function validation($data)
{
global $USER;
$errorlog = array();
$form_errorlog = $this->_form->_errors;
// Skip processing group if there were errors with any of the related group fields
if ($form_errorlog[TEXTBOX_GROUP] || $form_errorlog[SECTIONSID_FIELD]) {
return $errorlog;
}
// Parse form submission and glean necessary information
$section_id = $data[SECTIONSID_FIELD];
$department = $data[DEPARTMENT_FIELD];
$course_number = $data[COURSE_NUMBER_FIELD];
$section_number = $data[SECTION_NUMBER_FIELD];
// Build sections ID to courses ID lookup for data validation
$user = CoursePrefsUser::findByUnique($USER->username);
$sections = $user->getSectionsAsTeacher();
// Log an error if the user isn't the primary teacher of the section selected
if (!($sections[$section_id] && $user->isPrimaryTeacher($sections[$section_id]))) {
$errorlog[TEXTBOX_GROUP] = get_string('err_not_primary', 'block_courseprefs');
return $errorlog;
}
// Log an error if the section selected doesn't exist
$users_section = $sections[$section_id];
if (!$users_section) {
$errorlog[TEXTBOX_GROUP] = get_string('err_unknown_section', 'block_courseprefs');
return $errorlog;
}
// Retrieve course related to critera and log an error if course doesn't exist
$course = CoursePrefsCourse::findByUnique($department, $course_number);
if (!$course) {
$errorlog[TEXTBOX_GROUP] = get_string('err_unknown_course', 'block_courseprefs');
return $errorlog;
}
// Retrieve section related to critera and log an error if course doesn't exist
$section = CoursePrefsSection::findByUnique($users_section->getSemestersId(), $course->getId(), $section_number);
if (!$section) {
$errorlog[TEXTBOX_GROUP] = get_string('err_unknown_section', 'block_courseprefs');
return $errorlog;
}
// Log an error if the user has already selected these sections to be team taught
if (CoursePrefsTeamTeach::findByUnique($user->getId(), $users_section->getId(), $section->getId())) {
$errorlog[TEXTBOX_GROUP] = get_string('err_same_teamteach', 'block_courseprefs');
return $errorlog;
}
// Determine the primary teacher of the foreign section
$teachers = CoursePrefsTeacher::findBySectionId($section->getId());
$teacher_primary = null;
foreach ($teachers as $teacher) {
// Skip if teacher is not the primary teacher
if (!$teacher->getPrimaryFlag()) {
continue;
}
$teacher_primary = $teacher;
break;
}
// Log an error if there isn't a primary teacher to notify or if the user teaches both courses.
// Otherwise, store the ids of the sections selected for team teaching
if (!$teacher_primary) {
$errorlog[TEXTBOX_GROUP] = get_string('no_instructor', 'block_courseprefs');
} else {
if ($teacher_primary->getUsersId() == $user->getId()) {
$errorlog[TEXTBOX_GROUP] = get_string('same_teacher', 'block_courseprefs');
} else {
$this->section_selections = $section_id;
$this->secondary_teamteaches = $section->getId();
}
}
return $errorlog;
}
