/**
 * @file lib/kis/domestic-market-session.ts
 * @description KRX market-session helpers based on KST (Asia/Seoul)
 */

export type DomesticKisSession =
  | "openAuction"
  | "regular"
  | "closeAuction"
  | "afterCloseFixedPrice"
  | "afterHoursSinglePrice"
  | "closed";

export const DOMESTIC_KIS_SESSION_OVERRIDE_HEADER = "x-kis-session-override";
export const DOMESTIC_KIS_SESSION_OVERRIDE_STORAGE_KEY =
  "KIS_SESSION_OVERRIDE";

const OPEN_AUCTION_START_MINUTES = 8 * 60 + 30; // 08:30
const OPEN_AUCTION_END_MINUTES = 9 * 60; // 09:00
const REGULAR_START_MINUTES = 9 * 60; // 09:00
const REGULAR_END_MINUTES = 15 * 60 + 20; // 15:20
const CLOSE_AUCTION_START_MINUTES = 15 * 60 + 20; // 15:20
const CLOSE_AUCTION_END_MINUTES = 15 * 60 + 30; // 15:30
const AFTER_CLOSE_FIXED_START_MINUTES = 15 * 60 + 40; // 15:40
const AFTER_CLOSE_FIXED_END_MINUTES = 16 * 60; // 16:00
const AFTER_HOURS_SINGLE_START_MINUTES = 16 * 60; // 16:00
const AFTER_HOURS_SINGLE_END_MINUTES = 18 * 60; // 18:00

/**
 * @description Converts external string to strict session enum.
 * @see lib/kis/domestic.ts getDomesticOrderBook
 * @see features/dashboard/hooks/useKisTradeWebSocket.ts resolveSessionInClient
 */
export function parseDomesticKisSession(value?: string | null) {
  if (!value) return null;

  const normalized = value.trim();
  if (!normalized) return null;

  const allowed: DomesticKisSession[] = [
    "openAuction",
    "regular",
    "closeAuction",
    "afterCloseFixedPrice",
    "afterHoursSinglePrice",
    "closed",
  ];

  return allowed.includes(normalized as DomesticKisSession)
    ? (normalized as DomesticKisSession)
    : null;
}

/**
 * @description Returns current session in KST.
 * @see features/dashboard/hooks/useKisTradeWebSocket.ts WebSocket TR switching
 * @see lib/kis/domestic.ts REST orderbook source switching
 */
export function getDomesticKisSessionInKst(now = new Date()): DomesticKisSession {
  const { weekday, totalMinutes } = toKstWeekdayAndMinutes(now);

  if (weekday === "Sat" || weekday === "Sun") {
    return "closed";
  }

  if (
    totalMinutes >= OPEN_AUCTION_START_MINUTES &&
    totalMinutes < OPEN_AUCTION_END_MINUTES
  ) {
    return "openAuction";
  }

  if (
    totalMinutes >= REGULAR_START_MINUTES &&
    totalMinutes < REGULAR_END_MINUTES
  ) {
    return "regular";
  }

  if (
    totalMinutes >= CLOSE_AUCTION_START_MINUTES &&
    totalMinutes < CLOSE_AUCTION_END_MINUTES
  ) {
    return "closeAuction";
  }

  if (
    totalMinutes >= AFTER_CLOSE_FIXED_START_MINUTES &&
    totalMinutes < AFTER_CLOSE_FIXED_END_MINUTES
  ) {
    return "afterCloseFixedPrice";
  }

  if (
    totalMinutes >= AFTER_HOURS_SINGLE_START_MINUTES &&
    totalMinutes < AFTER_HOURS_SINGLE_END_MINUTES
  ) {
    return "afterHoursSinglePrice";
  }

  return "closed";
}

/**
 * @description If override is valid, use it. Otherwise use real KST time.
 * @see app/api/kis/domestic/orderbook/route.ts session override header
 * @see features/dashboard/hooks/useKisTradeWebSocket.ts localStorage override
 */
export function resolveDomesticKisSession(
  override?: string | null,
  now = new Date(),
) {
  return parseDomesticKisSession(override) ?? getDomesticKisSessionInKst(now);
}

/**
 * @description Maps detailed KIS session to dashboard phase.
 * @see lib/kis/domestic.ts getDomesticOverview
 */
export function mapDomesticKisSessionToMarketPhase(
  session: DomesticKisSession,
): "regular" | "afterHours" {
  if (
    session === "regular" ||
    session === "openAuction" ||
    session === "closeAuction"
  ) {
    return "regular";
  }

  return "afterHours";
}

/**
 * @description Whether orderbook should use overtime REST API.
 * @see lib/kis/domestic.ts getDomesticOrderBook
 */
export function shouldUseOvertimeOrderBookApi(session: DomesticKisSession) {
  return (
    session === "afterCloseFixedPrice" || session === "afterHoursSinglePrice"
  );
}

/**
 * @description Whether trade tick should use expected-execution TR.
 * @see features/dashboard/hooks/useKisTradeWebSocket.ts resolveTradeTrId
 */
export function shouldUseExpectedExecutionTr(session: DomesticKisSession) {
  return session === "openAuction" || session === "closeAuction";
}

/**
 * @description Whether trade tick/orderbook should use after-hours single-price TR.
 * @see features/dashboard/hooks/useKisTradeWebSocket.ts resolveTradeTrId
 */
export function shouldUseAfterHoursSinglePriceTr(session: DomesticKisSession) {
  return session === "afterHoursSinglePrice";
}

function toKstWeekdayAndMinutes(now: Date) {
  const parts = new Intl.DateTimeFormat("en-US", {
    timeZone: "Asia/Seoul",
    weekday: "short",
    hour: "2-digit",
    minute: "2-digit",
    hour12: false,
  }).formatToParts(now);

  const partMap = new Map(parts.map((part) => [part.type, part.value]));
  const weekday = partMap.get("weekday") ?? "Sun";
  const hour = Number(partMap.get("hour") ?? "0");
  const minute = Number(partMap.get("minute") ?? "0");
  const totalMinutes = hour * 60 + minute;

  return { weekday, totalMinutes };
}