Array Advanced Operations

<?php

$numbers = array_map('intval', explode(' ', readline()));

do{
    $input = readline();
    $commands = array_map('trim',explode(' ', $input));

    if (strtolower($commands[0]) === 'add'){
        $numbers[] = $commands[1];
    }elseif (strtolower($commands[0]) === 'insert'){
        if (array_key_exists($commands[2], $numbers)){
            array_splice($numbers, intval($commands[2]), 0, intval($commands[1]));
        }else{
            echo 'Invalid index' . PHP_EOL;
        }
    }elseif (strtolower($commands[0]) === 'remove'){
        if (array_key_exists($commands[1], $numbers)){
            array_splice($numbers, intval($commands[1]), 1);
        }else{
            echo 'Invalid index' . PHP_EOL;
        }
    }elseif ($commands[0] === 'Shift' && $commands[1] === 'left'){
        for ($i = 0; $i < intval($commands[2]); $i++){
            $shiftNum = $numbers[0];
            array_shift($numbers);
            $numbers[] = $shiftNum;
        }
    }elseif ($commands[0] === 'Shift' && $commands[1] === 'right'){
        for ($i = 0; $i < intval($commands[2]); $i++){
            array_unshift($numbers, $numbers[count($numbers)-1]);
            array_pop($numbers);
        }
    }
}while ($input !== "End");

echo implode(' ', $numbers);