<?php

namespace App\Servers\Wechat;
use App\Facades\Servers\Logs\Log;

/**
 * 微信网站应用
 * @author 唐远望
 * @version 1.0
 * @date 2026-01-19
 */
class WeChatWebApp
{
    private $appId;
    private $appSecret;
    private $redirectUri;

    /**
     * 构造函数
     * 
     * @param string $appId 应用唯一标识
     * @param string $appSecret 应用密钥
     * @param string $redirectUri 授权回调地址
     */
    public function __construct()
    {
        $this->appId = config('wechat.openplat.app_id',[]);
        $this->appSecret = config('wechat.openplat.secret',[]);
        $this->redirectUri = urlencode(config('wechat.openplat.release_host_url',[]));
    }

    /**
     * 第一步：生成授权URL，引导用户跳转到微信授权页面
     * 
     * @param string $scope 应用授权作用域
     *        snsapi_base - 静默授权，不弹出授权页面，只能获取openid
     *        snsapi_userinfo - 弹出授权页面，可获取用户信息
     * @param string $state 重定向后会带上state参数，开发者可以填写任意参数值
     * @return string 授权URL
     */
    public function getAuthorizeUrl($scope = 'snsapi_base', $state = 'STATE')
    {
        $url = "https://open.weixin.qq.com/connect/oauth2/authorize?appid={$this->appId}&redirect_uri={$this->redirectUri}&response_type=code&scope={$scope}&state={$state}#wechat_redirect";
        return $url;
    }

    /**
     * 第二步：通过code获取access_token和openid
     * 
     * @param string $code 授权code
     * @return array|false 成功返回数组，失败返回false
     */
    public function getAccessTokenByCode($code)
    {
        $url = "https://api.weixin.qq.com/sns/oauth2/access_token?appid={$this->appId}&secret={$this->appSecret}&code={$code}&grant_type=authorization_code";

        $result = $this->httpGet($url);

        if ($result) {
            $data = json_decode($result, true);

            if (!isset($data['errcode'])) {
                return $data; // 成功返回
            } else {
                $this->logError("获取access_token失败", $data);
                return false;
            }
        }

        return false;
    }

    /**
     * 刷新access_token
     * 
     * @param string $refreshToken 刷新token
     * @return array|false 成功返回数组，失败返回false
     */
    public function refreshAccessToken($refreshToken)
    {
        $url = "https://api.weixin.qq.com/sns/oauth2/refresh_token?appid={$this->appId}&grant_type=refresh_token&refresh_token={$refreshToken}";

        $result = $this->httpGet($url);

        if ($result) {
            $data = json_decode($result, true);

            if (!isset($data['errcode'])) {
                return $data; // 成功返回
            } else {
                $this->logError("刷新access_token失败", $data);
                return false;
            }
        }

        return false;
    }

    /**
     * 获取用户信息（需要scope为snsapi_userinfo）
     * 
     * @param string $accessToken 接口调用凭证
     * @param string $openid 用户唯一标识
     * @return array|false 成功返回数组，失败返回false
     */
    public function getUserInfo($accessToken, $openid)
    {
        $url = "https://api.weixin.qq.com/sns/userinfo?access_token={$accessToken}&openid={$openid}&lang=zh_CN";

        $result = $this->httpGet($url);

        if ($result) {
            $data = json_decode($result, true);

            if (!isset($data['errcode'])) {
                return $data; // 成功返回
            } else {
                $this->logError("获取用户信息失败", $data);
                return false;
            }
        }

        return false;
    }

    /**
     * 验证access_token是否有效
     * 
     * @param string $accessToken 接口调用凭证
     * @param string $openid 用户唯一标识
     * @return bool 是否有效
     */
    public function checkAccessToken($accessToken, $openid)
    {
        $url = "https://api.weixin.qq.com/sns/auth?access_token={$accessToken}&openid={$openid}";

        $result = $this->httpGet($url);

        if ($result) {
            $data = json_decode($result, true);

            if (isset($data['errcode']) && $data['errcode'] == 0) {
                return true; // 有效
            }
        }

        return false; // 无效
    }

    /**
     * 完整的授权流程处理
     * 
     * @return array|false 成功返回用户信息数组，失败返回false
     */
    public function handleAuthorization()
    {
        // 检查是否有授权code
        if (!isset($_GET['code'])) {
            // 没有code，跳转到授权页面
            $url = $this->getAuthorizeUrl('snsapi_userinfo', 'authorize');
            header("Location: {$url}");
            exit;
        }

        // 获取授权code
        $code = $_GET['code'];

        // 通过code获取access_token
        $tokenData = $this->getAccessTokenByCode($code);

        if (!$tokenData) {
            return false;
        }

        // 存储token信息到session
        session_start();
        $_SESSION['wechat_access_token'] = $tokenData['access_token'];
        $_SESSION['wechat_refresh_token'] = $tokenData['refresh_token'];
        $_SESSION['wechat_openid'] = $tokenData['openid'];
        $_SESSION['wechat_token_expire'] = time() + $tokenData['expires_in'];

        return $tokenData;
    }

    /**
     * 获取当前有效的access_token（自动刷新）
     * 
     * @return string|false 有效的access_token
     */
    public function getValidAccessToken()
    {
        session_start();

        // 检查session中是否有token信息
        if (!isset($_SESSION['wechat_access_token'])) {
            return false;
        }

        $accessToken = $_SESSION['wechat_access_token'];
        $refreshToken = $_SESSION['wechat_refresh_token'];
        $openid = $_SESSION['wechat_openid'];
        $expireTime = $_SESSION['wechat_token_expire'];

        // 检查token是否即将过期（提前5分钟刷新）
        if (time() > $expireTime - 300) {
            // 刷新token
            $newTokenData = $this->refreshAccessToken($refreshToken);

            if ($newTokenData) {
                // 更新session中的token信息
                $_SESSION['wechat_access_token'] = $newTokenData['access_token'];
                $_SESSION['wechat_refresh_token'] = $newTokenData['refresh_token'];
                $_SESSION['wechat_token_expire'] = time() + $newTokenData['expires_in'];

                $accessToken = $newTokenData['access_token'];
            } else {
                // 刷新失败，需要重新授权
                return false;
            }
        }

        return $accessToken;
    }

    /**
     * HTTP GET 请求
     * 
     * @param string $url 请求URL
     * @return string|false 响应内容
     */
    private function httpGet($url)
    {
        if (function_exists('curl_init')) {
            $ch = curl_init();
            curl_setopt($ch, CURLOPT_URL, $url);
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
            curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
            curl_setopt($ch, CURLOPT_TIMEOUT, 30);

            $response = curl_exec($ch);

            if (curl_errno($ch)) {
                $this->logError("CURL错误", curl_error($ch));
                curl_close($ch);
                return false;
            }

            curl_close($ch);
            return $response;
        } else {
            // 备用方法：使用file_get_contents
            $context = stream_context_create([
                'ssl' => [
                    'verify_peer' => false,
                    'verify_peer_name' => false,
                ]
            ]);

            return file_get_contents($url, false, $context);
        }
    }

    /**
     * 错误日志记录
     * 
     * @param string $message 错误信息
     * @param mixed $data 错误数据
     */
    private function logError($message, $data = null)
    {
        $log = date('Y-m-d H:i:s') . " - {$message}";

        if ($data !== null) {
            $log .= " - " . (is_array($data) ? json_encode($data) : $data);
        }
        Log::info('wechat_oauth_error', '微信登录错误日志', ['data' => $log, 'error' => PHP_EOL]);
    }

    /**
     * 获取当前openid
     * 
     * @return string|false openid
     */
    public function getOpenId()
    {
        session_start();
        return isset($_SESSION['wechat_openid']) ? $_SESSION['wechat_openid'] : false;
    }

    /**
     * 清除session中的授权信息
     */
    public function clearSession()
    {
        session_start();
        unset(
            $_SESSION['wechat_access_token'],
            $_SESSION['wechat_refresh_token'],
            $_SESSION['wechat_openid'],
            $_SESSION['wechat_token_expire']
        );
    }
}