/Main/Cookbook/Caliburn.Micro.Silverlight/ViewModelBinder.cs

namespace Caliburn.Micro

{

    using System;

    using System.Linq;

    using System.Collections.Generic;

    using System.Windows;

    using System.Windows.Interactivity;

#if WP7 || WP71

    using Microsoft.Phone.Controls;

#endif



    /// <summary>

    /// Binds a view to a view model.

    /// </summary>

    public static class ViewModelBinder

    {

        /// <summary>

        /// Gets or sets a value indicating whether to apply conventions by default.

        /// </summary>

        /// <value>

        /// 	<c>true</c> if conventions should be applied by default; otherwise, <c>false</c>.

        /// </value>

        public static bool ApplyConventionsByDefault = true;

        static readonly ILog Log = LogManager.GetLog(typeof(ViewModelBinder));



        /// <summary>

        /// Indicates whether or not the conventions have already been applied to the view.

        /// </summary>

        public static readonly DependencyProperty ConventionsAppliedProperty =

            DependencyProperty.RegisterAttached(

                "ConventionsApplied",

                typeof(bool),

                typeof(ViewModelBinder),

                null

                );



        /// <summary>

        /// Determines whether a view should have conventions applied to it.

        /// </summary>

        /// <param name="view">The view to check.</param>

        /// <returns>Whether or not conventions should be applied to the view.</returns>

        public static bool ShouldApplyConventions(FrameworkElement view) {

            var overriden = View.GetApplyConventions(view);

            return overriden.GetValueOrDefault(ApplyConventionsByDefault);

        }



        /// <summary>

        /// Creates data bindings on the view's controls based on the provided properties.

        /// </summary>

        /// <remarks>Parameters include named Elements to search through and the type of view model to determine conventions for. Returns unmatched elements.</remarks>

        public static Func<IEnumerable<FrameworkElement>, Type, IEnumerable<FrameworkElement>> BindProperties = (namedElements, viewModelType) => {

            var unmatchedElements = new List<FrameworkElement>();



            foreach(var element in namedElements) {

                var cleanName = element.Name.Trim('_');

                var parts = cleanName.Split(new[] { '_' }, StringSplitOptions.RemoveEmptyEntries);



                var property = viewModelType.GetPropertyCaseInsensitive(parts[0]);

                var interpretedViewModelType = viewModelType;



                for(int i = 1; i < parts.Length && property != null; i++) {

                    interpretedViewModelType = property.PropertyType;

                    property = interpretedViewModelType.GetPropertyCaseInsensitive(parts[i]);

                }



                if(property == null) {

                    unmatchedElements.Add(element);

                    Log.Info("Binding Convention Not Applied: Element {0} did not match a property.", element.Name);

                    continue;

                }



                var convention = ConventionManager.GetElementConvention(element.GetType());

                if(convention == null) {

                    unmatchedElements.Add(element);

                    Log.Warn("Binding Convention Not Applied: No conventions configured for {0}.", element.GetType());

                    continue;

                }



                var applied = convention.ApplyBinding(

                    interpretedViewModelType,

                    cleanName.Replace('_', '.'),

                    property,

                    element,

                    convention

                    );



                if(applied)

                    Log.Info("Binding Convention Applied: Element {0}.", element.Name);

                else {

                    Log.Info("Binding Convention Not Applied: Element {0} has existing binding.", element.Name);

                    unmatchedElements.Add(element);

                }

            }



            return unmatchedElements;

        };



        /// <summary>

        /// Attaches instances of <see cref="ActionMessage"/> to the view's controls based on the provided methods.

        /// </summary>

        /// <remarks>Parameters include the named elements to search through and the type of view model to determine conventions for. Returns unmatched elements.</remarks>

        public static Func<IEnumerable<FrameworkElement>, Type, IEnumerable<FrameworkElement>> BindActions = (namedElements, viewModelType) => {

            var methods = viewModelType.GetMethods();

            var unmatchedElements = namedElements.ToList();



            foreach(var method in methods) {

                var foundControl = unmatchedElements.FindName(method.Name);

                if(foundControl == null) {

                    Log.Info("Action Convention Not Applied: No actionable element for {0}.", method.Name);

                    continue;

                }



                unmatchedElements.Remove(foundControl);



                var triggers = Interaction.GetTriggers(foundControl);

                if(triggers != null && triggers.Count > 0) {

                    Log.Info("Action Convention Not Applied: Interaction.Triggers already set on {0}.", foundControl.Name);

                    continue;

                }



                var message = method.Name;

                var parameters = method.GetParameters();



                if(parameters.Length > 0) {

                    message += "(";



                    foreach(var parameter in parameters) {

                        var paramName = parameter.Name;

                        var specialValue = "$" + paramName.ToLower();



                        if(MessageBinder.SpecialValues.ContainsKey(specialValue))

                            paramName = specialValue;



                        message += paramName + ",";

                    }



                    message = message.Remove(message.Length - 1, 1);

                    message += ")";

                }



                Log.Info("Action Convention Applied: Action {0} on element {1}.", method.Name, message);

                Message.SetAttach(foundControl, message);

            }



            return unmatchedElements;

        };



        /// <summary>

        /// Allows the developer to add custom handling of named elements which were not matched by any default conventions.

        /// </summary>

        public static Action<IEnumerable<FrameworkElement>, Type> HandleUnmatchedElements = (elements, viewModelType) => {};



        /// <summary>

        /// Binds the specified viewModel to the view.

        /// </summary>

        ///<remarks>Passes the the view model, view and creation context (or null for default) to use in applying binding.</remarks>

        public static Action<object, DependencyObject, object> Bind = (viewModel, view, context) =>{

            Log.Info("Binding {0} and {1}.", view, viewModel);

            Action.SetTarget(view, viewModel);



            var viewAware = viewModel as IViewAware;

            if(viewAware != null)

            {

                Log.Info("Attaching {0} to {1}.", view, viewAware);

                viewAware.AttachView(view, context);

            }



            if ((bool)view.GetValue(ConventionsAppliedProperty))

                return;



			var element = View.GetFirstNonGeneratedView(view) as FrameworkElement;

            if(element == null)

                return;



            if(!ShouldApplyConventions(element))

            {

                Log.Info("Skipping conventions for {0} and {1}.", element, viewModel);

                return;

            }



            var viewModelType = viewModel.GetType();



            var namedElements = BindingScope.GetNamedElements(element);



#if SILVERLIGHT

            namedElements.Apply(x => x.SetValue(

                View.IsLoadedProperty,

                element.GetValue(View.IsLoadedProperty))

                );

#endif

            namedElements = BindActions(namedElements, viewModelType);

            namedElements = BindProperties(namedElements, viewModelType);

            HandleUnmatchedElements(namedElements, viewModelType);

#if WP7 || WP71

            BindAppBar(view);

#endif



            view.SetValue(ConventionsAppliedProperty, true);

        };



#if WP7 || WP71

        static void BindAppBar(DependencyObject view) {

            var page = view as PhoneApplicationPage;

            if (page == null || page.ApplicationBar == null)

                return;



            var triggers = Interaction.GetTriggers(view);



            foreach(var item in page.ApplicationBar.Buttons) {

                var button = item as AppBarButton;

                if (button == null)

                    continue;



                var parsedTrigger = Parser.Parse(view, button.Message).First();

                var trigger = new AppBarButtonTrigger(button);

                var actionMessages = parsedTrigger.Actions.OfType<ActionMessage>().ToList();

                actionMessages.Apply(x => {

                    x.buttonSource = button;

                    parsedTrigger.Actions.Remove(x);

                    trigger.Actions.Add(x);

                });

                

                triggers.Add(trigger);

            }



            foreach (var item in page.ApplicationBar.MenuItems) {

                var menuItem = item as AppBarMenuItem;

                if (menuItem == null)

					continue;



                var parsedTrigger = Parser.Parse(view, menuItem.Message).First();

                var trigger = new AppBarMenuItemTrigger(menuItem);

                var actionMessages = parsedTrigger.Actions.OfType<ActionMessage>().ToList();

                actionMessages.Apply(x => {

                    x.menuItemSource = menuItem;

                    parsedTrigger.Actions.Remove(x);

                    trigger.Actions.Add(x);

                });



                triggers.Add(trigger);

            }

        }

#endif

    }

}