port from perforce

intromat/NodeNetwork/ViewModels/NodeOutputViewModel.cs

@@ -0,0 +1,124 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.Specialized;
+using System.Linq;
+using System.Reactive.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using DynamicData;
+using NodeNetwork.Utilities;
+using NodeNetwork.Views;
+using ReactiveUI;
+
+namespace NodeNetwork.ViewModels
+{
+    /// <summary>
+    /// Viewmodel class for outputs on a node.
+    /// Outputs are endpoints that can only be connected to inputs.
+    /// </summary>
+    public class NodeOutputViewModel : Endpoint
+    {
+        static NodeOutputViewModel()
+        {
+            NNViewRegistrar.AddRegistration(() => new NodeOutputView(), typeof(IViewFor<NodeOutputViewModel>));
+        }
+
+        #region Logger
+        private static readonly log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
+        #endregion
+
+        public NodeOutputViewModel()
+        {
+            MaxConnections = Int32.MaxValue;
+            this.PortPosition = PortPosition.Right;
+        }
+
+        /// <summary>
+        /// Sets the pending connection in the network to a new connection with this endpoint as the output.
+        /// If the connection would be invalid, no pending connection is made.
+        /// Called when the user clicks on this endpoint.
+        /// </summary>
+        protected override void CreatePendingConnection()
+        {
+            NetworkViewModel network = Parent?.Parent;
+            if (network == null)
+            {
+                return;
+            }
+
+            if (Connections.Count >= MaxConnections)
+            {
+                return;
+            }
+
+            network.PendingConnection = new PendingConnectionViewModel(network) { Output = this, OutputIsLocked = true, LooseEndPoint = Port.CenterPoint };
+        }
+
+        /// <summary>
+        /// Sets this endpoint as the output of the pending connection and updates its validation.
+        /// Called when the user drags and holds a pending connection over this endpoint.
+        /// </summary>
+        /// <param name="previewActive">
+        /// True to set this endpoint as the output of the pending connection.
+        /// To remove this endpoint from the pending connection, set this to false.
+        /// </param>
+        protected override void SetConnectionPreview(bool previewActive)
+        {
+            PendingConnectionViewModel pendingCon = Parent.Parent.PendingConnection;
+            if (pendingCon.Output != null && (pendingCon.Output != this || pendingCon.OutputIsLocked))
+            {
+                return;
+            }
+
+            if (previewActive)
+            {
+                pendingCon.Output = this;
+                pendingCon.Validation = pendingCon.Input.ConnectionValidator(pendingCon);
+            }
+            else
+            {
+                pendingCon.Output = null;
+                pendingCon.Validation = null;
+            }
+        }
+
+        /// <summary>
+        /// Tries to create a new connection in the network based on the pending connection and this endpoint as the output.
+        /// If the connection would be invalid, no connection is made.
+        /// The pending connection is deleted.
+        /// Called when the user drags and releases a pending connection over this endpoint.
+        /// </summary>
+        protected override void FinishPendingConnection()
+        {
+            NetworkViewModel network = Parent?.Parent;
+            if (network == null)
+            {
+                return;
+            }
+
+            if (network.PendingConnection.Output == this && !network.PendingConnection.OutputIsLocked)
+            {
+                //Only allow drag from output to input, not input to input
+                if (network.PendingConnection.Input.Parent != network.PendingConnection.Output.Parent)
+                {
+                    //Dont allow connections between an input and an output on the same node
+                    if (network.PendingConnection.Validation.IsValid)
+                    {
+                        //Connection is valid
+                        if (MaxConnections > Connections.Count)
+                        {
+                            //MaxConnections hasn't been reached yet.
+                            if (!network.Connections.Items.Any(con => con.Output == this && con.Input == network.PendingConnection.Input))
+                            {
+                                //Connection does not exist already
+                                network.Connections.Add(network.ConnectionFactory(network.PendingConnection.Input, this));
+                            }
+                        }
+                    }
+                }
+            }
+
+            network.RemovePendingConnection();
+        }
+    }
+}