start undo/redo

src2/mesh/history.js

@@ -0,0 +1,92 @@
+/** Copyright Stewart Allen <sa@grid.space> -- All Rights Reserved */
+
+import { broker } from "../moto/broker.js";
+
+class History {
+    #pos = -1;
+    #stack = [];
+    #tracking = false;
+
+    constructor() {
+        broker.subscribe({
+
+            app_ready() {
+                this.#tracking = true
+            },
+
+            drag_start(selected) {
+                this.push('position', selected.map(model => ({
+                    model,
+                    pos: model.position().toArray()
+                })));
+            },
+
+            drag_end(selected) {
+                this.update(selected.map(model => ({
+                    model,
+                    pos: model.position().toArray()
+                })));
+            },
+
+            move(data) {
+                console.log('move', data);
+            },
+
+            rotate(data) {
+                console.log('rotate', data);
+            },
+
+            scale(data) {
+                console.log('scale', data);
+            },
+
+        }, this);
+    }
+
+    push(type, undo, redo) {
+        this.#stack.length = ++this.#pos;
+        this.#stack.push({
+            type,
+            undo,
+            redo
+        });
+    }
+
+    update(redo, undo) {
+        let peek = this.#stack.peek();
+        if (peek) {
+            Object.assign(peek, {
+                redo: redo || peek.redo,
+                undo: undo || peek.undo
+            });
+        }
+    }
+
+    do(type, data) {
+        switch (type) {
+            case 'position':
+                for (let { model, pos } of data) {
+                    model.position(...pos);
+                }
+                break;
+            default:
+                console.warn(`invalid record type: ${type}`);
+        }
+    }
+
+    undo() {
+        if (this.#pos >= 0) {
+            const rec = this.#stack[this.#pos--];
+            this.do(rec.type, rec.undo);
+        }
+    }
+
+    redo() {
+        if (this.#stack.length && this.#pos >= -1 && this.#pos < this.#stack.length - 1) {
+            const rec = this.#stack[++this.#pos];
+            this.do(rec.type, rec.redo);
+        }
+    }
+}
+
+export const history = new History();