<?php
namespace Yurun\OAuthLogin\Weixin;

use Yurun\OAuthLogin\Base;
use Yurun\OAuthLogin\ApiException;

class OAuth2 extends Base
{
	/**
	 * api接口域名
	 */
	const API_DOMAIN = 'https://api.weixin.qq.com/';

	/**
	 * 开放平台域名
	 */
	const OPEN_DOMAIN = 'https://open.weixin.qq.com/';

	/**
	 * 语言，默认为zh_CN
	 * @var string
	 */
	public $lang = 'zh_CN';

	/**
	 * openid从哪个字段取，默认为openid
	 * @var int
	 */
	public $openidMode = OpenidMode::OPEN_ID;

	/**
	 * 获取url地址
	 * @param string $name 跟在域名后的文本
	 * @param array $params GET参数
	 * @return string
	 */
	public function getUrl($name, $params = array())
	{
		if('http' === substr($name, 0, 4))
		{
			$domain = $name;
		}
		else
		{
			$domain = static::API_DOMAIN . $name;
		}
		return $domain . (empty($params) ? '' : ('?' . $this->http_build_query($params)));
	}

	/**
	 * 第一步:获取PC页登录所需的url，一般用于生成二维码
	 * @param string $callbackUrl 登录回调地址
	 * @param string $state 状态值，不传则自动生成，随后可以通过->state获取。用于第三方应用防止CSRF攻击，成功授权后回调时会原样带回。一般为每个用户登录时随机生成state存在session中，登录回调中判断state是否和session中相同
	 * @param array $scope 请求用户授权时向用户显示的可进行授权的列表。可空，默认snsapi_login
	 * @return string
	 */
	public function getAuthUrl($callbackUrl = null, $state = null, $scope = null)
	{
		$option = array(
			'appid'				=>	$this->appid,
			'redirect_uri'		=>	null === $callbackUrl ? (null === $this->callbackUrl ? (isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : '') : $this->callbackUrl) : $callbackUrl,
			'response_type'		=>	'code',
			'scope'				=>	null === $scope ? (null === $this->scope ? 'snsapi_login' : $this->scope) : $scope,
			'state'				=>	$this->getState($state),
		);
		if(null === $this->loginAgentUrl)
		{
			return $this->getUrl(static::OPEN_DOMAIN . 'connect/qrconnect', $option) . '#wechat_redirect';
		}
		else
		{
			return $this->loginAgentUrl . '?' . $this->http_build_query($option);
		}
	}

	/**
	 * 第一步:获取在微信中登录授权的url
	 * @param string $callbackUrl 登录回调地址
	 * @param string $state 状态值，不传则自动生成，随后可以通过->state获取。用于第三方应用防止CSRF攻击，成功授权后回调时会原样带回。一般为每个用户登录时随机生成state存在session中，登录回调中判断state是否和session中相同
	 * @param array $scope 请求用户授权时向用户显示的可进行授权的列表。可空，默认snsapi_userinfo
	 * @return string
	 */
	public function getWeixinAuthUrl($callbackUrl = null, $state = null, $scope = null)
	{
		$option = array(
			'appid'				=>	$this->appid,
			'redirect_uri'		=>	null === $callbackUrl ? (null === $this->callbackUrl ? (isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : '') : $this->callbackUrl) : $callbackUrl,
			'response_type'		=>	'code',
			'scope'				=>	null === $scope ? (null === $this->scope ? 'snsapi_userinfo' : $this->scope) : $scope,
			'state'				=>	$this->getState($state),
		);
		if(null === $this->loginAgentUrl)
		{
			return $this->getUrl(static::OPEN_DOMAIN . 'connect/oauth2/authorize', $option) . '#wechat_redirect';
		}
		else
		{
			$option['isMp'] = 1;
			return $this->loginAgentUrl . '?' . $this->http_build_query($option);
		}
	}

	/**
	 * 第二步:处理回调并获取access_token。与getAccessToken不同的是会验证state值是否匹配，防止csrf攻击。
	 * @param string $storeState 存储的正确的state
	 * @param string $code 第一步里$redirectUri地址中传过来的code，为null则通过get参数获取
	 * @param string $state 回调接收到的state，为null则通过get参数获取
	 * @return string
	 */
	protected function __getAccessToken($storeState, $code = null, $state = null)
	{
		$this->result = $this->http->get($this->getUrl('sns/oauth2/access_token', array(
			'appid'			=>	$this->appid,
			'secret'		=>	$this->appSecret,
			'code'			=>	isset($code) ? $code : (isset($_GET['code']) ? $_GET['code'] : ''),
			'grant_type'	=>	'authorization_code',
		)))->json(true);
		if(isset($this->result['errcode']) && 0 != $this->result['errcode'])
		{
			throw new ApiException($this->result['errmsg'], $this->result['errcode']);
		}
		else
		{
			switch((int)$this->openidMode)
			{
				case OpenidMode::OPEN_ID:
					$this->openid = $this->result['openid'];
					break;
				case OpenidMode::UNION_ID:
					$this->openid = $this->result['unionid'];
					break;
				case OpenidMode::UNION_ID_FIRST:
					$this->openid = empty($this->result['unionid']) ? $this->result['openid'] : $this->result['unionid'];
					break;
			}
			return $this->accessToken = $this->result['access_token'];
		}
	}

	/**
	 * 获取用户资料
	 * @param string $accessToken
	 * @return array
	 */
	public function getUserInfo($accessToken = null)
	{
		$this->result = $this->http->get($this->getUrl('sns/userinfo', array(
			'access_token'	=>	null === $accessToken ? $this->accessToken : $accessToken,
			'openid'		=>	$this->openid,
			'lang'			=>	$this->lang,
		)))->json(true);
		if(isset($this->result['errcode']) && 0 != $this->result['errcode'])
		{
			throw new ApiException($this->result['errmsg'], $this->result['errcode']);
		}
		else
		{
			return $this->result;
		}
	}
	
	/**
	 * 刷新AccessToken续期
	 * @param string $refreshToken
	 * @return bool
	 */
	public function refreshToken($refreshToken)
	{
		$this->result = $this->http->get($this->getUrl('sns/oauth2/refresh_token', array(
			'appid'			=>	$this->appid,
			'grant_type'	=>	'refresh_token',
			'refresh_token'	=>	$refreshToken,
		)))->json(true);
		return isset($this->result['errcode']) && 0 == $this->result['errcode'];
	}

	/**
	 * 检验授权凭证AccessToken是否有效
	 * @param string $accessToken
	 * @return bool
	 */
	public function validateAccessToken($accessToken = null)
	{
		$this->result = $this->http->get($this->getUrl('sns/auth', array(
			'access_token'	=>	null === $accessToken ? $this->accessToken : $accessToken,
			'openid'		=>	$this->openid,
		)))->json(true);
		return isset($this->result['errcode']) && 0 == $this->result['errcode'];
	}

	/**
	 * 微信小程序登录凭证校验，获取session_key、openid、unionid
	 * 返回session_key
	 * 调用后可以使用$this->result['openid']或$this->result['unionid']获取相应的值
	 * 
	 * @param string $jsCode
	 * @return string
	 */
	public function getSessionKey($jsCode)
	{
		$this->result = $this->http->get($this->getUrl('sns/jscode2session', array(
			'appid'		=>	$this->appid,
			'secret'	=>	$this->appSecret,
			'js_code'	=>	$jsCode,
			'grant_type'=>	'authorization_code',
		)))->json(true);

		if(isset($this->result['errcode']) && 0 != $this->result['errcode'])
		{
			throw new ApiException($this->result['errmsg'], $this->result['errcode']);
		}
		else
		{
			switch((int)$this->openidMode)
			{
				case OpenidMode::OPEN_ID:
					$this->openid = $this->result['openid'];
					break;
				case OpenidMode::UNION_ID:
					$this->openid = $this->result['unionid'];
					break;
				case OpenidMode::UNION_ID_FIRST:
					$this->openid = empty($this->result['unionid']) ? $this->result['openid'] : $this->result['unionid'];
					break;
			}
		}

		return $this->result['session_key'];
	}
}