/**
 * Event Bus — Types
 */

export type Topic =
	| "session.message"
	| "session.assistant_start"
	| "session.assistant_end"
	| "session.tool_start"
	| "session.tool_end"
	| "session.checkpoint"
	| "session.compact"
	| "task.assigned"
	| "task.started"
	| "task.completed"
	| "task.failed"
	| "review.requested"
	| "review.completed"
	| "decision.made"
	| "approval.requested"
	| "approval.granted"
	| "workflow.started"
	| "workflow.finished"
	| "knowledge.extracted"
	| "system.quota_exceeded"
	| "system.checkpoint_saved"
	| "system.error";

export interface EventPayload<T = unknown> {
	topic: string;
	data: T;
	timestamp: string;
	eventId: string;
	source: string;
}

export type Subscriber<T = unknown> = (
	payload: EventPayload<T>,
) => void | Promise<void>;

export interface Subscription {
	id: string;
	topic: string;
	subscriber: Subscriber<unknown>;
	filter?: (data: unknown) => boolean;
	priority: number;
	active: boolean;
}

export interface BusOptions {
	deliveryGuarantee?: "at_least_once" | "at_most_once" | "exactly_once";
}

export class EventBusError extends Error {
	constructor(message: string) {
		super(message);
		this.name = "EventBusError";
	}
}