1 files changed, 50 insertions, 0 deletions
diff --git a/LibMatrix.EventTypes/EventContent.cs b/LibMatrix.EventTypes/EventContent.cs
new file mode 100644
index 0000000..608550f
--- /dev/null
+++ b/LibMatrix.EventTypes/EventContent.cs
@@ -0,0 +1,50 @@
+using System.Text.Json;
+using System.Text.Json.Nodes;
+using System.Text.Json.Serialization;
+
+namespace LibMatrix.EventTypes;
+
+public abstract class EventContent;
+
+public class UnknownEventContent : TimelineEventContent;
+
+public abstract class TimelineEventContent : EventContent {
+    [JsonPropertyName("m.relates_to")]
+    public MessageRelatesTo? RelatesTo { get; set; }
+
+    [JsonPropertyName("m.new_content")]
+    public JsonObject? NewContent { get; set; }
+
+    public TimelineEventContent SetReplaceRelation(string eventId) {
+        NewContent = JsonSerializer.SerializeToNode(this, GetType())!.AsObject();
+        // NewContent = JsonSerializer.Deserialize(jsonText, GetType());
+        RelatesTo = new MessageRelatesTo {
+            RelationType = "m.replace",
+            EventId = eventId
+        };
+        return this;
+    }
+
+    public T SetReplaceRelation<T>(string eventId) where T : TimelineEventContent {
+        return SetReplaceRelation(eventId) as T ?? throw new InvalidOperationException();
+    }
+
+    public class MessageRelatesTo {
+        [JsonPropertyName("m.in_reply_to")]
+        public EventInReplyTo? InReplyTo { get; set; }
+
+        [JsonPropertyName("event_id")]
+        public string? EventId { get; set; }
+
+        [JsonPropertyName("rel_type")]
+        public string? RelationType { get; set; }
+
+        public class EventInReplyTo {
+            [JsonPropertyName("event_id")]
+            public string? EventId { get; set; }
+
+            [JsonPropertyName("rel_type")]
+            public string? RelType { get; set; }
+        }
+    }
+}
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