/**
 * Document operation types
 */
export enum DocumentOperation {
  CREATE = 'create',
  UPDATE = 'update',
  UPSERT = 'upsert',
  DELETE = 'delete',
}

/**
 * Document with metadata
 */
export interface DocumentWithMeta<T = unknown> {
  /** Document ID */
  _id: string;

  /** Document source */
  _source: T;

  /** Document version (for optimistic locking) */
  _version?: number;

  /** Sequence number (for optimistic locking) */
  _seq_no?: number;

  /** Primary term (for optimistic locking) */
  _primary_term?: number;

  /** Document index */
  _index?: string;

  /** Document score (from search) */
  _score?: number;
}

/**
 * Batch operation for bulk requests
 */
export interface BatchOperation<T = unknown> {
  operation: DocumentOperation;
  documentId: string;
  document?: T;
  version?: number;
  seqNo?: number;
  primaryTerm?: number;
}

/**
 * Batch result
 */
export interface BatchResult {
  successful: number;
  failed: number;
  errors: Array<{
    documentId: string;
    operation: DocumentOperation;
    error: string;
    statusCode: number;
  }>;
  took: number; // Time in milliseconds
}

/**
 * Session configuration
 */
export interface SessionConfig {
  /** Only process documents newer than a timestamp */
  onlyNew?: boolean;

  /** Start from a specific point in time */
  fromTimestamp?: Date;

  /** Delete documents not seen in session */
  cleanupStale?: boolean;

  /** Batch size for operations */
  batchSize?: number;
}

/**
 * Snapshot processor function
 */
export type SnapshotProcessor<T, R> = (
  iterator: AsyncIterableIterator<DocumentWithMeta<T>>,
  previousSnapshot: R | null
) => Promise<R>;

/**
 * Snapshot metadata
 */
export interface SnapshotMeta<T = unknown> {
  date: Date;
  data: T;
  documentCount: number;
  processingTime: number;
}

/**
 * Document iterator options
 */
export interface IteratorOptions {
  /** Batch size for scrolling */
  batchSize?: number;

  /** Filter by timestamp */
  fromTimestamp?: Date;

  /** Sort order */
  sort?: Array<{ [key: string]: 'asc' | 'desc' }>;

  /** Query filter */
  query?: unknown;
}

/**
 * Point-in-time ID for pagination
 */
export interface PitId {
  id: string;
  keepAlive: string;
}