Casino.php

<?php

class Game {

  private $doors;

  private $winner;


  public function __construct() {
    $this->doors = array(0,0,0);
    $win = rand(0, 2);
    $this->doors[$win] = 1;
  }

  public function playFor(Player $player) {
    $this->winner = null;
    $choice = $player->chooseDoor($this->doors);
    $door = $this->doors[$choice];

    for($i=0;$i<count($this->doors);$i++) {
      if (1 !== $this->doors[$i] && $i !== $choice) {
        $opened = $i;
      }
    }
    if ($player->wantsToChangeHisChoice()) {
      $new_doors = $this->doors;
      $new_choice = $player->chooseNewDoor($this->doors, $opened);

      $door = $new_doors[$new_choice];
    }

    if (1 === $door) {
      $this->winner = $player;
    }
  }

  public function getWinner() {
    return $this->winner;
  }
}

interface Strategy {

  public function shouldChangeChoice();

}

class AlwaysChangeStrategy implements Strategy {

  public function shouldChangeChoice() {
    return true;
  }
}

class NeverChangeStrategy implements Strategy {

  public function shouldChangeChoice() {
    return false;
  }
}

class MaybeChangeStrategy implements Strategy {

  private $probability;

  public function __construct($probability = 0.5) {
    $this->probability = $probability;
  }

  public function shouldChangeChoice() {
    if (mt_rand(1, 1000) < $this->probability * 1000) {
      return true;
    }
    return false;
  }
}

class Player {

  protected $name;

  protected $strategy;

  protected $money;

  protected $choice;

  public function __construct($name, Strategy $strategy, $money = 0) {
    $this->name = $name;
    $this->strategy = $strategy;
    $this->money = $money;
  }

  public function chooseDoor(array $doors) {
    $this->choice = rand(0, count($doors) -1);
    return $this->choice;
  }

  public function chooseNewDoor(array $doors, $except) {
    for($k=0;$k<count($doors);$k++) {
      if ($k !== $this->choice && $k !== $except) {
        return $k;
      }
    }
  }

  public function wantsToChangeHisChoice() {
    return $this->strategy->shouldChangeChoice();
  }

  public function getMoney() {
    $money = $this->money;
    $this->money = 0;
    return $money;
  }

  public function getName() {
    return $this->name;
  }

  public function giveMoney($money) {
    $this->money = $money;
  }
}

class Bouncer {

  public function kickPlayersAss(Player $player) {
    print sprintf('Kicked %s\'s ass<br/>', $player->getName());
  }
}

class Casino {

  private $bouncer;

  private $players;

  private $game;

  private $bank;

  private $bet;

  private $revenue;

  public function __construct(Bouncer $bouncer, array $players, Game $game, $bet = 10) {
    $this->bouncer = $bouncer;
    $this->players = $players;
    $this->game = $game;
    $this->bank = new \SplObjectStorage();
    $this->bet = $bet;
    foreach($this->players as $player) {
      $this->bank[$player] = $player->getMoney();
    }
    $this->revenue = 0;
  }

  public function play() {
    $loosers = $winners =  array();
    $bank = 0;
    foreach($this->players as $key => $player) {
      if ($this->bank[$player] >= $this->bet) {
        $bank += $this->bet;
        $this->bank[$player] -= $this->bet;
      }
      else {
        $this->bouncer->kickPlayersAss($player);
        unset($this->players[$key]);
        continue;
      }
      $this->game->playFor($player);
      if ($player === $this->game->getWinner()) {
        $winners[] = $player;
      }
      else {
        $loosers[] = $player;
      }
    }
    if ($winners) {
      $win = $bank / count($winners);
      foreach($winners as $winner) {
        $this->bank[$winner] += $win;
      }
    }
    else {
      $this->revenue += $bank;
    }
  }

  public function getBank() {
    return $this->bank;
  }

  public function getRevenue() {
    return $this->revenue;
  }
}


$n = 10000;
$players = array();
$nikita = new Player('Nikita', new AlwaysChangeStrategy(), 1000);
$olga = new Player('Olga', new NeverChangeStrategy(), 1000);
$players[] = $nikita;
$players[] = $olga;
for($k=0;$k<10;$k++) {
  $players[] = new Player('Robot'.$k, new MaybeChangeStrategy(), 1000);
}

$wins = 0;
$looses = 0;
$casino = new Casino(new Bouncer(), $players, new Game(), 10);

while($n > 0) {
  $casino->play();
  --$n;
}

$bank = $casino->getBank();
foreach($bank as $player) {
  var_dump($player->getName() .'__'.$bank[$player]);
}
var_dump($casino->getRevenue());
die;