From a6507af1e289d409aa595b1143f242338fedc4df Mon Sep 17 00:00:00 2001
From: Avinash Vora <avinashvora@gmail.com>
Date: Tue, 4 Jul 2023 23:55:17 +0400
Subject: [PATCH] Player movement implemented.

---
 README.md          |  6 +++--
 src/game-states.ts |  7 ++++++
 src/main.ts        | 61 +++++++++++++++++++++++++++++++++++++++++++---
 3 files changed, 68 insertions(+), 6 deletions(-)
 create mode 100644 src/game-states.ts

diff --git a/README.md b/README.md
index a14c333..ddce749 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ Built using Typescript and [Malwoden](https://malwoden.com), partially following
 
 This repository is participating in the 2023 edition of the [RoguelikeDev event](https://www.reddit.com/r/roguelikedev/comments/14kz7al/roguelikedev_does_the_complete_roguelike_tutorial/), running from 4 July 2023 till 22 August 2023.
 
-### Week 1 - 4 July 2023 - Setup, drawing an @, and moving around
+### [Week 1](https://www.reddit.com/r/roguelikedev/comments/14q58js/roguelikedev_does_the_complete_roguelike_tutorial/) - 4 July 2023 - Setup, drawing an @, and moving around
 
 - Getting this done a bit in advance because I know I am going to be busy over this year's sprint!
 - The Malwoden tutorial doesn't really spend any time explaining how to set up the development environment--it just asks for some files to be copy/pasted. I've used `vite` for packaging and am just using the `vanilla-ts` template.
@@ -21,6 +21,8 @@ This repository is participating in the 2023 edition of the [RoguelikeDev event]
 - A lot of logic keeps being shoved into the `main.ts` file and I am expecting a serious refactor down the road.
 - Malwoden itself seems to get out of the way--I enjoy this.
 - The ECS system is simple but seems sufficient--compared to Rust's `specs` or `legion` this feels much better for a beginner.
+- Lots of mistakes in the tutorial--in Chapter 3, for example, the entire input handling code is missing imports and declarations.
+- I prefered implementing game states in `game-states.ts` as an enum to reference.
 
 ### Week 2 - 11 July 2023 - The object system and generating your first map
 
@@ -52,7 +54,7 @@ Your hometown is suffering from a cataclysm of monters. You have been tasked wit
 
 ### MVP
 
-- [ ] Player can walk around
+- [x] Player can walk around
 - [ ] Create a basic procedural dungeon map
 - [ ] Player has field-of-view
 - [ ] Spawn monsters
diff --git a/src/game-states.ts b/src/game-states.ts
new file mode 100644
index 0000000..df7672d
--- /dev/null
+++ b/src/game-states.ts
@@ -0,0 +1,7 @@
+/**
+ * Possible game states
+ */
+export enum GameStates {
+    INIT,
+    PLAYER_TURN,
+}
\ No newline at end of file
diff --git a/src/main.ts b/src/main.ts
index 0818662..4c4991c 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -1,8 +1,9 @@
-import { Terminal, Color } from 'malwoden';
+import { Terminal, Color, Input, Vector2 } from 'malwoden';
 import { World, Entity } from 'ecsy';
 
 import * as Components from './components';
 import * as Systems from './systems';
+import { GameStates } from './game-states';
 
 /**
  * The main game engine.
@@ -19,6 +20,9 @@ export class Game {
   lastTime: number;
 
   player: Entity;
+  input = new Input.KeyboardHandler();
+
+  gameState: GameStates;
 
   constructor() {
     this.world = new World();
@@ -27,6 +31,8 @@ export class Game {
 
     this.registerECS();
     this.player = this.initWorld();
+
+    this.gameState = GameStates.INIT;
   }
 
   /**
@@ -78,23 +84,70 @@ export class Game {
    * @param delta Time passed since last tick
    * @param time Current time
    */
-  tick(delta: number, time: number) {
+  async tick(delta: number, time: number) {
+    // PLAYER_TURN
+    if (this.gameState == GameStates.PLAYER_TURN) {
+      // handle player input
+      const key = await this.input.waitForKeyDown();
+      
+      // create an actions map of potential keypresses
+      const actions = new Map<number, () => void>();
+      actions.set(Input.KeyCode.LeftArrow, () =>
+        tryMoveEntity(this.player, { x: -1, y: 0 })
+      );
+      actions.set(Input.KeyCode.RightArrow, () =>
+        tryMoveEntity(this.player, { x: 1, y: 0 })
+      );
+      actions.set(Input.KeyCode.UpArrow, () =>
+        tryMoveEntity(this.player, { x: 0, y: -1 })
+      );
+      actions.set(Input.KeyCode.DownArrow, () =>
+        tryMoveEntity(this.player, { x: 0, y: 1 })
+      );
+
+      // if the keypair in the map matches an input key, run the command
+      const command = actions.get(key);
+      if (command) command();
+    }
+
+    // execute game systems
     this.world.execute(delta, time);
+
+    if (this.gameState == GameStates.INIT) {
+      this.gameState = GameStates.PLAYER_TURN;
+    }
   }
 
   /**
    * The engine's bootstrap function. Sets up the main game loop and runs it.
    */
-  run() {
+  async run() {
     const time = performance.now();
     const delta = time - this.lastTime;
 
-    this.tick(delta, this.lastTime);
+    await this.tick(delta, this.lastTime);
     
     window.requestAnimationFrame(this.run.bind(this));
   }
 }
 
+/**
+ * Attempts to move an Entity in position.
+ * @param entity Entity with a Position component
+ * @param delta Movement vector delta
+ */
+function tryMoveEntity(entity: Entity, delta: Vector2) {
+  const position = entity.getMutableComponent(Components.Position);
+
+  if (!position) {
+    console.warn('WARNING: Can\'t move an entity without a Position!');
+    return;
+  }
+
+  position.x += delta.x;
+  position.y += delta.y;
+}
+
 // Modify the Window to include the Game object.
 declare global {
   interface Window {