<?php

/*

 * This file is part of SwiftMailer.

 * (c) 2004-2009 Chris Corbyn

 *

 * For the full copyright and license information, please view the LICENSE

 * file that was distributed with this source code.

 */

/**

 * A MIME entity, such as an attachment.

 * @package Swift

 * @subpackage Mime

 * @author Chris Corbyn

 */

interface Swift_Mime_MimeEntity

  extends Swift_Mime_CharsetObserver, Swift_Mime_EncodingObserver

{

  /** Main message document; there can only be one of these */

  const LEVEL_TOP = 16;

  /** An entity which nests with the same precedence as an attachment */

  const LEVEL_MIXED = 256;

  /** An entity which nests with the same precedence as a mime part */

  const LEVEL_ALTERNATIVE = 4096;

  /** An entity which nests with the same precedence as embedded content */

  const LEVEL_RELATED = 65536;

  /**

   * Get the level at which this entity shall be nested in final document.

   * The lower the value, the more outermost the entity will be nested.

   * @return int

   * @see LEVEL_TOP, LEVEL_MIXED, LEVEL_RELATED, LEVEL_ALTERNATIVE

   */

  public function getNestingLevel();

  /**

   * Get the qualified content-type of this mime entity.

   * @return string

   */

  public function getContentType();

  /**

   * Returns a unique ID for this entity.

   * For most entities this will likely be the Content-ID, though it has

   * no explicit semantic meaning and can be considered an identifier for

   * programming logic purposes.

   * If a Content-ID header is present, this value SHOULD match the value of

   * the header.

   * @return string

   */

  public function getId();

  /**

   * Get all children nested inside this entity.

   * These are not just the immediate children, but all children.

   * @return Swift_Mime_MimeEntity[]

   */

  public function getChildren();

  /**

   * Set all children nested inside this entity.

   * This includes grandchildren.

   * @param Swift_Mime_MimeEntity[] $children

   */

  public function setChildren(array $children);

  /**

   * Get the collection of Headers in this Mime entity.

   * @return Swift_Mime_Header[]

   */

  public function getHeaders();

  /**

   * Get the body content of this entity as a string.

   * Returns NULL if no body has been set.

   * @return string

   */

  public function getBody();

  /**

   * Set the body content of this entity as a string.

   * @param string $body

   * @param string $contentType optional

   */

  public function setBody($body, $contentType = null);

  /**

   * Get this entire entity in its string form.

   * @return string

   */

  public function toString();

  /**

   * Get this entire entity as a ByteStream.

   * @param Swift_InputByteStream $is to write to

   */

  public function toByteStream(Swift_InputByteStream $is);

}