Disable build button if cost of a building cannot be paid.

src/hud/BuildingCreator.svelte

@@ -1,7 +1,10 @@
 <script lang="ts">
+    import { createBuilding } from "../create";
     import buildings from "../data/buildings";
     import moves from "../moves";
     import showBuildingCreator from "../stores/showBuildingCreator";
+    import { canPayBuildingCost } from "../utils";
+    import village from "../village";
     import Cost from "./Cost.svelte";
 
     function close() {
@@ -19,7 +22,11 @@
         }
     }
 
-    const constructible = buildings.filter(b => !b.autoBuilt);
+    const constructible = buildings.filter(b => !b.autoBuilt).map(b =>{
+        const building = createBuilding(b.type);
+        building.level = 0;
+        return building;
+    });
 </script>
 
 { #if $showBuildingCreator !== null }
@@ -36,7 +43,12 @@
             <div>
                 <p>{ building.name }</p>
                 <Cost cost={ building.cost(1) } />
-                <button on:click={ () => build(building.type) }>Build</button>
+                <button
+                    on:click={ () => build(building.type) }
+                    disabled={ !canPayBuildingCost($village, building) }
+                >
+                    Build
+                </button>
             </div>
             { /each }
         </div>