<?php

/**
 * Hoa
 *
 *
 * @license
 *
 * New BSD License
 *
 * Copyright © 2007-2017, Hoa community. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Hoa nor the names of its contributors may be
 *       used to endorse or promote products derived from this software without
 *       specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS AND CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

namespace Hoa\Socket\Connection;

use Hoa\Socket;

/**
 * Class \Hoa\Socket\Connection\Group.
 *
 * Represent a group of connection handlers.
 * Add semantics around Hoa\Socket\Connection\Handler.
 *
 * @copyright  Copyright © 2007-2017 Hoa community
 * @license    New BSD License
 */
class Group implements \ArrayAccess, \IteratorAggregate, \Countable
{
    /**
     * All connections.
     *
     * @var array
     */
    protected $_connections = [];


    /**
     * Check if a connection offset exists.
     *
     * @param   mixed  $offset    Offset.
     * @return  bool
     */
    public function offsetExists($offset)
    {
        return true === array_key_exists($offset, $this->_connections);
    }

    /**
     * Get a specific connection.
     *
     * @param   mixed  $offset    Offset.
     * @return  \Hoa\Socket\Connection\Handler
     */
    public function offsetGet($offset)
    {
        if (false === $this->offsetExists($offset)) {
            return null;
        }

        return $this->_connections[$offset];
    }

    /**
     * Add a connection.
     *
     * @param   mixed                           $offset        Offset.
     * @param   \Hoa\Socket\Connection\Handler  $connection    Connection
     *                                                         (handler).
     * @return  void
     * @throws  \Hoa\Socket\Exception
     */
    public function offsetSet($offset, $connection)
    {
        if (!($connection instanceof Handler)) {
            throw new Socket\Exception(
                '%s only accepts %s\Handler objects.',
                0,
                [__CLASS__, __NAMESPACE__]
            );
        }

        if (null === $offset) {
            $this->_connections[] = $connection;
        } else {
            $this->_connections[$offset] = $connection;
        }

        if (1 < count($this)) {
            $this->getFirstConnection()->merge($connection);
        }

        return;
    }

    /**
     * Nothing (not allowed).
     *
     * @param   mixed  $offset    Offset.
     * @return  void
     * @throws  \Hoa\Socket\Exception
     */
    public function offsetUnset($offset)
    {
        throw new Socket\Exception(
            'This operation is not allowed: you cannot unset a connection ' .
            'from a group.',
            1
        );

        return;
    }

    /**
     * Get iterator of all declared connections.
     *
     * @return  \ArrayIterator
     */
    public function getIterator()
    {
        return new \ArrayIterator($this->_connections);
    }

    /**
     * Count number of declared connections.
     *
     * @return  int
     */
    public function count()
    {
        return count($this->_connections);
    }

    /**
     * Semantics alias of $this->offsetSet(null, $connection).
     *
     * @param   \Hoa\Socket\Connection\Handler  $connection    Connection
     *                                                         (handler).
     * @return  \Hoa\Socket\Connection\Group
     */
    public function merge(Handler $connection)
    {
        $this[] = $connection;

        return $this;
    }

    /**
     * Run the group of connections.
     *
     * @return  void
     * @throws  \Hoa\Socket\Exception
     */
    public function run()
    {
        if (0 === count($this)) {
            throw new Socket\Exception(
                'Nothing to run. You should merge a connection.',
                2
            );
        }

        return $this->getFirstConnection()->run();
    }

    /**
     * Get the first declared connection (where other connections have been
     * merged).
     *
     * @return  \Hoa\Socket\Connection\Handler
     */
    public function getFirstConnection()
    {
        return $this[key($this->_connections)];
    }
}