<?php
// This file is part of the Studyplan plugin for Moodle
//
// 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 <https://www.gnu.org/licenses/>.
/**
 *
 * @package    local_treestudyplan
 * @copyright  2023 P.M. Kuipers
 * @license    https://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

namespace local_treestudyplan;
use local_treestudyplan\local\helpers\webservicehelper;

require_once($CFG->libdir.'/externallib.php');
require_once($CFG->libdir.'/badgeslib.php');
require_once($CFG->libdir.'/gradelib.php');
require_once($CFG->dirroot.'/course/modlib.php');


class studyplanservice extends \external_api
{

    const CAP_EDIT = "local/treestudyplan:editstudyplan";
    const CAP_VIEW = "local/treestudyplan:viewuserreports";


    /************************
     *                      *
     * list_studyplans      *
     *                      *
     ************************/

    public static function list_studyplans_parameters() {
        return new \external_function_parameters([
            "context_id" => new \external_value(PARAM_INT, 'context to search in for studyplans', VALUE_DEFAULT),
        ]);
    }

    public static function list_studyplans_returns() {
        return new \external_multiple_structure( studyplan::simple_structure() );
    }

    public static function list_studyplans($contextid = 0) {
        global $CFG, $DB;

        // Check if the user has the correct permissions for this context.
        $context = webservicehelper::find_context($contextid);
        webservicehelper::require_capabilities([self::CAP_EDIT, self::CAP_VIEW], $context);

        // Now list all the studyplans in the relevant context.
        $list = [];
        $studyplans = studyplan::find_all($contextid);
        foreach ($studyplans as $studyplan) {
            $list[] = $studyplan->simple_model();
        }
        return $list;

    }

    /************************
     *                      *
     * get_studyplan_map    *
     *                      *
     ************************/

    public static function get_studyplan_map_parameters() {
        return new \external_function_parameters( [
            "id" => new \external_value(PARAM_INT, 'id of a studyplan to check usage on', VALUE_REQUIRED),
        ] );
    }

    public static function get_studyplan_map_returns() {
        return  studyplan::editor_structure();
    }

    public static function get_studyplan_map($id) {
        if (isset($id) && $id > 0) {
            $studyplan = studyplan::findById($id);
            webservicehelper::require_capabilities([self::CAP_EDIT, self::CAP_VIEW], $studyplan->context());
            return $studyplan->editor_model();
        } else {
            return null;
        }
    }

    /************************
     *                      *
     * get_studyline_map    *
     *                      *
     ************************/

    public static function get_studyline_map_parameters() {
        return new \external_function_parameters( [
            "id" => new \external_value(PARAM_INT, 'id of a studyline to check usage on', VALUE_DEFAULT),
        ]);
    }

    public static function get_studyline_map_returns() {
        return new \external_multiple_structure( studyline::editor_structure() );
    }

    public static function get_studyline_map($id) {

        $o = studyline::findById($id);
        webservicehelper::require_capabilities([self::CAP_EDIT, self::CAP_VIEW], $o->context());
        return $o->editor_model();
    }

    /************************
     *                      *
     * add_studyplan        *
     *                      *
     ************************/

    public static function add_studyplan_parameters() {
        return new \external_function_parameters( [
            "name" => new \external_value(PARAM_TEXT, 'name of studyplan'),
            "shortname"=> new \external_value(PARAM_TEXT, 'shortname of studyplan'),
            "idnumber"=> new \external_value(PARAM_TEXT, 'idnumber of studyplan'),
            "description"=> new \external_value(PARAM_TEXT, 'description of studyplan'),
            "periods" => new \external_value(PARAM_INT, 'number of periods in studyplan'),
            "startdate" => new \external_value(PARAM_TEXT, 'start date of studyplan'),
            "enddate" => new \external_value(PARAM_TEXT, 'end date of studyplan'),
            "aggregation" => new \external_value(PARAM_TEXT, 'selected aggregator', VALUE_DEFAULT),
            "aggregation_config" => new \external_value(PARAM_TEXT, 'config string for aggregator', VALUE_DEFAULT),
            "context_id" => new \external_value(PARAM_INT, 'context of the study plan', VALUE_DEFAULT),
        ] );
    }

    public static function add_studyplan_returns() {
        return studyplan::simple_structure();
    }

    public static function add_studyplan($name, $shortname, $idnumber, $description, $periods, $startdate, $enddate, $aggregation="bistate", $aggregationconfig='', $contextid=0) {
        // Check if we have the proper rights for the requested context.
        $context = webservicehelper::find_context($contextid);
        webservicehelper::require_capabilities(self::CAP_EDIT, $context);

        $o = studyplan::add([
            'name' => $name,
            'shortname' => $shortname,
            'idnumber' => $idnumber,
            'description' => $description,
            'periods' => $periods,
            'startdate' => $startdate,
            'enddate' => empty($enddate)?null:$enddate,
            'aggregation' => $aggregation,
            'aggregation_config' => $aggregationconfig,
            'context_id' => $contextid,
        ]);
        return $o->simple_model();
    }

    /************************
     *                      *
     * edit_studyplan       *
     *                      *
     ************************/

    public static function edit_studyplan_parameters() {
        return new \external_function_parameters( [
            "id" => new \external_value(PARAM_INT, 'id of studyplan'),
            "name" => new \external_value(PARAM_TEXT, 'name of studyplan'),
            "shortname"=> new \external_value(PARAM_TEXT, 'shortname of studyplan'),
            "idnumber"=> new \external_value(PARAM_TEXT, 'idnumber of studyplan'),
            "description"=> new \external_value(PARAM_TEXT, 'description of studyplan'),
            "periods" => new \external_value(PARAM_INT, 'number of periods in studyplan'),
            "startdate" => new \external_value(PARAM_TEXT, 'start date of studyplan'),
            "enddate" => new \external_value(PARAM_TEXT, 'end date of studyplan'),
            "aggregation" => new \external_value(PARAM_TEXT, 'selected aggregator', VALUE_DEFAULT),
            "aggregation_config" => new \external_value(PARAM_TEXT, 'config string for aggregator', VALUE_DEFAULT),
            "context_id" => new \external_value(PARAM_INT, 'context of the study plan', VALUE_DEFAULT),
        ] );
    }

    public static function edit_studyplan_returns() {
        return studyplan::simple_structure();
    }

    public static function edit_studyplan($id, $name, $shortname, $idnumber, $description, $periods, $startdate, $enddate, $aggregation="bistate", $aggregationconfig='', $contextid=0) {
        // Validate access in the intended context.
        $context = webservicehelper::find_context($contextid);
        webservicehelper::require_capabilities(self::CAP_EDIT, $context, false); // do not validate the context in this case, just check the permissions.

        $o = studyplan::findById($id);
        webservicehelper::require_capabilities(self::CAP_EDIT, $o->context());

        $o->edit([
            'name' => $name,
            'shortname' => $shortname,
            'idnumber' => $idnumber,
            'description' => $description,
            'periods' => $periods,
            'startdate' => $startdate,
            'enddate' => $enddate,
            'aggregation' => $aggregation,
            'aggregation_config' => $aggregationconfig,
            'context_id' => $contextid,
        ]);
        return $o->simple_model();
    }

    /************************
     *                      *
     * delete_studyplan     *
     *                      *
     ************************/

    public static function delete_studyplan_parameters() {
        return new \external_function_parameters( [
            "id" => new \external_value(PARAM_INT, 'id of studyplan'),
            "force" => new \external_value(PARAM_BOOL, 'id of studyplan', VALUE_DEFAULT),
        ] );
    }

    public static function delete_studyplan_returns() {
        return success::structure();
    }

    public static function delete_studyplan($id, $force=false) {
        $o = studyplan::findById($id);
        // validate if the requesting user has the right to edit the plan in it's current context.
        webservicehelper::require_capabilities(self::CAP_EDIT, $o->context());
        return $o->delete(!!$force)->model();
    }

    /************************
     *                      *
     * add_studyline        *
     *                      *
     ************************/

    public static function add_studyline_parameters() {
        return new \external_function_parameters( [
            "page_id" => new \external_value(PARAM_INT, 'id of studyplan to add line to'),
            "name" => new \external_value(PARAM_TEXT, 'shortname of studyline'),
            "shortname"=> new \external_value(PARAM_TEXT, 'idnumber of studyline'),
            "color"=> new \external_value(PARAM_TEXT, 'description of studyline'),
            "sequence" => new \external_value(PARAM_INT, 'sequence of studyline'),
        ] );
    }

    public static function add_studyline_returns() {
        return studyline::editor_structure();
    }

    public static function add_studyline($pageid, $name, $shortname, $color, $sequence) {
        // validate if the requesting user has the right to edit the plan in it's current context.
        $page = studyplanpage::findById($pageid);
        webservicehelper::require_capabilities(self::CAP_EDIT, $page->studyplan()->context());

        $o = studyline::add([
            'page_id' => $pageid,
            'name' => $name,
            'shortname' => $shortname,
            'color' => $color,
            'sequence' => $sequence,
        ]);
        return $o->editor_model();
    }

    /************************
     *                      *
     * edit_studyline       *
     *                      *
     ************************/

    public static function edit_studyline_parameters() {
        return new \external_function_parameters( [
            "id" => new \external_value(PARAM_INT, 'id of studyline'),
            "name" => new \external_value(PARAM_TEXT, 'shortname of studyline'),
            "shortname"=> new \external_value(PARAM_TEXT, 'idnumber of studyline'),
            "color"=> new \external_value(PARAM_TEXT, 'description of studyline'),
        ] );
    }

    public static function edit_studyline_returns() {
        return studyline::editor_structure();
    }

    public static function edit_studyline($id, $name, $shortname, $color) {
        $o = studyline::findById($id);
        // validate if the requesting user has the right to edit the plan in it's current context.
        webservicehelper::require_capabilities(self::CAP_EDIT, $o->context());

        $o->edit([
            'name' => $name,
            'shortname' => $shortname,
            'color' => $color,
        ]);
        return $o->editor_model();
    }


    /************************
     *                      *
     * delete_studyline     *
     *                      *
     ************************/

    public static function delete_studyline_parameters() {
        return new \external_function_parameters( [
            "id" => new \external_value(PARAM_INT, 'id of studyline'),
        ] );
    }

    public static function delete_studyline_returns() {
        return success::structure();
    }

    public static function delete_studyline($id) {
        $o = studyline::findById($id);
        // validate if the requesting user has the right to edit the plan in it's current context.
        webservicehelper::require_capabilities(self::CAP_EDIT, $o->context());
        return $o->delete()->model();

    }

    /************************
     *                      *
     * reorder_studylines   *
     *                      *
     ************************/

    public static function reorder_studylines_parameters() {
        return new \external_function_parameters( [
            "sequence" => new \external_multiple_structure(
                new \external_single_structure([
                    "id" => new \external_value(PARAM_INT, 'id of studyline '),
                    "sequence" => new \external_value(PARAM_INT, 'order of studyline'),
                ]),
            ),
        ] );
    }

    public static function reorder_studylines_returns() {
        return success::structure();
    }

    public static function reorder_studylines($resequence) {
        // validate if the requesting user has the right to edit the lines in it's current context.
        foreach ($resequence as $sq) {
            $o = studyline::findById(($sq['id']));
            webservicehelper::require_capabilities(self::CAP_EDIT, $o->context());
        }

        return studyline::reorder($resequence)->model();
    }

/***********************************
 * STUDYITEM FUNCTIONS
 ***********************************/

    /************************
     *                      *
     * get_studyitem    *
     *                      *
     ************************/

    public static function get_studyitem_parameters() {
        return new \external_function_parameters( [
            "id" => new \external_value(PARAM_INT, 'id of a study item to retrieve'),
        ] );
    }

    public static function get_studyitem_returns() {
        return studyitem::editor_structure();
    }


    public static function get_studyitem($id) {
        $o = studyitem::findById($id);
        webservicehelper::require_capabilities([self::CAP_EDIT, self::CAP_VIEW], $o->context());
        return $o->editor_model();

    }

    /************************
     *                      *
     * add_studyitem        *
     *                      *
     ************************/

    public static function add_studyitem_parameters() {
        return new \external_function_parameters( [
            "line_id" => new \external_value(PARAM_INT, 'id of related study line'),
            "type" => new \external_value(PARAM_TEXT, 'type of study item'),
            "details" => new \external_single_structure([
                "conditions"=> new \external_value(PARAM_TEXT, 'conditions for completion', VALUE_OPTIONAL),
                "competency_id" => new \external_value(PARAM_INT, 'id of referenced competency', VALUE_OPTIONAL),
                "course_id" => new \external_value(PARAM_INT, 'id of referenced course', VALUE_OPTIONAL),
                "badge_id" => new \external_value(PARAM_INT, 'id of referenced badge', VALUE_OPTIONAL),
                "continuation_id" => new \external_value(PARAM_INT, 'id of continued item', VALUE_OPTIONAL),
            ]),
            "slot" => new \external_value(PARAM_INT, 'slot in the study plan', VALUE_DEFAULT),
            "layer" => new \external_value(PARAM_INT, 'layer in the slot', VALUE_OPTIONAL),
        ] );
    }

    public static function add_studyitem_returns() {
        return studyitem::editor_structure();
    }

    public static function add_studyitem($lineid, $type, $details, $slot=-1, $layer=0) {
        webservicehelper::require_capabilities(self::CAP_EDIT, studyline::findById($lineid)->context());

        $o = studyitem::add([
            'line_id' => $lineid,
            'type' => $type,
            //'conditions' => $conditions,.
            'slot' => $slot,
            'layer' => $layer,
            'competency_id' => isset($details['competency_id'])?$details['competency_id']:null,
            'course_id' => isset($details['course_id'])?$details['course_id']:null,
            'badge_id' => isset($details['badge_id'])?$details['badge_id']:null,
            'continuation_id' => isset($details['continuation_id'])?$details['continuation_id']:null,
        ]);
        return $o->editor_model();
    }

    /************************
     *                      *
     * edit_studyitem       *
     *                      *
     ************************/

    public static function edit_studyitem_parameters() {
        return new \external_function_parameters( [
            "id" => new \external_value(PARAM_INT, 'id of study item'),
            "conditions"=> new \external_value(PARAM_TEXT, 'conditions for completion'),
            "continuation_id" => new \external_value(PARAM_INT, 'id of continued item', VALUE_DEFAULT),
        ]);
    }

    public static function edit_studyitem_returns() {
        return studyitem::editor_structure();
    }

    public static function edit_studyitem($id, $conditions, $continuationid=false) {

        $o = studyitem::findById($id);
        webservicehelper::require_capabilities(self::CAP_EDIT, $o->context());

        $config = [
            'conditions' => $conditions,
        ];
        if ($continuationid !== false) {
            $config['continuation_id'] = $continuationid;
        }

        $o->edit($config);
        return $o->editor_model();

    }

    /************************
     *                      *
     * reorder_studyitems   *
     *                      *
     ************************/

    public static function reorder_studyitems_parameters() {
        return new \external_function_parameters( [
            "items" => new \external_multiple_structure(
                new \external_single_structure([
                    "id" => new \external_value(PARAM_INT, 'id of studyitem '),
                    "line_id" => new \external_value(PARAM_INT, 'id of related study line'),
                    "slot" => new \external_value(PARAM_INT, 'slot in the study plan'),
                    "layer" => new \external_value(PARAM_INT, 'layer in the slot'),
                ]),
            ),
        ] );
    }

    public static function reorder_studyitems_returns() {
        return success::structure();
    }

    public static function reorder_studyitems($resequence) {
        // Check for permissions to modify the studyplan.
        foreach ($resequence as $sq) {
            webservicehelper::require_capabilities(self::CAP_EDIT, studyitem::findById(($sq['id']))->context());
        }

        return studyitem::reorder($resequence)->model();
    }


    /************************
     *                      *
     * delete_studyitem     *
     *                      *
     ************************/

    public static function delete_studyitem_parameters() {
        return new \external_function_parameters( [
            "id" => new \external_value(PARAM_INT, 'id of studyitem'),
        ] );
    }

    public static function delete_studyitem_returns() {
        return success::structure();
    }

    public static function delete_studyitem($id) {
        $o = studyitem::findById($id);
        webservicehelper::require_capabilities(self::CAP_EDIT, $o->context());

        return $o->delete()->model();
    }

    /************************
     *                      *
     * connect_studyitems   *
     *                      *
     ************************/

    public static function connect_studyitems_parameters() {
        return new \external_function_parameters( [
            "from_id" => new \external_value(PARAM_INT, 'id of studyitem connect start '),
            "to_id" => new \external_value(PARAM_INT, 'id ofstudyitem connect end'),
        ] );
    }

    public static function connect_studyitems_returns() {
        return studyitemconnection::structure();
    }

    public static function connect_studyitems($fromid, $toid) {
        // Validate permissions.
        webservicehelper::require_capabilities(self::CAP_EDIT, studyitem::findById($fromid)->context());
        webservicehelper::require_capabilities(self::CAP_EDIT, studyitem::findById($toid)->context());

        $o = studyitemconnection::connect($fromid, $toid);
        return $o->model();
    }

    /****************************
     *                          *
     * disconnect_studyitems    *
     *                          *
     ****************************/

    public static function disconnect_studyitems_parameters() {
        return new \external_function_parameters( [
            "from_id" => new \external_value(PARAM_INT, 'id of studyitem '),
            "to_id" => new \external_value(PARAM_INT, 'id of related study line'),
        ] );
    }

    public static function disconnect_studyitems_returns() {
        return success::structure();
    }

    public static function disconnect_studyitems($fromid, $toid) {
        // Validate permissions.
        webservicehelper::require_capabilities(self::CAP_EDIT, studyitem::findById($fromid)->context());
        webservicehelper::require_capabilities(self::CAP_EDIT, studyitem::findById($toid)->context());
        return studyitemconnection::disconnect($fromid, $toid)->model();
    }

    /****************************
     *                          *
     * list badges              *
     *                          *
     ****************************/

    public static function list_badges_parameters() {
        return new \external_function_parameters( [] );
    }

    public static function list_badges_returns() {
        return new \external_multiple_structure(badgeinfo::editor_structure());
    }

    public static function list_badges() {
        $systemcontext = webservicehelper::system_context();

        $result = [];
        $badges = badges_get_badges(BADGE_TYPE_SITE, "timemodified");
        foreach ($badges as $badge) {
// TODO: Add config option to list only active badges.
//            if ($badge->is_active()) {.
                $result[] = (new badgeinfo($badge))->editor_model();
//            }.

//TODO: Include course badges somehow... Just site badges is not enough.

        }
        return $result;

    }

    /****************************
     *                          *
     * include/remove grades    *
     *                          *
     ****************************/

    public static function include_grade_parameters() {
        return new \external_function_parameters( [
            "grade_id" => new \external_value(PARAM_INT, 'id of gradeitem '),
            "item_id" => new \external_value(PARAM_INT, 'id of studyitem '),
            "include" => new \external_value(PARAM_BOOL, 'include or not '),
            "required" => new \external_value(PARAM_BOOL, 'required grade or not', VALUE_DEFAULT),
            ] );
    }

    public static function include_grade_returns() {
        return success::structure();
    }

    public static function include_grade($gradeid, $itemid, $include, $required=false) {
        global $USER;

        // find related course and course context.
        $coursecontext = gradeinfo::getCourseContextById($gradeid);
        // do sanity checks.
        \external_api::validate_context($coursecontext);


        // check correct capabilities.
        if (has_capability('local/treestudyplan:editstudyplan', studyitem::findById($itemid)->context()) ||
           is_enrolled($coursecontext, $USER, 'local/treestudyplan:selectowngradables')) {
            return gradeinfo::include_grade($gradeid, $itemid, $include, $required)->model();
        } else {
            return success::fail("Access denied")->model();
        }

    }

    /****************************
     *                          *
     * list aggregators         *
     *                          *
     ****************************/

    public static function list_aggregators_parameters() {
        return new \external_function_parameters([]);
    }

    public static function list_aggregators_returns() {
        return aggregator::list_structure();
    }

    public static function list_aggregators() {
        return aggregator::list_model();

    }

    /****************************
     *                          *
     * force_studyplan_scale    *
     *                          *
     ****************************/

    public static function force_studyplan_scale_parameters() {
        return new \external_function_parameters( [
            "studyplan_id" => new \external_value(PARAM_INT, 'id of studyplan'),
            "scale_id" => new \external_value(PARAM_INT, 'scale_id to set'),
        ] );
    }

    public static function force_studyplan_scale_returns() {
        return new \external_multiple_structure(new \external_single_structure([
            "course" => courseinfo::simple_structure(),
            "grades" => new \external_multiple_structure(new \external_single_structure([
                "name" => new \external_value(PARAM_TEXT, 'grade name'),
                "changed" => new \external_value(PARAM_TEXT, 'changed or not'),
                "debug" => new \external_value(PARAM_TEXT, 'debug', VALUE_OPTIONAL),
            ])),
        ]));
    }

    public static function force_studyplan_scale($studyplanid, $scaleid) {
        global $DB;
        $dbman = $DB->get_manager();

        // Validate permissions.
        webservicehelper::require_capabilities(self::CAP_EDIT, studyplan::findById($studyplanid)->context());

        $list = [];
        // check if scaleid is valid.
        $scale = \grade_scale::fetch(['id' => $scaleid]);
        $scale->load_items();

        if ($scale) {
            $gradecfg = $DB->get_record("local_treestudyplan_gradecfg", ["scale_id"=>$scale->id]);
            $scalepass = ($gradecfg)?$gradecfg->min_completed:0;
            $scalemax = count($scale->scale_items);

            // find studyline id's.
            $studylineids = $DB->get_fieldset_select(studyline::TABLE, "id", "studyplan_id = :plan_id", ['plan_id' => $studyplanid]);
            foreach ($studylineids as $studylineid) {
                // find id's of studyitems of type course.
                $records = $DB->get_records(studyitem::TABLE, ['line_id' => $studylineid]);

                foreach ($records as $itemr) {
                    $studyitem = new studyitem($itemr->id);
                    if ($studyitem->isValid() && $studyitem->type() == studyitem::COURSE) {
                        $courseinfo = $studyitem->getcourseinfo();
                        $gradables = gradeinfo::list_studyitem_gradables($studyitem);

                        $gradelist = [];
                        foreach ($gradables as $g) {
                            $gi = $g->getGradeItem();

                            // only change items that do not yet have grades.
                            // otherwise we will need to implement grade recalculations and it is not worth the trouble. .
                            // if grades are given, you likely don't want to change it like this anyway.

                            if (!$gi->has_grades()) {
                                $gi->gradetype = GRADE_TYPE_SCALE;
                                $gi->scaleid = $scale->id;
                                $gi->grademin = 1;
                                $gi->grademax = $scalemax;
                                $gi->gradepass = $scalepass;

                                // Update grade_item.
                                $result = $gi->update("local/treestudyplan"); // update, signalling with our signature and bulkupdate.

                                $debug = "";
                                if ($result) { $updated = "converted";} else { $updated = "error";}

                                // next update the activity's table if it has a grade field.
                                // grade is generally set to the negative scale id if it is a scale.
                                $tablename = $gi->itemmodule;
                                $fieldname = "grade";
                                if ($result && $gi->itemtype == "mod" && $dbman->table_exists($tablename)) {
                                    if ($dbman->field_exists($tablename, $fieldname)) {
                                        $gradevalue = intval(0-($scale->id));
                                        try {
                                            $DB->set_field($tablename, $fieldname, $gradevalue, ["id" => $gi->iteminstance]);
                                        }
                                        catch(\dml_exception $x) {
                                            $updated = "fail";
                                            $debug = strval($x);
                                        }
                                    }
                                }

                            } else {
                                $updated = "skipped";
                            }

                            $gradelist[] = [
                                'name' => $gi->itemname,
                                'changed' => $updated,
                                'debug' => $debug,
                            ];
                        }

                        $list[] = [
                            'course' => $courseinfo->simple_model(),
                            'grades' => $gradelist,
                        ];
                    }
                }
            }
        }

        return $list;

    }

    /****************************
     *                          *
     * list_scales              *
     *                          *
     ****************************/

    public static function list_scales_parameters() {
        return new \external_function_parameters( [] );
    }

    public static function list_scales_returns() {
        return new \external_multiple_structure(new \external_single_structure([
            "id" => new \external_value(PARAM_INT, 'id of scale'),
            "name" => new \external_value(PARAM_TEXT, 'scale name'),
        ]));
    }

    public static function list_scales() {
        global $DB;
        $list = [];
        $scales = \grade_scale::fetch_all_global();

        foreach ($scales as $scale) {
            $list[] = [
                "id" => $scale->id,
                "name" => $scale->name,
            ];
        }

        return $list;

    }

  /****************************
     *                          *
     * disable_autoenddate    *
     *                          *
     ****************************/

    public static function disable_autoenddate_parameters() {
        return new \external_function_parameters( [
            "studyplan_id" => new \external_value(PARAM_INT, 'id of studyplan'),
        ] );
    }

    public static function disable_autoenddate_returns() {
        return success::structure();
    }

    public static function disable_autoenddate($studyplanid) {
        global $DB;

        // Validate permissions.
        webservicehelper::require_capabilities(self::CAP_EDIT, studyplan::findById($studyplanid)->context());

        // find studyline id's.
        $studylineids = $DB->get_fieldset_select(studyline::TABLE, "id", "studyplan_id = :plan_id", ['plan_id' => $studyplanid]);
        foreach ($studylineids as $studylineid) {
            // find id's of studyitems of type course.
            $records = $DB->get_records(studyitem::TABLE, ['line_id' => $studylineid]);

            foreach ($records as $itemr) {
                $studyitem = new studyitem($itemr->id);
                if ($studyitem->isValid() && $studyitem->type() == studyitem::COURSE) {
                    $record = $DB->get_record("course_format_options", ["courseid" => $studyitem->courseid(), "name" => "automaticenddate"]);
                    if ($record && $record->value) {
                        $record->value = false;
                        $DB->update_record("course_format_options", $record);
                    }
                }
            }
        }

        return success::success()->model();
    }
    /****************************
     *                          *
     * duplicate studyplan      *
     *                          *
     ****************************/

    public static function duplicate_plan_parameters() {
        return new \external_function_parameters( [
            "plan_id" => new \external_value(PARAM_INT, 'id of plan to copy '),
            "name" => new \external_value(PARAM_TEXT, 'name of copy '),
            "shortname" => new \external_value(PARAM_TEXT, 'shortname of copy '),
            ] );
    }

    public static function duplicate_plan_returns() {
        return studyplan::simple_structure();
    }

    public static function duplicate_plan($studyplanid, $name, $shortname) {
        // Validate permissions.
        webservicehelper::require_capabilities(self::CAP_EDIT, studyplan::findById($studyplanid)->context());

        return studyplan::duplicate_plan($studyplanid, $name, $shortname);
    }

    /****************************
     *                          *
     * export studyplan         *
     *                          *
     ****************************/

    public static function export_plan_parameters() {
        return new \external_function_parameters( [
            "studyplan_id" => new \external_value(PARAM_INT, 'id of plan to export '),
            "format" => new \external_value(PARAM_TEXT, 'export format', VALUE_OPTIONAL),
            ] );
    }

    public static function export_plan_returns() {
        return studyplan::export_structure();
    }

    public static function export_plan($studyplanid, $format="json") {
        try {
            // Validate permissions.
            webservicehelper::require_capabilities(self::CAP_EDIT, studyplan::findById($studyplanid)->context());

            $plan = studyplan::findById($studyplanid);
            if ($format == "csv") {
                // FIXME: Make sure this webservice function gets called for the page instead of the studyplan.
                return $plan->pages()[0]->export_page_csv();
            } else{
                return $plan->export_plan();
            }
        }
        catch(\webservice_access_exception $x) {
            return [ "format" => "", "content" => ""];
        }
    }

    public static function export_studylines_parameters() {
        return new \external_function_parameters( [
            "studyplan_id" => new \external_value(PARAM_INT, 'id of plan to export '),
            ] );
    }

    public static function export_studylines_returns() {
        return studyplan::export_structure();
    }

    public static function export_studylines($studyplanid) {
        $systemcontext = webservicehelper::system_context();

        try {
            webservicehelper::require_capabilities(self::CAP_EDIT, studyplan::findById($studyplanid)->context());
            $plan = studyplan::findById($studyplanid);
            // FIXME: Make sure this gets called for the page instead of the studyplan.
            return $plan->pages()[0]->export_studylines();
        }
        catch(\webservice_access_exception $x) {
            return [ "format" => "", "content" => ""];
        }
    }
    /****************************
     *                          *
     * import studyplan         *
     *                          *
     ****************************/

    public static function import_plan_parameters() {
        return new \external_function_parameters( [
            "content" => new \external_value(PARAM_TEXT, 'import file content'),
            "format" => new \external_value(PARAM_TEXT, 'import format'),
            "context_id" => new \external_value(PARAM_INT, 'context of the study plan', VALUE_DEFAULT),
            ] );
    }

    public static function import_plan_returns() {
        return success::structure();
    }

    public static function import_plan($content, $format="application/json", $contextid=1) {

        try {
            // Validate import context.
            $context = webservicehelper::find_context($contextid);
            webservicehelper::require_capabilities(self::CAP_EDIT, $context);

            $result = studyplan::import_studyplan($content, $format, $contextid);
            return (new success($result, "During study plan import"))->model();
        }
        catch(\webservice_access_exception $x) {
            return success::fail("Access denied")->model();
        }
    }

    public static function import_studylines_parameters() {
        return new \external_function_parameters( [
            "studyplan_id" => new \external_value(PARAM_INT, 'id of plan to export '),
            "content" => new \external_value(PARAM_TEXT, 'import file content'),
            "format" => new \external_value(PARAM_TEXT, 'import format'),
            ] );
    }

    public static function import_studylines_returns() {
        return success::structure();
    }

    public static function import_studylines($studyplanid, $content, $format="application/json") {

        try {
            $plan = studyplan::findById($studyplanid);
            // Validate import context.
            webservicehelper::require_capabilities(self::CAP_EDIT, $plan->context());

            // FIXME: Make sure this gets called for the page instead of the studyplan.
            // Once proper page management is implemented.
            $result = $plan->pages()[0]->import_studylines($content, $format);
            return ($result?success::success():success::fail())->model();
        }
        catch(\webservice_access_exception $x) {
            return success::fail("Access denied")->model();
        }
    }


    /********************************************************
     *                                                      *
     * Read and write course module title and desc          *
     * Used only in bistate aggregation method              *
     *                                                      *
     ********************************************************/

    public static function submit_cm_editform_parameters() {
        return new \external_function_parameters( [
            "cmid" => new \external_value(PARAM_INT, 'id of course module'),
            "formdata" => new \external_value(PARAM_RAW, 'url encoded form data'),
        ] );
    }

    public static function submit_cm_editform_returns() {
        return success::structure();
    }

    /** DEPRECATED, will remove hacked edit form in the future */
    public static function submit_cm_editform($cmid, $formdata) {
        global $CFG;
        global $DB;

        // Check the course module exists.
        $cm = \get_coursemodule_from_id('', $cmid, 0, false, MUST_EXIST);
        // Get some context ready.
        $context = \context_course::instance($cm->course);
        self::validate_context($context);

        // Check the course exists.
        $course = \get_course($cm->course);
        // require_login.
        require_login($course, false, $cm); // needed to setup proper $COURSE.

        // get needed info to create the correct form.
        list($cm, $context, $module, $data, $cw) = \get_moduleinfo_data($cm, $course);
        $modmoodleform = "$CFG->dirroot/mod/$module->name/mod_form.php";
        if (file_exists($modmoodleform)) {
            require_once($modmoodleform);
        } else {
            throw new \moodle_exception('noformdesc', 'error');
        }
        $mformclassname = 'mod_'.$module->name.'_mod_form';

        // now hack the received data into $_POST, so the mform thinks it has been submitted "normally".
        foreach (explode("&", $formdata) as $pair) {
            $p = explode("=", $pair, 2);
            $k = urldecode($p[0]);
            $v = (count($p)>1)?urldecode($p[1]):"";

            if (strpos($k, "[") > 0 && strpos($k, "]") == strlen($k) -1) {
                // its a bracketet field, like filename[text] which should be separated and put into a named array.
                list($k, $h) = explode("[", $k, 2);
                if (strlen($k) > 0 && strlen($h) > 1) {
                    $h = rtrim($h, "]");
                    if (!array_key_exists($k, $_POST) || !is_array($_POST[$k])) {
                        $_POST[$k] = [];
                    }
                    $_POST[$k][$h] = $v;
                }
            }else {
                $_POST[$k] = $v;
            }
        }

        // Now create the mform and update the module...
        // update_moduleinfo() actually needs the mform somehow. Hence the ugly hacks.
        $mform = new $mformclassname($data, $cw->section, $cm, $course);
        $mform->set_data($data);

        if ($fromform = $mform->get_data()) {
            update_moduleinfo($cm, $fromform, $course, $mform);
            return success::success()->model();
        } else {
            return success::fail("MForm did not recognize submission data")->model();
        }
    }

    /************************
     *                      *
     * edit_period       *
     *                      *
     ************************/

     public static function edit_period_parameters() {
         return new \external_function_parameters( [
             "id" => new \external_value(PARAM_INT, 'id of study item'),
             "fullname" => new \external_value(PARAM_TEXT, 'Full name of period'),
             "shortname"=> new \external_value(PARAM_TEXT, 'Short name of period'),
             "startdate" => new \external_value(PARAM_TEXT, 'start date of period'),
             "enddate" => new \external_value(PARAM_TEXT, 'end date of period'),
         ]);
     }

     public static function edit_period_returns() {
         return period::structure();
     }

     public static function edit_period($id, $fullname, $shortname, $startdate, $enddate) {

         $p = period::findById($id);
         webservicehelper::require_capabilities(self::CAP_EDIT, $p->page()->studyplan()->context());


         $p->edit([
            'fullname' => $fullname,
            'shortname' => $shortname,
            'startdate' => $startdate,
            'enddate' => $enddate,
         ]);
         return $p->model();

     }

     /************************
      *                      *
      * Change course timing *
      *                      *
      ************************/

     public static function course_period_timing_parameters() {
         return new \external_function_parameters( [
             "period_id" => new \external_value(PARAM_INT, 'Period number within page'),
             "course_id"=> new \external_value(PARAM_INT, 'Id of course to adjust dates for'),
             "span"=> new \external_value(PARAM_INT, 'Period span (default 1)', VALUE_DEFAULT),
         ]);
     }

     public static function course_period_timing_returns() {
         return courseinfo::editor_structure();
     }

     public static function course_period_timing($periodid, $courseid, $span=1) {
        global $DB;
        $period = period::findById($periodid);
        $periodnr = $period->period();
        $page = $period->page();
        // Check for studyplan edit permissions.
        webservicehelper::require_capabilities(self::CAP_EDIT, $page->studyplan()->context());
        $course = \get_course($courseid);
        $coursecontext = \context_course::instance($courseid);

        if (webservicehelper::has_capabilities("moodle/course:update", $coursecontext)) {

            // Get the proper list of all the periods for this page.
            $periods = period::findForPage($page);

            $pstart = $periods[$periodnr];

            // Determine end period number - Clip span between 1 and last period.
            if ($span <= 1) {
                $pend = $pstart;
            } else if ($periodnr + ($span - 1) > $page->periods()) {
                $pend = $periods[$page->periods()];
            } else {
                $pend = $periods[$periodnr + ($span - 1)];
            }

            // First disable the automatic end date option, since it messes with the timing.
            // Unfortunately there is still no default option to turn this off .
            $record = $DB->get_record("course_format_options", ["courseid" => $course->id, "name" => "automaticenddate"]);
            if ($record && $record->value) {
                $record->value = false;
                $DB->update_record("course_format_options", $record);
            }

            // Actually perform the timing changes, while also updating the module times.
            // Like what happens on a course "reset".
            reset_course_userdata((object)[
                'id' => $course->id,
                'reset_start_date' => $pstart->startdate()->getTimestamp(),
                'reset_end_date' => $pend->enddate()->getTimestamp(),
                'reset_start_date_old' => $course->startdate,
                'reset_end_date_old' => $course->enddate,
            ]);
            // purge course cache so the dates are properly reflected.
            \course_modinfo::purge_course_cache($course->id);

            return (new courseinfo($course->id))->editor_model();
        } else {
            // probably should return a nice message.
            throw new \webservice_access_exception("You do not have date change permissions on this course");
        }
     }

     public static function set_studyitem_span_parameters() {
         return new \external_function_parameters( [
             "id" => new \external_value(PARAM_INT, 'id of study item'),
             "span" => new \external_value(PARAM_INT, 'span of item'),
         ]);
     }

     public static function set_studyitem_span_returns() {
         return studyitem::editor_structure();
     }

     public static function set_studyitem_span($id, $span=null) {
         $o = studyitem::findById($id);
         webservicehelper::require_capabilities(self::CAP_EDIT, $o->context());

         $config = [ 'span' => $span];
         $o->edit($config);
         return $o->editor_model();

     }

}