/** Public configuration and typed failures for session-query. */

import { HarnessError } from '@deepseek-ai/dsh-llm'

/** Default maximum `before`/`after` raw-event window. */
export const SESSION_QUERY_READ_WINDOW_MAX = 50

/** Configuration for exact session-query reads and traces. */
export interface Config {
  /** Maximum accepted raw read context on either side. Defaults to 50. */
  readWindowMax?: number
}

/** Stable machine-routable failure taxonomy for exact session reads and traces. */
export type SessionQueryErrorCode =
  | 'SESSION_QUERY_EVENT_NOT_FOUND'
  | 'SESSION_QUERY_INVALID_CONFIG'
  | 'SESSION_QUERY_INVALID_LINEAGE'
  | 'SESSION_QUERY_INVALID_SURFACE'
  | 'SESSION_QUERY_INVALID_WINDOW'
  | 'SESSION_QUERY_PERSISTENCE_FAILED'
  | 'SESSION_QUERY_SESSION_NOT_FOUND'
  | 'SESSION_QUERY_SOURCE_CONFLICT'

/** Typed session-query failure whose `code` is one closed taxonomy member. */
export class SessionQueryError extends HarnessError {
  declare readonly code: SessionQueryErrorCode

  // The base stores the value; this signature narrows its open string code.
  // eslint-disable-next-line @typescript-eslint/no-useless-constructor
  constructor(message: string, code: SessionQueryErrorCode, options?: ErrorOptions) {
    super(message, code, options)
  }
}