made new snake and index and liberary improvements

sketches/snake.js

@@ -98,21 +98,21 @@ function buttonUpgradeAIPressed(){
 			break;
 
 		case "wallDetection":
-			AItype = "nearApple";
+			AItype = "snakeDetection";
 			UpgradeAIPrice = 12;
 			break;
 
+		case "snakeDetection":
+			AItype = "nearApple";
+			UpgradeAIPrice = 25;
+			break;
+
 		case "nearApple":
 			AItype = "appleBias";
-			UpgradeAIPrice = 25;
-			break;
-
-		case "appleBias":
-			AItype = "snakeDetection";
 			UpgradeAIPrice = 50;
 			break;
 
-		case "snakeDetection":
+		case "appleBias":
 			AItype = "smart";
 			UpgradeAIPrice = 120;
 			break;
@@ -121,6 +121,11 @@ function buttonUpgradeAIPressed(){
 			AItype = "survival";
 			UpgradeAIPrice = 300;
 			break;
+
+		case "survival":
+			AItype = "perfect";
+			UpgradeAIPrice = 1000;
+			break;
 	}
 }
 
@@ -235,6 +240,18 @@ function runSnake(){
 		summonApple();
 		eatenApples++;
 	}
+	if (
+		snake.length >=
+		(gridColumns * gridRows) - appleAmount
+	){
+
+		if (AItype == "perfect"){
+			rewardPerfectAI();
+		}
+
+		restartGame();
+		return;
+	}
 	drawSnakeOnGrid();
 }
 
@@ -349,6 +366,10 @@ function snakeAI(){
 			snakeAIwallDetection();
 			break;
 
+		case "snakeDetection":
+			snakeAIsnakeDetection();
+			break;
+
 		case "nearApple":
 			snakeAInearApple();
 			break;
@@ -357,10 +378,6 @@ function snakeAI(){
 			snakeAIappleBias();
 			break;
 
-		case "snakeDetection":
-			snakeAIsnakeDetection();
-			break;
-
 		case "smart":
 			snakeAIsmart();
 			break;
@@ -368,6 +385,10 @@ function snakeAI(){
 		case "survival":
 			snakeAIsurvival();
 			break;
+
+		case "perfect":
+			snakeAIperfect();
+			break;
 	}
 }
 
@@ -481,6 +502,43 @@ function countFreeNeighbors(x, y){
 	return count;
 }
 
+// got this inspiration by an LLM AI
+function getHamiltonianDirection(){
+
+	let x = snake[0][0];
+	let y = snake[0][1];
+
+	// snake-like scan pattern
+
+	if (y % 2 == 0){
+
+		// move right
+		if (x < gridColumns - 1){
+			return 0;
+		}
+
+		// move down
+		if (y < gridRows - 1){
+			return 1;
+		}
+
+	}else{
+
+		// move left
+		if (x > 0){
+			return 2;
+		}
+
+		// move down
+		if (y < gridRows - 1){
+			return 1;
+		}
+	}
+
+	// top fallback
+	return 3;
+}
+
 function snakeAIrandom() {
 	snakeDirection = floor(random(0, 4));
 }
@@ -712,4 +770,75 @@ function snakeAIsurvival(){
 	}
 
 	snakeDirection = bestDirection;
+}
+
+// instpired by an LLM AI
+function snakeAIperfect(){
+
+	let apple = getClosestApple();
+
+	// try smart movement first
+	if (apple != null){
+
+		let bestDirection = -1;
+		let bestDistance = Infinity;
+
+		for (let i = 0; i < 4; i++) {
+
+			if (!isDirectionSafe(i)){
+				continue;
+			}
+
+			let vec = directionToVector(i);
+
+			let newX = snake[0][0] + vec[0];
+			let newY = snake[0][1] + vec[1];
+
+			let distance =
+				abs(newX - apple[0]) +
+				abs(newY - apple[1]);
+
+			let freeNeighbors =
+				countFreeNeighbors(newX, newY);
+
+			// avoid traps
+			if (
+				freeNeighbors <= 1 &&
+				snake.length < (gridColumns * gridRows) - 5
+			){
+				continue;
+			}
+
+			if (distance < bestDistance){
+				bestDistance = distance;
+				bestDirection = i;
+			}
+		}
+
+		if (bestDirection != -1){
+			snakeDirection = bestDirection;
+			return;
+		}
+	}
+
+	// fallback to Hamiltonian path
+	let direction = getHamiltonianDirection();
+
+	if (isDirectionSafe(direction)){
+		snakeDirection = direction;
+		return;
+	}
+
+	// fallback survival
+	snakeAIsurvival();
+}
+
+function rewardPerfectAI(){
+
+	let reward =
+		floor(
+			(gridColumns * gridRows) * 0.75
+		);
+
+	eatenApples += reward;
 }