From cec1da14708e782801d0cc27fb13ff7586c0e96c Mon Sep 17 00:00:00 2001
From: nil <niljo@airmail.cc>
Date: Fri, 13 Dec 2024 16:42:57 +0100
Subject: liberty check demo

---
 src/engine/liberty.js        | 24 ++++++++++++++++++++++++
 src/engine/moves.js          |  8 +++++++-
 src/engine/turns.js          |  2 +-
 src/engine/vector2.js        | 13 +++++++++++++
 src/engine/visual/vector2.js |  6 ------
 src/link.js                  |  3 ++-
 src/stone.js                 |  2 +-
 7 files changed, 48 insertions(+), 10 deletions(-)
 create mode 100644 src/engine/liberty.js
 create mode 100644 src/engine/vector2.js
 delete mode 100644 src/engine/visual/vector2.js

(limited to 'src')

diff --git a/src/engine/liberty.js b/src/engine/liberty.js
new file mode 100644
index 0000000..372057e
--- /dev/null
+++ b/src/engine/liberty.js
@@ -0,0 +1,24 @@
+import { board } from "../board.js"
+import { Vector2 } from "../engine/vector2.js"
+
+const SURROUNDING = [
+    new Vector2(-1, 0),
+    new Vector2(0, 1),
+    new Vector2(0, -1),
+    new Vector2(1, 0),
+]
+
+export function hasLiberties({
+    position,
+    team
+}) {
+    return Array.from(SURROUNDING)
+	.map(v => Vector2.sum(v, position))
+	.filter(z => 0 <= z.x && z.x < board.size &&
+	    0 <= z.y && z.y < board.size
+	)
+	.some(z => board.stones[z.x][z.y] == undefined ?
+	    true :
+	    board.stones[z.x][z.y].team == team
+	)
+}
diff --git a/src/engine/moves.js b/src/engine/moves.js
index f820f97..26158a0 100644
--- a/src/engine/moves.js
+++ b/src/engine/moves.js
@@ -1,11 +1,17 @@
 import { board } from "../board.js"
+import { hasLiberties } from "./liberty.js"
 
 export function isMoveLegal({
     position,
-    turn = "none"
+    team = "none"
 }) {
     if (board.stones[position.y][position.x] != undefined) {
 	return false
     }
+
+    if (!hasLiberties({position: position, team: team})) {
+	return false
+    }
+
     return true
 }
diff --git a/src/engine/turns.js b/src/engine/turns.js
index 6a5e6fb..ee5b9e2 100644
--- a/src/engine/turns.js
+++ b/src/engine/turns.js
@@ -1,5 +1,5 @@
 import { board } from "../board.js"
-import { Vector2 } from "../engine/visual/vector2.js"
+import { Vector2 } from "../engine/vector2.js"
 import { Link } from "../link.js"
 import { PLAYER } from "../constants.js"
 import { isMoveLegal } from "../engine/moves.js"
diff --git a/src/engine/vector2.js b/src/engine/vector2.js
new file mode 100644
index 0000000..6c2a2a2
--- /dev/null
+++ b/src/engine/vector2.js
@@ -0,0 +1,13 @@
+export class Vector2 {
+    constructor(x, y) {
+        this.x = x
+        this.y = y
+    }
+
+    static sum(a, b) {
+	return new Vector2(
+	    a.x + b.x,
+	    a.y + b.y,
+	)
+    }
+}
diff --git a/src/engine/visual/vector2.js b/src/engine/visual/vector2.js
deleted file mode 100644
index a3a1bc2..0000000
--- a/src/engine/visual/vector2.js
+++ /dev/null
@@ -1,6 +0,0 @@
-export class Vector2 {
-    constructor(x, y) {
-        this.x = x
-        this.y = y
-    }
-}
diff --git a/src/link.js b/src/link.js
index e0c8266..192f1e9 100644
--- a/src/link.js
+++ b/src/link.js
@@ -1,5 +1,5 @@
 import { placeOnBoard } from "./engine/visual/placeOnBoard.js"
-import { Vector2 } from "./engine/visual/vector2.js"
+import { Vector2 } from "./engine/vector2.js"
 import { board } from "./board.js"
 import { ASSETS_BLACK, ASSETS_WHITE, PLAYER } from "./constants.js"
 import { Stone } from "./stone.js"
@@ -17,6 +17,7 @@ export class Link {
         board.links[position.y][position.x] = this
 
         this.span.addEventListener("click", _ => {
+	    console.log("link position", this.position)
             new Stone({
                 position: position,
                 team: this.team
diff --git a/src/stone.js b/src/stone.js
index 0fc8607..15035f0 100644
--- a/src/stone.js
+++ b/src/stone.js
@@ -1,5 +1,5 @@
 import { placeOnBoard } from "./engine/visual/placeOnBoard.js"
-import { Vector2 } from "./engine/visual/vector2.js"
+import { Vector2 } from "./engine/vector2.js"
 import { board } from "./board.js"
 import { ASSETS_BLACK, ASSETS_WHITE, PLAYER } from "./constants.js"
 
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