<?php
/** .-------------------------------------------------------------------
 * | Software: [HDCMS framework]
 * | Site: www.hdcms.com
 * |-------------------------------------------------------------------
 * | Author: 向军 <2300071698@qq.com>
 * | WeChat: aihoudun
 * | Copyright (c) 2012-2019, www.houdunwang.com. All Rights Reserved.
 * '-------------------------------------------------------------------*/
namespace hdphp\kernel;

use Closure;
use ArrayAccess;
use Exception;
use ReflectionClass;

class Container implements ArrayAccess {

 //绑定实例
 public $bindings = [ ];

 //单例服务
 public $instances = [ ];

 /**
 * 服务绑定到容器
 *
 * @param $name 服务名
 * @param $closure 返回服务对象的闭包函数
 * @param bool $force 是否单例
 */
 public function bind( $name, $closure, $force = FALSE ) {
 $this->bindings[ $name ] = compact( 'closure', 'force' );
 }

 /**
 * 注册单例服务
 *
 * @param $name 服务
 * @param $closure 闭包函数
 */
 public function single( $name, $closure ) {
 $this->bind( $name, $closure, TRUE );
 }

 /**
 * 单例服务
 *
 * @param $name 名称
 * @param $object 对象
 */
 public function instance( $name, $object ) {
 $this->instances[ $name ] = $object;
 }

 /**
 * 获取服务实例
 *
 * @param $name 服务名
 * @param bool|false $force 单例
 *
 * @return Object
 * @throws Exception
 */
 public function make( $name, $force = FALSE ) {
 if ( isset( $this->instances[ $name ] ) ) {
 return $this->instances[ $name ];
 }
 //获得实现提供者
 $closure = $this->getClosure( $name );
 //获取实例
 $object = $this->build( $closure );
 //单例绑定
 if ( isset( $this->bindings[ $name ]['force'] ) && $this->bindings[ $name ]['force'] || $force ) {
 $this->instances[ $name ] = $object;
 }

 return $object;
 }

 /**
 * 获得实例实现
 *
 * @param $name 创建实例方式:类名或闭包函数
 *
 * @return mixed
 */
 private function getClosure( $name ) {
 return isset( $this->bindings[ $name ] ) ? $this->bindings[ $name ]['closure'] : $name;
 }

 /**
 * 生成服务实例
 *
 * @param $className 生成方式 类或闭包函数
 *
 * @return object
 * @throws Exception
 */
 protected function build( $className ) {
 //匿名函数
 if ( $className instanceof Closure ) {
 //执行闭包函数
 return $className( $this );
 }
 //获取类信息
 $reflector = new ReflectionClass( $className );
 // 检查类是否可实例化, 排除抽象类abstract和对象接口interface
 if ( ! $reflector->isInstantiable() ) {
 throw new Exception( "$className 不能实例化." );
 }
 //获取类的构造函数
 $constructor = $reflector->getConstructor();
 //若无构造函数,直接实例化并返回
 if ( is_null( $constructor ) ) {
 return new $className;
 }
 //取构造函数参数,通过 ReflectionParameter 数组返回参数列表
 $parameters = $constructor->getParameters();
 //递归解析构造函数的参数
 $dependencies = $this->getDependencies( $parameters );

 //创建一个类的新实例,给出的参数将传递到类的构造函数。
 return $reflector->newInstanceArgs( $dependencies );
 }

 /**
 * 递归解析构造函数的参数
 *
 * @param $parameters
 *
 * @return array
 * @throws Exception
 */
 protected function getDependencies( $parameters ) {
 $dependencies = [ ];

 //参数列表
 foreach ( $parameters as $parameter ) {
 //获取参数类型
 $dependency = $parameter->getClass();

 if ( is_null( $dependency ) ) {
 // 是变量,有默认值则设置默认值
 $dependencies[] = $this->resolveNonClass( $parameter );
 } else {
 // 是一个类,递归解析
 $dependencies[] = $this->build( $dependency->name );
 }
 }

 return $dependencies;
 }

 /**
 * 提取参数默认值
 *
 * @param $parameter
 *
 * @return mixed
 * @throws Exception
 */
 protected function resolveNonClass( $parameter ) {
 // 有默认值则返回默认值
 if ( $parameter->isDefaultValueAvailable() ) {
 return $parameter->getDefaultValue();
 }

 throw new Exception( '参数无默认值,无法实例化' );
 }

 public function offsetExists( $key ) {
 return isset( $this->bindings[ $key ] );
 }

 public function offsetGet( $key ) {
 return $this->make( $key );
 }

 public function offsetSet( $key, $value ) {
 if ( ! $value instanceof Closure ) {
 $value = function () use ( $value ) {
 return $value;
 };
 }

 $this->bind( $key, $value );
 }

 public function offsetUnset( $key ) {
 unset( $this->bindings[ $key ], $this->instances[ $key ] );
 }

 public function __get( $key ) {
 return $this[ $key ];
 }

 public function __set( $key, $value ) {
 $this[ $key ] = $value;
 }
}