AI Engine: Log the conversations to local files

logchats.php

<?php

add_filter( 'mwai_chatbot_reply', function ( $reply, $query, $params ) {
  try {
    global $mwai_core;
    $newMessage = !empty( $params['newMessage'] ) ? $params['newMessage'] : "";

    // We need to identify the user or session
    $id = $mwai_core->get_user_id();
    if ( empty( $id ) ) {
      $id = $mwai_core->get_ip_address();
      if ( empty( $id ) ) {
        $id = 'RANDOM-' . uniqid();
      }
      else {
        $id = 'IP-' . $id;
      }
    }
    else {
      $id = 'USER-' . $id;
    }

    // Create or Update Logs
    $upload_dir = wp_upload_dir();
    $date = date( 'Y-m-d' );
    $chatbot_logs_dir = $upload_dir['basedir'] . '/chatbot';
    $file = $chatbot_logs_dir . '/' . $date . '-' . $id . '.txt';
    if ( !file_exists( $chatbot_logs_dir ) ) {
      mkdir( $chatbot_logs_dir, 0777, true );
    }
    $content = @file_get_contents( $file );
    $content .= "USER: " . $newMessage . "\n";
    $content .= "AI: " . $reply . "\n";
    file_put_contents( $file, $content );
  }
  catch ( Exception $e ) {
    error_log( $e->getMessage() );
  }
  return $reply;
}, 10, 3 );

Where does this get put?