import { GITVAULT_MIRROR_VALIDITY_NOT_FRESHNESS_STATEMENT } from "../namespaces/gitvault.crypto.js";
import type { GitvaultHeadTarget } from "../namespaces/gitvault.types.js";
import type { GitvaultKeystore } from "./gitvault-keystore.js";
import { type GitvaultMirrorBackend } from "./gitvault-mirror-backend.js";
import type { GitvaultRetainedRefsReconcileResult } from "./gitvault-publication.js";
/**
 * Trigger discipline (design D4): a chain/payload read falls back ONLY on a
 * genuinely network-class failure — the underlying `fetch` threw before a
 * response existed, or the gateway answered with a 5xx. An authorization
 * refusal (401/403/404, or any other 4xx) must NEVER silently reroute to the
 * mirror, so it is excluded even when it happens to arrive with no `.status`
 * (see below).
 *
 * Two wrinkles in how a gitvault read actually fails, both handled here:
 *
 * 1. Most gitvault byte reads (`getGenerationBytes`/`getObjectBytes` in
 *    `gitvault-publication.ts`, and this file's own mirror backend) call the
 *    injected `fetch` DIRECTLY rather than the kernel's typed
 *    `client.request()` — a raw connection/DNS failure therefore propagates
 *    UNBRANDED (a plain `TypeError`, never a `Run402Error`). That is, in
 *    practice, the primary shape a real "run402 is unreachable" outage
 *    takes, so an unbranded throw is treated as network-class.
 * 2. When those SAME call sites DO get a response but it is not `ok`, they
 *    throw via `gitvault-publication.ts`'s own local `fail()` helper — a
 *    `LocalError` whose real HTTP status rides in `details.status`, never on
 *    `e.status` itself (`LocalError` always passes `status: null` to the
 *    `Run402Error` constructor). This function reads BOTH places so a 5xx
 *    reaching through either path is classified alike, and a 4xx through
 *    either path is excluded alike.
 */
export declare function isNetworkClassGitvaultReadError(e: unknown): boolean;
/** `s3://bucket/prefix` or a directory path — never a credential, same redaction `mirrorStatus` already prints. */
export interface GitvaultDegradedReadSource {
    /** `"byo"` when this vault's own primary destination served the fallback (gitvault-byo-primary-bucket task 3.4); `"mirror"` for the opt-in customer mirror — see {@link resolveDegradedReadSource}'s precedence. */
    kind: "mirror" | "byo";
    destination: string;
    credential_kind: "profile" | "ambient" | null;
}
/** One degraded chain/payload read, served from {@link GitvaultDegradedReadSource} via `r402s-recover`. */
export interface GitvaultDegradedReadResult {
    degraded: true;
    source: GitvaultDegradedReadSource;
    refs: Record<string, string>;
    head_target: GitvaultHeadTarget;
    generation: string;
    retained_refs: GitvaultRetainedRefsReconcileResult;
    validity_not_freshness: typeof GITVAULT_MIRROR_VALIDITY_NOT_FRESHNESS_STATEMENT;
}
interface ResolvedDegradedReadSource extends GitvaultDegradedReadSource {
    backend: GitvaultMirrorBackend;
}
/**
 * The small seam design D4 calls out: which client-side destination a
 * degraded read should serve from, for one vault.
 *
 * Precedence (gitvault-byo-primary-bucket task 3.4): the opt-in customer
 * MIRROR wins when BOTH a mirror and a BYO write config are configured
 * locally on THIS machine. A BYO vault's own primary destination is
 * ALWAYS a complete `r402s-recover` source on its own (task 3.3's whole
 * point), so this is not a completeness question — it keeps the
 * PRE-EXISTING, already-shipped mirror substrate's behavior byte-identical
 * (a machine that already has a working mirror configured for degraded
 * reads keeps using it) rather than silently switching sources the moment
 * a BYO local config also exists. The BYO branch is the fallback: read
 * ONLY when no mirror is configured — no network call either way, purely
 * local file reads, matching this function's own "never touches the
 * network" contract.
 */
export declare function resolveDegradedReadSource(keystore: GitvaultKeystore, repoId: string): ResolvedDegradedReadSource | null;
export interface GitvaultDegradedReadLive {
    refs: Record<string, string>;
    head_target: GitvaultHeadTarget;
    generation: string;
}
export interface TryGitvaultDegradedReadOptions<T extends GitvaultDegradedReadLive> {
    /** The caller's own live gateway call (e.g. `vault.materialize()` or `vault.restoreObjectsInto(dir)`) — this module has no opinion on which. */
    attemptLive: () => Promise<T>;
    keystore: GitvaultKeystore;
    repo_id: string;
    /**
     * Where a degraded materialization writes objects (`recoverGitvaultMirror`'s
     * own `out_dir` — a bare-shaped, git-proven repository, e.g. the resolved
     * `GIT_DIR` from `resolveGitInvocationRepo`; never guessed from `cwd`).
     * `null` disables the fallback entirely — a repo-free read (a bare
     * `git ls-remote` outside any checkout) has nowhere to materialize into,
     * so it surfaces the original gateway error exactly as it always did.
     */
    out_dir: string | null;
    /** Test/advanced hook: an already-opened backend, bypassing {@link resolveDegradedReadSource}'s config resolution — mirrors `GitvaultMirrorSyncOptions`'s own `backend` override. */
    backend?: GitvaultMirrorBackend;
}
export type GitvaultDegradedReadOutcome<T extends GitvaultDegradedReadLive> = {
    degraded: false;
    live: T;
} | {
    degraded: true;
    result: GitvaultDegradedReadResult;
};
/**
 * Attempt `options.attemptLive`, with ONE bounded retry on a network-class
 * failure (so a transient blip does not flap between sources — design D4).
 * A non-network-class failure (an authorization refusal, or any other 4xx;
 * a protocol/chain error with no status signal at all) is NEVER retried and
 * NEVER falls back — it rethrows the ORIGINAL error UNCHANGED, exactly as a
 * non-degraded caller would see it.
 *
 * After the retry budget is exhausted on a genuinely network-class failure:
 * with no fallback source configured (or `out_dir: null`), the ORIGINAL
 * error is rethrown UNCHANGED — never wrapped, never re-typed, so its
 * `code`/`status`/`kind` survive for the caller exactly as they would
 * without this wrapper. Only the caller's own stderr hint may change.
 * With a fallback source, this degrades via the SHIPPED `r402s-recover`
 * engine (`recoverGitvaultMirror`) against it, returning
 * `{ degraded: true, result }` — a genuine recovery failure (an incomplete
 * or unreadable mirror) propagates from THAT call as its own honest error,
 * never silently swallowed back into the original gateway failure.
 */
export declare function tryGitvaultDegradedRead<T extends GitvaultDegradedReadLive>(options: TryGitvaultDegradedReadOptions<T>): Promise<GitvaultDegradedReadOutcome<T>>;
export {};
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