refactor

lib/editor/draft/draftDiff.ts

@@ -0,0 +1,55 @@
+import type {
+    Feature,
+    FeatureCollection,
+    FeatureProperties,
+    Geometry,
+} from "@/types/geo";
+import type { Change } from "@/lib/editor/draft/editorTypes";
+
+export const deepClone = <T,>(obj: T): T => JSON.parse(JSON.stringify(obj));
+
+export function geometryEquals(a: Geometry | undefined, b: Geometry | undefined): boolean {
+    if (!a || !b) return false;
+    return JSON.stringify(a) === JSON.stringify(b);
+}
+
+export function featureEquals(a: Feature | undefined, b: Feature | undefined): boolean {
+    if (!a || !b) return false;
+    return JSON.stringify(a.geometry) === JSON.stringify(b.geometry) &&
+        JSON.stringify(a.properties) === JSON.stringify(b.properties);
+}
+
+export function buildInitialMap(fc: FeatureCollection) {
+    const map = new Map<FeatureProperties["id"], Feature>();
+    for (const feature of fc.features) {
+        map.set(feature.properties.id, deepClone(feature));
+    }
+    return map;
+}
+
+export function diffDraftToInitial(
+    draft: FeatureCollection,
+    initialMap: Map<FeatureProperties["id"], Feature>
+) {
+    const next = new Map<FeatureProperties["id"], Change>();
+    const seen = new Set<FeatureProperties["id"]>();
+
+    for (const feature of draft.features) {
+        const id = feature.properties.id;
+        seen.add(id);
+        const initialFeature = initialMap.get(id);
+        if (!initialFeature) {
+            next.set(id, { action: "create", feature: deepClone(feature) });
+        } else if (!featureEquals(initialFeature, feature)) {
+            next.set(id, { action: "update", id, geometry: deepClone(feature.geometry) });
+        }
+    }
+
+    for (const [id] of initialMap.entries()) {
+        if (!seen.has(id)) {
+            next.set(id, { action: "delete", id });
+        }
+    }
+
+    return next;
+}