//===================================================================================

// Microsoft patterns & practices

// Composite Application Guidance for Windows Presentation Foundation and Silverlight

//===================================================================================

// Copyright (c) Microsoft Corporation.  All rights reserved.

// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY

// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT

// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

// FITNESS FOR A PARTICULAR PURPOSE.

//===================================================================================

// The example companies, organizations, products, domain names,

// e-mail addresses, logos, people, places, and events depicted

// herein are fictitious.  No association with any real company,

// organization, product, domain name, email address, logo, person,

// places, or events is intended or should be inferred.

//===================================================================================

using System;

using System.Globalization;

using System.Windows;

using Microsoft.Practices.Prism.Properties;

using Microsoft.Practices.Prism.Regions.Behaviors;



namespace Microsoft.Practices.Prism.Regions

{

    /// <summary>

    /// Base class to facilitate the creation of <see cref="IRegionAdapter"/> implementations.

    /// </summary>

    /// <typeparam name="T">Type of object to adapt.</typeparam>

    public abstract class RegionAdapterBase<T> : IRegionAdapter where T : class

    {

        /// <summary>

        /// Initializes a new instance of the <see cref="RegionAdapterBase&lt;T&gt;"/> class.

        /// </summary>

        public RegionAdapterBase(){}



        /// <summary>

        /// Initializes a new instance of <see cref="RegionAdapterBase{T}"/>.

        /// </summary>

        /// <param name="regionBehaviorFactory">The factory used to create the region behaviors to attach to the created regions.</param>

        protected RegionAdapterBase(IRegionBehaviorFactory regionBehaviorFactory)

        {

            this.RegionBehaviorFactory = regionBehaviorFactory;

        }



        /// <summary>

        /// Gets or sets the factory used to create the region behaviors to attach to the created regions.

        /// </summary>

        protected IRegionBehaviorFactory RegionBehaviorFactory { get; set; }



        /// <summary>

        /// Adapts an object and binds it to a new <see cref="IRegion"/>.

        /// </summary>

        /// <param name="regionTarget">The object to adapt.</param>

        /// <param name="regionName">The name of the region to be created.</param>

        /// <returns>The new instance of <see cref="IRegion"/> that the <paramref name="regionTarget"/> is bound to.</returns>

        public IRegion Initialize(T regionTarget, string regionName)

        {

            if (regionName == null)

            {

                throw new ArgumentNullException("regionName");

            }



            IRegion region = this.CreateRegion();

            region.Name = regionName;



            SetObservableRegionOnHostingControl(region, regionTarget);



            this.Adapt(region, regionTarget);

            this.AttachBehaviors(region, regionTarget);

            this.AttachDefaultBehaviors(region, regionTarget);

            return region;

        }



        /// <summary>

        /// Adapts an object and binds it to a new <see cref="IRegion"/>.

        /// </summary>

        /// <param name="regionTarget">The object to adapt.</param>

        /// <param name="regionName">The name of the region to be created.</param>

        /// <returns>The new instance of <see cref="IRegion"/> that the <paramref name="regionTarget"/> is bound to.</returns>

        /// <remarks>This methods performs validation to check that <paramref name="regionTarget"/>

        /// is of type <typeparamref name="T"/>.</remarks>

        /// <exception cref="ArgumentNullException">When <paramref name="regionTarget"/> is <see langword="null" />.</exception>

        /// <exception cref="InvalidOperationException">When <paramref name="regionTarget"/> is not of type <typeparamref name="T"/>.</exception>

        IRegion IRegionAdapter.Initialize(object regionTarget, string regionName)

        {

            return this.Initialize(GetCastedObject(regionTarget), regionName);

        }



        /// <summary>

        /// This method adds the default behaviors by using the <see cref="IRegionBehaviorFactory"/> object.

        /// </summary>

        /// <param name="region">The region being used.</param>

        /// <param name="regionTarget">The object to adapt.</param>

        protected virtual void AttachDefaultBehaviors(IRegion region, T regionTarget)

        {

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

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



            IRegionBehaviorFactory behaviorFactory = this.RegionBehaviorFactory;

            if (behaviorFactory != null)

            {

                DependencyObject dependencyObjectRegionTarget = regionTarget as DependencyObject;



                foreach (string behaviorKey in behaviorFactory)

                {

                    if (!region.Behaviors.ContainsKey(behaviorKey))

                    {

                        IRegionBehavior behavior = behaviorFactory.CreateFromKey(behaviorKey);



                        if (dependencyObjectRegionTarget != null)

                        {

                            IHostAwareRegionBehavior hostAwareRegionBehavior = behavior as IHostAwareRegionBehavior;

                            if (hostAwareRegionBehavior != null)

                            {

                                hostAwareRegionBehavior.HostControl = dependencyObjectRegionTarget;

                            }

                        }



                        region.Behaviors.Add(behaviorKey, behavior);

                    }

                }

            }

        }



        /// <summary>

        /// Template method to attach new behaviors.

        /// </summary>

        /// <param name="region">The region being used.</param>

        /// <param name="regionTarget">The object to adapt.</param>

        protected virtual void AttachBehaviors(IRegion region, T regionTarget)

        {

        }



        /// <summary>

        /// Template method to adapt the object to an <see cref="IRegion"/>.

        /// </summary>

        /// <param name="region">The new region being used.</param>

        /// <param name="regionTarget">The object to adapt.</param>

        protected abstract void Adapt(IRegion region, T regionTarget);



        /// <summary>

        /// Template method to create a new instance of <see cref="IRegion"/>

        /// that will be used to adapt the object.

        /// </summary>

        /// <returns>A new instance of <see cref="IRegion"/>.</returns>

        protected abstract IRegion CreateRegion();



        private static T GetCastedObject(object regionTarget)

        {

            if (regionTarget == null)

            {

                throw new ArgumentNullException("regionTarget");

            }



            T castedObject = regionTarget as T;

            if (castedObject == null)

            {

                throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, Resources.AdapterInvalidTypeException, typeof(T).Name));

            }



            return castedObject;

        }



        private static void SetObservableRegionOnHostingControl(IRegion region, T regionTarget)

        {

            DependencyObject targetElement = regionTarget as DependencyObject;



            if (targetElement != null)

            {

                // Set the region as a dependency property on the control hosting the region

                // Because we are using an observable region, the hosting control can detect that the

                // region has actually been created. This is an ideal moment to hook up custom behaviors

                RegionManager.GetObservableRegion(targetElement).Value = region;

            }

        }

    }

}