/**
 * V9 rectification Case state machine contracts.
 *
 * The server owns the authoritative Case status. The browser and the agent
 * never derive status from message counts, candidate existence or session
 * ordering.
 */

import {
  RECTIFICATION_CASE_STATUSES,
  RESUMABLE_CASE_STATUSES,
  TERMINAL_CASE_STATUSES,
} from "@/lib/contracts/rectification-entry";
import type { RectificationCaseStatus } from "@/lib/contracts/rectification-entry";

export {
  RECTIFICATION_CASE_STATUSES,
  RESUMABLE_CASE_STATUSES,
  TERMINAL_CASE_STATUSES,
};
export type { RectificationCaseStatus };

const RESUMABLE_SET = new Set<string>(RESUMABLE_CASE_STATUSES);
const TERMINAL_SET = new Set<string>(TERMINAL_CASE_STATUSES);

export function isRectificationCaseStatus(
  value: unknown,
): value is RectificationCaseStatus {
  return (
    typeof value === "string" &&
    (RESUMABLE_SET.has(value) || TERMINAL_SET.has(value))
  );
}

export function isResumableStatus(
  status: RectificationCaseStatus,
): boolean {
  return RESUMABLE_SET.has(status);
}

export function isTerminalStatus(status: RectificationCaseStatus): boolean {
  return TERMINAL_SET.has(status);
}

/**
 * Legal terminal transitions. A resumable case may move to any terminal
 * status; terminal statuses are immutable.
 */
export function canTransitToTerminal(
  from: RectificationCaseStatus,
  to: RectificationCaseStatus,
): boolean {
  if (isTerminalStatus(from)) return false;
  return isTerminalStatus(to);
}

/** statuses that reject evidence/turn writes. Terminal cases are read-only. */
export function evidenceWritesAllowed(
  status: RectificationCaseStatus,
): boolean {
  return isResumableStatus(status);
}

/**
 * The one-resumable-case-per-user invariant, mirrored from the database
 * partial unique index. The database is the enforcement point; this is the
 * contract the service layer relies on.
 */
export const MAX_RESUMABLE_CASES_PER_USER = 1;

export const RECTIFICATION_SKILL_NAME = "jyotish-birth-time-rectification";
// 原值: "10.0.28" / 新值: "10.0.29" / 原因: 年月阶段改口述并禁止追问本人
// 原值: "10.0.29" / 新值: "10.0.30" / 原因: D2 出卡句与 D4 卡上百分比规则写进 Skill（2026-09-26）
// 原值: "10.0.30" / 新值: "10.0.31" / 原因: 开场改大白话、题干带例子和示例回答写进 Skill OpeningPolicy（BUG-1049，2026-09-26）
// 原值: "10.0.31" / 新值: "10.0.32" / 原因: 训练门开后只问点选卡、交付正文去吻合率写进 Skill（BUG-1084/1085，2026-09-29）
// 原值: "10.0.32" / 新值: "10.0.33" / 原因: 持久opt-in盘型交付，nullable历史保持旧身份/方法（BUG-1115～1117）
export const RECTIFICATION_SKILL_VERSION = "10.0.33";