From 0b7d447c5b0dbeb9f7d81a20eb1d81bb582f0ebc Mon Sep 17 00:00:00 2001
From: Kistaro Windrider <kistaro@gmail.com>
Date: Sat, 22 Feb 2025 21:09:11 -0800
Subject: [PATCH] map connectedness checker (floodfill)

---
 src/engine/datatypes.ts | 27 ++++++++++++++++++++-----
 src/newmap.ts           | 45 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 5 deletions(-)

diff --git a/src/engine/datatypes.ts b/src/engine/datatypes.ts
index 6b012c1..61f440c 100644
--- a/src/engine/datatypes.ts
+++ b/src/engine/datatypes.ts
@@ -111,6 +111,15 @@ export class Point {
     let dy = other.y - this.y;
     return Math.sqrt(dx * dx + dy * dy);
   }
+
+  neighbors() : Point[] {
+    return [
+      new Point(this.x, this.y-1),
+      new Point(this.x-1, this.y),
+      new Point(this.x, this.y+1),
+      new Point(this.x+1, this.y),
+    ];
+  }
 }
 
 export class Size {
@@ -264,19 +273,27 @@ export class Grid<T> {
     return new Grid(this.size, (xy) => cbCell(this.get(xy), xy));
   }
 
-  #checkPosition(position: Point) {
-    if (
-      position.x < 0 ||
+  #invalidPosition(position: Point) : boolean {
+    return position.x < 0 ||
       position.x >= this.size.w ||
       Math.floor(position.x) != position.x ||
       position.y < 0 ||
       position.y >= this.size.h ||
-      Math.floor(position.y) != position.y
-    ) {
+      Math.floor(position.y) != position.y;;
+  }
+  #checkPosition(position: Point) {
+    if (this.#invalidPosition(position)) {
       throw new Error(`invalid position for ${this.size}: ${position}`);
     }
   }
 
+  maybeGet(position: Point): T | null {
+    if (this.#invalidPosition(position)) {
+      return null;
+    }
+    return this.#data[position.y][position.x];
+  }
+
   get(position: Point): T {
     this.#checkPosition(position);
     return this.#data[position.y][position.x];
diff --git a/src/newmap.ts b/src/newmap.ts
index a8fc213..d97fdaf 100644
--- a/src/newmap.ts
+++ b/src/newmap.ts
@@ -105,6 +105,51 @@ export class LoadedNewMap {
   getZoneLabel(point: Point): string | null {
     return this.#zoneLabels.get(point);
   }
+
+  isConnected(): boolean {
+    const size = this.#size;
+    let reached = new Grid<boolean>(size, ()=>false);
+
+    // find starting location
+    const found: Point | null = (()=>{
+      for(let x = 0; x < size.w; x++) {
+        for(let y = 0; y < size.w; y++) {
+          const p = new Point(x, y)
+          if (this.#architecture.get(p) == Architecture.Floor) {
+            return p;
+          }
+        }
+      }
+      return null;
+    })();
+    if (found === null) {
+      // technically, all open floors on the map are indeed connected
+      return true
+    }
+
+    let stack : Point[] = [found];
+    reached.set(found, true);
+    while (stack.length > 0) {
+      const loc = stack.pop() as Point;
+      for (var p of loc.neighbors()) {
+        if ((this.#architecture.maybeGet(p) === Architecture.Floor) && !reached.get(p)) {
+          reached.set(p, true);
+          stack.push(p);
+        }
+      }
+    }
+
+    for(let x = 0; x < size.w; x++) {
+      for(let y = 0; y < size.w; y++) {
+        const p = new Point(x, y)
+        if (this.#architecture.get(p) == Architecture.Floor && !reached.get(p)) {
+          return false;
+        }
+      }
+    }
+
+    return true;
+  }
 }
 
 export class CellView {