<?php

namespace Lib\Imap;

class ImapClient {

    /**
     * 资源
     * @var resource|false
     */
    private $socket;

    protected bool $debug = false;

    protected string $host;


    /**
     * 每请求一次就会+1
     * @var int
     */
    public int $tagNum = 0;

    /**
     * 是否是非阻塞模式
     * @var bool
     */
    public $isBlocking = false;

    public function __construct(string $host){
        $this->host = $host;
        $this->socket = false;
    }



    public function open(){
        $content = stream_context_create([
            'ssl' => [
                'verify_peer' => false, // 有的证书和域名不匹配，这里关闭认证
                'verify_peer_name' => false,// 有的证书和域名不匹配，这里关闭认证
            ]
        ]);

        $flags = STREAM_CLIENT_CONNECT;

        $this->socket = stream_socket_client(
            $this->host,
            $errno,
            $error,
            30,
            $flags,
            $content
        );


        if($error){
            throw new \Exception($error);
        }

        if (!$this->socket) {
            throw new \Exception($this->host." connection fail.");
        }

        // 设置为非阻塞模式
        $this->isBlocking = stream_set_blocking($this->socket, false);

    }


    /**
     * @param bool $debug
     * @return $this
     * @author：dc
     * @time 2024/9/18 9:57
     */
    public function setDebug(bool $debug = true): static
    {
        $this->debug = $debug;
        return $this;
    }



    /**
     * 写
     * @param string $cmd
     * @return false|int
     * @author：dc
     * @time 2024/9/13 15:47
     */
    protected function write(string $cmd){
        if($this->debug){
            echo 'write: '.$cmd;
        }

        $totalBytes = strlen($cmd);
        $bytesWritten = 0;
        $maxW = 50;
        while ($bytesWritten < $totalBytes) {
            $result = fwrite($this->socket, substr($cmd, $bytesWritten));
            // 写失败了
            if ($result === false) {    return false;   }

            // 更新已写入的字节数
            $bytesWritten += $result;

            // 如果没有写入任何字节，可能是缓冲区满了，稍后再试
            if ($result === 0) {
                $maxW--;
                if(!$maxW){
                    throw new \Exception('socket write error time out');
                }
                // 兼容下swoole
                if(function_exists('go') && \co::getCid()>0){
                    \co::sleep(0.1);
                }else{
                    // 等待 100 毫秒
                    usleep(100000);
                }
            }
        }

        return $bytesWritten;
    }

    /**
     * 读
     * @return false|string
     * @author：dc
     * @time 2024/9/13 15:49
     */
    protected function readLine(){
        $i = 50; // 非阻塞模式下，只等待5秒，没返回数据就返回
        $str = false;
        while ($i>0){
            $str = fgets($this->socket,2048);
            // 非阻塞模式
            if($this->isBlocking && $str === false){
                $i--;
                // 兼容下swoole
                if(function_exists('go') && \co::getCid()>0){
                    \co::sleep(0.1);
                }else{
                    // 等待 100 毫秒
                    usleep(100000);
                }

            }else{
                break;
            }
        }
        // 超时了，异常
        if(!$i && $str===false){
            throw new \Exception('read time out');
        }

        if($this->debug){
            echo 'read: '.$str;
        }
        return $str;
    }

    /**
     *
     * @param string $cmd 执行的命令
     * @return array
     * @author：dc
     * @time 2024/9/13 15:57
     */
    public function request(string $cmd):array {
        $this->tagNum++;
        $tag = 'TAG'.$this->tagNum;
        // 请求数据
        $writeNumber = $this->write($tag.' '.$cmd."\r\n");
        $result = [];
        if($writeNumber){
            // 读取数据
            while (1){
                $line = $this->readLine();
                $result[] = $line;
                list($token) = explode(' ',$line,2);
                // 结束了
                if($token == $tag || $line === false){
                    break;
                }
            }
        }

        return $result;

    }


    public function __destruct()
    {
        if($this->socket) @fclose($this->socket);
        unset($this->socket);
        // TODO: Implement __destruct() method.
    }

}