/**
 * Request kernel — the one place in the SDK that touches `fetch`.
 *
 * Isomorphic: uses only platform globals, no Node-only APIs. The kernel is
 * safe to execute inside a V8 isolate where `fs`, `child_process`, and
 * `process` are absent.
 *
 * Failure translation: maps HTTP status codes and network errors to the
 * appropriate {@link Run402Error} subclass. Callers never see `undefined`
 * or a response-shaped error value — they either get the parsed body as T
 * or an exception.
 */
import type { AuthRequestMeta, CredentialsProvider, ProjectKeys } from "./credentials.js";
export interface KernelConfig {
    apiBase: string;
    fetch: typeof globalThis.fetch;
    credentials: CredentialsProvider;
    clientMetadata?: Run402ClientMetadata | false;
    /**
     * Per-client observability accumulator, mutated by every request made
     * through this kernel config. Set by {@link buildClient} — a fresh
     * {@link ClientStats} object per `Run402` instance, monotonic (no reset)
     * for the instance's lifetime. Exposed to callers via `Client.stats()` /
     * `Run402.stats()`. Not meant to be set directly by SDK consumers.
     * @internal
     */
    stats?: ClientStats;
}
export interface Run402ClientMetadata {
    surface?: string;
    version?: string;
    sdkVersion?: string;
}
export interface RequestOptions {
    method?: string;
    headers?: Record<string, string>;
    body?: unknown;
    /** Send body as a raw string (e.g. `text/plain` SQL) or bytes, skipping JSON.stringify. */
    rawBody?: string | Uint8Array;
    /** Include credential headers from `credentials.getAuth(path)`. Default: true. */
    withAuth?: boolean;
    /** Optional write capability + target, passed to `getAuth` for operator-approval matching. */
    authMeta?: AuthRequestMeta;
    /** Short verb phrase attached to thrown errors (e.g. "provisioning project"). */
    context: string;
    /**
     * Logical retry attempt number, surfaced verbatim in the `RUN402_TRACE`
     * line's `attempt=<n>` field. Default 1 — the kernel itself never retries
     * a request; a caller that re-issues the same logical request after a
     * higher-level retry (e.g. a safe release-race replan) may pass an
     * incrementing value so the trace reads as one logical operation's history
     * rather than unrelated single-attempt calls.
     */
    attempt?: number;
}
/** Cumulative request-kernel observability for one SDK instance (`Run402.stats()`). Monotonic — never resets. */
export interface ClientStats {
    /** Number of fetch calls made (successful or not). */
    round_trips: number;
    /** Summed wall-clock time spent in fetch + body read, in milliseconds. */
    wire_ms: number;
    /** Summed request body bytes sent, where knowable. */
    bytes_up: number;
    /** Summed response body bytes received (Content-Length when present, measured otherwise). */
    bytes_down: number;
}
/**
 * What the seller's `PAYMENT-RESPONSE` receipt says actually settled.
 *
 * OBSERVED, never inferred. `network` is the chain the payment landed on
 * according to the settlement receipt — not a guess from local wallet config.
 * That distinction is the point: a caller must be able to tell a real payment
 * from a testnet one, and a buyer holding mainnet funds makes any config-derived
 * guess wrong.
 */
export interface PaymentSettlement {
    success: boolean;
    network: string;
    transaction: string;
    payer: string | null;
}
export interface ResponseEnvelope<T = unknown> {
    status: number;
    body: T;
    /**
     * Present only when the response carried an x402 settlement receipt, i.e.
     * this request actually moved money. Absent/`null` means no payment was made
     * on this request — NOT that a payment failed.
     */
    settlement?: PaymentSettlement | null;
}
/**
 * Decode the `PAYMENT-RESPONSE` receipt if the response carries one.
 *
 * Deliberately total: a malformed or unexpected receipt yields `null` rather
 * than throwing. A caller asking "what did I just pay?" must never have its
 * SUCCESSFUL response turned into an error by a reporting concern.
 *
 * Strict receipt VALIDATION — matching the receipt against the challenge the
 * buyer accepted — belongs to the paid-fetch buyer path, which does it. This is
 * disclosure of what the seller reported, and is labelled as such.
 */
export declare function decodeSettlementReceipt(res: {
    headers: {
        get(name: string): string | null;
    };
}): PaymentSettlement | null;
/** Internal client surface passed to each namespace. */
export interface Client {
    /** API base URL, e.g. `https://api.run402.com`. Exposed for namespaces that need to compute derived URLs (e.g. REST endpoints). */
    readonly apiBase: string;
    request<T>(path: string, opts: RequestOptions): Promise<T>;
    requestWithResponse<T>(path: string, opts: RequestOptions): Promise<ResponseEnvelope<T>>;
    getProjectCredentials(id: string): Promise<ProjectKeys | null>;
    /** @deprecated Use getProjectCredentials. */
    getProject(id: string): Promise<ProjectKeys | null>;
    /** The underlying credentials provider. Namespaces use this to access optional methods (saveProject, setActiveProject, ...). */
    readonly credentials: CredentialsProvider;
    /**
     * The injected fetch (or default `globalThis.fetch`). Namespaces use this
     * when they need to hit a non-gateway URL — e.g. an S3 presigned URL from
     * a multipart upload, where auth + apiBase injection would be wrong.
     */
    readonly fetch: typeof globalThis.fetch;
    /** Cumulative observability for this client instance. See {@link ClientStats}. */
    stats(): ClientStats;
}
export declare function request<T>(kernel: KernelConfig, path: string, opts: RequestOptions): Promise<T>;
export declare function requestWithResponse<T>(kernel: KernelConfig, path: string, opts: RequestOptions): Promise<ResponseEnvelope<T>>;
export declare function buildClient(kernel: KernelConfig): Client;
export declare function clientMetadataHeaders(metadata: KernelConfig["clientMetadata"]): Record<string, string>;
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