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;
+}

lib/editor/draft/editorTypes.ts

@@ -0,0 +1,15 @@
+import type {
+    Feature,
+    FeatureProperties,
+    Geometry,
+    GeometryChange,
+} from "@/types/geo";
+
+export type Change = GeometryChange;
+
+export type UndoAction =
+    | { type: "update"; id: FeatureProperties["id"]; prevGeometry: Geometry }
+    | { type: "properties"; id: FeatureProperties["id"]; prevProperties: FeatureProperties }
+    | { type: "delete"; feature: Feature }
+    | { type: "create"; id: FeatureProperties["id"] };
+

lib/editor/draft/useDraftState.ts

@@ -0,0 +1,29 @@
+import { useCallback, useEffect, useRef, useState } from "react";
+import type { FeatureCollection } from "@/types/geo";
+import { deepClone } from "@/lib/editor/draft/draftDiff";
+
+export function useDraftState(initialData: FeatureCollection) {
+    const [draft, setDraft] = useState<FeatureCollection>(() => deepClone(initialData));
+    const draftRef = useRef<FeatureCollection>(deepClone(initialData));
+
+    const commitDraft = useCallback((nextDraft: FeatureCollection) => {
+        const cloned = deepClone(nextDraft);
+        draftRef.current = cloned;
+        setDraft(cloned);
+    }, []);
+
+    useEffect(() => {
+        draftRef.current = draft;
+    }, [draft]);
+
+    const resetDraft = useCallback((nextDraft: FeatureCollection) => {
+        commitDraft(nextDraft);
+    }, [commitDraft]);
+
+    return {
+        draft,
+        draftRef,
+        commitDraft,
+        resetDraft,
+    };
+}

lib/editor/draft/useUndoStack.ts

@@ -0,0 +1,80 @@
+import { useCallback, useState } from "react";
+import type { UndoAction } from "@/lib/editor/draft/editorTypes";
+import { geometryEquals } from "@/lib/editor/draft/draftDiff";
+
+type Options = {
+    applyUndoAction: (action: UndoAction) => boolean;
+};
+
+export function useUndoStack(options: Options) {
+    const { applyUndoAction } = options;
+    const [undoStack, setUndoStack] = useState<UndoAction[]>([]);
+
+    const pushUndo = useCallback((action: UndoAction) => {
+        setUndoStack((prev) => {
+            const last = prev[prev.length - 1];
+            if (isSameUndo(last, action)) return prev;
+            return [...prev, action];
+        });
+    }, []);
+
+    const undo = useCallback(() => {
+        let applied = false;
+        setUndoStack((prev) => {
+            if (applied) return prev;
+            if (!prev.length) return prev;
+
+            const last = prev[prev.length - 1];
+            const remaining = prev.slice(0, -1);
+            applied = true;
+
+            const didApply = applyUndoAction(last);
+            return didApply ? remaining : prev;
+        });
+    }, [applyUndoAction]);
+
+    const clearUndo = useCallback(() => {
+        setUndoStack([]);
+    }, []);
+
+    return {
+        undoStack,
+        pushUndo,
+        undo,
+        clearUndo,
+    };
+}
+
+function isSameUndo(a: UndoAction | undefined, b: UndoAction) {
+    if (!a) return false;
+    if (a.type !== b.type) return false;
+    switch (a.type) {
+        case "create": {
+            const next = b as Extract<UndoAction, { type: "create" }>;
+            return a.id === next.id;
+        }
+        case "delete": {
+            const next = b as Extract<UndoAction, { type: "delete" }>;
+            return (
+                a.feature.properties.id === next.feature.properties.id &&
+                geometryEquals(a.feature.geometry, next.feature.geometry)
+            );
+        }
+        case "update": {
+            const next = b as Extract<UndoAction, { type: "update" }>;
+            return (
+                a.id === next.id &&
+                geometryEquals(a.prevGeometry, next.prevGeometry)
+            );
+        }
+        case "properties": {
+            const next = b as Extract<UndoAction, { type: "properties" }>;
+            return (
+                a.id === next.id &&
+                JSON.stringify(a.prevProperties) === JSON.stringify(next.prevProperties)
+            );
+        }
+        default:
+            return false;
+    }
+}