/**
 * Structured choice / stop commands for birth-time rectification.
 *
 * A/B/C/D taps and “先这样” are server-owned state transitions. They are not
 * chat messages and must not be interpreted by the language model.
 */

import type { AnswerClass } from "../core/types";
import { classifyChoiceAnswer } from "../core/build-state";
import { RECTIFICATION_TERMINATION_COPY } from "../core/rectification-decision";
import {
  CHOICE_STOP_LABEL,
  CHOICE_STOP_MESSAGE,
  CHOICE_SKIP_QUESTION_LABEL,
  CHOICE_SKIP_QUESTION_MESSAGE,
  HOLDOUT_MESSAGE_PREFIX,
  type ChoiceKey,
  type RectificationChoiceCard,
} from "./choice-card";

export const CHOICE_ACTION = "answer_choice" as const;
export const STOP_ACTION = "stop_and_review" as const;
export const DETERMINISTIC_CHOICE_MODEL = "deterministic:choice";

export type ChoiceActionKind = typeof CHOICE_ACTION | typeof STOP_ACTION;
export type ChoiceOptionId = ChoiceKey | "stop";
export type ChoiceActionStatus = "received" | "applied" | "narrated";

export type StructuredProbeDerivedContext = Readonly<{
  sourceType: "structured_probe_answer";
  derivedFromProbeId: string | null;
  referencedDateRange: Readonly<{ start: string; end: string }> | null;
  answerClass: AnswerClass | null;
}>;

export function outcomeIdForOption(optionId: ChoiceKey, schema?: unknown): AnswerClass | null {
  return classifyChoiceAnswer(optionId, schema);
}

export function focusStatusForAnswer(answerClass: AnswerClass | null, optionId: ChoiceOptionId): "resolved" | "declined" | "skipped" {
  if (optionId === "stop" || answerClass === "unsure") return "skipped";
  if (answerClass === "no") return "declined";
  return "resolved";
}

export function choiceOptionQuote(card: RectificationChoiceCard, key: ChoiceKey): string {
  return (card.options.find((item) => item.key === key)?.label ?? "").trim();
}

export function userVisibleChoiceLine(card: RectificationChoiceCard, key: ChoiceKey): string {
  const label = choiceOptionQuote(card, key);
  return `${key}. ${label}`.trim();
}

const STRUCTURED_CHOICE_LINE = /^(?:盘外核对（不计分）：)?[A-D]\. \S/;

/** Taps are state transitions. Hide the synthetic A/B/C/D or 先这样 chat line. */
export function isStructuredChoiceUserText(text: string | null | undefined): boolean {
  const trimmed = text?.trim() ?? "";
  if (!trimmed) return false;
  if (trimmed === CHOICE_STOP_MESSAGE || trimmed === CHOICE_STOP_LABEL) return true;
  if (trimmed === CHOICE_SKIP_QUESTION_MESSAGE || trimmed === CHOICE_SKIP_QUESTION_LABEL) return true;
  if (trimmed.startsWith(`${HOLDOUT_MESSAGE_PREFIX}：`) && STRUCTURED_CHOICE_LINE.test(trimmed)) return true;
  return STRUCTURED_CHOICE_LINE.test(trimmed) && trimmed.length <= 90;
}

export function derivedProbeDateRange(year: number | null | undefined): { start: string; end: string } | null {
  if (!year || year < 1900 || year > 2100) return null;
  return { start: `${year}-01-01`, end: `${year}-12-31` };
}

export function structuredProbeContext(input: {
  probeId: string | null;
  year?: number | null;
  answerClass: AnswerClass | null;
}): StructuredProbeDerivedContext {
  return {
    sourceType: "structured_probe_answer",
    derivedFromProbeId: input.probeId,
    referencedDateRange: derivedProbeDateRange(input.year),
    answerClass: input.answerClass,
  };
}

export function quoteIsFromAssistantQuestion(quote: string, question: string): boolean {
  const normalizedQuote = quote.replace(/\s+/g, "");
  const normalizedQuestion = question.replace(/\s+/g, "");
  if (!normalizedQuote || normalizedQuote.length < 2) return false;
  if (normalizedQuote === normalizedQuestion) return true;
  return /(?:19|20)\d{2}年/.test(normalizedQuote) && normalizedQuestion.includes(normalizedQuote);
}

export function composeChoiceNarration(input: {
  optionId: ChoiceOptionId;
  scoring: boolean;
  appliedInference: boolean;
  answerClass?: AnswerClass | null;
}): string {
  if (input.optionId === "stop") {
    return `已记录你的选择，并结束本次校正，交付当前可信区间和代表性工作时间。${RECTIFICATION_TERMINATION_COPY}`;
  }
  if (input.answerClass === "unsure") {
    return "已记录。这题先不计分，换一件事问。";
  }
  if (!input.scoring) {
    return "已记录你的选择。这是盘外核对，不会改候选分数。";
  }
  if (input.appliedInference) {
    return "已记录你的选择，并更新了候选比较。";
  }
  return "已记录你的选择。";
}

export function shouldContinueAfterStructuredChoice(
  nextAction: unknown,
  receipt?: { nextInterviewPersisted?: boolean } | null,
): boolean {
  if (receipt?.nextInterviewPersisted) return false;
  if (!nextAction || typeof nextAction !== "object") return false;
  const type = (nextAction as { type?: unknown }).type;
  return type === "ask_fact_collection"
    || type === "ask_candidate_discriminator"
    || type === "ask_holdout_validation";
}

export function stableChoiceActionKey(focusId: string, optionId: ChoiceOptionId): string {
  return `${focusId}:${optionId}`;
}