<?php

require_once($CFG->dirroot.'/user/filters/lib.php');

/**
 * Generic filter based on a list of values.
 */
class user_filter_select extends user_filter_type {
    /**
     * options for the list values
     */
    var $_options;

    var $_field;

    var $_default;

    /**
     * Constructor
     * @param string $name the name of the filter instance
     * @param string $label the label of the filter instance
     * @param boolean $advanced advanced form element flag
     * @param string $field user table filed name
     * @param array $options select options
     * @param mixed $default option
     */
    function user_filter_select($name, $label, $advanced, $field, $options, $default=null) {
        parent::user_filter_type($name, $label, $advanced);
        $this->_field   = $field;
        $this->_options = $options;
        $this->_default = $default;
    }

    /**
     * Returns an array of comparison operators
     * @return array of comparison operators
     */
    function get_operators() {
        return array(0 => get_string('isanyvalue','filters'),
                     1 => get_string('isequalto','filters'),
                     2 => get_string('isnotequalto','filters'));
    }

    /**
     * Adds controls specific to this filter in the form.
     * @param object $mform a MoodleForm object to setup
     */
    function setupForm(&$mform) {
        $objs = array();
        $objs[] =& $mform->createElement('select', $this->_name.'_op', null, $this->get_operators());
        $objs[] =& $mform->createElement('select', $this->_name, null, $this->_options);
        $grp =& $mform->addElement('group', $this->_name.'_grp', $this->_label, $objs, '', false);
        $mform->disabledIf($this->_name, $this->_name.'_op', 'eq', 0);
        if (!is_null($this->_default)) {
            $mform->setDefault($this->_name, $this->_default);
        }
        if ($this->_advanced) {
            $mform->setAdvanced($this->_name.'_grp');
        }
    }

    /**
     * Retrieves data from the form data
     * @param object $formdata data submited with the form
     * @return mixed array filter data or false when filter not set
     */
    function check_data($formdata) {
        $field    = $this->_name;
        $operator = $field.'_op';

        if (array_key_exists($field, $formdata) and !empty($formdata->$operator)) {
            return array('operator' => (int)$formdata->$operator,
                         'value'    => (string)$formdata->$field);
        }

        return false;
    }

    /**
     * Returns the condition to be used with SQL where
     * @param array $data filter settings
     * @return array sql string and $params
     */
    function get_sql_filter($data) {
        static $counter = 0;
        $name = 'ex_select'.$counter++;

        $operator = $data['operator'];
        $value    = $data['value'];
        $field    = $this->_field;

        $params = array();

        switch($operator) {
            case 1: // equal to
                $res = "=:$name";
                $params[$name] = $value;
                break;
            case 2: // not equal to
                $res = "<>:$name";
                $params[$name] = $value;
                 break;
            default:
                return array('', array());
        }
        return array($field.$res, $params);
    }

    /**
     * Returns a human friendly description of the filter used as label.
     * @param array $data filter settings
     * @return string active filter label
     */
    function get_label($data) {
        $operators = $this->get_operators();
        $operator  = $data['operator'];
        $value     = $data['value'];

        if (empty($operator)) {
            return '';
        }

        $a = new stdClass();
        $a->label    = $this->_label;
        $a->value    = '"'.s($this->_options[$value]).'"';
        $a->operator = $operators[$operator];

        return get_string('selectlabel', 'filters', $a);
    }
}