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);
      }
    }
  }
}