6 files changed, 100 insertions, 19 deletions
diff --git a/src/engine/systems/Collision.ts b/src/engine/systems/Collision.ts
index 8ef8215..7d843cc 100644
--- a/src/engine/systems/Collision.ts
+++ b/src/engine/systems/Collision.ts
@@ -6,6 +6,7 @@ import { BoundingBox, Colliding, ComponentNames, Grid } from "../components";
 const collisionMap: Record<string, Set<string>> = {
   [EntityNames.Key]: new Set([EntityNames.LockedDoor]),
   [EntityNames.Curry]: new Set([EntityNames.Player]),
+  [EntityNames.FunctionApplication]: new Set([EntityNames.FunctionBox]),
 };
 
 export class Collision extends System {
diff --git a/src/engine/systems/Grid.ts b/src/engine/systems/Grid.ts
index 1d4a623..9ab28e3 100644
--- a/src/engine/systems/Grid.ts
+++ b/src/engine/systems/Grid.ts
@@ -33,8 +33,8 @@ export class Grid extends System {
     this.rebuildGrid(game);
 
     this.highlightEntitiesLookedAt(game);
-    this.propogateEntityMovements(game);
 
+    this.propogateEntityMovements(game);
     this.updateMovingEntities(dt, game);
   }
 
@@ -209,9 +209,11 @@ export class Grid extends System {
   ) {
     game.forEachEntityWithComponent(ComponentNames.Grid, (entity) => {
       const grid = entity.getComponent<GridComponent>(ComponentNames.Grid)!;
+
       if (grid.movingDirection === Direction.NONE) {
         return;
       }
+      grid.previousDirection = grid.movingDirection;
 
       const boundingBox = entity.getComponent<BoundingBox>(
         ComponentNames.BoundingBox,
@@ -270,7 +272,7 @@ export class Grid extends System {
     });
   }
 
-  private getNewGridPosition(prev: Coord2D, direction: Direction) {
+  public getNewGridPosition(prev: Coord2D, direction: Direction) {
     let { x: newX, y: newY } = prev;
     switch (direction) {
       case Direction.LEFT:
@@ -290,6 +292,25 @@ export class Grid extends System {
     return { x: newX, y: newY };
   }
 
+  public oppositeDirection(direction: Direction) {
+    let opposite = Direction.NONE;
+    switch (direction) {
+      case Direction.LEFT:
+        opposite = Direction.RIGHT;
+        break;
+      case Direction.RIGHT:
+        opposite = Direction.LEFT;
+        break;
+      case Direction.UP:
+        opposite = Direction.DOWN;
+        break;
+      case Direction.DOWN:
+        opposite = Direction.UP;
+        break;
+    }
+    return opposite;
+  }
+
   private isEntityPastCenterWhenMoving(
     direction: Direction,
     gridPosition: Coord2D,
diff --git a/src/engine/systems/Input.ts b/src/engine/systems/Input.ts
index 8900f4e..c527f29 100644
--- a/src/engine/systems/Input.ts
+++ b/src/engine/systems/Input.ts
@@ -2,7 +2,7 @@ import { Grid as GridSystem, SystemNames, System } from ".";
 import { Game } from "..";
 import { ComponentNames, Grid, Interactable } from "../components";
 import { Control } from "../components/Control";
-import { Action, KeyConstants } from "../config";
+import { Action, KeyConstants, MovingSound, SOUNDS } from "../config";
 import { Entity, Particles } from "../entities";
 import { Coord2D, Direction } from "../interfaces";
 import { colors } from "../utils";
@@ -105,27 +105,44 @@ export class Input extends System {
     }
 
     if (moveUp || moveLeft || moveRight || moveDown) {
-      const gridPosition = gridComponent.gridPosition;
-      const gridSystem = game.getSystem<GridSystem>(SystemNames.Grid);
-      const particles = new Particles({
-        center: gridSystem.gridToScreenPosition(gridPosition),
-        particleCount: 5,
-        particleShape: "circle",
-        particleMeanSpeed: 0.05,
-        particleSpeedVariance: 0.005,
-        particleMeanLife: 120,
-        particleMeanSize: 5,
-        particleSizeVariance: 2,
-        particleLifeVariance: 30,
-        particleColors: [colors.gray, colors.darkGray],
-      });
-
-      game.addEntity(particles);
+      this.spawnParticlesAround(entity, game);
+      this.playMoveSound();
     }
 
     entity.addComponent(gridComponent);
   }
 
+  private playMoveSound() {
+    const movingSounds = Array.from(MovingSound.states!.values());
+    const soundName =
+      movingSounds[Math.floor(Math.random() * movingSounds.length)].name;
+    SOUNDS.get(soundName)!.play();
+  }
+
+  private spawnParticlesAround(entity: Entity, game: Game) {
+    const gridSystem = game.getSystem<GridSystem>(SystemNames.Grid);
+    const gridComponent = entity.getComponent<Grid>(ComponentNames.Grid)!;
+    const particles = new Particles({
+      center: gridSystem.gridToScreenPosition(gridComponent.gridPosition),
+      particleCount: 4,
+      spawnerShape: "circle",
+      spawnerDimensions: {
+        width: 10,
+        height: 10,
+      },
+      particleShape: "rectangle",
+      particleMeanSpeed: 0.05,
+      particleSpeedVariance: 0.005,
+      particleMeanLife: 120,
+      particleMeanSize: 3,
+      particleSizeVariance: 1,
+      particleLifeVariance: 30,
+      particleColors: [colors.gray, colors.darkGray, colors.lightPurple],
+    });
+
+    game.addEntity(particles);
+  }
+
   private hasSomeKey(keys?: string[]): boolean {
     if (keys) {
       return keys.some((key) => this.keys.has(key));
diff --git a/src/engine/systems/Music.ts b/src/engine/systems/Music.ts
new file mode 100644
index 0000000..6e2004d
--- /dev/null
+++ b/src/engine/systems/Music.ts
@@ -0,0 +1,40 @@
+import { System, SystemNames } from ".";
+import { Music as GameMusic, SOUNDS } from "../config";
+
+export class Music extends System {
+  private songs: string[] = [];
+  private currentSong?: string;
+
+  constructor() {
+    super(SystemNames.Music);
+
+    this.songs = Array.from(GameMusic.states!.values()).map(
+      (state) => state.name,
+    );
+  }
+
+  private chooseRandomSong() {
+    return this.songs[Math.floor(Math.random() * this.songs.length)];
+  }
+
+  public playNext() {
+    let nextSong = this.chooseRandomSong();
+    while (nextSong === this.currentSong) {
+      nextSong = this.chooseRandomSong();
+    }
+
+    this.currentSong = nextSong;
+    SOUNDS.get(this.currentSong)?.play();
+
+    // when done, play next song
+    SOUNDS.get(this.currentSong)?.addEventListener("ended", () => {
+      this.playNext();
+    });
+  }
+
+  public update(_dt: number) {
+    if (!this.currentSong) {
+      this.playNext();
+    }
+  }
+}
diff --git a/src/engine/systems/SystemNames.ts b/src/engine/systems/SystemNames.ts
index 738dfba..363c72c 100644
--- a/src/engine/systems/SystemNames.ts
+++ b/src/engine/systems/SystemNames.ts
@@ -6,4 +6,5 @@ export namespace SystemNames {
   export const GridSpawner = "GridSpawner";
   export const Collision = "Collision";
   export const Life = "Life";
+  export const Music = "Music";
 }
diff --git a/src/engine/systems/index.ts b/src/engine/systems/index.ts
index a420216..46c534d 100644
--- a/src/engine/systems/index.ts
+++ b/src/engine/systems/index.ts
@@ -7,3 +7,4 @@ export * from "./Grid";
 export * from "./GridSpawner";
 export * from "./Collision";
 export * from "./Life";
+export * from "./Music";