nodes/app/src/lib/history-manager.ts

102 lines
2.5 KiB
TypeScript

import { create, type Delta } from "jsondiffpatch";
import type { Graph } from "@nodes/types";
import { createLogger, clone } from "./helpers";
const diff = create({
objectHash: function (obj, index) {
if (obj === null) return obj;
if ("id" in obj) return obj.id;
if (Array.isArray(obj)) {
return obj.join("-")
}
return obj?.id || obj._id || '$$index:' + index;
}
})
const log = createLogger("history")
export class HistoryManager {
index: number = -1;
history: Delta[] = [];
private initialState: Graph | undefined;
private state: Graph | undefined;
private opts = {
debounce: 400,
maxHistory: 100,
}
constructor({ maxHistory = 100, debounce = 100 } = {}) {
this.history = [];
this.index = -1;
this.opts.debounce = debounce;
this.opts.maxHistory = maxHistory;
globalThis["_history"] = this;
}
save(state: Graph) {
if (!this.state) {
this.state = clone(state);
this.initialState = this.state;
log.log("initial state saved")
} else {
const newState = state;
const delta = diff.diff(this.state, newState);
if (delta) {
log.log("saving state")
// Add the delta to history
if (this.index < this.history.length - 1) {
// Clear the history after the current index if new changes are made
this.history.splice(this.index + 1);
}
this.history.push(delta);
this.index++;
// Limit the size of the history
if (this.history.length > this.opts.maxHistory) {
this.history.shift();
}
this.state = newState;
} else {
log.log("no changes")
}
}
}
reset() {
this.history = [];
this.index = -1;
this.state = undefined;
this.initialState = undefined;
}
undo() {
if (this.index === -1 && this.initialState) {
log.log("reached start, loading initial state")
return clone(this.initialState);
} else {
const delta = this.history[this.index];
const prevState = diff.unpatch(this.state, delta) as Graph;
this.state = prevState;
this.index = Math.max(-1, this.index - 1);
return clone(prevState);
}
}
redo() {
if (this.index <= this.history.length - 1) {
const nextIndex = Math.min(this.history.length - 1, this.index + 1);
const delta = this.history[nextIndex];
const nextState = diff.patch(this.state, delta) as Graph;
this.index = nextIndex;
this.state = nextState;
return clone(nextState);
} else {
log.log("reached end")
}
}
}