refactoring(maplibre): WIP

Logic/Actors/InitialMapPositioning.ts

@@ -0,0 +1,64 @@
+import { UIEventSource } from "../UIEventSource"
+import LayoutConfig from "../../Models/ThemeConfig/LayoutConfig"
+import { LocalStorageSource } from "../Web/LocalStorageSource"
+import { QueryParameters } from "../Web/QueryParameters"
+
+/**
+ * This actor is responsible to set the map location.
+ * It will attempt to
+ * - Set the map to the position as passed in by the query parameters (if available)
+ * - Set the map to the position remembered in LocalStorage (if available)
+ * - Set the map to the layout default
+ *
+ * Additionally, it will save the map location to local storage
+ */
+export default class InitialMapPositioning {
+    public zoom: UIEventSource<number>
+    public location: UIEventSource<{ lon: number; lat: number }>
+    constructor(layoutToUse: LayoutConfig) {
+        function localStorageSynced(
+            key: string,
+            deflt: number,
+            docs: string
+        ): UIEventSource<number> {
+            const localStorage = LocalStorageSource.Get(key)
+            const previousValue = localStorage.data
+            const src = UIEventSource.asFloat(
+                QueryParameters.GetQueryParameter(key, "" + deflt, docs).syncWith(localStorage)
+            )
+
+            if (src.data === deflt) {
+                const prev = Number(previousValue)
+                if (!isNaN(prev)) {
+                    src.setData(prev)
+                }
+            }
+
+            return src
+        }
+
+        // -- Location control initialization
+        this.zoom = localStorageSynced(
+            "z",
+            layoutToUse?.startZoom ?? 1,
+            "The initial/current zoom level"
+        )
+        const lat = localStorageSynced(
+            "lat",
+            layoutToUse?.startLat ?? 0,
+            "The initial/current latitude"
+        )
+        const lon = localStorageSynced(
+            "lon",
+            layoutToUse?.startLon ?? 0,
+            "The initial/current longitude of the app"
+        )
+
+        this.location = new UIEventSource({ lon: lon.data, lat: lat.data })
+        this.location.addCallbackD((loc) => {
+            lat.setData(loc.lat)
+            lon.setData(loc.lon)
+        })
+        // Note: this syncs only in one direction
+    }
+}