#region MigraDoc - Creating Documents on the Fly
//
// Authors:
//   Stefan Lange
//   Klaus Potzesny
//   David Stephensen
//
// Copyright (c) 2001-2017 empira Software GmbH, Cologne Area (Germany)
//
// http://www.pdfsharp.com
// http://www.migradoc.com
// http://sourceforge.net/projects/pdfsharp
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.
#endregion

using System;

namespace MigraDoc.DocumentObjectModel
{
    /// <summary>
    /// Provides relational information between document objects.
    /// </summary>
    public class DocumentRelations
    {
        /// <summary>
        /// Determines whether the specified documentObject has a
        /// parent of the given type somewhere within the document hierarchy.
        /// </summary>
        /// <param name="documentObject">The document object to check.</param>
        /// <param name="type">The parent type to search for.</param>
        public static bool HasParentOfType(DocumentObject documentObject, Type type)
        {
            if (documentObject == null)
                throw new ArgumentNullException("documentObject");

            if (type == null)
                throw new ArgumentNullException("type");

            return GetParentOfType(documentObject, type) != null;
        }

        /// <summary>
        /// Gets the direct parent of the given document object.
        /// </summary>
        /// <param name="documentObject">The document object the parent is searched for.</param>
        public static DocumentObject GetParent(DocumentObject documentObject)
        {
            if (documentObject == null)
                throw new ArgumentNullException("documentObject");

            return documentObject.Parent;
        }

        /// <summary>
        /// Gets a parent of the document object with the given type somewhere within the document hierarchy.
        /// Returns null if none exists.
        /// </summary>
        /// <param name="documentObject">The document object the parent is searched for.</param>
        /// <param name="type">The parent type to search for.</param>
        public static DocumentObject GetParentOfType(DocumentObject documentObject, Type type)
        {
            if (documentObject == null)
                throw new ArgumentNullException("documentObject");

            if (type == null)
                throw new ArgumentNullException("type");

            if (documentObject._parent != null)
            {
                if (documentObject._parent.GetType() == type)
                    return documentObject._parent;
                return GetParentOfType(documentObject._parent, type);
            }
            return null;
        }
    }
}