Creating A Game With PHP Part 2: Tic Tac Toe (see https://www.hashbangcode.com/article/creating-game-php-part-2-tic-tac-toe)

tictactoe.php

<?php

function renderGame($state, $activeCell, $player) {
  $output = '';

  $output .= 'Player:' . $player . PHP_EOL;

  foreach ($state as $x => $line) {
    $output .= '|';
    foreach ($line as $y => $item) {

      switch ($item) {
        case '';
          $cell = ' ';
          break;
        case 'X';
          $cell = 'X';
          break;
        case 'O';
          $cell = 'O';
          break;
      }
      if ($activeCell[0] == $x && $activeCell[1] == $y) {
        $cell = '-'. $cell . '-';
      }
      else {
        $cell = ' ' . $cell . ' ';
      }

      $output .= $cell . '|';
    }
    $output .= PHP_EOL;
  }

  return $output;
}

function isWinState($state) {
  foreach (['X', 'O'] as $player) {
    foreach ($state as $x => $line) {
      if ($state[$x][0] == $player && $state[$x][1] == $player && $state[$x][2] == $player) {
        die($player . ' wins');
      }

      foreach ($line as $y => $item) {
        if ($state[0][$y] == $player && $state[1][$y] == $player && $state[2][$y] == $player) {
          die($player . ' wins');
        }
      }
    }
    if ($state[0][0] == $player && $state[1][1] == $player && $state[2][2] == $player) {
      die($player . ' wins');
    }
    if ($state[2][0] == $player && $state[1][1] == $player && $state[0][2] == $player) {
      die($player . ' wins');
    }
  }

  // Game might be a draw.
  $blankQuares = 0;
  foreach ($state as $x => $line) {
    foreach ($line as $y => $item) {
      if ($state[$x][$y] == '') {
        $blankQuares++;
      }
    }
  }
  if ($blankQuares == 0) {
    die('DRAW!');
  }
}

function move($stdin, &$state, &$activeCell, &$player) {
  $key = fgets($stdin);
  if ($key) {
    $key = translateKeypress($key);
    switch ($key) {
      case "UP":
        if ($activeCell[0] >= 1) {
          $activeCell[0]--;
        }
        break;
      case "DOWN":
        if ($activeCell[0] < 2) {
          $activeCell[0]++;
        }
        break;
      case "RIGHT":
        if ($activeCell[1] < 2) {
          $activeCell[1]++;
        }
        break;
      case "LEFT":
        if ($activeCell[1] >= 1) {
          $activeCell[1]--;
        }
        break;
      case "ENTER":
      case "SPACE":
        if ($state[$activeCell[0]][$activeCell[1]] == '') {
          $state[$activeCell[0]][$activeCell[1]] = $player;
          if ($player == 'X') {
            $player = 'O';
          } else {
            $player = 'X';
          }
        }
        break;
     }
  }
}

function translateKeypress($string) {
  switch ($string) {
    case "\033[A":
      return "UP";
    case "\033[B":
      return "DOWN";
    case "\033[C":
      return "RIGHT";
    case "\033[D":
      return "LEFT";
    case "\n":
    case " ":
     return "ENTER";
   }
  return $string;
}

$state = [
  ['', '', ''],
  ['', '', ''],
  ['', '', ''],
];

system('stty cbreak -echo');
$stdin = fopen('php://stdin', 'r');
stream_set_blocking($stdin, 0);

$activeCell = [0 => 0, 1 => 0];
$player = 'X';

while (1) {
  system('clear');
  move($stdin, $state, $activeCell, $player);
  echo renderGame($state, $activeCell, $player);
  isWinState($state);
}