Add definition for messages from the API

ts/type/api.ts

@@ -606,6 +606,40 @@ export class Communication {
 	}
 }
 
+export enum MessageType {
+	Unknown = 0,
+	Email = 1,
+	Mailer = 2,
+	Text = 3,
+}
+
+export interface MessageDTO {
+	content: string;
+	created: string;
+	destination: string;
+	source: string;
+	type: number;
+}
+
+export class Message {
+	constructor(
+		public content: string,
+		public created: Date,
+		public destination: string,
+		public source: string,
+		public type: MessageType,
+	) {}
+	static fromJSON(json: MessageDTO): Message {
+		return new Message(
+			json.content,
+			new Date(json.created),
+			json.destination,
+			json.source,
+			json.type as MessageType,
+		);
+	}
+}
+
 export interface Pool {
 	condition: string;
 	id: number;