/**
 * Notification context — provides a `push()` helper that surfaces
 * toast-style notifications via `react-native-toast-message`.
 *
 * Mount `<NotificationProvider>` somewhere above the components that
 * consume `useNotificationContext()`. The `<Toast />` component itself
 * must be rendered separately in the app root (see
 * `react-native-toast-message` docs).
 *
 * The vault notification provider also bridged a WebSocket service into
 * this context to dispatch server-pushed toasts; that piece is
 * app-specific and not included here. Consumers that need it can build
 * a thin wrapper around this provider.
 */

import React, { createContext, useCallback, useContext, useMemo } from "react";
import Toast from "react-native-toast-message";

export type NotificationLevel = "success" | "error" | "warning" | "info";

export interface ToastOptions {
  level: NotificationLevel;
  title: string;
  message?: string;
  /** Milliseconds before auto-dismiss. Defaults to 4000. */
  ttl_ms?: number;
}

interface NotificationContextValue {
  push: (options: ToastOptions) => void;
}

const NotificationContext = createContext<NotificationContextValue | null>(null);

const LEVEL_TO_TOAST_TYPE: Record<NotificationLevel, "success" | "error" | "info"> = {
  success: "success",
  error: "error",
  // react-native-toast-message only ships success/error/info — warnings
  // map onto error so they show with the warning-coloured icon.
  warning: "error",
  info: "info",
};

export function NotificationProvider({ children }: { children: React.ReactNode }) {
  const push = useCallback((options: ToastOptions) => {
    Toast.show({
      type: LEVEL_TO_TOAST_TYPE[options.level],
      text1: options.title,
      text2: options.message,
      visibilityTime: options.ttl_ms ?? 4000,
    });
  }, []);

  // Memoize the context value so an inline-object identity churn
  // doesn't re-render every consumer on each NotificationProvider
  // render. `push` is already `useCallback`-stable, so the memo
  // effectively pins the value across the provider's lifetime.
  const value = useMemo(() => ({ push }), [push]);

  return <NotificationContext.Provider value={value}>{children}</NotificationContext.Provider>;
}

export function useNotificationContext(): NotificationContextValue {
  const ctx = useContext(NotificationContext);
  if (!ctx) {
    throw new Error("useNotificationContext must be used inside <NotificationProvider>");
  }
  return ctx;
}