Remotes

remotes.php

<?php

interface RemoteControl
{
    public function powerOn() : void;
}

class Television
{
    public function setPower(bool $state) : void
    {
        // truncated code
    }
}

class CableBox
{
    public function setPower(bool $state) : void
    {
        // truncated code
    }
}

class TVRemote implements RemoteControl
{
    private $_tv;

    public function __construct(Television $tv)
    {
        $this->_tv = $tv;
    }

    public function powerOn() :void
    {
        $this->_tv->setPower(true);
    }
}

////////////////// MY CODE //////////////////////////

class CableRemote implements RemoteControl
{
    private $_box;

    public function __construct(CableBox $box)
    {
        $this->_box = $box;
    }

    public function powerOn() :void
    {
        $this->_box->setPower(true);
    }
}

// This will allow the user to select which device they want to turn on.
// I may have taken it further than intended. I'm not sure if the goal 
// was to turn both on at the same time with the universal remote
// or to allow the user to select the device to control.

class UniversalRemote implements RemoteControl
{
    private $device;

    public function __construct(RemoteControl $device)
    {
        $this->device = $device;
    }

    public function powerOn() :void
    {
        $this->device->powerOn();
    }
}

class User
{
    private $remoteType;

    public function pickupRemote(RemoteControl $remoteType)
    {
        $this->remoteType = $remoteType;
    }

    public function pressPowerOn()
    {
        return $this->remoteType->powerOn();
    }
}

$user = new User();

// Pick up tv remote and press power on
$user->pickupRemote(new TVRemote(new Television()));
$user->pressPowerOn();

// Pick up universal remote, select TV, and press power on
$user->pickupRemote(new UniversalRemote(new TVRemote(new Television())));
$user->pressPowerOn();

// Pick up universal remote, select Cable Box, and press power on
$user->pickupRemote(new UniversalRemote(new CableRemote(new CableBox())));
$user->pressPowerOn();