import { ISync, EntityType, SyncStatus } from '../types/CalendarTypes';

/**
 * IEntityService<T> - Generic interface for entity services with sync capabilities
 *
 * All entity services (Event, Booking, Customer, Resource) implement this interface
 * to enable polymorphic operations across different entity types.
 *
 * ENCAPSULATION: Services encapsulate sync status manipulation.
 * SyncManager does NOT directly manipulate entity.syncStatus - it delegates to the service.
 *
 * POLYMORPHISM: Both SyncManager and DataSeeder work with Array<IEntityService<any>>
 * and use entityType property for runtime routing, avoiding switch statements.
 */
export interface IEntityService<T extends ISync> {
  /**
   * Entity type discriminator for runtime routing
   * Must match EntityType values: 'Event', 'Booking', 'Customer', 'Resource'
   */
  readonly entityType: EntityType;

  // ============================================================================
  // CRUD Operations (used by DataSeeder and other consumers)
  // ============================================================================

  /**
   * Get all entities from IndexedDB
   * Used by DataSeeder to check if store is empty before seeding
   *
   * @returns Promise<T[]> - Array of all entities
   */
  getAll(): Promise<T[]>;

  /**
   * Save an entity (create or update) to IndexedDB
   * Used by DataSeeder to persist fetched data
   *
   * @param entity - Entity to save
   */
  save(entity: T): Promise<void>;

  // ============================================================================
  // SYNC Methods (used by SyncManager)
  // ============================================================================

  /**
   * Mark entity as successfully synced with backend
   * Sets syncStatus = 'synced' and persists to IndexedDB
   *
   * @param id - Entity ID
   */
  markAsSynced(id: string): Promise<void>;

  /**
   * Mark entity as sync error (max retries exceeded)
   * Sets syncStatus = 'error' and persists to IndexedDB
   *
   * @param id - Entity ID
   */
  markAsError(id: string): Promise<void>;

  /**
   * Get current sync status for an entity
   * Used by SyncManager to check entity state
   *
   * @param id - Entity ID
   * @returns SyncStatus or null if entity not found
   */
  getSyncStatus(id: string): Promise<SyncStatus | null>;
}