/** Schedule-owned use of the shared session durability barrier. */

import type { Context } from 'cordis'
import type { Session } from '@deepseek-ai/dsh-session'

/** Failure to prove that the current live prefix reached a persistence listener. */
export class SchedulePersistenceError extends Error {
  /**
   * Construct a contained persistence failure.
   * @param cause - Rejection returned by the shared barrier, when present.
   */
  constructor(cause?: unknown) {
    super('Schedule persistence did not complete.', cause === undefined ? undefined : { cause })
    this.name = 'SchedulePersistenceError'
  }
}

/**
 * Require one successful shared persistence checkpoint.
 * @param ctx - Context carrying the live session store.
 * @param session - Exact live session to checkpoint.
 * @returns After at least one listener explicitly acknowledges completed durability work.
 */
export async function flushSchedulePersistence(ctx: Context, session: Session): Promise<void> {
  try {
    if (!await ctx.sessions.flush(session)) throw new SchedulePersistenceError()
  } catch (error: unknown) {
    if (error instanceof SchedulePersistenceError) throw error
    throw new SchedulePersistenceError(error)
  }
}