// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
// Description: 
//  NavigationHelper is an internal utility class for Mongoose to deal
//  with Uri navigations.
 
using System;
 
namespace MS.Internal.Documents.Application
{
    /// <summary>
    /// Helper class for handling browser navigations.
    /// </summary>
    internal static class NavigationHelper
    {
        /// <summary>
        /// Invokes a navigation to a new document
        /// </summary>
        internal static void NavigateToDocument(Document document)
        {
            Trace.SafeWrite(
               Trace.File,
               "Attempting to navigate to new document {0}.",
               document.Uri);
 
            Invariant.Assert(
               _navigate is not null,
                "Navigation delegate has not been assigned.");
 
            Invariant.Assert(
                document != null,
                "Target document has not been assigned.");
 
            _navigate(document.Uri);
        }
 
        /// <summary>
        /// Invokes a top-level browserNavigation action to the specified Uri.
        /// </summary>
        internal static void NavigateToExternalUri(Uri uri)
        {
            Trace.SafeWrite(
                Trace.File,
                "Attempting to navigate to external Uri {0}.",
                uri);
 
            Invariant.Assert(
                _navigate is not null,
                "Navigation delegate has not been assigned.");
 
            Invariant.Assert(
                uri != null,
                "Target uri has not been assigned.");
 
            _navigate(uri);
        }
 
 
        /// <summary>
        /// A delegate that will navigate the root browser window.
        /// </summary>
        /// <remarks>
        /// If we are going to add more functionality a IBrowserService interface
        /// of some type should be defined and set vs many delegates.
        /// </remarks>
        internal static NavigateDelegate Navigate
        {
            get => _navigate;
            set => _navigate = value;
        }
 
        internal delegate void NavigateDelegate(Uri uri);
 
        private static NavigateDelegate _navigate;
    }
}