How to create a simple AI with PHP programming language?

composer require php-ai/php-ml

use Phpml\Classification\KNearestNeighbors;
use Phpml\Dataset\ArrayDataset;

$trainingSamples = [
    ['Hi there!', 'greeting'],
    ['Hello!', 'greeting'],
    ['Hey!', 'greeting'],
    ['Goodbye!', 'farewell'],
    ['Bye!', 'farewell'],
    ['See you later!', 'farewell'],
    ['How are you?', 'how_are_you'],
    ['How have you been?', 'how_are_you'],
    ['What can you do?', 'what_can_you_do']
];

$trainingLabels = array_column($trainingSamples, 1);
$trainingSamples = array_column($trainingSamples, 0);

$dataset = new ArrayDataset($trainingSamples, $trainingLabels);

$classifier = new KNearestNeighbors();
$classifier->train($dataset->getSamples(), $dataset->getTargets());

$input = "Hi there!";
$predictedLabel = $classifier->predict([$input]);

switch ($predictedLabel[0]) {
    case 'greeting':
        echo "Hello! How can I help you?";
        break;
    case 'farewell':
        echo "Goodbye! Have a nice day.";
        break;
    case 'how_are_you':
        echo "I'm doing well, thank you. How can I assist you today?";
        break;
    case 'what_can_you_do':
        echo "I can help you with general questions or concerns. Please let me know how I can assist you.";
        break;
    default:
        echo "I'm sorry, I didn't understand that. Can you please repeat?";
        break;
}