) {
        $seq->delivery = null;
        $seq->exception = 'SB.2.5-1';
        return $seq;
    }
    $sco = $DB->get_record('scorm_scoes', array('scoid'=>$scoid,'userid'=>$userid));
    if (($sco->parent == '/') && scorm_is_leaf($sco)) {//if the activity is the root and is leaf
        $seq->delivery = $sco;
    }
    else{
        $ancestors = scorm_get_ancestors($sco);
        $ancestorsroot = array_reverse($ancestors);
        $res = scorm_seq_flow($ancestorsroot[0],'forward',$seq,true,$userid);
        if($res){
            return $res;
        }
        else{
            //return end and exception
        }
    }
}

function scorm_seq_resume_all_sequencing($scoid,$userid,$seq){
    global $DB;

    if (!empty($seq->currentactivity)){
        $seq->delivery = null;
        $seq->exception = 'SB.2.6-1';
        return $seq;
    }
    $track = $DB->get_record('scorm_scoes_track', array('scoid'=>$scoid,'userid'=>$userid,'element'=>'suspendedactivity'));
    if (!$track) {
        $seq->delivery = null;
        $seq->exception = 'SB.2.6-2';
        return $seq;
    }
    $seq->delivery = $DB->get_record('scorm_scoes', array('scoid'=>$scoid,'userid'=>$userid));//we assign the sco to the delivery

}

function scorm_seq_continue_sequencing($scoid,$userid,$seq){
    if (empty($seq->currentactivity)) {
        $seq->delivery = null;
        $seq->exception = 'SB.2.7-1';
        return $seq;
    }
    $currentact= $seq->currentactivity;
    if ($currentact->parent != '/') {//if the activity is the root and is leaf
        $parent = scorm_get_parent ($currentact);

         if (!isset($parent->flow) || ($parent->flow == false)) {
            $seq->delivery = null;
            $seq->exception = 'SB.2.7-2';
            return $seq;
        }

        $res = scorm_seq_flow($currentact,'forward',$seq,false,$userid);
        if($res){
            return $res;
        }
        else{
            //return end and exception
        }

    }
}

function scorm_seq_previous_sequencing($scoid,$userid,$seq){
    if (empty($seq->currentactivity)) {
        $seq->delivery = null;
        $seq->exception = 'SB.2.8-1';
        return $seq;
    }

    $currentact= $seq->currentactivity;
    if ($currentact->parent != '/') {//if the activity is the root and is leaf
        $parent = scorm_get_parent ($currentact);
        if (!isset($parent->flow) || ($parent->flow == false)) {
            $seq->delivery = null;
            $seq->exception = 'SB.2.8-2';
            return $seq;
        }

        $res = scorm_seq_flow($currentact,'backward',$seq,false,$userid);
        if($res){
            return $res;
        }
        else{
            //return end and exception
        }

    }

}

function scorm_seq_exit_sequencing($scoid,$userid,$seq){
    if (empty($seq->currentactivity)) {
        $seq->delivery = null;
        $seq->exception = 'SB.2.11-1';
        return $seq;
    }

     if ($seq->active){
         $seq->endsession = false;
         $seq->exception = 'SB.2.11-2';
         return $seq;
     }
     $currentact= $seq->currentactivity;
     if ($currentact->parent == '/'){
         $seq->endsession = true;
         return $seq;
     }

    $seq->endsession = false;
    return $seq;
}

function scorm_seq_retry_sequencing($scoid,$userid,$seq){
    if (empty($seq->currentactivity)) {
        $seq->delivery = null;
        $seq->exception = 'SB.2.10-1';
        return $seq;
    }
    if ($seq->active || $seq->suspended){
        $seq->delivery = null;
        $seq->exception = 'SB.2.10-2';
        return $seq;
    }

    if (!scorm_is_leaf($seq->currentactivity)){
        $res = scorm_seq_flow($seq->currentactivity,'forward',$seq,true,$userid);
        if($res != null){
            return $res;
            //return deliver
        }
        else{
            $seq->delivery = null;
            $seq->exception = 'SB.2.10-3';
            return $seq;
        }
    }
    else{
        $seq->delivery = $seq->currentactivity;
        return $seq;
    }

}

function scorm_seq_choice_sequencing($sco,$userid,$seq){

    $avchildren = Array ();
    $comancestor = null;
    $traverse = null;

    if ($sco == null){
        $seq->delivery = null;
        $seq->exception = 'SB.2.9-1';
        return $seq;
    }

    $ancestors = scorm_get_ancestors($sco);
    $arrpath = array_reverse($ancestors);
    array_push ($arrpath,$sco);//path from the root to the target

    foreach ($arrpath as $activity){

        if ($activity->parent != '/') {
            $avchildren = scorm_get_available_children (scorm_get_parent($activity));
            $position = array_search($avchildren, $activity);
            if ($position !== false){
                $seq->delivery = null;
                $seq->exception = 'SB.2.9-2';
                return $seq;
            }
        }

        if (scorm_seq_rules_check($activity,'hidefromchoice' != null)){

            $seq->delivery = null;
            $seq->exception = 'SB.2.9-3';
            return $seq;

        }

    }

    if ($sco->parent != '/') {
        $parent = scorm_sco_get_parent ($sco);
        if ( isset($parent->choice) && ($parent->choice == false)){
            $seq->delivery = null;
            $seq->exception = 'SB.2.9-4';
            return $seq;
        }
    }

    if ($seq->currentactivity != null){
        $commonpos = scorm_find_common_ancestor($ancestors,$seq->currentactivity);
        $comancestor = $arrpath [$commonpos];
    }
    else{
        $comancestor = $arrpath [0];
    }

    if($seq->currentactivity === $sco) {
        break;
    }

    $sib = scorm_get_siblings($seq->currentactivity);
    $pos = array_search($sib, $sco);

    if ($pos !== false){

        $siblings = array_slice($sib, 0, $pos-1);

        if (empty($siblings)){

            $seq->delivery = null;
            $seq->exception = 'SB.2.9-5';
            return $seq;

        }

        $children = scorm_get_children (scorm_get_parent ($sco));
        $pos1 = array_search($children, $sco);
        $pos2 = array_search($seq->currentactivity, $sco);
        if ($pos1>$pos2){
            $traverse = 'forward';
        }
        else{
            $traverse = 'backward';
        }

        foreach ($siblings as $sibling){
            $seq = scorm_seq_choice_activity_traversal($sibling,$userid,$seq,$traverse);
            if(!$seq->reachable){
                $seq->delivery = null;
                return $seq;
            }
        }
        break;

    }

    if($seq->currentactivity == null || $seq->currentactivity == $comancestor){
        $commonpos = scorm_find_common_ancestor($ancestors,$seq->currentactivity);
        $comtarget = array_slice($ancestors, 1,$commonpos-1);//path from the common ancestor to the target activity
        $comtarget = array_reverse($comtarget);

        if (empty($comtarget)){
            $seq->delivery = null;
            $seq->exception = 'SB.2.9-5';
            return $seq;
        }
        foreach ($comtarget as $act){
            $seq = scorm_seq_choice_activity_traversal($act,$userid,$seq,'forward');
            if(!$seq->reachable){
                $seq->delivery = null;
                return $seq;
            }
            $act = scorm_get_sco ($acti->id);
            if(scorm_seq_is('active',$act->id,$userid) && ($act->id != $comancestor->id && $act->preventactivation)){//adlseq:can i write it like another property for the $seq object?
                $seq->delivery = null;
                $seq->exception = 'SB.2.9-6';
                return $seq;
            }
        }
        break;

    }

    if ($comancestor->id == $sco->id){

        $ancestorscurrent = scorm_get_ancestors($seq->currentactivity);
        $possco = array_search ($ancestorscurrent, $sco);
        $curtarget = array_slice($ancestorscurrent,0,$possco);//path from the current activity to the target

        if (empty($curtarget)){
            $seq->delivery = null;
            $seq->exception = 'SB.2.9-5';
            return $seq;
        }
        $i=0;
        foreach ($curtarget as $activ){
            $i++;
            if ($i != sizeof($curtarget)){
                if ( isset($activ->choiceexit) && ($activ->choiceexit == false)){
                    $seq->delivery = null;
                    $seq->exception = 'SB.2.9-7';
                    return $seq;
                }
            }
        }
        break;
    }

    if (array_search ($ancestors, $comancestor)!== false){
        $ancestorscurrent = scorm_get_ancestors($seq->currentactivity);
        $commonpos = scorm_find_common_ancestor($ancestors,$sco);
        $curcommon = array_slice($ancestorscurrent,0,$commonpos-1);
        if(empty($curcommon)){
            $seq->delivery = null;
            $seq->exception = 'SB.2.9-5';
            return $seq;
        }

        $constrained = null;
        foreach ($curcommon as $acti){
            $acti = scorm_get_sco($acti->id);
            if ( isset($acti->choiceexit) && ($acti->choiceexit == false)){
                    $seq->delivery = null;
                    $seq->exception = 'SB.2.9-7';
                    return $seq;
            }
            if ($constrained == null){
                if($acti->constrainchoice == true){
                    $constrained = $acti;
                }
            }
        }
        if ($constrained != null){
            $fwdir = scorm_get_preorder($constrained);

            if(array_search ($fwdir, $sco)!== false){
                $traverse = 'forward';
            }
            else{
                $traverse = 'backward';
            }
            $seq = scorm_seq_choice_flow ($constrained, $traverse, $seq);
            $actconsider = $seq->identifiedactivity;
            $avdescendents = Array();
            $avdescendents= scorm_get_available_descendents ($actconsider);
            if (array_search ($avdescendents, $sco) !== false && $sco->id != $actconsider->id && $constrained->id != $sco->id ){
                $seq->delivery = null;
                $seq->exception = 'SB.2.9-8';
                return $seq;
            }

//CONTINUE 11.5.5
        }

        $commonpos = scorm_find_common_ancestor($ancestors,$seq->currentactivity);
        $comtarget = array_slice($ancestors, 1,$commonpos-1);//path from the common ancestor to the target activity
        $comtarget = array_reverse($comtarget);

        if (empty($comtarget)){
            $seq->delivery = null;
            $seq->exception = 'SB.2.9-5';
            return $seq;
        }

        $fwdir = scorm_get_preorder($seq->currentactivity);

        if(array_search ($fwdir, $sco)!== false){

            foreach ($comtarget as $act){
                $seq = scorm_seq_choice_activity_traversal($act,$userid,$seq,'forward');
                if(!$seq->reachable){
                    $seq->delivery = null;
                    return $seq;
                }
                $act = scorm_get_sco($act->id);
                if(scorm_seq_is('active',$act->id,$userid) && ($act->id != $comancestor->id && ($act->preventactivation == true))){
                    $seq->delivery = null;
                    $seq->exception = 'SB.2.9-6';
                    return $seq;
                }
            }

        }
        else{
            foreach ($comtarget as $act){
                $act = scorm_get_sco($act->id);
                if(scorm_seq_is('active',$act->id,$userid) && ($act->id != $comancestor->id && ($act->preventactivation==true))){
                    $seq->delivery = null;
                    $seq->exception = 'SB.2.9-6';
                    return $seq;
                }
            }
        }
        break;
    }

    if(scorm_is_leaf ($sco)){
        $seq->delivery = $sco;
        $seq->exception = 'SB.2.9-6';
        return $seq;
    }

    $seq = scorm_seq_flow ($sco,'forward',$seq,true,$userid);
    if ($seq->deliverable == false){
        scorm_terminate_descendent_attempts($comancestor,$userid,$seq);
        scorm_seq_end_attempt($comancestor,$userid,$seq->attempt);
        $seq->currentactivity = $sco;
        $seq->delivery = null;
        $seq->exception = 'SB.2.9-9';
        return $seq;

    }
    else{
        return $seq;
    }

}

function scorm_seq_choice_flow ($constrained, $traverse, $seq){
    $seq = scorm_seq_choice_flow_tree ($constrained, $traverse, $seq);
    if ($seq->identifiedactivity == null){
        $seq->identifiedactivity = $constrained;
        return $seq;
    }
    else{
        return $seq;
    }
}

function scorm_seq_choice_flow_tree ($constrained, $traverse, $seq){
    $islast = false;
    $parent = scorm_get_parent ($constrained);
    if ($traverse== 'forward'){
        $preord = scorm_get_preorder ($constrained);
        if (sizeof($preorder) == 0 || (sizeof($preorder) == 0 && $preorder[0]->id = $constrained->id)){ // TODO: undefined
            $islast = true;//the function is the last activity available
        }
        if ($constrained->parent == '/' || $islast){
            $seq->nextactivity = null;
            return $seq;
        }
        $avchildren = scorm_get_available_children ($parent);//available children
        if ($avchildren [sizeof($avchildren)-1]->id == $constrained->id){
            $seq = scorm_seq_choice_flow_tree ($parent, 'forward', $seq);
            return $seq;
        }
        else{
            $i=0;
            while($i < sizeof($avchildren)){
                if ($avchildren [$i]->id == $constrained->id){
                    $seq->nextactivity = $avchildren [$i+1];
                    return $seq;
                }
                else{
                    $i++;
                }
            }
        }

    }

    if ($traverse== 'backward'){
        if($constrained->parent == '/' ){
            $seq->nextactivity = null;
            return $seq;
        }

        $avchildren = scorm_get_available_children ($parent);//available children
        if ($avchildren [0]->id == $constrained->id){
            $seq = scorm_seq_choice_flow_tree ($parent, 'backward', $seq);
            return $seq;
        }
        else{
            $i=sizeof($avchildren)-1;
            while($i >=0){
                if ($avchildren [$i]->id == $constrained->id){
                    $seq->nextactivity = $avchildren [$i-1];
                    return $seq;
                }
                else{
                    $i--;
                }
            }
        }
    }
}
function scorm_seq_choice_activity_traversal($activity,$userid,$seq,$direction){

    if($direction == 'forward'){

        $act = scorm_seq_rules_check($activity,'stopforwardtraversal');

        if($act != null){
            $seq->reachable = false;
            $seq->exception = 'SB.2.4-1';
            return $seq;
        }
        $seq->reachable = false;
        return $seq;
    }

    if($direction == 'backward'){
        $parentsco = scorm_get_parent($activity);
        if($parentsco!= null){
             if (isset($parentsco->forwardonly) && ($parentsco->forwardonly == true)){
                 $seq->reachable = false;
                 $seq->exception = 'SB.2.4-2';
                 return $seq;
             }
             else{
                $seq->reachable = false;
                $seq->exception = 'SB.2.4-3';
                return $seq;
             }
        }
    }
    $seq->reachable = true;
    return $seq;

}

//Delivery Request Process

function scorm_sequencing_delivery($scoid,$userid,$seq){

    if(!scorm_is_leaf ($seq->delivery)){
        $seq->deliveryvalid = false;
        $seq->exception = 'DB.1.1-1';
        return $seq;
    }
    $ancestors = scorm_get_ancestors($seq->delivery);
    $arrpath = array_reverse($ancestors);
    array_push ($arrpath,$seq->delivery);//path from the root to the target

    if (empty($arrpath)){
        $seq->deliveryvalid = false;
        $seq->exception = 'DB.1.1-2';
        return $seq;
    }

    foreach ($arrpath as $activity){
        if(scorm_check_activity ($activity,$userid)){
            $seq->deliveryvalid = false;
            $seq->exception = 'DB.1.1-3';
            return $seq;
        }
    }

    $seq->deliveryvalid = true;
    return $seq;

}

function scorm_content_delivery_environment ($seq,$userid){
    global $DB;

    $act = $seq->currentactivity;
    if(scorm_seq_is('active',$act->id,$userid)){
        $seq->exception = 'DB.2-1';
        return $seq;
    }
    $track = $DB->get_record('scorm_scoes_track', array('scoid'=>$act->id,'userid'=>$userid,'element'=>'suspendedactivity'));
    if ($track != null){
        $seq = scorm_clear_suspended_activity($seq->delivery, $seq, $userid);

    }
    $seq = scorm_terminate_descendent_attempts ($seq->delivery,$userid,$seq);
    $ancestors = scorm_get_ancestors($seq->delivery);
    $arrpath = array_reverse($ancestors);
    array_push ($arrpath,$seq->delivery);
    foreach ($arrpath as $activity){
        if(!scorm_seq_is('active',$activity->id,$userid)){
            if(!isset($activity->tracked) || ($activity->tracked == 1)){
                if(!scorm_seq_is('suspended',$activity->id,$userid)){
                    $r = $DB->get_record('scorm_scoes_track', array('scoid'=>$activity->id,'userid'=>$userid,'element'=>'activityattemptcount'));
                    $r->value = ($r->value)+1;
                    $DB->update_record ('scorm_scoes_track',$r);
                    if ($r->value == 1){
                        scorm_seq_set('activityprogressstatus', $activity->id, $userid, 'true');
                    }
                    scorm_insert_track($userid, $activity->scorm, $activity->id, 0, 'objectiveprogressstatus', 'false');
                    scorm_insert_track($userid, $activity->scorm, $activity->id, 0, 'objectivesatisfiedstatus', 'false');
                    scorm_insert_track($userid, $activity->scorm, $activity->id, 0, 'objectivemeasurestatus', 'false');
                    scorm_insert_track($userid, $activity->scorm, $activity->id, 0, 'objectivenormalizedmeasure', 0.0);

                    scorm_insert_track($userid, $activity->scorm, $activity->id, 0, 'attemptprogressstatus', 'false');
                    scorm_insert_track($userid, $activity->scorm, $activity->id, 0, 'attemptcompletionstatus', 'false');
                    scorm_insert_track($userid, $activity->scorm, $activity->id, 0, 'attemptabsoluteduration', 0.0);
                    scorm_insert_track($userid, $activity->scorm, $activity->id, 0, 'attemptexperiencedduration', 0.0);
                    scorm_insert_track($userid, $activity->scorm, $activity->id, 0, 'attemptcompletionamount', 0.0);
                }
            }
            scorm_seq_set('active', $activity->id, $userid, 'true');
        }
    }
    $seq->delivery = $seq->currentactivity;
    scorm_seq_set('suspendedactivity', $activity->id, $userid, 'false');

    //ONCE THE DELIVERY BEGINS (How should I check that?)

    if(isset($activity->tracked) || ($activity->tracked == 0)){
        //How should I track the info and what should I do to not record the information for the activity during delivery?
        $atabsdur = $DB->get_record('scorm_scoes_track', array('scoid'=>$activity->id,'userid'=>$userid,'element'=>'attemptabsoluteduration'));
        $atexpdur = $DB->get_record('scorm_scoes_track', array('scoid'=>$activity->id,'userid'=>$userid,'element'=>'attemptexperiencedduration'));
    }
    return $seq;


}
function scorm_clear_suspended_activity($act,$seq, $userid){
    global $DB;
    $currentact= $seq->currentactivity;
    $track = $DB->get_record('scorm_scoes_track', array('scoid'=>$currentact->id,'userid'=>$userid,'element'=>'suspendedactivity')); // TODO: undefined
    if ($track != null){
        $ancestors = scorm_get_ancestors($act);
        $commonpos = scorm_find_common_ancestor($ancestors,$currentact);
        if ($commonpos !== false) {
            if ($activitypath = array_slice($ancestors,0,$commonpos)) {
                if (!empty ($activitypath)){

                    foreach ($activitypath as $activity) {
                        if (scorm_is_leaf($activity)){
                            scorm_seq_set('suspended',$activity->id,$userid,false);
                        }
                        else{
                            $children = scorm_get_children($activity);
                            $bool= false;
                            foreach ($children as $child){
                                if(scorm_seq_is('suspended',$child->id,$userid)){
                                    $bool= true;
                                }
                            }
                             if(!$bool){
                                scorm_seq_set('suspended',$activity->id,$userid,false);
                             }
                        }
                    }
                }
            }
        }
        scorm_seq_set('suspendedactivity',$act->id,$userid,false);

    }
}

function scorm_select_children_process($scoid,$userid){
    global $DB;

    $sco = scorm_get_sco($scoid);
    if (!scorm_is_leaf($sco)){
        if(!scorm_seq_is('suspended',$scoid,$userid) && !scorm_seq_is('active',$scoid,$userid)){
            $r = $DB->get_record('scorm_scoes_track', array('scoid'=>$scoid,'userid'=>$userid,'element'=>'selectiontiming'));

             switch($r->value) {

                case 'oneachnewattempt':
                case 'never':
                break;

                case 'once':
                    if(!scorm_seq_is('activityprogressstatus',$scoid,$userid)){
                        if(scorm_seq_is('selectioncountsstatus',$scoid,$userid)){
                            $childlist = '';
                            $res = $DB->get_record('scorm_scoes_track', array('scoid'=>$scoid,'userid'=>$userid,'element'=>'selectioncount'));
                            $i = ($res->value)-1;
                            $children = scorm_get_children ($sco);

                            while ($i>=0){
                                $pos = array_rand($children);
                                array_push($childlist,$children [$pos]);
                                array_splice($children,$pos,1);
                                $i--;
                            }
                            sort ($childlist);
                            $clist = serialize ($childlist);
                            scorm_seq_set('availablechildren', $scoid, $userid, false);
                            scorm_seq_set('availablechildren', $scoid, $userid, $clist);


                        }
                    }
                break;

            }

        }
    }
}

function scorm_randomize_children_process($scoid,$userid){
    global $DB;

    $sco = scorm_get_sco($scoid);
    if (!scorm_is_leaf($sco)){
        if(!scorm_seq_is('suspended',$scoid,$userid) && !scorm_seq_is('active',$scoid,$userid)){
            $r = $DB->get_record('scorm_scoes_track', array('scoid'=>$scoid,'userid'=>$userid,'element'=>'randomizationtiming'));

             switch($r->value) {


                case 'never':
                break;

                case 'oneachnewattempt':
                case 'once':
                    if(!scorm_seq_is('activityprogressstatus',$scoid,$userid)){
                        if(scorm_seq_is('randomizechildren',$scoid,$userid)){
                            $childlist = array();
                            $res = scorm_get_available_children($sco);
                            $i = sizeof($res)-1;
                            $children = $res->value;

                            while ($i>=0){
                                $pos = array_rand($children);
                                array_push($childlist,$children [$pos]);
                                array_splice($children,$pos,1);
                                $i--;
                            }

                            $clist = serialize ($childlist);
                            scorm_seq_set('availablechildren', $scoid, $userid, false);
                            scorm_seq_set('availablechildren', $scoid, $userid, $clist);


                        }
                    }
                break;


            }

        }
    }
}

function scorm_terminate_descendent_attempts ($activity,$userid,$seq){
    $ancestors = scorm_get_ancestors($seq->currentactivity);
    $commonpos = scorm_find_common_ancestor($ancestors,$activity);
        if ($commonpos !== false) {
            if ($activitypath = array_slice($ancestors,1,$commonpos-2)) {
                if (!empty ($activitypath)){

                    foreach ($activitypath as $sco) {
                        scorm_seq_end_attempt($sco,$userid,$seq->attempt);

                    }
                }
            }
        }
}

function scorm_sequencing_exception($seq){
    global $OUTPUT;
    if($seq->exception != null){
        switch($seq->exception){

            case 'NB.2.1-1':
                echo $OUTPUT->notification("Sequencing session has already begun");
            break;
            case 'NB.2.1-2':
                echo $OUTPUT->notification("Sequencing session has not begun");
            break;
            case 'NB.2.1-3':
                echo $OUTPUT->notification("Suspended activity is not defined");
            break;
            case 'NB.2.1-4':
                echo $OUTPUT->notification("Flow Sequencing Control Model Violation");
            break;
            case 'NB.2.1-5':
                echo $OUTPUT->notification("Flow or Forward only Sequencing Control Model Violation");
            break;
            case 'NB.2.1-6':
                echo $OUTPUT->notification("No activity is previous to the root");
            break;
            case 'NB.2.1-7':
                echo $OUTPUT->notification("Unsupported Navigation Request");
            break;
            case 'NB.2.1-8':
                echo $OUTPUT->notification("Choice Exit Sequencing Control Model Violation");
            break;
            case 'NB.2.1-9':
                echo $OUTPUT->notification("No activities to consider");
            break;
            case 'NB.2.1-10':
                echo $OUTPUT->notification("Choice Sequencing Control Model Violation");
            break;
            case 'NB.2.1-11':
                echo $OUTPUT->notification("Target Activity does not exist");
            break;
            case 'NB.2.1-12':
                echo $OUTPUT->notification("Current Activity already terminated");
            break;
            case 'NB.2.1-13':
                echo $OUTPUT->notification("Undefined Navigation Request");
            break;

            case 'TB.2.3-1':
                echo $OUTPUT->notification("Current Activity already terminated");
            break;
            case 'TB.2.3-2':
                echo $OUTPUT->notification("Current Activity already terminated");
            break;
            case 'TB.2.3-4':
                echo $OUTPUT->notification("Current Activity already terminated");
            break;
            case 'TB.2.3-5':
                echo $OUTPUT->notification("Nothing to suspend; No active activities");
            break;
            case 'TB.2.3-6':
                echo $OUTPUT->notification("Nothing to abandon; No active activities");
            break;

            case 'SB.2.1-1':
                echo $OUTPUT->notification("Last activity in the tree");
            break;
            case 'SB.2.1-2':
                echo $OUTPUT->notification("Cluster has no available children");
            break;
            case 'SB.2.1-3':
                echo $OUTPUT->notification("No activity is previous to the root");
            break;
            case 'SB.2.1-4':
                echo $OUTPUT->notification("Forward Only Sequencing Control Model Violation");
            break;

            case 'SB.2.2-1':
                echo $OUTPUT->notification("Flow Sequencing Control Model Violation");
            break;
            case 'SB.2.2-2':
                echo $OUTPUT->notification("Activity unavailable");
            break;

            case 'SB.2.3-1':
                echo $OUTPUT->notification("Forward Traversal Blocked");
            break;
            case 'SB.2.3-2':
                echo $OUTPUT->notification("Forward Only Sequencing Control Model Violation");
            break;
            case 'SB.2.3-3':
                echo $OUTPUT->notification("No activity is previous to the root");
            break;

            case 'SB.2.5-1':
                echo $OUTPUT->notification("Sequencing session has already begun");
            break;

            case 'SB.2.6-1':
                echo $OUTPUT->notification("Sequencing session has already begun");
            break;
            case 'SB.2.6-2':
                echo $OUTPUT->notification("No Suspended activity is defined");
            break;

            case 'SB.2.7-1':
                echo $OUTPUT->notification("Sequencing session has not begun");
            break;
            case 'SB.2.7-2':
                echo $OUTPUT->notification("Flow Sequencing Control Model Violation");
            break;

            case 'SB.2.8-1':
                echo $OUTPUT->notification("Sequencing session has not begun");
            break;
            case 'SB.2.8-2':
                echo $OUTPUT->notification("Flow Sequencing Control Model Violation");
            break;

            case 'SB.2.9-1':
                echo $OUTPUT->notification("No target for Choice");
            break;
            case 'SB.2.9-2':
                echo $OUTPUT->notification("Target Activity does not exist or is unavailable");
            break;
            case 'SB.2.9-3':
                echo $OUTPUT->notification("Target Activity hidden from choice");
            break;
            case 'SB.2.9-4':
                echo $OUTPUT->notification("Choice Sequencing Control Model Violation");
            break;
            case 'SB.2.9-5':
                echo $OUTPUT->notification("No activities to consider");
            break;
            case 'SB.2.9-6':
                echo $OUTPUT->notification("Unable to activate target; target is not a child of the Current Activity");
            break;
            case 'SB.2.9-7':
                echo $OUTPUT->notification("Choice Exit Sequencing Control Model Violation");
            break;
            case 'SB.2.9-8':
                echo $OUTPUT->notification("Unable to choose target activity - constrained choice");
            break;
            case 'SB.2.9-9':
                echo $OUTPUT->notification("Choice Request Prevented by Flow-only Activity");
            break;

            case 'SB.2.10-1':
                echo $OUTPUT->notification("Sequencing session has not begun");
            break;
            case 'SB.2.10-2':
                echo $OUTPUT->notification("Current Activity is active or suspended");
            break;
            case 'SB.2.10-3':
                echo $OUTPUT->notification("Flow Sequencing Control Model Violation");
            break;

            case 'SB.2.11-1':
                echo $OUTPUT->notification("Sequencing session has not begun");
            break;
            case 'SB.2.11-2':
                echo $OUTPUT->notification("Current Activity has not been terminated");
            break;

            case 'SB.2.12-2':
                echo $OUTPUT->notification("Undefined Sequencing Request");
            break;

            case 'DB.1.1-1':
                echo $OUTPUT->notification("Cannot deliver a non-leaf activity");
            break;
            case 'DB.1.1-2':
                echo $OUTPUT->notification("Nothing to deliver");
            break;
            case 'DB.1.1-3':
                echo $OUTPUT->notification("Activity unavailable");
            break;

            case 'DB.2-1':
                echo $OUTPUT->notification("Identified activity is already active");
            break;

        }

    }
}