<?php

// $config= [
//  'DB_HOST'=>'localhost',
//  'DB_USER'=>'root',
//  'DB_PWD'=>'root',
//  'DB_NAME'=>'test',
//  'DB_CHARSET'=>'utf8',
//  'DB_PREFIX'=>'php34_'

// ];
 //$m = new Model($config);
// $data = ['age'=>20,'name'=>'老王'];
// $insertId=$m ->table('php34_demo')->insert($data);
// var_dump($insertId);

//var_dump($m->table('php34_demo')->where('id=3')->delete());

// $data = ['age'=>33];
// var_dump($m->table('php34_demo')->where('id=1')->update($data));

// var_dump($m->table('php34_demo')->max('age'));
//var_dump($m->getByName('小红'));

class Model{

    protected $host;
    protected $user;
    protected $pwd;
    protected $dbname;
    protected $charset;
    protected $prefix;
    protected $link;
    protected $tableName;
    protected $sql;
    //存放所有查询条件的
    protected $options;

    //构造方法，对成员变量进行初始化、
    function __construct($config){
        $this->host = $config['DB_HOST'];
        $this->user = $config['DB_USER'];
        $this->pwd = $config['DB_PWD'];
        $this->dbname = $config['DB_NAME'];
        $this->charset = $config['DB_CHARSET'];
        $this->prefix = $config['DB_PREFIX'];

        //链接数据库
        $this->link =$this->connect();

        //得到数据表名
        $this->tableName = $this->getTableName();

        //初始化options数组
        $this->initOptions();


    }
    protected function connect(){
        $link = mysqli_connect($this->host,$this->user,$this->pwd);
        if(!$link){
            die('数据库连接失败');
        }
        mysqli_select_db($link,$this->dbname);
        mysqli_set_charset($link,$this->charset);
        return $link;
    }
    protected function getTableName(){
        //1,如何设置了成员变量，那么通过成员变量来得到表名
        if(!empty($this->tableName)){
            return $this->prefix.$this->tableName;
        }
        //2.如果没有设置成员变量，通过类名获得
        $className = get_class($this);
        //user  UserModel
        $table = strtolower( substr($className, 0,-5));
        return $this->prefix.$table;
    }

    protected function initOptions(){
        $arr = ['where','table','field','order','group','having','limit'];
        //将options数组中这些键对应的值全部清空
        foreach($arr as $value){
            $this->options[$value] = '';
            //将table默认设置为tableName
            if($value == 'table'){
                $this->options[$value] = $this->tableName;
            }else if($value == 'field'){
                $this->options[$value] = '*';
            }

        }
    }

    //field方法
    function field($field){
        //如果不为空，在进行处理
        if(!empty($field)){
            if(is_string($field)){
                $this->options['field']=$field;
            }else if(is_array($field)){
                $this->options['field']= join(',',$field);
            }
        }
        return $this;
    }

    //table方法

    function table($table){
        if(!empty($table)){
            $this->options['table'] = $table;
        }
        return $this;
    }
    //where

    function where($where){
        if(!empty($where)){
            $this->options['where'] = 'where '. $where;
        }
        return $this;
    }
    //group方法
    function group($group){
        if(!empty($group)){
            $this->options['group'] = 'group by '. $group;
        }
        return $this;
    }

    //having方法
    function having($having){
        if(!empty($having)){
            $this->options['having'] = 'having '. $having;
        }
        return $this;
    }
    //order方法
    function order($order){
        if(!empty($order)){
            $this->options['order'] = 'order by '. $order;
        }
        return $this;
    }
    //limit方法
    function limit($limit){
        if(!empty($limit)){
            if(is_string($limit)){
            $this->options['limit'] = 'limit '. $limit;
        }else if(is_array($limit)){
            $this->options['limit'] = 'limit '. join(',',$limit);
            }
        }
        return $this;
    }
    //select
    function select(){
        //先写一个带有占位符的sql语句

        $sql = 'select %FIELD% from %TABLE% %WHERE% %GROUP% %HAVING% %ORDER% %LIMIT%';
        //将options中对应的值依次的替换上面的占位符

        $sql = str_replace(['%FIELD%','%TABLE%','%WHERE%','%GROUP%','%HAVING%','%ORDER%','%LIMIT%'],[$this->options['field'],$this->options['table'],$this->options['where'],$this->options['group'],$this->options['having'],$this->options['order'],$this->options['limit']],$sql);
        //保存一份sql语句
        $this->sql = $sql;
        var_dump($sql);
        die();
        //执行sql语句
        return $this->query($sql);
    }
    //query
    function query($sql){
        //清空options数组
        $this->initOptions();
    
        $result = mysqli_query($this->link,$sql);
            if($result && mysqli_affected_rows($this->link)){
                while($data = mysqli_fetch_assoc($result)){
                    $newData[] = $data;
                        
                }
        
            }

            return $newData;
        

    }
    //exec

        function __get($name){
            if($name == 'sql'){
                return $this->sql;
            }
            return false;
        }

            //$data关联数组，键是字段名，值是字段值
        function insert($data){
            //处理字符串问题，两边需要添加单或双引号
            $data = $this->parseValue($data);
            //提取所有的键，即提取所有的字段
            $keys = array_keys($data);
            //提取所有的值
            $values = array_values($data);

            $sql = 'insert into %TABLE%(%FIELD%) values(%VALUES%)';

            $sql = str_replace(['%TABLE%','%FIELD%','%VALUES%'], [$this->options['table'],join(',',$keys),join(',',$values)], $sql);
            $this->sql = $sql;
            return $this->exec($sql,true);
        }

        function exec($sql,$isInsert = false){
            //清空options数组
            $this->initOptions();

            $result = mysqli_query($this->link,$sql);
            if($result && mysqli_affected_rows($this->link)){
                //判断是否是插入语句，是就插入
                if($isInsert){
                    return mysqli_insert_id($this->link);
                }else{
                    return mysqli_affected_rows($this->link);
                }
            }


        }
        //传递进来一个数组，将数组中值为字符串的两边加上引号

        protected function parseValue($data){
            foreach($data as $key=>$value){
                if(is_string($value)){
                    $value = '"'.$value.'"';
                }
                $newData[$key] = $value;
            }
            return $newData;
        }

        //删除函数

        function delete(){
            $sql = 'delete from %TABLE% %WHERE%';
            $sql = str_replace(['%TABLE%','%WHERE%'], [$this->options['table'],$this->options['where']], $sql);
            $this->sql = $sql;
            return $this->exec($sql);
        }

        //更新函数
            //update 表名 set 字段名=字段值，字段名=字段值 where 
        function update($data){
            //处理$data数组中值为字符串加引号的问题
            $data = $this->parseValue($data);

            $value = $this->parseUpdate($data);

            $sql = 'update %TABLE% set %VALUE% %WHERE%';
            $sql = str_replace(['%TABLE%','%VALUE%','%WHERE%'], [$this->options['table'],$value,$this->options['where']], $sql);
            $this->sql = $sql;
            return $this->exec($sql);

        }

        protected function parseUpdate($data){
            foreach ($data as $key => $value) {
                $newData[] = $key.'='.$value;
            }
            return join(',',$newData);
        }

        function max($field){
            $result = $this->field('max('.$field.') as max')->select();
            //select 方法返回的事一个二维数组
            return $result[0]['max'];
        }

        function __destruct(){
            mysqli_close($this->link);
        }
        //getByName,getByAge
        function __call($name ,$args){
            //获取前5个字符

            $str = substr($name, 0,5);
            $field=strtolower(substr($name,5));
            //判断前五个字符是否是getBy
            if($str == 'getBy'){
                return $this->where($field.'="'.$args[0].'"')->select();
            }
            return false;
        }
}