<?php

class DI

{

    private $container;

    public function set($key, $obj, ...$args)

    {

        $this->container[$key] = [

            'obj'    => $obj,

            'params' => $args

        ];

    }

    public function delete($key)

    {

        unset($this->container[$key]);

    }

    public function clear()

    {

        $this->container = [];

    }

    public function get($key)

    {

        if (isset($this->container[$key])) {

            $res = $this->container[$key];

            if (is_object($res['obj']) && !is_callable($res['obj'])) {

                return $res['obj'];

            } elseif (is_callable($res['obj'])) {

                $this->container[$key]['obj'] = call_user_func($res['obj']);

                return $this->container[$key]['obj'];

            } elseif (is_string($res['obj']) && class_exists($res['obj'])) {

                $reflection                   = new \ReflectionClass ($res['obj']);

                $ins                          = $reflection->newInstanceArgs($res['params']);

                $this->container[$key]['obj'] = $ins;

                return $this->container[$key]['obj'];

            } else {

                return $res['obj'];

            }

        } else {

            return null;

        }

    }

}

class Test1

{

    public function show()

    {

        echo "hello World \n";

    }

}

class Test2

{

    public function __construct($name)

    {

        echo '我是参数' . $name . PHP_EOL;

    }

    function show()

    {

        echo "我是test2";

    }

}

class Test4

{

    public function show()

    {

        echo "test4";

    }

}

$DI = new DI();

$DI->set('name', 'zhangsan');

echo "注入字符串" . $DI->get('name') . PHP_EOL;

$test1 = new Test1();

$DI->set('test1', $test1);

echo "获取对象" . $DI->get('test1')->show() . PHP_EOL;

$DI->set('test2', Test2::class, 'zhangsa');

$DI->get('test2')->show();

$DI->set('test3', function () {

    return new Test4();

});

$DI->get('test3')->show();