import { R as Result, U as UnexpectedError } from './types-BQ9vv0nD.js';

/**
 * @onrails/result internal — the single payload-extraction pair.
 *
 * `InferOk` / `InferErr` pull the success/error type out of a {@link Result}
 * (tagged union) or a {@link ResultAsync} (class carrier), resolving to
 * `never` for anything else. Every module that needs to extract a payload
 * type imports from here; do not redeclare local copies.
 *
 * Internal only: not listed in package.json `exports` or tsup entries.
 * The package index re-exports the pair under the same names.
 */

/**
 * Extracts the `Ok` value type from a {@link Result} or {@link ResultAsync},
 * resolving to `never` for any other type.
 *
 * @example
 * ```ts
 * type T = InferOk<Result<number, string>>;        // number
 * type U = InferOk<ResultAsync<User, AppError>>;    // User
 * ```
 */
type InferOk<R> = R extends {
    _tag: "Ok";
    readonly value: infer T;
} ? T : R extends ResultAsync<infer T, unknown> ? T : never;
/**
 * Extracts the `Err` error type from a {@link Result} or {@link ResultAsync},
 * resolving to `never` for any other type. Mirror of {@link InferOk}.
 *
 * @example
 * ```ts
 * type E = InferErr<Result<number, string>>;        // string
 * type F = InferErr<ResultAsync<User, AppError>>;    // AppError
 * ```
 */
type InferErr<R> = R extends {
    _tag: "Err";
    readonly error: infer E;
} ? E : R extends ResultAsync<unknown, infer E> ? E : never;

type PromiseFactory<T, E> = () => Promise<Result<T, E>>;
type CombineTupleAsync<R extends readonly ResultAsync<unknown, unknown>[]> = ResultAsync<{
    [K in keyof R]: InferOk<R[K]>;
}, {
    [K in keyof R]: InferErr<R[K]>;
}[number]>;
/**
 * Async railway carrier. Wraps a deferred `Promise<Result<T, E>>` and exposes
 * the same dual-track transforms as the sync {@link Result} — `map`, `flatMap`,
 * `recover`, `tap`, `match`. The public API never surfaces `Promise<Result<…>>`
 * directly: `await` the instance (it is thenable) or call {@link resolve} /
 * {@link match} to settle it.
 *
 * Construct via the static factories ({@link ok}, {@link err}, {@link fromPromise},
 * {@link defer}, …) rather than `new` — the constructor is `protected`.
 *
 * @typeParam T - the `Ok` value type
 * @typeParam E - the `Err` error type
 *
 * @example
 * ```ts
 * const user = ResultAsync.fromPromise(api.getUser(id), toAppError)
 *   .map((u) => u.profile)
 *   .recover(() => ResultAsync.ok(guestProfile));
 *
 * const r = await user;          // Result<Profile, AppError>
 * ```
 */
declare class ResultAsync<T, E> {
    protected readonly run: PromiseFactory<T, E>;
    private promise;
    protected constructor(run: PromiseFactory<T, E>);
    /**
     * Lifts an already-settled sync {@link Result} into a {@link ResultAsync}.
     *
     * @example
     * ```ts
     * const ra = ResultAsync.fromResult(ok(42));   // ResultAsync<number, never>
     * ```
     */
    static fromResult<T, E>(result: Result<T, E>): ResultAsync<T, E>;
    /**
     * Wraps a `PromiseLike<T>` that may reject. Rejections pass through `onReject`
     * to become a typed `Err`; resolution becomes `Ok<T>`.
     *
     * @param promise - the promise to wrap
     * @param onReject - maps a rejection reason to the `Err` channel
     *
     * @example
     * ```ts
     * const body = ResultAsync.fromPromise(
     *   fetch(url).then((r) => r.text()),
     *   (e): NetError => ({ kind: "net", cause: String(e) }),
     * );
     * ```
     */
    static fromPromise<T, E>(promise: PromiseLike<T>, onReject: (error: unknown) => E): ResultAsync<T, E>;
    /**
     * Wraps a `PromiseLike<T>` that is **guaranteed not to reject**, skipping the
     * `onReject` mapper. Use only when rejection is provably impossible.
     *
     * @example
     * ```ts
     * const now = ResultAsync.fromSafePromise(Promise.resolve(Date.now()));
     * ```
     */
    static fromSafePromise<T, E = never>(promise: PromiseLike<T>): ResultAsync<T, E>;
    /**
     * Defers work until {@link resolve}. Unlike {@link fromPromise}, the factory
     * does not run until the `ResultAsync` is resolved (e.g. by `combineTuple` /
     * `combineTupleParallel`). The factory runs at most once — `resolve` memoizes.
     *
     * @example
     * ```ts
     * const insert = ResultAsync.defer(() => db.orders.insert(row));
     * // nothing has run yet
     * const r = await insert;   // factory runs exactly once here
     * ```
     */
    static defer<T, E>(fn: () => Promise<Result<T, E>>): ResultAsync<T, E>;
    /**
     * Lifts a value into an `Ok` async result.
     *
     * @example
     * ```ts
     * const r = ResultAsync.ok(42);   // ResultAsync<number, never>
     * ```
     */
    static ok<T>(value: T): ResultAsync<T, never>;
    static ok<T, E>(value: T): ResultAsync<T, E>;
    /**
     * Fantasy Land `pure` — alias of {@link ResultAsync.ok}. One lift name
     * shared across the trio (`of` / `Maybe.of` / `ResultAsync.of`).
     */
    static of<T>(value: T): ResultAsync<T, never>;
    static of<T, E>(value: T): ResultAsync<T, E>;
    /**
     * Lifts an error into an `Err` async result.
     *
     * @example
     * ```ts
     * const r = ResultAsync.err({ kind: "not_found" as const });
     * ```
     */
    static err<T = never, E = unknown>(error: E): ResultAsync<T, E>;
    /**
     * Lifts an existing `Promise<Result<T, E>>` (e.g. from interop code) into a
     * {@link ResultAsync}. A thrown defect is routed through `onDefect`,
     * defaulting to {@link UnexpectedError}. The `Ok` value passes through
     * verbatim — even when it happens to be Result-shaped.
     *
     * @param promise - a promise that already yields a `Result`
     * @param onDefect - maps an unexpected throw to the `Err` channel
     * @see {@link fromAsync} from `@onrails/result`
     */
    static fromResultPromise<T, E>(promise: Promise<Result<T, E>>, onDefect?: (error: unknown) => E | UnexpectedError): ResultAsync<T, E | UnexpectedError>;
    /**
     * Combines a homogeneous array of async results into one. Resolves
     * **sequentially** in input order, short-circuiting on the first `Err`.
     * For heterogeneous tuples that preserve per-index types, use
     * {@link combineTuple}; for wall-clock overlap, {@link combineTupleParallel}.
     *
     * @example
     * ```ts
     * const all = ResultAsync.combine([loadA(), loadB(), loadC()]);
     * // ResultAsync<Item[], LoadError>
     * ```
     */
    static combine<T, E>(results: readonly ResultAsync<T, E>[]): ResultAsync<T[], E>;
    /**
     * Heterogeneous async tuple combine — resolves branches **sequentially**
     * (left-to-right), returning the first `Err` in input order. Preserves each
     * branch's `Ok` type by position, so the result destructures type-safely.
     * This is the canonical sequential async combine (replaces the former
     * `sequenceTupleAsync`).
     *
     * @example
     * ```ts
     * const combined = ResultAsync.combineTuple([loadCfg(), loadCatalog()] as const);
     * // ResultAsync<readonly [Cfg, Catalog], CfgError | CatalogError>
     * const r = await combined;
     * if (isOk(r)) {
     *   const [cfg, catalog] = r.value;  // typed per position
     * }
     * ```
     */
    static combineTuple<const R extends readonly ResultAsync<unknown, unknown>[]>(results: R): CombineTupleAsync<R>;
    /**
     * Like {@link combineTuple}, but starts every branch before awaiting (wall-clock
     * parallel for independent IO). On failure, returns the first `Err` in input order.
     *
     * @example
     * ```ts
     * // independent IO — overlap them
     * const combined = ResultAsync.combineTupleParallel([
     *   loadProfile(id),
     *   loadMetrics(id),
     * ] as const);
     * ```
     */
    static combineTupleParallel<const R extends readonly ResultAsync<unknown, unknown>[]>(results: R): CombineTupleAsync<R>;
    /**
     * Transforms the `Ok` value, passing `Err` through unchanged.
     *
     * @example
     * ```ts
     * ResultAsync.ok(2).map((n) => n * 3);   // ResultAsync<number> → Ok 6
     * ```
     */
    map<U>(fn: (value: T) => U): ResultAsync<U, E>;
    /**
     * Transforms the `Err` value, passing `Ok` through unchanged — useful for
     * unifying heterogeneous failures into one app-level union.
     *
     * @example
     * ```ts
     * load(id).mapErr((e): AppError => ({ kind: "load", cause: e })); // ResultAsync<T, AppError>
     * ```
     */
    mapErr<F>(fn: (error: E) => F): ResultAsync<T, F>;
    /**
     * Canonical bind — chains a step that itself returns a `ResultAsync` or sync
     * `Result`, short-circuiting on `Err`. Error types accumulate (`E | F`).
     *
     * @example
     * ```ts
     * authenticate(req)
     *   .flatMap((user) => loadProfile(user.id))   // ResultAsync
     *   .flatMap((p) => validate(p));              // sync Result also accepted
     * ```
     */
    flatMap<U, F = E>(fn: (value: T) => ResultAsync<U, F> | Result<U, F>): ResultAsync<U, E | F>;
    /**
     * neverthrow-compat alias of {@link flatMap}. Kept as the documented compat
     * tier; prefer {@link flatMap} in new code.
     *
     * @example
     * ```ts
     * authenticate(req).andThen((user) => loadProfile(user.id));
     * ```
     */
    andThen<U, F = E>(fn: (value: T) => ResultAsync<U, F> | Result<U, F>): ResultAsync<U, E | F>;
    /**
     * Error-channel bind — runs `fn` only on `Err`, swapping in a recovery
     * `ResultAsync` or sync `Result`. `Ok` passes through. The mirror of
     * {@link flatMap} on the error track.
     *
     * @example
     * ```ts
     * loadFromCache(id).recover(() => loadFromOrigin(id)); // ResultAsync<T, F>
     * ```
     */
    recover<F>(fn: (error: E) => ResultAsync<T, F> | Result<T, F>): ResultAsync<T, F>;
    /**
     * neverthrow-compat alias of {@link recover}. Kept as the documented compat
     * tier; prefer {@link recover} in new code.
     *
     * @example
     * ```ts
     * loadFromCache(id).orElse(() => loadFromOrigin(id));
     * ```
     */
    orElse<F>(fn: (error: E) => ResultAsync<T, F> | Result<T, F>): ResultAsync<T, F>;
    /**
     * Runs a side effect on the `Ok` value and passes the result through
     * unchanged; a no-op on `Err`. Mirrors {@link tapErr}.
     *
     * @example
     * ```ts
     * saveUser(u).tap((saved) => analytics.track("user_saved", saved.id));
     * ```
     */
    tap(fn: (value: T) => void): ResultAsync<T, E>;
    /**
     * Runs a side effect on the `Err` value and passes the result through
     * unchanged; a no-op on `Ok`. The error-track mirror of {@link tap}.
     *
     * @example
     * ```ts
     * saveUser(u).tapErr((e) => logger.warn("save failed", e));
     * ```
     */
    tapErr(fn: (error: E) => void): ResultAsync<T, E>;
    /**
     * Settles to the `Ok` value, or `defaultValue` if `Err`. Terminal — returns a
     * plain `Promise`, not a `ResultAsync`.
     *
     * @example
     * ```ts
     * const profile = await loadProfile(id).unwrapOr(guestProfile);
     * ```
     */
    unwrapOr<U>(defaultValue: U): Promise<T | U>;
    /**
     * Terminal collapse — folds both tracks into a single awaited value. Returns
     * a plain `Promise`, settling the carrier exactly once.
     *
     * @param onOk - handles the `Ok` value
     * @param onErr - handles the `Err` value
     *
     * @example
     * ```ts
     * const status = await save(row).match(
     *   () => 200,
     *   (e) => (e.kind === "conflict" ? 409 : 500),
     * );
     * ```
     */
    match<U1, U2 = U1>(onOk: (value: T) => U1, onErr: (error: E) => U2): Promise<U1 | U2>;
    /**
     * Settles the carrier to a bare sync {@link Result}, memoizing so the
     * underlying factory runs at most once. Prefer `await ra` (the thenable) or
     * {@link match} in app code; use `resolve` when you need the tagged union back.
     *
     * @example
     * ```ts
     * const r = await load(id).resolve();   // Result<Data, LoadError>
     * if (isOk(r)) use(r.value);
     * ```
     */
    resolve(): Promise<Result<T, E>>;
    /**
     * Thenable shim — `await ra` resolves to a bare tagged-union `Result<T, E>`.
     * Narrow with `isOk(r)` / `isErr(r)` to read `.value` / `.error`.
     */
    then<R1 = Result<T, E>, R2 = never>(onfulfilled?: ((value: Result<T, E>) => R1 | PromiseLike<R1>) | undefined | null, onrejected?: ((reason: unknown) => R2 | PromiseLike<R2>) | undefined | null): Promise<R1 | R2>;
}

export { type InferErr as I, ResultAsync as R, type InferOk as a };