import { type HeaderMap, HeaderValue, type HttpRequest, type HttpResponse } from "../http/index.js";
import type { HttpLayer } from "../layer/index.js";
import type { HttpService } from "../service/index.js";
export type WithHeaders = {
    headers: HeaderMap;
};
export type MakeHeaderValue<T extends WithHeaders> = HeaderValue | string | null | ((message: T) => HeaderValue | string | null);
/**
 * A layer that sets a specific HTTP response header.
 *
 * @example
 * ```ts
 * import { SetResponseHeaderLayer } from "@taxum/core/middleware/set-header";
 * import { m, Router } from "@taxum/core/routing";
 *
 * const router = new Router()
 *     .route("/", m.get(() => "Hello World))
 *     .layer(new SetResponseHeaderLayer("Content-Type", "text/plain"));
 * ```
 */
export declare class SetResponseHeaderLayer implements HttpLayer {
    private readonly mode;
    private readonly name;
    private readonly make;
    private constructor();
    /**
     * Creates a new {@link SetResponseHeaderLayer}.
     *
     * If a previous value exists for the same header, it is removed and
     * replaced with the new header value.
     */
    static overriding(name: string, make: MakeHeaderValue<HttpResponse>): SetResponseHeaderLayer;
    /**
     * Creates a new {@link SetResponseHeaderLayer}.
     *
     * The new header is always added, preserving any existing values. If
     * previous values exist, the header will have multiple values.
     */
    static appending(name: string, make: MakeHeaderValue<HttpResponse>): SetResponseHeaderLayer;
    /**
     * Creates a new {@link SetResponseHeaderLayer}.
     *
     * If a previous value exists for the header, the new value is not inserted.
     */
    static ifNotPresent(name: string, make: MakeHeaderValue<HttpResponse>): SetResponseHeaderLayer;
    layer(inner: HttpService): HttpService;
}
/**
 * A layer that sets a specific HTTP request header.
 *
 * @example
 * ```ts
 * import { SetRequestHeaderLayer } from "@taxum/core/middleware/set-header";
 * import { m, Router } from "@taxum/core/routing";
 *
 * const router = new Router()
 *     .route("/", m.get(() => "Hello World))
 *     .layer(new SetRequestHeaderLayer("Content-Type", "text/plain"));
 * ```
 */
export declare class SetRequestHeaderLayer implements HttpLayer {
    private readonly mode;
    private readonly name;
    private readonly make;
    private constructor();
    /**
     * Creates a new {@link SetRequestHeaderLayer}.
     *
     * If a previous value exists for the same header, it is removed and
     * replaced with the new header value.
     */
    static overriding(name: string, make: MakeHeaderValue<HttpRequest>): SetRequestHeaderLayer;
    /**
     * Creates a new {@link SetRequestHeaderLayer}.
     *
     * The new header is always added, preserving any existing values. If
     * previous values exist, the header will have multiple values.
     */
    static appending(name: string, make: MakeHeaderValue<HttpRequest>): SetRequestHeaderLayer;
    /**
     * Creates a new {@link SetRequestHeaderLayer}.
     *
     * If a previous value exists for the header, the new value is not inserted.
     */
    static ifNotPresent(name: string, make: MakeHeaderValue<HttpRequest>): SetRequestHeaderLayer;
    layer(inner: HttpService): HttpService;
}