Refactoring: move all code files into a src directory

src/UI/BigComponents/LevelSelector.svelte

@@ -0,0 +1,32 @@
+<script lang="ts">
+  /**
+   * Shows a 'floorSelector' and maps the selected floor onto a global filter
+   */
+  import LayerState from "../../Logic/State/LayerState"
+  import FloorSelector from "../InputElement/Helpers/FloorSelector.svelte"
+  import { Store, UIEventSource } from "../../Logic/UIEventSource"
+
+  export let layerState: LayerState
+  export let floors: Store<string[]>
+  export let zoom: Store<number>
+  const maxZoom = 16
+
+  let selectedFloor: UIEventSource<string> = new UIEventSource<string>(undefined)
+
+  selectedFloor.stabilized(5).map(
+    (floor) => {
+      if (floors.data === undefined || floors.data.length <= 1 || zoom.data < maxZoom) {
+        // Only a single floor is visible -> disable the 'level' global filter
+        // OR we might have zoomed out to much ant want to show all
+        layerState.setLevelFilter(undefined)
+      } else {
+        layerState.setLevelFilter(floor)
+      }
+    },
+    [floors, zoom]
+  )
+</script>
+
+{#if $zoom >= maxZoom}
+  <FloorSelector {floors} value={selectedFloor} />
+{/if}