<?php



// +----------------------------------------------------------------------

// | EcTouch [ 专注移动电商: 商创网络科技 ]

// +----------------------------------------------------------------------

// | Copyright (c) 2014 http://ectouch.cn All rights reserved.

// +----------------------------------------------------------------------

// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )

// +----------------------------------------------------------------------

// | Author: EcTouch Team <zhong@ecmoban.com> (QQ: 2880175560)

// +----------------------------------------------------------------------



//模型类，加载了外部的数据库驱动类和缓存类

class EcModel {



    public $db = NULL; // 当前数据库操作对象

    public $cache = NULL; //缓存对象

    public $sql = ''; //sql语句，主要用于输出构造成的sql语句

    public $pre = ''; //表前缀，主要用于在其他地方获取表前缀

    public $config = array(); //配置

    protected $options = array(); // 查询表达式参数	



    public function __construct($config = array()) {

        $this->config = array_merge(EcConfig::get('DB'), $config); //参数配置	

        $this->options['field'] = '*'; //默认查询字段

        $this->pre = $this->config['DB_PREFIX']; //数据表前缀

        $this->connect();

    }



    //连接数据库

    public function connect() {

        $dbDriver = 'Ec' . ucfirst($this->config['DB_TYPE']);

        require_once( dirname(__FILE__) . '/driver/' . $dbDriver . '.class.php' );

        $this->db = new $dbDriver($this->config); //实例化数据库驱动类	  

    }



    //设置表，$$ignore_prefix为true的时候，不加上默认的表前缀

    public function table($table, $ignorePre = false) {

        if ($ignorePre) {

            $this->options['table'] = $table;

        } else {

            $this->options['table'] = $this->config['DB_PREFIX'] . $table;

        }

        return $this;

    }



    //回调方法，连贯操作的实现

    public function __call($method, $args) {

        $method = strtolower($method);

        if (in_array($method, array('field', 'data', 'where', 'group', 'having', 'order', 'limit', 'cache'))) {

            $this->options[$method] = $args[0]; //接收数据

            if ($this->options['field'] == '')

                $this->options['field'] = '*';

            return $this; //返回对象，连贯查询

        } else {

            throw new Exception($method . '方法在EcModel.class.php类中没有定义');

        }

    }



    //执行原生sql语句，如果sql是查询语句，返回二维数组

    public function query($sql, $params = array(), $is_query = false) {

        if (empty($sql))

            return false;

        $sql = str_replace('{pre}', $this->pre, $sql); //表前缀替换

        $this->sql = $sql;

        //判断当前的sql是否是查询语句

        if ($is_query || stripos(trim($sql), 'select') === 0) {

            $data = $this->_readCache();

            if (!empty($data))

                return $data;



            $query = $this->db->query($this->sql, $params);

            while ($row = $this->db->fetchArray($query)) {

                $data[] = $row;

            }

            $this->_writeCache($data);

            return $data;

        } else {

            return $this->db->execute($this->sql, $params); //不是查询条件，直接执行

        }

    }



    //统计行数

    public function count() {

        $table = $this->options['table']; //当前表

        $field = 'count(*)'; //查询的字段

        $where = $this->_parseCondition(); //条件

        $this->sql = "SELECT $field FROM $table $where"; //这不是真正执行的sql，仅作缓存的key使用



        $data = $this->_readCache();

        if (!empty($data))

            return $data;



        $data = $this->db->count($table, $where);

        $this->_writeCache($data);

        $this->sql = $this->db->sql; //从驱动层返回真正的sql语句，供调试使用

        return $data;

    }



    //只查询一条信息，返回一维数组	

    public function find() {

        $this->options['limit'] = 1; //限制只查询一条数据

        $data = $this->select();

        return isset($data[0]) ? $data[0] : false;

    }



    //查询多条信息，返回数组

    public function select() {

        $table = $this->options['table']; //当前表

        $field = $this->options['field']; //查询的字段

        $where = $this->_parseCondition(); //条件

        return $this->query("SELECT $field FROM $table $where", array(), true);

    }



    //获取一张表的所有字段

    public function getFields() {

        $table = $this->options['table'];

        $this->sql = "SHOW FULL FIELDS FROM {$table}"; //这不是真正执行的sql，仅作缓存的key使用



        $data = $this->_readCache();

        if (!empty($data))

            return $data;



        $data = $this->db->getFields($table);

        $this->_writeCache($data);

        $this->sql = $this->db->sql; //从驱动层返回真正的sql语句，供调试使用

        return $data;

    }



    //插入数据

    public function insert($replace = false) {

        $table = $this->options['table']; //当前表

        $data = $this->_parseData('add'); //要插入的数据

        $INSERT = $replace ? 'REPLACE' : 'INSERT';

        $this->sql = "$INSERT INTO $table $data";

        $query = $this->db->execute($this->sql);

        if ($this->db->affectedRows()) {

            $id = $this->db->lastId();

            return empty($id) ? $this->db->affectedRows() : $id;

        }

        return false;

    }



    //替换数据

    public function replace() {

        return $this->insert(true);

    }



    //修改更新

    public function update() {

        $table = $this->options['table']; //当前表

        $data = $this->_parseData('save'); //要更新的数据

        $where = $this->_parseCondition(); //更新条件

        if (empty($where))

            return false; //修改条件为空时，则返回false，避免不小心将整个表数据修改了



        $this->sql = "UPDATE $table SET $data $where";

        $query = $this->db->execute($this->sql);

        return $this->db->affectedRows();

    }



    //删除

    public function delete() {

        $table = $this->options['table']; //当前表

        $where = $this->_parseCondition(); //条件

        if (empty($where))

            return false; //删除条件为空时，则返回false，避免数据不小心被全部删除



        $this->sql = "DELETE FROM $table $where";

        $query = $this->db->execute($this->sql);

        return $this->db->affectedRows();

    }



    //数据过滤

    public function escape($value) {

        return $this->db->escape($value);

    }



    //返回sql语句

    public function getSql() {

        return $this->sql;

    }



    //删除数据库缓存

    public function clear() {

        if ($this->initCache()) {

            return $this->cache->clear();

        }

        return false;

    }



    //初始化缓存类，如果开启缓存，则加载缓存类并实例化

    public function initCache() {

        if (is_object($this->cache)) {

            return true;

        } else if ($this->config['DB_CACHE_ON']) {

            require_once( dirname(__FILE__) . '/EcCache.class.php' );

            $this->cache = new EcCache($this->config, $this->config['DB_CACHE_TYPE']);

            return true;

        } else {

            return false;

        }

    }



    //读取缓存

    private function _readCache() {

        isset($this->options['cache']) or $this->options['cache'] = $this->config['DB_CACHE_TIME'];

        //缓存时间为0，不读取缓存

        if ($this->options['cache'] == 0)

            return false;

        if ($this->initCache()) {

            $data = $this->cache->get($this->sql);

            if (!empty($data)) {

                unset($this->options['cache']);

                return $data;

            }

        }

        return false;

    }



    //写入缓存

    private function _writeCache($data) {

        //缓存时间为0，不设置缓存

        if ($this->options['cache'] == 0)

            return false;

        if ($this->initCache()) {

            $expire = $this->options['cache'];

            unset($this->options['cache']);

            return $this->cache->set($this->sql, $data, $expire);

        }

        return false;

    }



    //解析数据  

    private function _parseData($type) {

        $data = $this->db->parseData($this->options, $type);

        $this->options['data'] = '';

        return $data;

    }



    //解析条件

    private function _parseCondition() {

        $condition = $this->db->parseCondition($this->options);

        $this->options['where'] = '';

        $this->options['group'] = '';

        $this->options['having'] = '';

        $this->options['order'] = '';

        $this->options['limit'] = '';

        $this->options['field'] = '*';

        return $condition;

    }



}