import { ReactiveNode } from './alien.js';
export type Selection<TSelected> = Readable<TSelected>;
export interface InteropSubscribable<T> {
    subscribe: (observer: Observer<T>) => Subscription;
}
export type Observer<T> = {
    next?: (value: T) => void;
    error?: (err: unknown) => void;
    complete?: () => void;
};
export interface Subscription {
    unsubscribe: () => void;
}
export interface Subscribable<T> extends InteropSubscribable<T> {
    subscribe: ((observer: Observer<T>) => Subscription) & ((next: (value: T) => void, error?: (error: any) => void, complete?: () => void) => Subscription);
}
export interface Readable<T> extends Subscribable<T> {
    get: () => T;
}
export interface BaseAtom<T> extends Subscribable<T>, Readable<T> {
}
export interface InternalBaseAtom<T> extends Subscribable<T>, Readable<T> {
    /** @internal */
    _snapshot: T;
    /** @internal */
    _update: (getValue?: T | ((snapshot: T) => T)) => boolean;
}
export interface Atom<T> extends BaseAtom<T> {
    /** Sets the value of the atom using a function. */
    set: ((fn: (prevVal: T) => T) => void) & ((value: T) => void);
}
export interface AtomOptions<T> {
    compare?: (prev: T, next: T) => boolean;
}
export type AnyAtom = BaseAtom<any>;
export interface InternalReadonlyAtom<T> extends InternalBaseAtom<T>, ReactiveNode {
}
/**
 * An atom that is read-only and cannot be set.
 *
 * @example
 *
 * ```ts
 * const atom = createAtom(() => 42);
 * // @ts-expect-error - Cannot set a readonly atom
 * atom.set(43);
 * ```
 */
export interface ReadonlyAtom<T> extends BaseAtom<T> {
}