basic state switching from loading to running to editing

bundle.js

@@ -2,6 +2,7 @@
   // lib/context.ts
   var contextStack = [];
   var defaultContext = {};
+  var debug = JSON.parse(localStorage.getItem("debug") || "false");
   function setDefaultContext(context) {
     Object.assign(defaultContext, context);
   }
@@ -17,9 +18,58 @@
       }
     }
   );
+  function getContext() {
+    return ctx;
+  }
   function getContextItem(prop) {
     return ctx[prop];
   }
+  function setContextItem(prop, value) {
+    Object.assign(contextStack[contextStack.length - 1] ?? defaultContext, {
+      [prop]: value
+    });
+  }
+  if (debug) {
+    setInterval(() => {
+      let ctxEl = document.getElementById("context");
+      if (!ctxEl) {
+        ctxEl = document.createElement("div");
+        ctxEl.id = "context";
+        document.body.append(ctxEl);
+      }
+      ctxEl.innerHTML = "";
+      const div = document.createElement("div");
+      const pre = document.createElement("pre");
+      const h3 = document.createElement("h3");
+      h3.textContent = "Default";
+      div.append(h3);
+      pre.textContent = safeStringify(defaultContext);
+      div.append(pre);
+      ctxEl.append(div);
+      for (const [idx, ctx2] of contextStack.entries()) {
+        const div2 = document.createElement("div");
+        const pre2 = document.createElement("pre");
+        const h32 = document.createElement("h3");
+        h32.textContent = "CTX " + idx;
+        div2.append(h32);
+        pre2.textContent = safeStringify(ctx2);
+        div2.append(pre2);
+        ctxEl.append(div2);
+      }
+    }, 1e3);
+  }
+  function safeStringify(obj) {
+    const seen = /* @__PURE__ */ new WeakSet();
+    return JSON.stringify(obj, (key, value) => {
+      if (typeof value === "object" && value !== null) {
+        if (seen.has(value)) {
+          return "[Circular]";
+        }
+        seen.add(value);
+      }
+      return value;
+    }, 2);
+  }
 
   // lib/input.ts
   var InputManager = class {
@@ -71,7 +121,9 @@
       this.mouseEvents.set(key, cb);
     }
     offKey(key) {
+      const events = this.keyEvents.get(key);
       this.keyEvents.delete(key);
+      return events;
     }
     offMouse(key) {
       this.mouseEvents.delete(key);
@@ -1077,6 +1129,164 @@
     };
   }
 
+  // state/machine.ts
+  var StateMachine = class {
+    _states = /* @__PURE__ */ new Map();
+    currentState;
+    update(dt, ctx2) {
+      this.currentState?.update(dt, ctx2);
+    }
+    get current() {
+      return this.currentState;
+    }
+    get states() {
+      return this._states;
+    }
+    addState(state2) {
+      this.states.set(state2.name, state2);
+    }
+    transitionTo(state2) {
+      if (!this.current) {
+        this.currentState = this._states.get(state2);
+        this.currentState.start();
+        return;
+      }
+      if (this.current?.canTransitionTo(state2) && this._states.has(state2)) {
+        this.current.stop();
+        this.currentState = this._states.get(state2);
+        this.current.start();
+      }
+    }
+  };
+  var State = class {
+    stateMachine;
+    constructor(stateMachine) {
+      this.stateMachine = stateMachine;
+    }
+    canTransitionTo(state2) {
+      return this.validTransitions.has(state2);
+    }
+  };
+
+  // state/states/EditTrainState.ts
+  var EditTrainState = class extends State {
+    name = 4 /* EDIT_TRAIN */;
+    validTransitions = /* @__PURE__ */ new Set([
+      1 /* RUNNING */,
+      2 /* PAUSED */
+    ]);
+    update(dt) {
+      throw new Error("Method not implemented.");
+    }
+    start() {
+      throw new Error("Method not implemented.");
+    }
+    stop() {
+      throw new Error("Method not implemented.");
+    }
+  };
+
+  // state/states/EditTrackState.ts
+  var EditTrackState = class extends State {
+    name = 3 /* EDIT_TRACK */;
+    validTransitions = /* @__PURE__ */ new Set([
+      1 /* RUNNING */,
+      2 /* PAUSED */
+    ]);
+    heldEvents = /* @__PURE__ */ new Map();
+    update(dt) {
+      const inputManager2 = getContextItem("inputManager");
+      const track = getContextItem("track");
+      const firstSegment = track.firstSegment;
+      if (firstSegment) {
+        const firstPoint = firstSegment.points[0].copy();
+        const { x, y } = inputManager2.getMouseLocation();
+        firstSegment.points.forEach((p, i) => {
+          const relativePoint = Vector.sub(p, firstPoint);
+          p.set(x, y);
+          p.add(relativePoint);
+        });
+      }
+      track.draw(true);
+    }
+    start() {
+      const inputManager2 = getContextItem("inputManager");
+      this.heldEvents.set("e", inputManager2.offKey("e"));
+      this.heldEvents.set("Escape", inputManager2.offKey("Escape"));
+      inputManager2.onKey("e", () => {
+        const state2 = getContextItem("state");
+        state2.transitionTo(1 /* RUNNING */);
+      });
+      const track = getContextItem("track");
+      setContextItem("trackCopy", track.copy());
+      inputManager2.onKey("Escape", () => {
+        const trackCopy = getContextItem("trackCopy");
+        setContextItem("track", trackCopy);
+        const state2 = getContextItem("state");
+        state2.transitionTo(1 /* RUNNING */);
+      });
+    }
+    stop() {
+      if (this.heldEvents.size > 0) {
+        for (const [key, cb] of this.heldEvents) {
+          if (cb) {
+            getContextItem("inputManager").onKey(key, cb);
+          }
+          this.heldEvents.delete(key);
+        }
+      }
+    }
+  };
+
+  // state/states/PausedState.ts
+  var PausedState = class extends State {
+    name = 2 /* PAUSED */;
+    validTransitions = /* @__PURE__ */ new Set([
+      0 /* LOAD */,
+      1 /* RUNNING */,
+      3 /* EDIT_TRACK */,
+      4 /* EDIT_TRAIN */
+    ]);
+    update(dt) {
+      throw new Error("Method not implemented.");
+    }
+    start() {
+      throw new Error("Method not implemented.");
+    }
+    stop() {
+      throw new Error("Method not implemented.");
+    }
+  };
+
+  // state/states/RunningState.ts
+  var RunningState = class extends State {
+    name = 1 /* RUNNING */;
+    validTransitions = /* @__PURE__ */ new Set([
+      2 /* PAUSED */,
+      3 /* EDIT_TRACK */
+    ]);
+    update(dt) {
+      const ctx2 = getContext();
+      ctx2.track.draw();
+      for (const train of ctx2.trains) {
+        train.draw();
+      }
+    }
+    start() {
+    }
+    stop() {
+    }
+  };
+
+  // inputs.ts
+  function bootstrapInputs() {
+    const inputManager2 = getContextItem("inputManager");
+    inputManager2.onKey("e", () => {
+      const state2 = getContextItem("state");
+      state2.transitionTo(3 /* EDIT_TRACK */);
+    });
+  }
+
   // math/path.ts
   var PathSegment = class {
     points;
@@ -1224,11 +1434,16 @@
     doodler;
     constructor(segments) {
       this.doodler = getContextItem("doodler");
-      this.segments = segments;
+      for (const segment of segments) {
+        this.segments.set(segment.id, segment);
+      }
     }
-    draw() {
-      for (const segment of this.segments) {
-        segment.draw();
+    get firstSegment() {
+      return this.segments.values().next().value;
+    }
+    draw(showControls = false) {
+      for (const segment of this.segments.values()) {
+        segment.draw(showControls);
       }
       try {
         if (getContextItem("showEnds")) {
@@ -1256,7 +1471,7 @@
     }
     findEnds() {
       const ends = [];
-      for (const segment of this.segments) {
+      for (const segment of this.segments.values()) {
         const [a, b, c, d] = segment.points;
         {
           const tangent = Vector.sub(a, b).normalize();
@@ -1274,12 +1489,33 @@
     serialize() {
       return this.segments.values().map((s) => s.serialize()).toArray();
     }
-    static deserialize(data) {
-      const track2 = new _TrackSystem([]);
-      for (const segment of data) {
-        track2.segments.set(segment.id, TrackSegment.deserialize(segment));
+    copy() {
+      const track = new _TrackSystem([]);
+      for (const segment of this.segments.values()) {
+        track.segments.set(segment.id, segment.copy());
       }
-      return track2;
+      return track;
+    }
+    static deserialize(data) {
+      if (data.length === 0) return void 0;
+      const track = new _TrackSystem([]);
+      const neighborMap = /* @__PURE__ */ new Map();
+      for (const segment of data) {
+        track.segments.set(segment.id, TrackSegment.deserialize(segment));
+      }
+      for (const segment of track.segments.values()) {
+        segment.setTrack(track);
+        const neighbors = neighborMap.get(segment.id);
+        if (neighbors) {
+          segment.backNeighbours = neighbors[1].map(
+            (id) => track.segments.get(id)
+          ).filter((s) => s);
+          segment.frontNeighbours = neighbors[0].map(
+            (id) => track.segments.get(id)
+          ).filter((s) => s);
+        }
+      }
+      return track;
     }
   };
   var TrackSegment = class _TrackSegment extends PathSegment {
@@ -1296,7 +1532,7 @@
     setTrack(t) {
       this.track = t;
     }
-    draw() {
+    draw(showControls = false) {
       this.doodler.drawBezier(
         this.points[0],
         this.points[1],
@@ -1306,6 +1542,16 @@
           strokeColor: "#ffffff50"
         }
       );
+      if (showControls) {
+        this.doodler.drawCircle(this.points[1], 4, {
+          color: "red",
+          weight: 3
+        });
+        this.doodler.drawCircle(this.points[2], 4, {
+          color: "red",
+          weight: 3
+        });
+      }
     }
     serialize() {
       return {
@@ -1315,6 +1561,12 @@
         fNeighbors: this.frontNeighbours.map((n) => n.id)
       };
     }
+    copy() {
+      return new _TrackSegment(
+        this.points.map((p) => p.copy()),
+        this.id
+      );
+    }
     static deserialize(data) {
       return new _TrackSegment(
         data.p.map((p) => new Vector(p[0], p[1], p[2])),
@@ -1328,7 +1580,7 @@
     constructor(start) {
       start = start || new Vector(100, 100);
       super([
-        start.copy(),
+        start,
         start.copy().add(25, 0),
         start.copy().add(75, 0),
         start.copy().add(100, 0)
@@ -1336,6 +1588,52 @@
     }
   };
 
+  // state/states/LoadState.ts
+  var LoadState = class extends State {
+    name = 0 /* LOAD */;
+    validTransitions = /* @__PURE__ */ new Set([
+      1 /* RUNNING */
+    ]);
+    update() {
+    }
+    start() {
+      const track = this.loadTrack() ?? new TrackSystem([new StraightTrack()]);
+      setContextItem("track", track);
+      const trains = this.loadTrains() ?? [];
+      setContextItem("trains", trains);
+      const resources2 = new ResourceManager();
+      setContextItem("resources", resources2);
+      const inputManager2 = new InputManager();
+      setContextItem("inputManager", inputManager2);
+      bootstrapInputs();
+      this.stateMachine.transitionTo(1 /* RUNNING */);
+    }
+    stop() {
+    }
+    loadTrack() {
+      const track = TrackSystem.deserialize(
+        JSON.parse(localStorage.getItem("track") || "[]")
+      );
+      return track;
+    }
+    loadTrains() {
+      const trains = JSON.parse(localStorage.getItem("trains") || "[]");
+      return trains;
+    }
+  };
+
+  // state/states/index.ts
+  function bootstrapGameStateMachine() {
+    const stateMachine = new StateMachine();
+    stateMachine.addState(new LoadState(stateMachine));
+    stateMachine.addState(new RunningState(stateMachine));
+    stateMachine.addState(new PausedState(stateMachine));
+    stateMachine.addState(new EditTrackState(stateMachine));
+    stateMachine.addState(new EditTrainState(stateMachine));
+    stateMachine.transitionTo(0 /* LOAD */);
+    return stateMachine;
+  }
+
   // main.ts
   var inputManager = new InputManager();
   var resources = new ResourceManager();
@@ -1350,6 +1648,8 @@
     debug: true,
     showEnds: true
   });
+  var state = bootstrapGameStateMachine();
+  setContextItem("state", state);
   doodler.init();
   addButton({
     text: "Hello World!",
@@ -1365,8 +1665,7 @@
       color: "white"
     }
   });
-  var track = new TrackSystem([new StraightTrack()]);
-  doodler.createLayer(() => {
-    track.draw();
+  doodler.createLayer((_, __, dTime) => {
+    state.update(dTime);
   });
 })();

deno.json

@@ -13,7 +13,6 @@
     "dev": "deno run -RWEN --allow-run dev.ts dev"
   },
   "imports": {
-    "@bearmetal/doodler": "jsr:@bearmetal/doodler@^0.0.3",
-    "@lib/": "./lib/"
+    "@bearmetal/doodler": "jsr:@bearmetal/doodler@^0.0.3"
   }
 }

deno.lock

@@ -3,6 +3,7 @@
   "specifiers": {
     "jsr:@bearmetal/doodler@^0.0.3": "0.0.3",
     "jsr:@luca/esbuild-deno-loader@*": "0.11.0",
+    "jsr:@luca/esbuild-deno-loader@0.11.1": "0.11.1",
     "jsr:@std/assert@*": "1.0.10",
     "jsr:@std/assert@^1.0.10": "1.0.10",
     "jsr:@std/bytes@^1.0.2": "1.0.2",
@@ -32,6 +33,14 @@
         "jsr:@std/path@^1.0.6"
       ]
     },
+    "@luca/esbuild-deno-loader@0.11.1": {
+      "integrity": "dc020d16d75b591f679f6b9288b10f38bdb4f24345edb2f5732affa1d9885267",
+      "dependencies": [
+        "jsr:@std/bytes",
+        "jsr:@std/encoding",
+        "jsr:@std/path@^1.0.6"
+      ]
+    },
     "@std/assert@1.0.10": {
       "integrity": "59b5cbac5bd55459a19045d95cc7c2ff787b4f8527c0dd195078ff6f9481fbb3",
       "dependencies": [

dev.ts

@@ -1,7 +1,7 @@
 /// <reference lib="deno.ns" />
 
 import * as esbuild from "npm:esbuild";
-import { denoPlugins } from "jsr:@luca/esbuild-deno-loader";
+import { denoPlugins } from "jsr:@luca/esbuild-deno-loader@0.11.1";
 import { serveDir } from "jsr:@std/http";
 
 async function* crawl(dir: string): AsyncIterable<string> {

index.html

@@ -14,6 +14,18 @@
       height: 100%;
       width: 100%;
     }
+    #context {
+      position: absolute;
+      top: 0;
+      left: 0;
+      background-color: rgba(0, 0, 0, 0.5);
+      color: white;
+      padding: 10px;
+      display: flex;
+      gap: 10px;
+      max-height: 50vh;
+      overflow-y: auto;
+    }
   </style>
 </head>
 <body>

inputs.ts

@@ -0,0 +1,12 @@
+import { getContextItem } from "./lib/context.ts";
+import { InputManager } from "./lib/input.ts";
+import { StateMachine } from "./state/machine.ts";
+import { States } from "./state/states/index.ts";
+
+export function bootstrapInputs() {
+  const inputManager = getContextItem<InputManager>("inputManager");
+  inputManager.onKey("e", () => {
+    const state = getContextItem<StateMachine<States>>("state");
+    state.transitionTo(States.EDIT_TRACK);
+  });
+}

lib/context.ts

@@ -3,6 +3,8 @@ type ContextStore = Record<string, any>;
 const contextStack: ContextStore[] = [];
 const defaultContext: ContextStore = {};
 
+const debug = JSON.parse(localStorage.getItem("debug") || "false");
+
 export function setDefaultContext(context: ContextStore) {
   Object.assign(defaultContext, context);
 }
@@ -23,7 +25,7 @@ export const ctx = new Proxy(
       for (let i = contextStack.length - 1; i >= 0; i--) {
         if (prop in contextStack[i]) return contextStack[i][prop];
       }
-      if (prop in defaultContext) return defaultContext[prop]; // ✅ Fallback to default
+      if (prop in defaultContext) return defaultContext[prop];
       throw new Error(`Context variable '${prop}' is not defined.`);
     },
   },
@@ -35,3 +37,51 @@ export function getContext() {
 export function getContextItem<T>(prop: string): T {
   return ctx[prop] as T;
 }
+export function setContextItem<T>(prop: string, value: T) {
+  Object.assign(contextStack[contextStack.length - 1] ?? defaultContext, {
+    [prop]: value,
+  });
+}
+
+if (debug) {
+  setInterval(() => {
+    let ctxEl = document.getElementById("context");
+    if (!ctxEl) {
+      ctxEl = document.createElement("div");
+      ctxEl.id = "context";
+      document.body.append(ctxEl);
+    }
+    ctxEl.innerHTML = "";
+    const div = document.createElement("div");
+    const pre = document.createElement("pre");
+    const h3 = document.createElement("h3");
+    h3.textContent = "Default";
+    div.append(h3);
+    pre.textContent = safeStringify(defaultContext);
+    div.append(pre);
+    ctxEl.append(div);
+    for (const [idx, ctx] of contextStack.entries()) {
+      const div = document.createElement("div");
+      const pre = document.createElement("pre");
+      const h3 = document.createElement("h3");
+      h3.textContent = "CTX " + idx;
+      div.append(h3);
+      pre.textContent = safeStringify(ctx);
+      div.append(pre);
+      ctxEl.append(div);
+    }
+  }, 1000);
+}
+
+function safeStringify(obj: any) {
+  const seen = new WeakSet();
+  return JSON.stringify(obj, (key, value) => {
+    if (typeof value === "object" && value !== null) {
+      if (seen.has(value)) {
+        return "[Circular]"; // Replace circular references
+      }
+      seen.add(value);
+    }
+    return value;
+  }, 2);
+}

lib/input.ts

@@ -53,7 +53,9 @@ export class InputManager {
   }
 
   offKey(key: string | number) {
+    const events = this.keyEvents.get(key);
     this.keyEvents.delete(key);
+    return events;
   }
   offMouse(key: string | number) {
     this.mouseEvents.delete(key);

main.ts

@@ -1,4 +1,8 @@
-import { setDefaultContext } from "./lib/context.ts";
+import {
+  getContext,
+  setContextItem,
+  setDefaultContext,
+} from "./lib/context.ts";
 import { InputManager } from "./lib/input.ts";
 
 import { Doodler, Vector, ZoomableDoodler } from "@bearmetal/doodler";
@@ -6,6 +10,8 @@ import { ResourceManager } from "./lib/resources.ts";
 import { addButton } from "./ui/button.ts";
 import { TrackSystem } from "./track/system.ts";
 import { StraightTrack } from "./track/shapes.ts";
+import { StateMachine } from "./state/machine.ts";
+import { bootstrapGameStateMachine } from "./state/states/index.ts";
 
 const inputManager = new InputManager();
 const resources = new ResourceManager();
@@ -22,6 +28,9 @@ setDefaultContext({
   showEnds: true,
 });
 
+const state = bootstrapGameStateMachine();
+setContextItem("state", state);
+
 doodler.init();
 addButton({
   text: "Hello World!",
@@ -38,8 +47,6 @@ addButton({
   },
 });
 
-const track = new TrackSystem([new StraightTrack()]);
-
-doodler.createLayer(() => {
-  track.draw();
+doodler.createLayer((_, __, dTime) => {
+  state.update(dTime);
 });

state/machine.ts

@@ -1,13 +1,9 @@
-export class StateMachine {
-  private _states: Map<string, State> = new Map();
-  private currentState: State;
+export class StateMachine<T> {
+  private _states: Map<T, State<T>> = new Map();
+  private currentState?: State<T>;
 
-  constructor(states: State[]) {
-    this.currentState = states[0];
-  }
-
-  update(dt: number) {
-    this.currentState.update(dt);
+  update(dt: number, ctx?: CanvasRenderingContext2D) {
+    this.currentState?.update(dt, ctx);
   }
 
   get current() {
@@ -18,32 +14,37 @@ export class StateMachine {
     return this._states;
   }
 
-  addState(state: State) {
+  addState(state: State<T>) {
     this.states.set(state.name, state);
   }
 
-  transitionTo(state: State) {
-    if (this.current.canTransitionTo(state)) {
+  transitionTo(state: T) {
+    if (!this.current) {
+      this.currentState = this._states.get(state)!;
+      this.currentState.start();
+      return;
+    }
+    if (this.current?.canTransitionTo(state) && this._states.has(state)) {
       this.current.stop();
-      this.currentState = state;
+      this.currentState = this._states.get(state)!;
       this.current.start();
     }
   }
 }
 
 export abstract class State<T> {
-  private stateMachine: StateMachine;
+  protected stateMachine: StateMachine<T>;
   protected abstract validTransitions: Set<T>;
 
   abstract readonly name: T;
 
   constructor(
-    stateMachine: StateMachine,
+    stateMachine: StateMachine<T>,
   ) {
     this.stateMachine = stateMachine;
   }
 
-  abstract update(dt: number): void;
+  abstract update(dt: number, ctx?: CanvasRenderingContext2D): void;
   abstract start(): void;
   abstract stop(): void;
 
@@ -51,3 +52,25 @@ export abstract class State<T> {
     return this.validTransitions.has(state);
   }
 }
+
+export abstract class ExtensibleState<T> extends State<T> {
+  extensions: Map<string, (...args: unknown[]) => void> = new Map();
+  registerExtension(name: string, cb: (...args: unknown[]) => void) {
+    this.extensions.set(name, cb);
+  }
+
+  constructor(stateMachine: StateMachine<T>) {
+    super(stateMachine);
+    const oldUpdate = this.update;
+    this.update = function (dt: number, ctx?: CanvasRenderingContext2D) {
+      oldUpdate.apply(this, [dt, ctx]);
+      this.runExtensions(dt, ctx);
+    };
+  }
+
+  runExtensions(...args: unknown[]) {
+    for (const [name, cb] of this.extensions) {
+      cb(...args);
+    }
+  }
+}

state/states.ts

@@ -1,139 +0,0 @@
-import { State } from "./machine.ts";
-
-enum States {
-  LOAD,
-  RUNNING,
-  PAUSED,
-  EDIT_TRACK,
-  EDIT_TRAIN,
-}
-
-export class LoadState extends State<States> {
-  override name: States = States.LOAD;
-  override validTransitions: Set<States> = new Set([
-    States.RUNNING,
-  ]);
-
-  override update(dt: number): void {
-    throw new Error("Method not implemented.");
-    // TODO
-    // Do nothing
-  }
-  override start(): void {
-    throw new Error("Method not implemented.");
-    // TODO
-    // load track into context
-    // Load trains into context
-    // Load resources into context
-    // Switch to running state
-  }
-  override stop(): void {
-    throw new Error("Method not implemented.");
-    // TODO
-    // Do nothing
-  }
-}
-
-export class RunningState extends State<States> {
-  override name: States = States.RUNNING;
-  override validTransitions: Set<States> = new Set([
-    States.PAUSED,
-    States.EDIT_TRACK,
-  ]);
-  override update(dt: number): void {
-    throw new Error("Method not implemented.");
-    // TODO
-    // Update trains
-    // Update world
-    // Handle input
-    // Draw (maybe via a layer system that syncs with doodler)
-    // Monitor world events
-  }
-  override start(): void {
-    throw new Error("Method not implemented.");
-    // TODO
-    // Do nothing
-  }
-  override stop(): void {
-    throw new Error("Method not implemented.");
-    // TODO
-    // Do nothing
-  }
-}
-
-export class PausedState extends State<States> {
-  override name: States = States.PAUSED;
-  override validTransitions: Set<States> = new Set([
-    States.LOAD,
-    States.RUNNING,
-    States.EDIT_TRACK,
-    States.EDIT_TRAIN,
-  ]);
-  override update(dt: number): void {
-    throw new Error("Method not implemented.");
-    // TODO
-    // Handle input
-    // Draw ui
-  }
-  override start(): void {
-    throw new Error("Method not implemented.");
-    // TODO
-    // Save tracks to cache
-    // Save trains to cache
-    // Save resources to cache
-  }
-  override stop(): void {
-    throw new Error("Method not implemented.");
-    // TODO
-    // Do nothing
-  }
-}
-
-export class EditTrackState extends State<States> {
-  override name: States = States.EDIT_TRACK;
-  override validTransitions: Set<States> = new Set([
-    States.RUNNING,
-    States.PAUSED,
-  ]);
-  override update(dt: number): void {
-    throw new Error("Method not implemented.");
-    // TODO
-    // Handle input
-    // Draw ui
-    // Draw track
-    // Draw track points
-    // Draw track tangents
-  }
-  override start(): void {
-    throw new Error("Method not implemented.");
-    // TODO
-    // Cache trains and save
-    // Stash track in context
-  }
-  override stop(): void {
-    throw new Error("Method not implemented.");
-  }
-}
-
-export class EditTrainState extends State<States> {
-  override name: States = States.EDIT_TRAIN;
-  override validTransitions: Set<States> = new Set([
-    States.RUNNING,
-    States.PAUSED,
-  ]);
-
-  override update(dt: number): void {
-    throw new Error("Method not implemented.");
-  }
-  override start(): void {
-    throw new Error("Method not implemented.");
-    // TODO
-    // Cache trains
-    // Stash train in context
-    // Draw track
-    // Draw train (filtered by train ID)
-  }
-  override stop(): void {
-    throw new Error("Method not implemented.");
-  }
-}

state/states/EditTrackState.ts

@@ -0,0 +1,70 @@
+import { Vector } from "@bearmetal/doodler";
+import { getContextItem, setContextItem } from "../../lib/context.ts";
+import { InputManager } from "../../lib/input.ts";
+import { TrackSystem } from "../../track/system.ts";
+import { State, StateMachine } from "../machine.ts";
+import { States } from "./index.ts";
+
+export class EditTrackState extends State<States> {
+  override name: States = States.EDIT_TRACK;
+  override validTransitions: Set<States> = new Set([
+    States.RUNNING,
+    States.PAUSED,
+  ]);
+
+  private heldEvents: Map<string | number, (() => void) | undefined> =
+    new Map();
+
+  override update(dt: number): void {
+    const inputManager = getContextItem<InputManager>("inputManager");
+    const track = getContextItem<TrackSystem>("track");
+
+    const firstSegment = track.firstSegment;
+    if (firstSegment) {
+      const firstPoint = firstSegment.points[0].copy();
+      const { x, y } = inputManager.getMouseLocation();
+      firstSegment.points.forEach((p, i) => {
+        const relativePoint = Vector.sub(p, firstPoint);
+        p.set(x, y);
+        p.add(relativePoint);
+      });
+    }
+
+    track.draw(true);
+    // TODO
+    // Draw ui
+    // Draw track points
+    // Draw track tangents
+  }
+  override start(): void {
+    const inputManager = getContextItem<InputManager>("inputManager");
+    this.heldEvents.set("e", inputManager.offKey("e"));
+    this.heldEvents.set("Escape", inputManager.offKey("Escape"));
+    inputManager.onKey("e", () => {
+      const state = getContextItem<StateMachine<States>>("state");
+      state.transitionTo(States.RUNNING);
+    });
+
+    const track = getContextItem<TrackSystem>("track");
+    setContextItem("trackCopy", track.copy());
+    inputManager.onKey("Escape", () => {
+      const trackCopy = getContextItem<TrackSystem>("trackCopy");
+      setContextItem("track", trackCopy);
+      const state = getContextItem<StateMachine<States>>("state");
+      state.transitionTo(States.RUNNING);
+    });
+    // TODO
+    // Cache trains and save
+    // Stash track in context
+  }
+  override stop(): void {
+    if (this.heldEvents.size > 0) {
+      for (const [key, cb] of this.heldEvents) {
+        if (cb) {
+          getContextItem<InputManager>("inputManager").onKey(key, cb);
+        }
+        this.heldEvents.delete(key);
+      }
+    }
+  }
+}

state/states/EditTrainState.ts

@@ -0,0 +1,25 @@
+import { State } from "../machine.ts";
+import { States } from "./index.ts";
+
+export class EditTrainState extends State<States> {
+  override name: States = States.EDIT_TRAIN;
+  override validTransitions: Set<States> = new Set([
+    States.RUNNING,
+    States.PAUSED,
+  ]);
+
+  override update(dt: number): void {
+    throw new Error("Method not implemented.");
+  }
+  override start(): void {
+    throw new Error("Method not implemented.");
+    // TODO
+    // Cache trains
+    // Stash train in context
+    // Draw track
+    // Draw train (filtered by train ID)
+  }
+  override stop(): void {
+    throw new Error("Method not implemented.");
+  }
+}

state/states/LoadState.ts

@@ -0,0 +1,51 @@
+import { bootstrapInputs } from "../../inputs.ts";
+import { setContextItem } from "../../lib/context.ts";
+import { InputManager } from "../../lib/input.ts";
+import { ResourceManager } from "../../lib/resources.ts";
+import { StraightTrack } from "../../track/shapes.ts";
+import { TrackSystem } from "../../track/system.ts";
+import { State } from "../machine.ts";
+import { States } from "./index.ts";
+
+export class LoadState extends State<States> {
+  override name: States = States.LOAD;
+  override validTransitions: Set<States> = new Set([
+    States.RUNNING,
+  ]);
+
+  override update(): void {
+    // noop
+  }
+  override start(): void {
+    const track = this.loadTrack() ?? new TrackSystem([new StraightTrack()]);
+    setContextItem("track", track);
+
+    const trains = this.loadTrains() ?? [];
+    setContextItem("trains", trains);
+
+    const resources = new ResourceManager();
+    setContextItem("resources", resources);
+
+    const inputManager = new InputManager();
+    setContextItem("inputManager", inputManager);
+
+    bootstrapInputs();
+
+    this.stateMachine.transitionTo(States.RUNNING);
+  }
+  override stop(): void {
+    // noop
+  }
+
+  private loadTrack() {
+    const track = TrackSystem.deserialize(
+      JSON.parse(localStorage.getItem("track") || "[]"),
+    );
+    return track;
+  }
+
+  private loadTrains() {
+    const trains = JSON.parse(localStorage.getItem("trains") || "[]");
+    return trains;
+  }
+}

state/states/PausedState.ts

@@ -0,0 +1,30 @@
+import { State } from "../machine.ts";
+import { States } from "./index.ts";
+
+export class PausedState extends State<States> {
+  override name: States = States.PAUSED;
+  override validTransitions: Set<States> = new Set([
+    States.LOAD,
+    States.RUNNING,
+    States.EDIT_TRACK,
+    States.EDIT_TRAIN,
+  ]);
+  override update(dt: number): void {
+    throw new Error("Method not implemented.");
+    // TODO
+    // Handle input
+    // Draw ui
+  }
+  override start(): void {
+    throw new Error("Method not implemented.");
+    // TODO
+    // Save tracks to cache
+    // Save trains to cache
+    // Save resources to cache
+  }
+  override stop(): void {
+    throw new Error("Method not implemented.");
+    // TODO
+    // Do nothing
+  }
+}

state/states/RunningState.ts

@@ -0,0 +1,32 @@
+import { getContext } from "../../lib/context.ts";
+import { TrackSystem } from "../../track/system.ts";
+import { Train } from "../../train/train.ts";
+import { State } from "../machine.ts";
+import { States } from "./index.ts";
+
+export class RunningState extends State<States> {
+  override name: States = States.RUNNING;
+  override validTransitions: Set<States> = new Set([
+    States.PAUSED,
+    States.EDIT_TRACK,
+  ]);
+  override update(dt: number): void {
+    const ctx = getContext() as { trains: Train[]; track: TrackSystem };
+    // TODO
+    // Update trains
+    // Update world
+    // Handle input
+    // Draw (maybe via a layer system that syncs with doodler)
+    ctx.track.draw();
+    for (const train of ctx.trains) {
+      train.draw();
+    }
+    // Monitor world events
+  }
+  override start(): void {
+    // noop
+  }
+  override stop(): void {
+    // noop
+  }
+}

state/states/index.ts

@@ -0,0 +1,26 @@
+import { StateMachine } from "../machine.ts";
+import { Track } from "../../track.ts";
+import { EditTrainState } from "./EditTrainState.ts";
+import { EditTrackState } from "./EditTrackState.ts";
+import { PausedState } from "./PausedState.ts";
+import { RunningState } from "./RunningState.ts";
+import { LoadState } from "./LoadState.ts";
+
+export enum States {
+  LOAD,
+  RUNNING,
+  PAUSED,
+  EDIT_TRACK,
+  EDIT_TRAIN,
+}
+
+export function bootstrapGameStateMachine() {
+  const stateMachine = new StateMachine<States>();
+  stateMachine.addState(new LoadState(stateMachine));
+  stateMachine.addState(new RunningState(stateMachine));
+  stateMachine.addState(new PausedState(stateMachine));
+  stateMachine.addState(new EditTrackState(stateMachine));
+  stateMachine.addState(new EditTrainState(stateMachine));
+  stateMachine.transitionTo(States.LOAD);
+  return stateMachine;
+}

test/contextBench.test.js

@@ -1,10 +1,16 @@
 import {
   getContextItem,
+  setContextItem,
   setDefaultContext,
   withContext,
-} from "@lib/context.ts"; // adjust path as needed
+} from "../lib/context.ts"; // adjust path as needed
 import { testPerformance } from "./bench.ts";
 
+/**
+ * Benchmarks the performance of setting and getting context items.
+ * All context transactions should run 10000 times within the 60 FPS frame time.
+ * getContextItem should run 100000 times within the 240 FPS frame time to ensure adequate performance.
+ */
 Deno.test("Context Benchmark", () => {
   console.log("Context Benchmark - run within frame time");
   testPerformance(
@@ -32,4 +38,12 @@ Deno.test("Context Benchmark", () => {
     100000,
     240,
   );
+
+  testPerformance(
+    () => {
+      setContextItem("a", 1);
+    },
+    10000,
+    60,
+  );
 });

track/system.ts

@@ -13,9 +13,13 @@ export class TrackSystem {
     }
   }
 
-  draw() {
+  get firstSegment() {
+    return this.segments.values().next().value;
+  }
+
+  draw(showControls = false) {
     for (const segment of this.segments.values()) {
-      segment.draw();
+      segment.draw(showControls);
     }
 
     try {
@@ -65,15 +69,39 @@ export class TrackSystem {
     return this.segments.values().map((s) => s.serialize()).toArray();
   }
 
-  static deserialize(data: any) {
+  copy() {
     const track = new TrackSystem([]);
+    for (const segment of this.segments.values()) {
+      track.segments.set(segment.id, segment.copy());
+    }
+    return track;
+  }
+
+  static deserialize(data: any) {
+    if (data.length === 0) return undefined;
+    const track = new TrackSystem([]);
+    const neighborMap = new Map<string, [string[], string[]]>();
     for (const segment of data) {
       track.segments.set(segment.id, TrackSegment.deserialize(segment));
     }
+    for (const segment of track.segments.values()) {
+      segment.setTrack(track);
+      const neighbors = neighborMap.get(segment.id);
+      if (neighbors) {
+        segment.backNeighbours = neighbors[1].map((id) =>
+          track.segments.get(id)
+        ).filter((s) => s) as TrackSegment[];
+        segment.frontNeighbours = neighbors[0].map((id) =>
+          track.segments.get(id)
+        ).filter((s) => s) as TrackSegment[];
+      }
+    }
     return track;
   }
 }
 
+type VectorSet = [Vector, Vector, Vector, Vector];
+
 export class TrackSegment extends PathSegment {
   frontNeighbours: TrackSegment[] = [];
   backNeighbours: TrackSegment[] = [];
@@ -84,7 +112,7 @@ export class TrackSegment extends PathSegment {
 
   id: string;
 
-  constructor(p: [Vector, Vector, Vector, Vector], id?: string) {
+  constructor(p: VectorSet, id?: string) {
     super(p);
     this.doodler = getContextItem<Doodler>("doodler");
     this.id = id ?? crypto.randomUUID();
@@ -94,7 +122,7 @@ export class TrackSegment extends PathSegment {
     this.track = t;
   }
 
-  draw() {
+  draw(showControls = false) {
     this.doodler.drawBezier(
       this.points[0],
       this.points[1],
@@ -104,6 +132,24 @@ export class TrackSegment extends PathSegment {
         strokeColor: "#ffffff50",
       },
     );
+    if (showControls) {
+      // this.doodler.drawCircle(this.points[0], 4, {
+      //   color: "red",
+      //   weight: 3,
+      // });
+      this.doodler.drawCircle(this.points[1], 4, {
+        color: "red",
+        weight: 3,
+      });
+      this.doodler.drawCircle(this.points[2], 4, {
+        color: "red",
+        weight: 3,
+      });
+      // this.doodler.drawCircle(this.points[3], 4, {
+      //   color: "red",
+      //   weight: 3,
+      // });
+    }
   }
 
   serialize() {
@@ -115,6 +161,13 @@ export class TrackSegment extends PathSegment {
     };
   }
 
+  copy() {
+    return new TrackSegment(
+      this.points.map((p) => p.copy()) as VectorSet,
+      this.id,
+    );
+  }
+
   static deserialize(data: any) {
     return new TrackSegment(
       data.p.map((p: [number, number, number]) => new Vector(p[0], p[1], p[2])),

train/train.ts

@@ -1,9 +1,9 @@
-import { drawLine } from "../drawing/line.ts";
 import { ComplexPath, PathSegment } from "../math/path.ts";
-import { Vector } from "doodler";
 import { Follower } from "../physics/follower.ts";
 import { Mover } from "../physics/mover.ts";
 import { Spline, Track } from "../track.ts";
+import { getContextItem } from "../lib/context.ts";
+import { Doodler, Vector } from "@bearmetal/doodler";
 
 export class Train {
   nodes: Vector[] = [];
@@ -83,6 +83,12 @@ export class Train {
   //   }
   // }
 
+  draw() {
+    for (const car of this.cars) {
+      car.draw();
+    }
+  }
+
   real2Track(length: number) {
     return length / this.path.pointSpacing;
   }
@@ -113,6 +119,7 @@ export class TrainCar {
 
   draw() {
     if (!this.points) return;
+    const doodler = getContextItem<Doodler>("doodler");
     const [a, b] = this.points;
     const origin = Vector.add(Vector.sub(a, b).div(2), b);
     const angle = Vector.sub(b, a).heading();