import { stripQuestionSentences } from "./collect-prompt";
import { parseAgentChoiceCopy, type ChoiceKey } from "./choice-card";
import type { ConversationFocus } from "./tool-service";

export type TurnQuestionKind = "choice" | "collect_spoken" | "reverse_verify";

export type TurnQuestionOption = Readonly<{
  key: ChoiceKey;
  label: string;
}>;

export type TurnQuestion = Readonly<{
  focus_id: string;
  question_id: string;
  kind: TurnQuestionKind;
  prompt: string;
  options: readonly TurnQuestionOption[] | null;
  status: string;
  answer_option: ChoiceKey | "stop" | "skip_probe" | null;
  probe_id: string | null;
}>;

const ANSWER_OPTIONS = new Set(["A", "B", "C", "D", "stop", "skip_probe"]);

export function focusSpokenPrompt(schema: Readonly<Record<string, unknown>> | null | undefined): string | null {
  if (!schema) return null;
  const top = typeof schema.prompt === "string" ? schema.prompt.trim() : "";
  if (top.length >= 8 && top.length <= 120) return top;
  const copy = parseAgentChoiceCopy(schema);
  const fromChoice = copy?.prompt?.trim() ?? "";
  return fromChoice || null;
}

export function turnQuestionKind(focus: {
  intent?: string | null;
  expectedAnswerSchema?: Readonly<Record<string, unknown>> | null;
}): TurnQuestionKind {
  const intent = focus.intent ?? "";
  if (intent === "reverse_verify" || intent === "out_of_sample_check") return "reverse_verify";
  if (parseAgentChoiceCopy(focus.expectedAnswerSchema)) return "choice";
  return "collect_spoken";
}

export function turnQuestionFromFocus(focus: ConversationFocus): TurnQuestion | null {
  const prompt = focusSpokenPrompt(focus.expectedAnswerSchema);
  if (!prompt || !focus.id || !focus.questionId) return null;
  const copy = parseAgentChoiceCopy(focus.expectedAnswerSchema);
  const probeId = typeof focus.expectedAnswerSchema.probe_id === "string"
    ? focus.expectedAnswerSchema.probe_id
    : null;
  const answer = focus.answerOption;
  return {
    focus_id: focus.id,
    question_id: focus.questionId,
    kind: turnQuestionKind(focus),
    prompt,
    options: copy
      ? copy.options.map((option) => ({ key: option.key, label: option.label }))
      : null,
    status: focus.status,
    answer_option: answer && ANSWER_OPTIONS.has(answer) ? answer : null,
    probe_id: probeId,
  };
}

export function parseTurnQuestion(value: unknown): TurnQuestion | null {
  if (!value || typeof value !== "object" || Array.isArray(value)) return null;
  const row = value as Record<string, unknown>;
  if (typeof row.focus_id !== "string" || typeof row.question_id !== "string") return null;
  if (row.kind !== "choice" && row.kind !== "collect_spoken" && row.kind !== "reverse_verify") {
    return null;
  }
  const prompt = typeof row.prompt === "string" ? row.prompt.trim() : "";
  if (!prompt) return null;
  const answer = row.answer_option;
  const options = Array.isArray(row.options)
    ? row.options.flatMap((item): TurnQuestionOption[] => {
      if (!item || typeof item !== "object") return [];
      const option = item as Record<string, unknown>;
      if (option.key !== "A" && option.key !== "B" && option.key !== "C" && option.key !== "D") {
        return [];
      }
      if (typeof option.label !== "string" || !option.label.trim()) return [];
      return [{ key: option.key, label: option.label.trim() }];
    })
    : [];
  return {
    focus_id: row.focus_id,
    question_id: row.question_id,
    kind: row.kind,
    prompt,
    options: options.length === 4 ? options : (row.kind === "choice" || row.kind === "reverse_verify" ? options : null),
    status: typeof row.status === "string" ? row.status : "active",
    answer_option: answer === "A" || answer === "B" || answer === "C" || answer === "D"
      || answer === "stop" || answer === "skip_probe"
      ? answer
      : null,
    probe_id: typeof row.probe_id === "string" ? row.probe_id : null,
  };
}

export function attachQuestionsToTurns<T extends { id: string; role: string; text: string | null }>(
  turns: readonly T[],
  focuses: readonly ConversationFocus[],
): Array<T & { question: TurnQuestion | null; text: string | null }> {
  const byTurn = new Map<string, ConversationFocus>();
  const hanging: ConversationFocus[] = [];
  for (const focus of focuses) {
    if (!focus.askedTurnId) {
      if (focus.status === "active" && turnQuestionKind(focus) === "choice") {
        hanging.push(focus);
      }
      continue;
    }
    byTurn.set(focus.askedTurnId, focus);
  }
  const lastAssistant = [...turns].reverse().find((turn) => turn.role === "assistant");
  if (hanging[0] && lastAssistant && !byTurn.has(lastAssistant.id)) {
    byTurn.set(lastAssistant.id, hanging[0]);
  }
  return turns.map((turn) => {
    if (turn.role !== "assistant") return { ...turn, question: null };
    const focus = byTurn.get(turn.id);
    if (!focus) return { ...turn, question: null };
    const question = turnQuestionFromFocus(focus);
    const text = question && turn.text
      ? stripQuestionSentences(turn.text, question.prompt)
      : turn.text;
    return { ...turn, text, question };
  });
}

export function interviewQuestionBlocksAdoptOffer(
  question: TurnQuestion | null | undefined,
  adopted: boolean,
): boolean {
  if (adopted) return false;
  if (!question || questionIsAnswered(question)) return false;
  return question.kind === "collect_spoken" || question.kind === "choice";
}

export type CandidateOfferAnchor = {
  renderKey: string;
  role: string;
  state?: string;
  text?: string | null;
  failed?: boolean;
  question?: TurnQuestion | null;
  candidateOffer?: Readonly<{ resultId: string }>;
};

function isSettledAssistant(message: CandidateOfferAnchor): boolean {
  if (message.role !== "assistant" || message.failed) return false;
  if (message.state && message.state !== "settled") return false;
  return Boolean(message.text);
}

export function applyLiveCandidateOffer<T extends CandidateOfferAnchor>(
  messages: readonly T[],
  input: { resultId: string; canOffer: boolean; adopted: boolean },
): T[] {
  if (input.adopted) {
    if (!messages.some((message) => message.candidateOffer)) return [...messages];
    return messages.map((message) => (
      message.candidateOffer
        ? { ...message, candidateOffer: { resultId: input.resultId } }
        : message
    ));
  }
  if (!input.canOffer) return [...messages];
  const liveInterview = messages.some((message) => (
    interviewQuestionBlocksAdoptOffer(message.question, false)
  ));
  if (liveInterview) {
    return messages.map((message) => (
      message.candidateOffer ? { ...message, candidateOffer: undefined } : message
    ));
  }
  const owner = [...messages].reverse().find((message) => (
    isSettledAssistant(message)
    && !interviewQuestionBlocksAdoptOffer(message.question, false)
  ));
  if (!owner) {
    return messages.map((message) => (
      message.candidateOffer ? { ...message, candidateOffer: undefined } : message
    ));
  }
  return messages.map((message) => ({
    ...message,
    candidateOffer: message.renderKey === owner.renderKey
      ? { resultId: input.resultId }
      : undefined,
  }));
}

export function persistedOfferFromTurn(
  offerResultId: string | null | undefined,
  previous: Readonly<{ resultId: string }> | undefined,
  turnHydrated: boolean,
): Readonly<{ resultId: string }> | undefined {
  if (typeof offerResultId === "string" && offerResultId.length > 0) {
    return { resultId: offerResultId };
  }
  if (turnHydrated) return undefined;
  return previous;
}

export type SelectionCardLock = Readonly<{ resultId: string; key: string }>;

/** Keep the offering message once the reader has seen the card for this result. */
export function nextSelectionCardLock(
  current: SelectionCardLock | null,
  input: { resultId: string | null | undefined; key: string | undefined },
): SelectionCardLock | null {
  if (!input.resultId) return null;
  if (input.key) {
    if (current?.resultId === input.resultId && current.key === input.key) return current;
    return { resultId: input.resultId, key: input.key };
  }
  if (current?.resultId === input.resultId) return current;
  return null;
}

/**
 * After adopt, do not re-anchor onto the follow-up turn. Prefer a live offer,
 * then the pre-adopt fallback, then the lock from when the card first appeared.
 */
export function resolveSelectionCardMessageKey(input: {
  persistedOfferKey: string | undefined;
  fallbackKey: string | undefined;
  locked: SelectionCardLock | null;
  resultId: string | null | undefined;
  selectedTime: string | null | undefined;
  canOffer: boolean;
}): string | undefined {
  if (!input.resultId) return undefined;
  const live = input.persistedOfferKey
    ?? (input.canOffer && !input.selectedTime ? input.fallbackKey : undefined);
  if (live) return live;
  if (input.locked?.resultId === input.resultId) return input.locked.key;
  return undefined;
}

function assistantCanOwnAdoptOffer(
  turn: { role?: string; question?: TurnQuestion | null },
  adopted: boolean,
): boolean {
  return turn.role === "assistant"
    && !interviewQuestionBlocksAdoptOffer(turn.question, adopted);
}

export function attachOfferResultToTurns<T extends {
  id: string;
  role: string;
  question?: TurnQuestion | null;
}>(
  turns: readonly T[],
  input: {
    resultId: string | null | undefined;
    canAdopt: boolean;
    acceptedTime: string | null | undefined;
  },
): Array<T & { offer_result_id: string | null }> {
  const resultId = input.resultId ?? null;
  const offered = Boolean(resultId && (input.canAdopt || input.acceptedTime));
  if (!offered || !resultId) {
    return turns.map((turn) => ({ ...turn, offer_result_id: null }));
  }
  const adopted = Boolean(input.acceptedTime);
  const firstVerify = turns.findIndex((turn) => (
    turn.role === "assistant" && turn.question?.kind === "reverse_verify"
  ));
  const searchUntil = firstVerify >= 0 ? firstVerify : turns.length;
  let ownerIndex = -1;
  for (let index = searchUntil - 1; index >= 0; index -= 1) {
    if (assistantCanOwnAdoptOffer(turns[index] ?? {}, adopted)) {
      ownerIndex = index;
      break;
    }
  }
  if (ownerIndex < 0) {
    for (let index = turns.length - 1; index >= 0; index -= 1) {
      if (assistantCanOwnAdoptOffer(turns[index] ?? {}, adopted)) {
        ownerIndex = index;
        break;
      }
    }
  }
  return turns.map((turn, index) => ({
    ...turn,
    offer_result_id: index === ownerIndex ? resultId : null,
  }));
}

export function questionIsAnswered(question: TurnQuestion): boolean {
  return question.status !== "active";
}

export function copyTextForMessage(body: string, question: TurnQuestion | null | undefined): string {
  const spoken = body.trim();
  if (!question?.prompt) return spoken;
  const lines = [spoken, "", question.prompt];
  if (question.options?.length) {
    lines.push("");
    for (const option of question.options) {
      const mark = question.answer_option === option.key ? " ✓" : "";
      lines.push(`${option.key}. ${option.label}${mark}`);
    }
  }
  return lines.join("\n").trim();
}