/**
 * Slack Events API verification and Phase 1 event normalization.
 *
 * These helpers are pure library primitives for the managed channel service.
 * They do not perform HTTP I/O or durable enqueue.
 */
import { type InstallationKind, type SourceThreadMode } from "./source-thread.js";
import type { ChannelEvent } from "../types.js";
import type { RequiredSlackChannelConfig, SlackChannelTrigger } from "./index.js";
export interface SlackSignatureHeaders {
    signature: string;
    timestamp: string;
}
export interface SlackInstallationContext {
    kind: InstallationKind;
    id: string;
    /** Workspace context for the conversation (team_id or context_team_id). */
    contextTeamId: string;
    /**
     * Optional install pin for the bot user id. When unset, normalize reads the
     * installing bot from the Events envelope `authorizations` field.
     */
    botUserId?: string;
    apiAppId: string;
}
export interface NormalizeSlackEventInput {
    body: unknown;
    config: RequiredSlackChannelConfig;
    installation: SlackInstallationContext;
    deliveryId: string;
    /** When true, treat `message` events as `message.im` (DM surface). */
    isDirectMessageSurface?: boolean;
}
export type NormalizeSlackEventResult = {
    status: "url_verification";
    challenge: string;
} | {
    status: "filtered";
    reason: string;
    eventId?: string;
} | {
    status: "accepted";
    event: ChannelEvent;
    userId: string;
    sourceThreadKey: string;
    trigger: SlackChannelTrigger;
    groupingMode: SourceThreadMode;
};
/**
 * Verify a Slack request signature over the exact raw body bytes.
 *
 * Computes HMAC-SHA256 of `v0:{timestamp}:{raw_body}` and compares safely.
 * Rejects timestamps older than five minutes.
 */
export declare function verifySlackRequest(rawBody: string | Uint8Array, headers: SlackSignatureHeaders, signingSecret: string, nowSeconds?: number): Promise<void>;
/**
 * Normalize a verified Slack Events API payload into a channel-neutral event.
 *
 * Filters bot/system/unsupported shapes and applies declarative trigger/filters.
 */
export declare function normalizeSlackEvent(input: NormalizeSlackEventInput): NormalizeSlackEventResult;
/** Decode Slack transport escaping (`&amp;` `&lt;` `&gt;`). */
export declare function decodeSlackEscaping(text: string): string;
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