<?php

namespace Pheanstalk\Socket;

use Pheanstalk\Exception;
use Pheanstalk\Socket;

/**
 * A Socket implementation around a fsockopen() stream.
 *
 * @author Paul Annesley
 * @package Pheanstalk
 * @license http://www.opensource.org/licenses/mit-license.php
 */
class NativeSocket implements Socket
{
    /**
     * The default timeout for a blocking read on the socket
     */
    const SOCKET_TIMEOUT = 1;

    /**
     * Number of retries for attempted writes which return zero length.
     */
    const WRITE_RETRIES = 8;

    private $_socket;

    /**
     * @param string $host
     * @param int    $port
     * @param int    $connectTimeout
     */
    public function __construct($host, $port, $connectTimeout, $connectPersistent)
    {
        if ($connectPersistent) {
            $this->_socket = $this->_wrapper()
                ->pfsockopen($host, $port, $errno, $errstr, $connectTimeout, $connectPersistent);
        } else {
            $this->_socket = $this->_wrapper()
                ->fsockopen($host, $port, $errno, $errstr, $connectTimeout, $connectPersistent);
        }

        if (!$this->_socket) {
            throw new Exception\ConnectionException($errno, $errstr . " (connecting to $host:$port)");
        }

        $this->_wrapper()
            ->stream_set_timeout($this->_socket, self::SOCKET_TIMEOUT);
    }

    /* (non-phpdoc)
     * @see Socket::write()
     */
    public function write($data)
    {
        $history = new WriteHistory(self::WRITE_RETRIES);

        for ($written = 0, $fwrite = 0; $written < strlen($data); $written += $fwrite) {
            $fwrite = $this->_wrapper()
                ->fwrite($this->_socket, substr($data, $written));

            $history->log($fwrite);

            if ($history->isFullWithNoWrites()) {
                throw new Exception\SocketException(sprintf(
                    'fwrite() failed to write data after %u tries',
                    self::WRITE_RETRIES
                ));
            }
        }
    }

    /* (non-phpdoc)
     * @see Socket::write()
     */
    public function read($length)
    {
        $read = 0;
        $parts = '';

        while ($read < $length && !$this->_wrapper()->feof($this->_socket)) {
            $data = $this->_wrapper()
                ->fread($this->_socket, $length - $read);

            if ($data === false) {
                throw new Exception\SocketException('fread() returned false');
            }

            $read += strlen($data);
            $parts .= $data;
        }

        return $parts;
    }

    /* (non-phpdoc)
     * @see Socket::write()
     */
    public function getLine($length = null)
    {
        do {
            $data = isset($length) ?
                $this->_wrapper()->fgets($this->_socket, $length) :
                $this->_wrapper()->fgets($this->_socket);

            if ($this->_wrapper()->feof($this->_socket)) {
                throw new Exception\SocketException("Socket closed by server!");
            }
        } while ($data === false);

        return rtrim($data);
    }

    public function disconnect()
    {
        $this->_wrapper()->fclose($this->_socket);
    }

    // ----------------------------------------

    /**
     * Wrapper class for all stream functions.
     * Facilitates mocking/stubbing stream operations in unit tests.
     */
    private function _wrapper()
    {
        return StreamFunctions::instance();
    }
}