"use client";

import { useCallback, useEffect, useMemo, useRef, useState } from "react";
import type { KisRuntimeCredentials } from "@/features/settings/store/use-kis-runtime-store";
import {
  fetchDashboardBalance,
  fetchDashboardIndices,
} from "@/features/dashboard/apis/dashboard.api";
import type {
  DashboardBalanceResponse,
  DashboardHoldingItem,
  DashboardIndicesResponse,
} from "@/features/dashboard/types/dashboard.types";

interface UseDashboardDataResult {
  balance: DashboardBalanceResponse | null;
  indices: DashboardIndicesResponse["items"];
  selectedHolding: DashboardHoldingItem | null;
  selectedSymbol: string | null;
  setSelectedSymbol: (symbol: string) => void;
  isLoading: boolean;
  isRefreshing: boolean;
  balanceError: string | null;
  indicesError: string | null;
  lastUpdatedAt: string | null;
  refresh: () => Promise<void>;
}

const POLLING_INTERVAL_MS = 60_000;

/**
 * @description 대시보드 잔고/지수 상태를 관리하는 훅입니다.
 * @param credentials KIS 인증 정보
 * @returns 대시보드 데이터/로딩/오류 상태
 * @remarks UI 흐름: 대시보드 진입 -> refresh("initial") -> balance/indices API 병렬 호출 -> 카드별 상태 반영
 * @see features/dashboard/components/DashboardContainer.tsx 대시보드 루트 컨테이너
 * @see features/dashboard/apis/dashboard.api.ts 실제 API 호출 함수
 */
export function useDashboardData(
  credentials: KisRuntimeCredentials | null,
): UseDashboardDataResult {
  const [balance, setBalance] = useState<DashboardBalanceResponse | null>(null);
  const [indices, setIndices] = useState<DashboardIndicesResponse["items"]>([]);
  const [selectedSymbol, setSelectedSymbolState] = useState<string | null>(null);
  const [isLoading, setIsLoading] = useState(true);
  const [isRefreshing, setIsRefreshing] = useState(false);
  const [balanceError, setBalanceError] = useState<string | null>(null);
  const [indicesError, setIndicesError] = useState<string | null>(null);
  const [lastUpdatedAt, setLastUpdatedAt] = useState<string | null>(null);

  const requestSeqRef = useRef(0);

  const hasAccountNo = Boolean(credentials?.accountNo?.trim());

  /**
   * @description 잔고/지수 데이터를 병렬로 갱신합니다.
   * @param mode 초기 로드/수동 새로고침/주기 갱신 구분
   * @see features/dashboard/hooks/use-dashboard-data.ts useEffect 초기 호출/폴링/수동 새로고침
   */
  const refreshInternal = useCallback(
    async (mode: "initial" | "manual" | "polling") => {
      if (!credentials) return;

      const requestSeq = ++requestSeqRef.current;
      const isInitial = mode === "initial";

      if (isInitial) {
        setIsLoading(true);
      } else {
        setIsRefreshing(true);
      }

      const tasks: [
        Promise<DashboardBalanceResponse | null>,
        Promise<DashboardIndicesResponse>,
      ] = [
        hasAccountNo
          ? fetchDashboardBalance(credentials)
          : Promise.resolve(null),
        fetchDashboardIndices(credentials),
      ];

      const [balanceResult, indicesResult] = await Promise.allSettled(tasks);
      if (requestSeq !== requestSeqRef.current) return;

      let hasAnySuccess = false;

      if (!hasAccountNo) {
        setBalance(null);
        setBalanceError(
          "계좌번호가 없어 잔고를 조회할 수 없습니다. 설정에서 계좌번호(8-2)를 입력해 주세요.",
        );
        setSelectedSymbolState(null);
      } else if (balanceResult.status === "fulfilled") {
        hasAnySuccess = true;
        setBalance(balanceResult.value);
        setBalanceError(null);

        setSelectedSymbolState((prev) => {
          const nextHoldings = balanceResult.value?.holdings ?? [];
          if (nextHoldings.length === 0) return null;
          if (prev && nextHoldings.some((item) => item.symbol === prev)) {
            return prev;
          }
          return nextHoldings[0]?.symbol ?? null;
        });
      } else {
        setBalanceError(balanceResult.reason instanceof Error ? balanceResult.reason.message : "잔고 조회에 실패했습니다.");
      }

      if (indicesResult.status === "fulfilled") {
        hasAnySuccess = true;
        setIndices(indicesResult.value.items);
        setIndicesError(null);
      } else {
        setIndicesError(indicesResult.reason instanceof Error ? indicesResult.reason.message : "시장 지수 조회에 실패했습니다.");
      }

      if (hasAnySuccess) {
        setLastUpdatedAt(new Date().toISOString());
      }

      if (isInitial) {
        setIsLoading(false);
      } else {
        setIsRefreshing(false);
      }
    },
    [credentials, hasAccountNo],
  );

  /**
   * @description 대시보드 수동 새로고침 핸들러입니다.
   * @see features/dashboard/components/StatusHeader.tsx 새로고침 버튼 onClick
   */
  const refresh = useCallback(async () => {
    await refreshInternal("manual");
  }, [refreshInternal]);

  useEffect(() => {
    if (!credentials) return;

    const timeout = window.setTimeout(() => {
      void refreshInternal("initial");
    }, 0);

    return () => window.clearTimeout(timeout);
  }, [credentials, refreshInternal]);

  useEffect(() => {
    if (!credentials) return;

    const interval = window.setInterval(() => {
      void refreshInternal("polling");
    }, POLLING_INTERVAL_MS);

    return () => window.clearInterval(interval);
  }, [credentials, refreshInternal]);

  const selectedHolding = useMemo(() => {
    if (!selectedSymbol || !balance) return null;
    return balance.holdings.find((item) => item.symbol === selectedSymbol) ?? null;
  }, [balance, selectedSymbol]);

  const setSelectedSymbol = useCallback((symbol: string) => {
    setSelectedSymbolState(symbol);
  }, []);

  return {
    balance,
    indices,
    selectedHolding,
    selectedSymbol,
    setSelectedSymbol,
    isLoading,
    isRefreshing,
    balanceError,
    indicesError,
    lastUpdatedAt,
    refresh,
  };
}