<?php
/**
 * 统计访问量类
 *
 * 表:
 * CREATE TABLE `meng_stats` (
 * `type` char(16) NOT NULL,
 * `variable` char(20) NOT NULL,
 * `count` int(12) unsigned NOT NULL default '0',
 * PRIMARY KEY (`type`,`variable`)
 * ) ENGINE=MyISAM DEFAULT CHARSET=utf8;
 *
 * type:统计类型
 * variable统计标识量
 * count统计值
 *
 */
class Stats {

    /**
     * 统计需要用session
     *
     */
    function __construct() {
        if (session_id() == '') {
            session_start();
        }
    }

    /**
     * 验证该统计是否已经存在
     *
     * @param string $type
     * @param string $variable
     * @return bool
     */
    private function _verify($type, $variable) {
        $sql = "select count from " . $GLOBALS['cms']->table('stats') ."
     where `type` = '$type' and `variable` = '$variable';";
        $qr = $GLOBALS['db']->query($sql);
        if ($rs = $GLOBALS['db']->fetchArray($qr)) {
            return true; // 该统计已经存在

        } else {
            return false; // 该统计尚未存在

        }
    }

    /**
     * 新建统计
     *
     * @param string $type 统计分类
     * @param string $variable 统计标志变量
     * @return bool
     */
    public function _create($type, $variable) {
        $sql = "INSERT INTO " . $GLOBALS['cms']->table('stats') ."
         VALUES ('$type', '$variable', 0);";
        if ($qr = $GLOBALS['db']->query($sql)) {
            return true; // 创建统计成功

        } else {
            return false; // 创建统计失败

        }
    }

    /**
     * 获取统计信息
     *
     * @param string $type
     * @param string $variable
     * @return string
     */
    public function get($type, $variable, $verify = true, $update = true){

        /* 验证是否添加一个统计 */
        if ($verify) {
            /* 如果还没有该统计,则添加 */
            if (!$this->_verify($type, $variable)) {
                $this->_create($type, $variable);
            }
        }

        /* 更新统计 */
        if ($update) {
            $this->_update($type, $variable);
        }

        /* 获取统计信息 */
        $sql = "select count from " . $GLOBALS['cms']->table('stats') ."
     where `type` = '$type' and `variable` = '$variable';";
        $qr = $GLOBALS['db']->query($sql);
        $rs = $GLOBALS['db']->fetchArray($qr);
        return $rs['count'];
    }

    /**
     * 更新统计信息
     *
     * @param string $type
     * @param string $variable
     * @return bool
     */
    private function _update($type, $variable) {
        /* 防刷新 */
        if (isset($_SESSION['stats_' . $type . $variable])) {
            return true; // 函数运行完成,不更新数据库

        } else {
            $_SESSION['stats_' . $type . $variable] = true;
        }

        /* 更新统计 */
        $sql = "UPDATE " . $GLOBALS['cms']->table('stats') ."
         SET `count` = ' ". ($this->get($type, $variable)+1) . "'
         WHERE CONVERT( `type` USING utf8 ) = '$type' AND CONVERT( `variable` USING utf8 ) = '$variable'
         LIMIT 1 ";
        if ($qr = $GLOBALS['db']->query($sql)) {
            return true;
        } else {
            return false;
        }
    }
}

?>