/**
 * Pure reads of the Case snapshot payload for the rectification chat surface:
 * the current question, its source, and the initial state that arrives with
 * the reveal. Moved out of rectification-agentic-chat.tsx unchanged
 * (TASK-rectification-code-split-20260926); no React hooks here.
 */
import {
  parseRectificationCandidateResult,
  type RectificationCandidateResult,
} from "@/lib/rectification-candidate-result";
import {
  searchWindowFromSnapshot,
  caseStageFromSnapshot,
  interviewStopReasonFromSnapshot,
  interviewSessionOutcomeFromSnapshot,
  birthTimeSourceFromSnapshot,
  type RectificationCaseSnapshotPayload,
} from "@/lib/rectification-surface-state";
import type { RectificationTimelineStage } from "@/lib/rectification-timeline-scale";
import { isRectificationCaseStatus, type RectificationCaseStatus } from "@/lib/rectification-agentic/v9/case-status";
import { parseRectificationChoiceCard, type RectificationChoiceCard as ChoiceCardModel } from "@/lib/rectification-agentic/v9/choice-card";

export type CandidateResult = RectificationCandidateResult | null;
export type CurrentQuestionModel = Readonly<{
  kind: "choice" | "collect_spoken";
  prompt: string | null;
  focus_id: string | null;
  question_id: string | null;
}>;

export function currentQuestionFromSnapshot(value: unknown): CurrentQuestionModel | null {
  if (!value || typeof value !== "object" || Array.isArray(value)) return null;
  const question = value as { kind?: unknown; prompt?: unknown; focus_id?: unknown; question_id?: unknown };
  if (question.kind !== "choice" && question.kind !== "collect_spoken" && question.kind !== "reverse_verify") {
    return null;
  }
  return {
    kind: question.kind === "collect_spoken" ? "collect_spoken" : "choice",
    prompt: typeof question.prompt === "string" && question.prompt.trim()
      ? question.prompt.trim()
      : null,
    focus_id: typeof question.focus_id === "string" ? question.focus_id : null,
    question_id: typeof question.question_id === "string" ? question.question_id : null,
  };
}

export function questionSourceFromSnapshot(value: unknown): "focus" | "unavailable" | null {
  if (value === "unavailable") return "unavailable";
  if (value === "focus") return "focus";
  return null;
}

export type CaseSnapshotState = Readonly<{
  candidate: CandidateResult;
  question: CurrentQuestionModel | null;
  questionSource: "focus" | "unavailable" | null;
  choice: ChoiceCardModel | null;
  caseStatus: RectificationCaseStatus | null;
  savedTime: string | null;
  savedStatus: "accepted" | "confirmed" | null;
  nextUserActionId: string | null;
  searchWindow: readonly [string, string] | null;
  stage: RectificationTimelineStage | null;
  interviewStopReason: string | null;
  interviewSessionOutcome: string | null;
  birthTimeSource: ReturnType<typeof birthTimeSourceFromSnapshot>;
}>;

export function nextUserActionIdFromSnapshot(payload: RectificationCaseSnapshotPayload | null): string | null {
  const id = payload?.next_user_action?.id;
  return typeof id === "string" && id.trim() ? id.trim() : null;
}

/** The snapshot that arrived with the reveal, as initial state; nothing is fetched on mount. */
export function caseSnapshotState(payload: RectificationCaseSnapshotPayload | null): CaseSnapshotState | null {
  if (!payload) return null;
  const confirmedTime = typeof payload.case?.confirmed_time === "string" ? payload.case.confirmed_time : null;
  const acceptedTime = typeof payload.case?.accepted_time === "string" ? payload.case.accepted_time : null;
  return {
    candidate: parseRectificationCandidateResult(payload.latest_result),
    question: currentQuestionFromSnapshot(payload.current_question),
    questionSource: questionSourceFromSnapshot(payload.question_source),
    choice: parseRectificationChoiceCard(payload.choice_card),
    caseStatus: isRectificationCaseStatus(payload.case?.status) ? payload.case.status : null,
    savedTime: confirmedTime ?? acceptedTime,
    savedStatus: confirmedTime ? "confirmed" : acceptedTime ? "accepted" : null,
    nextUserActionId: nextUserActionIdFromSnapshot(payload),
    searchWindow: searchWindowFromSnapshot(payload.case?.candidate_range),
    stage: caseStageFromSnapshot(payload.case?.stage),
    interviewStopReason: interviewStopReasonFromSnapshot(payload),
    interviewSessionOutcome: interviewSessionOutcomeFromSnapshot(payload),
    birthTimeSource: birthTimeSourceFromSnapshot(payload),
  };
}