/**
 * Hoover — reactivity.js
 *
 * Reactive Proxy state + batched render requests via queueMicrotask.
 * Multiple property mutations in the same microtask tick produce a single
 * render cycle across all registered render roots.
 */

/**
 * Global flag to prevent duplicate microtask scheduling.
 */
let _scheduled = false;

/**
 * Callback invoked by render.js to perform the actual batched re-render.
 * Set via setCommitFn() during render engine initialization.
 */
let _commitFn = null;

/**
 * Register the commit callback that performs batched re-renders.
 * Called by render.js during initialization.
 */
export function setCommitFn(fn) {
    _commitFn = fn;
}

/**
 * Schedule a single batched re-render for all active render roots.
 * Multiple reactive property mutations in the same tick produce one diff pass.
 */
export function requestUpdate() {
    if (_scheduled) return;
    _scheduled = true;
    queueMicrotask(() => {
        _scheduled = false;
        if (_commitFn) _commitFn();
    });
}

/**
 * Wrap an object in a reactive Proxy.
 * Any property *assignment* that changes the value automatically triggers
 * a batched re-render via requestUpdate().
 */
export function reactive(obj = {}) {
    return new Proxy(obj, {
        set(target, key, value, receiver) {
            const old = target[key];
            const ok = Reflect.set(target, key, value, receiver);
            if (ok && !Object.is(old, value)) {
                requestUpdate();
            }
            return ok;
        }
    });
}