/*!
 * Mode Atom — TypeScript Definitions
 * MIT License — Copyright (c) 2025 Silvio Corigliano
 */

/** A reactive source speaking the atom protocol ({ get, sub }), plus writes. */
export interface Atom<T> {
  get(): T;
  set(next: T): void;
  update(fn: (v: T) => T): void;
  upd(fn: (v: T) => T): void;
  /** Subscribe; `runNow` (default true) fires the callback immediately. Returns an unsubscribe. */
  sub(fn: (v: T) => void, runNow?: boolean): () => void;
}

export interface Computed<T> extends Atom<T> {
  /** Release the subscriptions to the dependencies. */
  dispose(): void;
}

/** Minimal reactive dependency (anything with `sub`). */
export interface Subscribable {
  sub(fn: (...args: any[]) => void, runNow?: boolean): () => void;
}

/** Create a writable reactive cell. */
export function atom<T>(initial: T): Atom<T>;

/** Derive a read value from dependencies; recomputes when any dependency changes. */
export function computed<T>(getter: () => T, deps: Subscribable[]): Computed<T>;

/** Run `fn` now and again whenever a dependency changes; returns a stop function. */
export function effect(fn: () => void | (() => void), deps: Subscribable[]): () => void;