/**
 * a2a/tasks.ts — the Task store behind AIBroker's A2A server.
 *
 * Pure functions over a JSON file, path-injectable so tests never touch the
 * real store. Three properties the spec does not hand you for free and a
 * naive implementation gets wrong:
 *
 * IDEMPOTENCY. Spec 6.4 gives every Message a `messageId`, generated by the
 * sender. A client that retries a `message/send` after a timeout must not
 * spawn a second task for work already accepted — `findByMessageId` is
 * checked before a new task is created, so the same id always resolves to
 * the same task.
 *
 * THREADING. `contextId` groups a multi-turn conversation (spec 6.1, 6.4).
 * A second message carrying a contextId whose task is still open (not in a
 * terminal state) is appended to that task's history rather than starting a
 * new one — the same session keeps the thread instead of forking a new task
 * per reply.
 *
 * BOUNDED AND EXPIRED. Capped at 500 tasks; terminal tasks older than 7 days
 * are swept by `cleanupExpired`. Eviction prefers the oldest TERMINAL task
 * over the oldest task outright, so a burst of short-lived tasks does not
 * push out something still `working`.
 */
import type { TaskState } from "./schema/types.js";
export type { TaskState } from "./schema/types.js";
export interface TaskHistoryEntry {
    role: "user" | "agent";
    text: string;
    messageId: string;
    at: string;
}
export interface TaskArtifactEntry {
    artifactId: string;
    name?: string;
    text: string;
    /** Set when the artifact's text was validated as an AG2 message and passed. */
    agentishOk?: boolean;
}
export interface A2ATask {
    id: string;
    contextId: string;
    /** The exposed session this task was addressed to. */
    session: string;
    state: TaskState;
    statusMessage?: string;
    createdAt: string;
    updatedAt: string;
    history: TaskHistoryEntry[];
    artifacts: TaskArtifactEntry[];
}
export declare function defaultTaskFile(): string;
export declare function findByMessageId(messageId: string, file?: string): A2ATask | undefined;
export declare function getTask(id: string, file?: string): A2ATask | undefined;
export declare function listForSession(session: string, file?: string): A2ATask[];
export declare function listAll(file?: string): A2ATask[];
export interface CreateOrThreadResult {
    task: A2ATask;
    /** False when an existing open task on the same contextId was reused. */
    created: boolean;
}
/**
 * Create a task for `session`, or thread onto an existing open one sharing
 * `contextId`, or return the task a repeated `messageId` already produced.
 */
export declare function createOrThreadTask(opts: {
    session: string;
    text: string;
    messageId: string;
    contextId?: string;
}, file?: string): CreateOrThreadResult;
export declare function setStatus(id: string, state: TaskState, opts?: {
    message?: string;
}, file?: string): A2ATask | undefined;
export declare function addArtifact(id: string, text: string, opts?: {
    name?: string;
    agentishOk?: boolean;
}, file?: string): A2ATask | undefined;
/** Remove terminal tasks past EXPIRY_MS. Returns how many were removed. */
export declare function cleanupExpired(file?: string, now?: number): number;
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