From 01349724a938db9a76b7317dd6ea379d2382c36a Mon Sep 17 00:00:00 2001
From: Tangent Wantwight <tangent128@gmail.com>
Date: Sun, 16 Feb 2020 00:42:58 -0500
Subject: [PATCH] stub "loopback" server

---
 src/Game/Main.ts          |  3 +++
 src/Net/LockstepClient.ts |  4 ++--
 src/Net/LoopbackServer.ts | 24 ++++++++++++++++++++++++
 3 files changed, 29 insertions(+), 2 deletions(-)
 create mode 100644 src/Net/LoopbackServer.ts

diff --git a/src/Game/Main.ts b/src/Game/Main.ts
index f45dac9..521cb09 100644
--- a/src/Game/Main.ts
+++ b/src/Game/Main.ts
@@ -8,6 +8,7 @@ import { Create } from "../Ecs/Data";
 import {} from "../Ecs/Lockstep";
 import { RunRenderBounds } from "../Ecs/Renderers";
 import { LockstepClient } from "../Net/LockstepClient";
+import { Loopback } from "../Net/LoopbackServer";
 import { Data, Engine } from "./GameComponents";
 import { Buttons } from "./Input";
 
@@ -20,6 +21,8 @@ export class Main extends LockstepClient<KeyName[], Data> {
         super(new Engine());
         keys.setHandler(this.buttons);
 
+        this.connect(Loopback);
+
         subscribe((frame: Data) => {
             const drawSet = new DrawSet();
 
diff --git a/src/Net/LockstepClient.ts b/src/Net/LockstepClient.ts
index 7d09322..2f1d0d9 100644
--- a/src/Net/LockstepClient.ts
+++ b/src/Net/LockstepClient.ts
@@ -13,13 +13,13 @@ export const enum MessageTypes {
 export type Packet<TypeId, Payload> = { t: TypeId } & Payload;
 
 export type ClientMessage<Input, State> =
-    | Packet<MessageTypes.INPUT, { i: Partial<Input> }>;
+    | Packet<MessageTypes.INPUT, { i: Input }>;
 
 export type ServerMessage<Input, State> =
     | Packet<MessageTypes.RESET, { s: Partial<State> }>
     | Packet<MessageTypes.INPUT, { i: Input }>;
 
-type Server<Input, State> = Callbag<ClientMessage<Input, State>, ServerMessage<Input, State>>;
+export type Server<Input, State> = Callbag<ClientMessage<Input, State>, ServerMessage<Input, State>>;
 
 export abstract class LockstepClient<Input, State> {
 
diff --git a/src/Net/LoopbackServer.ts b/src/Net/LoopbackServer.ts
new file mode 100644
index 0000000..e2bbb1b
--- /dev/null
+++ b/src/Net/LoopbackServer.ts
@@ -0,0 +1,24 @@
+import { Callbag } from "callbag";
+
+import { ClientMessage, MessageTypes, ServerMessage } from "./LockstepClient";
+
+type Client<Input, State> = Callbag<ServerMessage<Input, State>, ClientMessage<Input, State>>;
+
+export function Loopback<Input, State>(start: number, data?: Client<Input, State> | ClientMessage<Input, State>) {
+    if(start != 0) return;
+
+    const sink = data as Client<Input, State>;
+
+    sink(0, (type: number, data?: Client<Input, State> | ClientMessage<Input, State>) => {
+        if(type == 1) {
+            // message from client; just reflect for now
+            const message = data as ClientMessage<Input, State>;
+            switch(message.t) {
+                case MessageTypes.INPUT:
+                    sink(1, message);
+                    break;
+            }
+        }
+    });
+    sink(1, {t: MessageTypes.RESET, s: {}});
+};