<?php

/*
 * The Filter class contains all functions relating to filtering,
 * the removing of documents from the result set
*/

class filter {

    public function __construct() {
    }

    public function execute($docs, $filter) {
        foreach ($filter['basic'] as $current_filter) {
            if (!is_array($current_filter) || !$current_filter) {
                continue;
            }
            $docs = $this->_basicFilter($docs, $this->_getParams($current_filter));
        }
        foreach ($filter['custom'] as $current_filter) {
            $docs = array_filter($docs, $current_filter);
        }
        return $docs;
    }

    private function _basicFilter($docs, $param) {
        foreach($docs as $i=>$doc) {
            $unset = $this->isTrue($doc, $param);
            if($param['flip_mode']) {
                $unset = !$unset;
            }
            if($unset) {
                unset($docs[$i]);
            }
        }
        return $docs;
    }

    private function _getParams($param) {
        global $modx;

        $rs = array();
        $op = $this->_get_operator_name($param['mode']);
        if(!$op) {
            $op = $this->_get_operator_name($param['value']);
            if($op) {
                $param['value'] = $param['mode'];
            } else {
                $op = '9';
            }
        }
        $rs['op'] = $op;

        if(stripos($param['value'], '@EVAL') === 0) {
            $eval_code = trim(
                substr($param['value'],6)
                , ';'
            ) . ';';
            if(strpos($eval_code,'return')===false) {
                $eval_code = 'return ' . $eval_code;
            }
            $rs['creteria'] = eval($eval_code);
        } else {
            $rs['creteria'] = $param['value'];
        }

        if(strpos($rs['creteria'],'[+') !== false) {
            $rs['creteria'] = $modx->mergePlaceholderContent($rs['creteria']);
        }

        $rs['creteria'] = trim($rs['creteria']);

        if ($this->is_datetime_field($param['source'])) {
            if (!preg_match('@^[0-9]+$@',$rs['creteria'])) {
                $rs['creteria'] = strtotime($rs['creteria']);
            }
        }

        $rs['field_name'] = $param['source'];

        if (strpos($rs['op'], '!') !== 0 || strpos($rs['op'], '!!') === 0) {
            $rs['flip_mode'] = 0;
            return $rs;
        }
        $rs['flip_mode'] = 1;
        $rs['op'] = substr($rs['op'], 1);
        if ($rs['op'] === '=') {
            $rs['op'] = '==';
        }

        return $rs;
    }

    private function isTrue($doc, $param) {
        $field_name = $param['field_name'];
        $doc_value = isset($doc[$field_name]) ? $doc[$field_name] : false;
        $creteria = $param['creteria'];

        switch ($param['op']) {
            case '!=' : return ($doc_value != $creteria || $doc_value===false);
            case '==' : return ($doc_value == $creteria);
            case '<'  : return ($doc_value <  $creteria);
            case '>'  : return ($doc_value >  $creteria);
            case '>=' : return ($doc_value >= $creteria);
            case '<=' : return ($doc_value <= $creteria);
            case '=~' : return (strpos($doc_value, $creteria)===false);
            case '!~' : return (strpos($doc_value, $creteria)!==false);
            case 9    : return (stripos($doc_value, $creteria)===false);
            case 10   : return (stripos($doc_value, $creteria)!==false);
            case 'regex': return (preg_match($doc_value, $creteria)===false);
            case 11   :
                $firstChr = strtoupper(substr($doc_value, 0, 1));
                return ($firstChr!=$creteria);
        }
        return false;
    }

    private function _get_operator_name($op) {
        if (in_array($op, array('!=','1','<>','ne'),true))  return '!=';
        if (in_array($op, array('==',2,'eq')))       return '==';
        if (in_array($op, array('<',3,'lt')))        return '<';
        if (in_array($op, array('<=',6,'lte','le'))) return '<=';
        if (in_array($op, array('>',4,'gt')))        return '>';
        if (in_array($op, array('>=',5,'gte','ge'))) return '>=';
        if (in_array($op, array('regex','preg')))    return 'regex';
        if (in_array($op, array('=~',7,'find','search','strpos'))) return '=~';
        if (in_array($op, array('!=~',8,'!~','!find','!search','!strpos'))) return '!=~';
        return false;
    }

    private function is_datetime_field($field_name='') {
        if(in_array($field_name, explode(',','pub_date,unpub_date'))) {
            return true;
        };
        if(in_array($field_name, explode(',','published,createdon,editedon,publishedon,deletedon'))) {
            return true;
        };
        return false;
    }
}