import { ComKey, Item, PriKey } from '@fjell/types';
/**
 * Base event interface that all events extend.
 * Provides core event properties with full type safety using the existing PriKey/ComKey system.
 */
export interface BaseEvent<S extends string, L1 extends string = never, L2 extends string = never, L3 extends string = never, L4 extends string = never, L5 extends string = never> {
    /** Type of event - "create", "update", "delete", etc. */
    eventType: string;
    /** The key of the item that was affected - maintains full type safety */
    key: PriKey<S> | ComKey<S, L1, L2, L3, L4, L5>;
    /** Which storage backend(s) generated this event - enables filtering by implementation */
    scopes: string[];
    /** When the event occurred */
    timestamp: Date;
    /** Optional: the full item content - fully typed, no loss of type information */
    item?: Item<S, L1, L2, L3, L4, L5>;
}
/**
 * Event emitted when an item is created.
 * The item property is required since we always have the created item data.
 */
export interface CreateEvent<S extends string, L1 extends string = never, L2 extends string = never, L3 extends string = never, L4 extends string = never, L5 extends string = never> extends BaseEvent<S, L1, L2, L3, L4, L5> {
    eventType: 'create';
    /** The created item - always available for create events */
    item: Item<S, L1, L2, L3, L4, L5>;
}
/**
 * Event emitted when an item is updated.
 * Provides detailed change tracking with before/after states.
 */
export interface UpdateEvent<S extends string, L1 extends string = never, L2 extends string = never, L3 extends string = never, L4 extends string = never, L5 extends string = never> extends BaseEvent<S, L1, L2, L3, L4, L5> {
    eventType: 'update';
    /** List of field names that were changed */
    changes: string[];
    /** Optional: item state before the update */
    before?: Item<S, L1, L2, L3, L4, L5>;
    /** Optional: item state after the update */
    after?: Item<S, L1, L2, L3, L4, L5>;
}
/**
 * Event emitted when an item is deleted.
 * May include the deleted item data for cleanup/undo operations.
 */
export interface DeleteEvent<S extends string, L1 extends string = never, L2 extends string = never, L3 extends string = never, L4 extends string = never, L5 extends string = never> extends BaseEvent<S, L1, L2, L3, L4, L5> {
    eventType: 'delete';
    /** Optional: the deleted item content - useful for cleanup/undo */
    item?: Item<S, L1, L2, L3, L4, L5>;
}
/**
 * Event emitted when a custom action is performed on an item.
 * Allows libraries to define custom event types beyond standard CRUD.
 */
export interface ActionEvent<S extends string, L1 extends string = never, L2 extends string = never, L3 extends string = never, L4 extends string = never, L5 extends string = never> extends BaseEvent<S, L1, L2, L3, L4, L5> {
    eventType: 'action';
    /** Name of the action that was performed */
    actionName: string;
    /** Optional: action-specific data */
    actionData?: Record<string, unknown>;
}
/**
 * Union type of all standard event types.
 * Libraries can extend this with custom events if needed.
 */
export type Event<S extends string, L1 extends string = never, L2 extends string = never, L3 extends string = never, L4 extends string = never, L5 extends string = never> = CreateEvent<S, L1, L2, L3, L4, L5> | UpdateEvent<S, L1, L2, L3, L4, L5> | DeleteEvent<S, L1, L2, L3, L4, L5> | ActionEvent<S, L1, L2, L3, L4, L5>;
/**
 * Type guard to check if an event is a CreateEvent
 */
export declare function isCreateEvent<S extends string, L1 extends string = never, L2 extends string = never, L3 extends string = never, L4 extends string = never, L5 extends string = never>(event: BaseEvent<S, L1, L2, L3, L4, L5>): event is CreateEvent<S, L1, L2, L3, L4, L5>;
/**
 * Type guard to check if an event is an UpdateEvent
 */
export declare function isUpdateEvent<S extends string, L1 extends string = never, L2 extends string = never, L3 extends string = never, L4 extends string = never, L5 extends string = never>(event: BaseEvent<S, L1, L2, L3, L4, L5>): event is UpdateEvent<S, L1, L2, L3, L4, L5>;
/**
 * Type guard to check if an event is a DeleteEvent
 */
export declare function isDeleteEvent<S extends string, L1 extends string = never, L2 extends string = never, L3 extends string = never, L4 extends string = never, L5 extends string = never>(event: BaseEvent<S, L1, L2, L3, L4, L5>): event is DeleteEvent<S, L1, L2, L3, L4, L5>;
/**
 * Type guard to check if an event is an ActionEvent
 */
export declare function isActionEvent<S extends string, L1 extends string = never, L2 extends string = never, L3 extends string = never, L4 extends string = never, L5 extends string = never>(event: BaseEvent<S, L1, L2, L3, L4, L5>): event is ActionEvent<S, L1, L2, L3, L4, L5>;