1 files changed, 186 insertions, 0 deletions
diff --git a/client/src/net/game.ts b/client/src/net/game.ts
new file mode 100644
index 0000000..c8e5991
--- /dev/null
+++ b/client/src/net/game.ts
@@ -0,0 +1,186 @@
+import { Frame, GameState, Input, Key, KeyMap, PlayerInput } from "../types.js";
+import { startInputListener } from "./input.js";
+import { multiplayer } from "./multiplayer.js";
+
+/**
+ * @author tint
+ * @template Data, Input
+ */
+export class Game {
+
+    historysize: number
+    history: Frame[]
+    historyStart: number
+    currentFrame: number
+    advance: (pastData: GameState, input: Input, frame: number) => GameState
+
+	constructor(history: number) {
+		this.historysize = history;
+		
+		this.history = [];
+		this.historyStart = 0;
+		
+		// the game may have inputs from the "future"
+		// (local input delay to make sure inputs play at the same time on all machines)
+		// so the "present" isn't always the latest frame
+		// the game loop should set this every frame
+		this.currentFrame = 0;
+	}
+	
+	startHistory(frame: number, data: GameState) {
+		this.historyStart = frame;
+		this.history = [{ data, input: { players: {} }}];
+		this.currentFrame = frame;
+	}
+	
+	getHistory(frame: number): Frame {
+		return this.history[frame - this.historyStart];
+	}
+	
+	getFrame(): number {
+		return this.historyStart + this.history.length - 1;
+	}
+	
+	getCurrentData(): GameState {
+		const entry = this.history[this.history.length - 1];
+		return entry && entry.data;
+	}
+	
+	/**
+	 * Sets the input at a specific frame. If that frame is in history,
+	 * the game will be rewound, the input applied, and then fast-forwarded to the current head.
+	 * If the frame is ahead of the current latest frame, the game will be run until that frame.
+	 */
+	setInput(frame: number, input: Input) {
+        console.log('input', frame, input)
+		this.editFrame(frame, (index: number): void => {
+			let past = this.history[index - 1];
+			if(index === 0) {
+				past = { data: undefined, input: undefined };
+			}
+			this.history[index] = {
+				input,
+				data: this.advance(past ? past.data : undefined, input, frame),
+			};
+		});
+	}
+	
+	setData(frame: number, data: GameState) {
+        console.log('data', frame, data)
+		this.editFrame(frame, (index: number): void => {
+			this.history[index] = {
+				data,
+				input: this.history[index] && this.history[index].input,
+			}
+		});
+	}
+	
+	editFrame(frame: number, edit: (index: number) => void) {
+		const head = this.historyStart + this.history.length;
+		if(frame < head) {
+			if(frame < this.historyStart) {
+				throw new Error("Tried to edit a past frame not in history: " + frame);
+			}
+			
+			edit(frame - this.historyStart);
+			// fast forward back to the present with the new data
+			for(let i = frame + 1; i < head; i++) {
+				const past = this.history[i - this.historyStart - 1];
+				this.history[i - this.historyStart].data = this.advance(
+					past ? past.data : undefined,
+					this.history[i - this.historyStart].input,
+					i
+				);
+			}
+		} else {
+			// fast forward the inbetween frames with no input
+			for(let i = head; i < frame; i++) {
+				const entry = this.history[i - this.historyStart - 1];
+				this.history[i - this.historyStart] = {
+					input: undefined,
+					data: this.advance(entry ? entry.data : undefined, undefined, i),
+				};
+			}
+			edit(frame - this.historyStart);
+		}
+		
+		while(this.history.length > this.historysize) {
+			this.history.shift();
+			this.historyStart++;
+		}
+	}
+
+    start (
+        code: string,
+        keymap: KeyMap, 
+        onLoad: (startFrame: Frame) => boolean,
+        onFrame: (data: Frame, frame: number) => void,
+        onLogic: (pastData: GameState, input: Input, frame: number) => GameState, 
+        data: PlayerInput = { start: false, key: Key.NOTHING }
+    ): void {
+        
+	    const fps = 60;
+	    let delay = 3;
+
+        this.advance = onLogic
+
+        const onStart = (
+            startFrame: number, 
+            latency: number,
+            _connection: number,
+            update: (input: PlayerInput, frame: number) => void, 
+            _ping: () => Promise<number>, 
+            _desyncCheck: (frame: number) => Promise<boolean>,
+        ) => { 
+		    console.log("started game at frame", startFrame);
+		    // window.desyncCheck = () => desyncCheck(this.currentFrame - 5);
+            
+		    let startTs = performance.now() - latency;
+		    let lastFrame = startFrame;
+		    update(data, startFrame + 1);
+
+            let getInput = startInputListener(keymap)
+            
+            const startData = this.getHistory(startFrame)
+
+            if (!onLoad(startData)) return false
+
+		    let lastTs = performance.now();
+            
+            let loop = (ts: number) => {
+                
+			    const frame = Math.floor((ts - startTs) / 1000 * fps) + startFrame;
+
+			    if(frame !== lastFrame) { // update input once per frame, regardless of the display refresh rate
+			    	lastFrame = frame;
+			    	
+			    	// gather input
+			    	const input: PlayerInput = getInput();
+			    	
+			    	// apply input
+			    	update(input, frame + delay);
+			    }
+
+                this.currentFrame = frame
+                const data = this.getHistory(frame)
+
+                onFrame(data, frame)
+
+                lastTs = ts
+
+                requestAnimationFrame(loop)
+            }
+
+            requestAnimationFrame(loop)
+
+		    if(startFrame === -1) {
+			    update(data, 0);
+		    }
+
+            return true
+        }
+
+        multiplayer(this, code, onStart)
+
+    }
+}