'use client';

import {
  createContext,
  useCallback,
  useMemo,
  useRef,
  useState,
  type ReactNode,
} from 'react';

export type ToastVariant = 'info' | 'success' | 'danger' | 'warning';
export type AlertVariant = 'info' | 'danger';

const DEFAULT_TOAST_DURATION_MS = 3000;

export interface ToastItem {
  id: number;
  variant: ToastVariant;
  message: ReactNode;
}

export interface AlertItem {
  variant: AlertVariant;
  title: string;
  message?: ReactNode;
  actions?: ReactNode;
}

export interface ShowToastOptions {
  variant?: ToastVariant;
  message: ReactNode;
  /** 자동 소멸까지의 시간(ms). 기본 3000ms. */
  durationMs?: number;
}

export interface ShowAlertOptions {
  variant?: AlertVariant;
  title: string;
  message?: ReactNode;
  actions?: ReactNode;
}

export interface FeedbackContextValue {
  toasts: ToastItem[];
  alert: AlertItem | null;
  spinnerCount: number;
  showToast: (options: ShowToastOptions) => void;
  dismissToast: (id: number) => void;
  showAlert: (options: ShowAlertOptions) => void;
  hideAlert: () => void;
  showSpinner: () => void;
  hideSpinner: () => void;
}

export const FeedbackContext = createContext<FeedbackContextValue | null>(null);

/**
 * 전역 피드백(토스트 큐 / 알럿 1건 / 스피너 카운트) 상태 보유 — 루트 레이아웃에 한 번만
 * 마운트한다. 실제 비주얼(Toast·Alert·Spinner)은 FeedbackHost가 이 상태를 구독해 그린다.
 * children은 Server Component가 렌더한 결과를 그대로 통과시켜 RSC를 유지한다.
 */
export function FeedbackProvider({ children }: { children: ReactNode }) {
  const [toasts, setToasts] = useState<ToastItem[]>([]);
  const [alert, setAlert] = useState<AlertItem | null>(null);
  const [spinnerCount, setSpinnerCount] = useState(0);
  const nextToastId = useRef(0);

  const dismissToast = useCallback((id: number) => {
    setToasts((prev) => prev.filter((toast) => toast.id !== id));
  }, []);

  const showToast = useCallback(
    (options: ShowToastOptions) => {
      const id = nextToastId.current++;
      setToasts((prev) => [
        ...prev,
        { id, variant: options.variant ?? 'info', message: options.message },
      ]);
      setTimeout(() => {
        dismissToast(id);
      }, options.durationMs ?? DEFAULT_TOAST_DURATION_MS);
    },
    [dismissToast]
  );

  const showAlert = useCallback((options: ShowAlertOptions) => {
    setAlert({
      variant: options.variant ?? 'info',
      title: options.title,
      message: options.message,
      actions: options.actions,
    });
  }, []);

  const hideAlert = useCallback(() => {
    setAlert(null);
  }, []);

  const showSpinner = useCallback(() => {
    setSpinnerCount((prev) => prev + 1);
  }, []);

  const hideSpinner = useCallback(() => {
    setSpinnerCount((prev) => Math.max(0, prev - 1));
  }, []);

  const value = useMemo<FeedbackContextValue>(
    () => ({
      toasts,
      alert,
      spinnerCount,
      showToast,
      dismissToast,
      showAlert,
      hideAlert,
      showSpinner,
      hideSpinner,
    }),
    [
      toasts,
      alert,
      spinnerCount,
      showToast,
      dismissToast,
      showAlert,
      hideAlert,
      showSpinner,
      hideSpinner,
    ]
  );

  return (
    <FeedbackContext.Provider value={value}>{children}</FeedbackContext.Provider>
  );
}