MDL-59395 core_user: move participants table to own class

Removed the edit link variable which was used in the heading
'Users with the role ..' but was never displayed due to filters.

Other minor tidy ups as well.

Part of MDL-59290.

user/lib.php

@@ -1212,3 +1212,177 @@ function user_get_tagged_users($tag, $exclusivemode = false, $fromctx = 0, $ctx
     return new core_tag\output\tagindex($tag, 'core', 'user', $content,
             $exclusivemode, $fromctx, $ctx, $rec, $page, $totalpages);
 }
+
+/**
+ * Returns the SQL used by the participants table.
+ *
+ * @param int $courseid The course id
+ * @param int $groupid The groupid, 0 means all groups
+ * @param int $accesssince The time since last access, 0 means any time
+ * @param int $roleid The role id, 0 means all roles
+ * @param string $search The search that was performed, empty means perform no search
+ * @param string $additionalwhere Any additional SQL to add to where
+ * @param array $additionalparams The additional params
+ * @return array
+ */
+function user_get_participants_sql($courseid, $groupid = 0, $accesssince = 0, $roleid = 0, $search = '', $additionalwhere = '',
+        $additionalparams = array()) {
+    global $DB;
+
+    // Get the context.
+    $context = \context_course::instance($courseid, MUST_EXIST);
+
+    $isfrontpage = ($courseid == SITEID);
+
+    list($esql, $params) = get_enrolled_sql($context, null, $groupid, true);
+
+    $joins = array('FROM {user} u');
+    $wheres = array();
+
+    $userfields = array('username', 'email', 'city', 'country', 'lang', 'timezone', 'maildisplay');
+    $mainuserfields = user_picture::fields('u', $userfields);
+    $extrasql = get_extra_user_fields_sql($context, 'u', '', $userfields);
+
+    if ($isfrontpage) {
+        $select = "SELECT $mainuserfields, u.lastaccess$extrasql";
+        $joins[] = "JOIN ($esql) e ON e.id = u.id"; // Everybody on the frontpage usually.
+        if ($accesssince) {
+            $wheres[] = user_get_user_lastaccess_sql($accesssince);
+        }
+    } else {
+        $select = "SELECT $mainuserfields, COALESCE(ul.timeaccess, 0) AS lastaccess$extrasql";
+        $joins[] = "JOIN ($esql) e ON e.id = u.id"; // Course enrolled users only.
+        // Not everybody has accessed the course yet.
+        $joins[] = 'LEFT JOIN {user_lastaccess} ul ON (ul.userid = u.id AND ul.courseid = :courseid)';
+        $params['courseid'] = $courseid;
+        if ($accesssince) {
+            $wheres[] = user_get_course_lastaccess_sql($accesssince);
+        }
+    }
+
+    // Performance hacks - we preload user contexts together with accounts.
+    $ccselect = ', ' . context_helper::get_preload_record_columns_sql('ctx');
+    $ccjoin = 'LEFT JOIN {context} ctx ON (ctx.instanceid = u.id AND ctx.contextlevel = :contextlevel)';
+    $params['contextlevel'] = CONTEXT_USER;
+    $select .= $ccselect;
+    $joins[] = $ccjoin;
+
+    // Limit list to users with some role only.
+    if ($roleid) {
+        // We want to query both the current context and parent contexts.
+        list($relatedctxsql, $relatedctxparams) = $DB->get_in_or_equal($context->get_parent_context_ids(true),
+            SQL_PARAMS_NAMED, 'relatedctx');
+
+        $wheres[] = "u.id IN (SELECT userid FROM {role_assignments} WHERE roleid = :roleid AND contextid $relatedctxsql)";
+        $params = array_merge($params, array('roleid' => $roleid), $relatedctxparams);
+    }
+
+    if (!empty($search)) {
+        $fullname = $DB->sql_fullname('u.firstname', 'u.lastname');
+        $wheres[] = '(' . $DB->sql_like($fullname, ':search1', false, false) .
+            ' OR ' . $DB->sql_like('email', ':search2', false, false) .
+            ' OR ' . $DB->sql_like('idnumber', ':search3', false, false) . ') ';
+        $params['search1'] = "%$search%";
+        $params['search2'] = "%$search%";
+        $params['search3'] = "%$search%";
+    }
+
+    if (!empty($additionalwhere)) {
+        $wheres[] = $additionalwhere;
+        $params = array_merge($params, $additionalparams);
+    }
+
+    $from = implode("\n", $joins);
+    if ($wheres) {
+        $where = 'WHERE ' . implode(' AND ', $wheres);
+    } else {
+        $where = '';
+    }
+
+    return array($select, $from, $where, $params);
+}
+
+/**
+ * Returns the total number of participants for a given course.
+ *
+ * @param int $courseid The course id
+ * @param int $groupid The groupid, 0 means all groups
+ * @param int $accesssince The time since last access, 0 means any time
+ * @param int $roleid The role id, 0 means all roles
+ * @param string $search The search that was performed, empty means perform no search
+ * @param string $additionalwhere Any additional SQL to add to where
+ * @param array $additionalparams The additional params
+ * @return int
+ */
+function user_get_total_participants($courseid, $groupid = 0, $accesssince = 0, $roleid = 0, $search = '', $additionalwhere = '',
+        $additionalparams = array()) {
+    global $DB;
+
+    list($select, $from, $where, $params) = user_get_participants_sql($courseid, $groupid, $accesssince, $roleid,
+        $search, $additionalwhere, $additionalparams);
+
+    return $DB->count_records_sql("SELECT COUNT(u.id) $from $where", $params);
+}
+
+/**
+ * Returns the participants for a given course.
+ *
+ * @param int $courseid The course id
+ * @param int $groupid The group id
+ * @param int $accesssince The time since last access
+ * @param int $roleid The role id
+ * @param string $search The search that was performed
+ * @param string $additionalwhere Any additional SQL to add to where
+ * @param array $additionalparams The additional params
+ * @param string $sort The SQL sort
+ * @param int $limitfrom return a subset of records, starting at this point (optional).
+ * @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
+ * @return moodle_recordset
+ */
+function user_get_participants($courseid, $groupid = 0, $accesssince, $roleid, $search, $additionalwhere = '',
+        $additionalparams = array(), $sort = '', $limitfrom = 0, $limitnum = 0) {
+    global $DB;
+
+    list($select, $from, $where, $params) = user_get_participants_sql($courseid, $groupid, $accesssince, $roleid,
+        $search, $additionalwhere, $additionalparams);
+
+    return $DB->get_recordset_sql("$select $from $where $sort", $params, $limitfrom, $limitnum);
+}
+
+/**
+ * Returns SQL that can be used to limit a query to a period where the user last accessed a course.
+ *
+ * @param int $accesssince The time since last access
+ * @param string $tableprefix
+ * @return string
+ */
+function user_get_course_lastaccess_sql($accesssince = null, $tableprefix = 'ul') {
+    if (empty($accesssince)) {
+        return '';
+    }
+
+    if ($accesssince == -1) { // Never.
+        return $tableprefix . '.timeaccess = 0';
+    } else {
+        return $tableprefix . '.timeaccess != 0 AND ul.timeaccess < ' . $accesssince;
+    }
+}
+
+/**
+ * Returns SQL that can be used to limit a query to a period where the user last accessed the system.
+ *
+ * @param int $accesssince The time since last access
+ * @param string $tableprefix
+ * @return string
+ */
+function user_get_user_lastaccess_sql($accesssince = null, $tableprefix = 'u') {
+    if (empty($accesssince)) {
+        return '';
+    }
+
+    if ($accesssince == -1) { // Never.
+        return $tableprefix . '.lastaccess = 0';
+    } else {
+        return $tableprefix . '.lastaccess != 0 AND u.lastaccess < ' . $accesssince;
+    }
+}