<?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/>.

/**
 * Bulk activity completion manager class
 *
 * @package     core_completion
 * @category    completion
 * @copyright   2017 Adrian Greeve
 * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

namespace core_completion;

use core\context;
use core\output\local\properties\iconsize;
use core_course\output\activity_icon;
use stdClass;
use context_course;
use cm_info;
use moodle_url;

/**
 * Bulk activity completion manager class
 *
 * @package     core_completion
 * @category    completion
 * @copyright   2017 Adrian Greeve
 * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class manager {

    /**
     * @var int $courseid the course id.
     */
    protected $courseid;

    /**
     * manager constructor.
     * @param int $courseid the course id.
     */
    public function __construct($courseid) {
        $this->courseid = $courseid;
    }

    /**
     * Returns current course context or system level for $SITE courseid.
     *
     * @return context The course based on current courseid or system context.
     */
    protected function get_context(): context {
        global $SITE;

        if ($this->courseid && $this->courseid != $SITE->id) {
            return context_course::instance($this->courseid);
        }
        return \context_system::instance();
    }

    /**
     * Gets the data (context) to be used with the bulkactivitycompletion template.
     *
     * @return stdClass data for use with the bulkactivitycompletion template.
     */
    public function get_activities_and_headings() {
        global $OUTPUT;
        $moduleinfo = get_fast_modinfo($this->courseid);
        $sections = $moduleinfo->get_sections();
        $data = new stdClass;
        $data->courseid = $this->courseid;
        $data->sesskey = sesskey();
        $data->helpicon = $OUTPUT->help_icon('bulkcompletiontracking', 'core_completion');
        $data->sections = [];
        foreach ($sections as $sectionnumber => $section) {
            $sectioninfo = $moduleinfo->get_section_info($sectionnumber);

            $sectionobject = new stdClass();
            $sectionobject->sectionnumber = $sectionnumber;
            $sectionobject->name = get_section_name($this->courseid, $sectioninfo);
            $sectionobject->activities = $this->get_activities($section, true);
            $data->sections[] = $sectionobject;
        }
        return $data;
    }

    /**
     * Gets the data (context) to be used with the activityinstance template
     *
     * @param array $cmids list of course module ids
     * @param bool $withcompletiondetails include completion details
     * @return array
     */
    public function get_activities($cmids, $withcompletiondetails = false) {
        $output = \core\di::get(\core\output\renderer_helper::class)->get_core_renderer();
        $moduleinfo = get_fast_modinfo($this->courseid);
        $activities = [];
        foreach ($cmids as $cmid) {
            $mod = $moduleinfo->get_cm($cmid);
            if (!$mod->uservisible) {
                continue;
            }

            $icon = activity_icon::from_cm_info($mod)
                ->set_icon_size(iconsize::SIZE5);

            $moduleobject = new stdClass();
            $moduleobject->cmid = $cmid;
            $moduleobject->modname = $mod->get_formatted_name();
            $moduleobject->icon = $mod->get_icon_url()->out();
            $moduleobject->url = $mod->url;
            $moduleobject->activityicon = $icon->export_for_template($output);
            $moduleobject->canmanage = $withcompletiondetails && self::can_edit_bulk_completion($this->courseid, $mod);

            // Get activity completion information.
            if ($moduleobject->canmanage) {
                $moduleobject->completionstatus = $this->get_completion_detail($mod);
            } else {
                $moduleobject->completionstatus = ['icon' => null, 'string' => null];
            }
            if (self::can_edit_bulk_completion($this->courseid, $mod)) {
                $activities[] = $moduleobject;
            }
        }
        return $activities;
    }


    /**
     * Get completion information on the selected module or module type
     *
     * @param cm_info|stdClass $mod either instance of cm_info (with 'customcompletionrules' in customdata) or
     *      object with fields ->completion, ->completionview, ->completionexpected, ->completionusegrade
     *      and ->customdata['customcompletionrules']
     * @return array
     */
    private function get_completion_detail($mod) {
        global $OUTPUT;
        $strings = [];
        switch ($mod->completion) {
            case COMPLETION_TRACKING_NONE:
                $strings['string'] = get_string('none');
                break;

            case COMPLETION_TRACKING_MANUAL:
                $strings['string'] = get_string('manual', 'completion');
                $strings['icon'] = $OUTPUT->pix_icon('i/completion-manual-y', get_string('completion_manual', 'completion'));
                break;

            case COMPLETION_TRACKING_AUTOMATIC:
                $strings['string'] = get_string('withconditions', 'completion');
                $strings['icon'] = $OUTPUT->pix_icon('i/completion-auto-y', get_string('completion_automatic', 'completion'));
                break;

            default:
                $strings['string'] = get_string('none');
                break;
        }

        // Get the descriptions for all the active completion rules for the module.
        if ($ruledescriptions = $this->get_completion_active_rule_descriptions($mod)) {
            foreach ($ruledescriptions as $ruledescription) {
                $strings['string'] .= \html_writer::empty_tag('br') . $ruledescription;
            }
        }
        return $strings;
    }

    /**
     * Get the descriptions for all active conditional completion rules for the current module.
     *
     * @param cm_info|stdClass $moduledata either instance of cm_info (with 'customcompletionrules' in customdata) or
     *      object with fields ->completion, ->completionview, ->completionexpected, ->completionusegrade
     *      and ->customdata['customcompletionrules']
     * @return array $activeruledescriptions an array of strings describing the active completion rules.
     */
    protected function get_completion_active_rule_descriptions($moduledata) {
        $activeruledescriptions = [];

        if ($moduledata->completion == COMPLETION_TRACKING_AUTOMATIC) {
            // Generate the description strings for the core conditional completion rules (if set).
            if (!empty($moduledata->completionview)) {
                $activeruledescriptions[] = get_string('completionview_desc', 'completion');
            }
            if ($moduledata instanceof cm_info && !is_null($moduledata->completiongradeitemnumber) ||
                ($moduledata instanceof stdClass && !empty($moduledata->completionusegrade))) {

                $description = 'completionusegrade_desc';
                if (!empty($moduledata->completionpassgrade)) {
                    $description = 'completionpassgrade_desc';
                }

                $activeruledescriptions[] = get_string($description, 'completion');
            }

            // Now, ask the module to provide descriptions for its custom conditional completion rules.
            if ($customruledescriptions = component_callback($moduledata->modname,
                'get_completion_active_rule_descriptions', [$moduledata])) {
                $activeruledescriptions = array_merge($activeruledescriptions, $customruledescriptions);
            }
        }

        if ($moduledata->completion != COMPLETION_TRACKING_NONE) {
            if (!empty($moduledata->completionexpected)) {
                $activeruledescriptions[] = get_string('completionexpecteddesc', 'completion',
                    userdate($moduledata->completionexpected));
            }
        }

        return $activeruledescriptions;
    }

    /**
     * Gets the course modules for the current course.
     *
     * @param bool $includedefaults Whether the default values should be included or not.
     * @return stdClass $data containing the modules
     */
    public function get_activities_and_resources(bool $includedefaults = true) {
        global $DB, $OUTPUT, $CFG;
        require_once($CFG->dirroot.'/course/lib.php');

        // Get enabled activities and resources.
        $modules = $DB->get_records('modules', ['visible' => 1], 'name ASC');
        $data = new stdClass();
        $data->courseid = $this->courseid;
        $data->sesskey = sesskey();
        $data->helpicon = $OUTPUT->help_icon('bulkcompletiontracking', 'core_completion');
        // Add icon information.
        $data->modules = array_values($modules);
        $context = $this->get_context();
        $canmanage = has_capability('moodle/course:manageactivities', $context);
        $course = get_course($this->courseid);
        $availablemodules = [];
        foreach ($data->modules as $module) {
            $libfile = "$CFG->dirroot/mod/$module->name/lib.php";
            if (!file_exists($libfile)) {
                continue;
            }
            if (!plugin_supports('mod', $module->name, FEATURE_MODEDIT_DEFAULT_COMPLETION, true)) {
                continue;
            }
            $module->icon = $OUTPUT->image_url('monologo', $module->name)->out();
            $module->formattedname = format_string(get_string('modulename', 'mod_' . $module->name),
                true, ['context' => $context]);
            $module->canmanage = $canmanage && course_allowed_module($course, $module->name);
            if ($includedefaults) {
                $defaults = self::get_default_completion($course, $module, false);
                $defaults->modname = $module->name;
                $module->completionstatus = $this->get_completion_detail($defaults);
            }
            $availablemodules[] = $module;
        }
        // Order modules by displayed name.
        usort($availablemodules, function($a, $b) {
            return strcmp($a->formattedname, $b->formattedname);
        });
        $data->modules = $availablemodules;

        return $data;
    }

    /**
     * Checks if current user can edit activity completion
     *
     * @param int|stdClass $courseorid
     * @param \cm_info|null $cm if specified capability for a given coursemodule will be check,
     *     if not specified capability to edit at least one activity is checked.
     */
    public static function can_edit_bulk_completion($courseorid, $cm = null) {
        if ($cm) {
            if (!plugin_supports('mod', $cm->modname, FEATURE_COMPLETION, true)) {
                return false;
            }
            return $cm->uservisible && has_capability('moodle/course:manageactivities', $cm->context);
        }
        $coursecontext = context_course::instance(is_object($courseorid) ? $courseorid->id : $courseorid);
        if (has_capability('moodle/course:manageactivities', $coursecontext)) {
            return true;
        }
        $modinfo = get_fast_modinfo($courseorid);
        foreach ($modinfo->cms as $mod) {
            if ($mod->uservisible && has_capability('moodle/course:manageactivities', $mod->context)) {
                return true;
            }
        }
        return false;
    }

    /**
     * Returns an array with the available completion options (url => name) for the current course and user.
     *
     * @param int $courseid The course id.
     * @return array
     */
    public static function get_available_completion_options(int $courseid): array {
        $coursecontext = context_course::instance($courseid);
        $options = [];

        if (has_capability('moodle/course:update', $coursecontext)) {
            $completionlink = new moodle_url('/course/completion.php', ['id' => $courseid]);
            $options[$completionlink->out(false)] = get_string('coursecompletionsettings', 'completion');
        }

        if (has_capability('moodle/course:manageactivities', $coursecontext)) {
            $defaultcompletionlink = new moodle_url('/course/defaultcompletion.php', ['id' => $courseid]);
            $options[$defaultcompletionlink->out(false)] = get_string('defaultcompletion', 'completion');
        }

        if (self::can_edit_bulk_completion($courseid)) {
            $bulkcompletionlink = new moodle_url('/course/bulkcompletion.php', ['id' => $courseid]);
            $options[$bulkcompletionlink->out(false)] = get_string('bulkactivitycompletion', 'completion');
        }

        return $options;
    }

    /**
     * Applies completion from the bulk edit form to all selected modules
     *
     * @param stdClass $data data received from the core_completion_bulkedit_form
     * @param bool $updateinstances if we need to update the instance tables of the module (i.e. 'assign', 'forum', etc.) -
     *      if no module-specific completion rules were added to the form, update of the module table is not needed.
     */
    public function apply_completion($data, $updateinstances) {
        $updated = false;
        $needreset = [];
        $modinfo = get_fast_modinfo($this->courseid);

        $cmids = $data->cmid;

        $data = (array)$data;
        unset($data['id']); // This is a course id, we don't want to confuse it with cmid or instance id.
        unset($data['cmid']);
        unset($data['submitbutton']);

        foreach ($cmids as $cmid) {
            $cm = $modinfo->get_cm($cmid);
            if (self::can_edit_bulk_completion($this->courseid, $cm) && $this->apply_completion_cm($cm, $data, $updateinstances)) {
                $updated = true;
                if ($cm->completion != COMPLETION_TRACKING_MANUAL || $data['completion'] != COMPLETION_TRACKING_MANUAL) {
                    // If completion was changed we will need to reset it's state. Exception is when completion was and remains as manual.
                    $needreset[] = $cm->id;
                }
            }
            // Update completion calendar events.
            $completionexpected = ($data['completionexpected']) ? $data['completionexpected'] : null;
            \core_completion\api::update_completion_date_event($cm->id, $cm->modname, $cm->instance, $completionexpected);
        }
        if ($updated) {
            // Now that modules are fully updated, also update completion data if required.
            // This will wipe all user completion data and recalculate it.
            rebuild_course_cache($this->courseid, true);
            $modinfo = get_fast_modinfo($this->courseid);
            $completion = new \completion_info($modinfo->get_course());
            foreach ($needreset as $cmid) {
                $completion->reset_all_state($modinfo->get_cm($cmid));
            }

            // And notify the user of the result.
            \core\notification::add(get_string('activitycompletionupdated', 'core_completion'), \core\notification::SUCCESS);
        }
    }

    /**
     * Applies new completion rules to one course module
     *
     * @param \cm_info $cm
     * @param array $data
     * @param bool $updateinstance if we need to update the instance table of the module (i.e. 'assign', 'forum', etc.) -
     *      if no module-specific completion rules were added to the form, update of the module table is not needed.
     * @return bool if module was updated
     */
    protected function apply_completion_cm(\cm_info $cm, $data, $updateinstance) {
        global $DB;

        $defaults = [
            'completion' => COMPLETION_DISABLED, 'completionview' => COMPLETION_VIEW_NOT_REQUIRED,
            'completionexpected' => 0, 'completiongradeitemnumber' => null,
            'completionpassgrade' => 0
        ];

        $data += ['completion' => $cm->completion,
            'completionexpected' => $cm->completionexpected,
            'completionview' => $cm->completionview];

        if ($cm->completion == $data['completion'] && $cm->completion == COMPLETION_TRACKING_NONE) {
            // If old and new completion are both "none" - no changes are needed.
            return false;
        }

        if ($cm->completion == $data['completion'] && $cm->completion == COMPLETION_TRACKING_NONE &&
                $cm->completionexpected == $data['completionexpected']) {
            // If old and new completion are both "manual" and completion expected date is not changed - no changes are needed.
            return false;
        }

        if (array_key_exists('completionusegrade', $data)) {
            // Convert the 'use grade' checkbox into a grade-item number: 0 if checked, null if not.
            $data['completiongradeitemnumber'] = !empty($data['completionusegrade']) ? 0 : null;
            unset($data['completionusegrade']);
        } else {
            // Completion grade item number is classified in mod_edit forms as 'use grade'.
            $data['completionusegrade'] = is_null($cm->completiongradeitemnumber) ? 0 : 1;
            $data['completiongradeitemnumber'] = $cm->completiongradeitemnumber;
        }

        // Update module instance table.
        if ($updateinstance) {
            $moddata = ['id' => $cm->instance, 'timemodified' => time()] + array_diff_key($data, $defaults);
            $DB->update_record($cm->modname, $moddata);
        }

        // Update course modules table.
        $cmdata = ['id' => $cm->id, 'timemodified' => time()] + array_intersect_key($data, $defaults);
        $DB->update_record('course_modules', $cmdata);

        \core\event\course_module_updated::create_from_cm($cm, $cm->context)->trigger();

        // We need to reset completion data for this activity.
        return true;
    }


    /**
     * Saves default completion from edit form to all selected module types
     *
     * @param stdClass $data data received from the core_completion_bulkedit_form
     * @param bool $updatecustomrules if we need to update the custom rules of the module -
     *      if no module-specific completion rules were added to the form, update of the module table is not needed.
     * @param string $suffix the suffix to add to the name of the completion rules.
     */
    public function apply_default_completion($data, $updatecustomrules, string $suffix = '') {
        global $DB;

        if (!empty($suffix)) {
            // Fields were renamed to avoid conflicts, but they need to be stored in DB with the original name.
            $modules = property_exists($data, 'modules') ? $data->modules : null;
            if ($modules !== null) {
                unset($data->modules);
                $data = (array)$data;
                foreach ($data as $name => $value) {
                    if (str_ends_with($name, $suffix)) {
                        $data[substr($name, 0, strpos($name, $suffix))] = $value;
                        unset($data[$name]);
                    } else if ($name == 'customdata') {
                        $customrules = $value['customcompletionrules'];
                        foreach ($customrules as $rulename => $rulevalue) {
                            if (str_ends_with($rulename, $suffix)) {
                                $customrules[substr($rulename, 0, strpos($rulename, $suffix))] = $rulevalue;
                                unset($customrules[$rulename]);
                            }
                        }
                        $data['customdata'] = $customrules;
                    }
                }
                $data = (object)$data;
            }
        }

        $courseid = $data->id;
        // MDL-72375 Unset the id here, it should not be stored in customrules.
        unset($data->id);
        $coursecontext = context_course::instance($courseid);
        if (!$modids = $data->modids) {
            return;
        }
        $defaults = [
            'completion' => COMPLETION_DISABLED,
            'completionview' => COMPLETION_VIEW_NOT_REQUIRED,
            'completionexpected' => 0,
            'completionusegrade' => 0,
            'completionpassgrade' => 0
        ];

        $data = (array)$data;
        if (!array_key_exists('completionusegrade', $data)) {
            $data['completionusegrade'] = 0;
        }
        if (!array_key_exists('completionpassgrade', $data)) {
            $data['completionpassgrade'] = 0;
        }
        if ($data['completionusegrade'] == 0) {
            $data['completionpassgrade'] = 0;
        }

        if ($updatecustomrules) {
            $customdata = array_diff_key($data, $defaults);
            $data['customrules'] = $customdata ? json_encode($customdata) : null;
            $defaults['customrules'] = null;
        }
        $data = array_merge($defaults, $data);

        // Get names of the affected modules.
        list($modidssql, $params) = $DB->get_in_or_equal($modids);
        $params[] = 1;
        $modules = $DB->get_records_select_menu('modules', 'id ' . $modidssql . ' and visible = ?', $params, '', 'id, name');

        // Get an associative array of [module_id => course_completion_defaults_id].
        list($in, $params) = $DB->get_in_or_equal($modids);
        $params[] = $courseid;
        $defaultsids = $DB->get_records_select_menu('course_completion_defaults', 'module ' . $in . ' and course = ?', $params, '',
                                                      'module, id');

        foreach ($modids as $modid) {
            if (!array_key_exists($modid, $modules)) {
                continue;
            }
            if (isset($defaultsids[$modid])) {
                $DB->update_record('course_completion_defaults', $data + ['id' => $defaultsids[$modid]]);
            } else {
                $defaultsids[$modid] = $DB->insert_record('course_completion_defaults', $data + ['course' => $courseid,
                                                                                                 'module' => $modid]);
            }
            // Trigger event.
            \core\event\completion_defaults_updated::create([
                'objectid' => $defaultsids[$modid],
                'context' => $coursecontext,
                'other' => ['modulename' => $modules[$modid]],
            ])->trigger();
        }

        // Add notification.
        \core\notification::add(get_string('defaultcompletionupdated', 'completion'), \core\notification::SUCCESS);
    }

    /**
     * Returns default completion rules for given module type in the given course
     *
     * @param stdClass $course
     * @param stdClass $module
     * @param bool $flatten if true all module custom completion rules become properties of the same object,
     *   otherwise they can be found as array in ->customdata['customcompletionrules']
     * @param string $suffix the suffix to add to the name of the completion rules.
     * @return stdClass
     */
    public static function get_default_completion($course, $module, $flatten = true, string $suffix = '') {
        global $DB, $CFG, $SITE;

        $fields = 'completion, completionview, completionexpected, completionusegrade, completionpassgrade, customrules';
        // Check course default completion values.
        $params = ['course' => $course->id, 'module' => $module->id];
        $data = $DB->get_record('course_completion_defaults', $params, $fields);
        if (!$data && $course->id != $SITE->id) {
            // If there is no course default completion, check site level default completion values ($SITE->id).
            $params['course'] = $SITE->id;
            $data = $DB->get_record('course_completion_defaults', $params, $fields);
        }
        if ($data) {
            if ($data->customrules && ($customrules = @json_decode($data->customrules, true))) {
                // MDL-72375 This will override activity id for new mods. Skip this field, it is already exposed as courseid.
                unset($customrules['id']);

                if ($flatten) {
                    foreach ($customrules as $key => $value) {
                        $data->$key = $value;
                    }
                } else {
                    $data->customdata['customcompletionrules'] = $customrules;
                }
            }
            unset($data->customrules);
        } else {
            $data = new stdClass();
            $data->completion = COMPLETION_TRACKING_NONE;
        }

        // If the suffix is not empty, the completion rules need to be renamed to avoid conflicts.
        if (!empty($suffix)) {
            $data = (array)$data;
            foreach ($data as $name => $value) {
                if (str_starts_with($name, 'completion')) {
                    $data[$name . $suffix] = $value;
                    unset($data[$name]);
                } else if ($name == 'customdata') {
                    $customrules = $value['customcompletionrules'];
                    foreach ($customrules as $rulename => $rulevalue) {
                        if (str_starts_with($rulename, 'completion')) {
                            $customrules[$rulename . $suffix] = $rulevalue;
                            unset($customrules[$rulename]);
                        }
                    }
                    $data['customdata'] = $customrules;
                }
            }
            $data = (object)$data;
        }

        return $data;
    }

    /**
     * Return a mod_form of the given module.
     *
     * @param string $modname   Module to get the form from.
     * @param stdClass $course  Course object.
     * @param ?cm_info $cm      cm_info object to use.
     * @param string $suffix    The suffix to add to the name of the completion rules.
     * @return ?\moodleform_mod The moodleform_mod object if everything goes fine. Null otherwise.
     */
    public static function get_module_form(
            string $modname,
            stdClass $course,
            ?cm_info $cm = null,
            string $suffix = ''
    ): ?\moodleform_mod {
        global $CFG, $PAGE;

        $modmoodleform = "$CFG->dirroot/mod/$modname/mod_form.php";
        if (file_exists($modmoodleform)) {
            require_once($modmoodleform);
        } else {
            throw new \moodle_exception('noformdesc');
        }

        if ($cm) {
            [$cmrec, $context, $module, $data, $cw] = get_moduleinfo_data($cm, $course);
            $data->update = $modname;
        } else {
            [$module, $context, $cw, $cmrec, $data] = prepare_new_moduleinfo_data($course, $modname, 0, $suffix);
            $data->add = $modname;
        }
        $data->return = 0;
        $data->sr = 0;

        // Initialise the form but discard all JS requirements it adds, our form has already added them.
        $mformclassname = 'mod_'.$modname.'_mod_form';
        $PAGE->start_collecting_javascript_requirements();
        try {
            $moduleform = new $mformclassname($data, 0, $cmrec, $course);
            if (!$cm) {
                $moduleform->set_suffix('_' . $modname);
            }
        } catch (\Exception $e) {
            // The form class has thrown an error when instantiating.
            // This could happen because some conditions for the module are not met.
            $moduleform = null;
        } finally {
            $PAGE->end_collecting_javascript_requirements();
        }

        return $moduleform;
    }
}
