Implement support to send delayed push notification using .NET SDK.

Parse/Internal/Push/Coder/ParsePushEncoder.cs

@@ -36,6 +36,9 @@ public IDictionary<string, object> Encode(IPushState state) {
       } else if (state.ExpirationInterval.HasValue) {
         payload["expiration_interval"] = state.ExpirationInterval.Value.TotalSeconds;
       }
+      if (state.PushTime.HasValue) {
+        payload["push_time"] = state.PushTime.Value.ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ssZ");
+      }
 
       return payload;
     }

Parse/Internal/Push/State/IPushState.cs

@@ -9,6 +9,7 @@ internal interface IPushState {
     IEnumerable<string> Channels { get; }
     DateTime? Expiration { get; }
     TimeSpan? ExpirationInterval { get; }
+    DateTime? PushTime { get; }
     IDictionary<string, object> Data { get; }
     String Alert { get; }
 

Parse/Internal/Push/State/MutablePushState.cs

@@ -10,6 +10,7 @@ internal class MutablePushState : IPushState {
     public IEnumerable<string> Channels { get; set; }
     public DateTime? Expiration { get; set; }
     public TimeSpan? ExpirationInterval { get; set; }
+    public DateTime? PushTime { get; set; }
     public IDictionary<string, object> Data { get; set; }
     public String Alert { get; set; }
 
@@ -25,6 +26,7 @@ protected virtual MutablePushState MutableClone() {
         Channels = Channels == null ? null: new List<string>(Channels),
         Expiration = Expiration,
         ExpirationInterval = ExpirationInterval,
+        PushTime = PushTime,
         Data = Data == null ? null : new Dictionary<string, object>(Data),
         Alert = Alert
       };
@@ -40,6 +42,7 @@ public override bool Equals(object obj) {
              this.Channels.CollectionsEqual(other.Channels) &&
              Object.Equals(this.Expiration, other.Expiration) &&
              Object.Equals(this.ExpirationInterval, other.ExpirationInterval) &&
+             Object.Equals(this.PushTime, other.PushTime) &&
              this.Data.CollectionsEqual(other.Data) &&
              Object.Equals(this.Alert, other.Alert);
     }

Parse/ParsePush.cs

@@ -82,6 +82,19 @@ public DateTime? Expiration {
       }
     }
 
+    public DateTime? PushTime {
+      get { return state.PushTime; }
+      set {
+        MutateState(s => {
+          DateTime now = DateTime.Now;
+          if (value < now || value > now.AddDays(14)) {
+            throw new InvalidOperationException("Cannot set PushTime in the past or more than two weeks later than now");
+          }
+          s.PushTime = value;
+        });
+      }
+    }
+
     /// <summary>
     /// The time from initial schedul when this push will expire. This should not be used in tandem with Expiration.
     /// </summary>