import { Platform } from 'react-native';
import { requireOptionalNativeModule } from 'expo-modules-core';

interface BbpNotifyNative {
  /**
   * Post/replace the ongoing session notification: a native chronometer counting
   * down to endTimeMillis, pinned by a foreground service, with "End" and "Extend"
   * action buttons. Returns a short diagnostic string (e.g. "service-started …").
   */
  showSession(
    title: string,
    body: string,
    endTimeMillis: number,
    endLabel: string,
    extendLabel: string,
  ): Promise<string>;
  /** No active session: stop the service and remove the notification. */
  clearSession(): Promise<void>;
  /** Read + clear the action a notification button set: 'end' | 'extend' | ''. */
  consumePendingAction(): Promise<string>;
  /** Whether the native side still holds a live (unexpired) session record. */
  hasActiveSession(): Promise<boolean>;
}

export type PendingAction = 'end' | 'extend' | null;

// Android-only, and only present in a build that includes the native module
// (returns null in Expo Go / other platforms — callers degrade gracefully).
const native =
  Platform.OS === 'android'
    ? (requireOptionalNativeModule('BbpNotify') as BbpNotifyNative | null)
    : null;

/** True when the native ticking-countdown module is available. */
export const hasNativeCountdown = native != null;

export async function showSession(
  title: string,
  body: string,
  endTimeMillis: number,
  endLabel: string,
  extendLabel: string,
): Promise<string> {
  if (!native) return 'no-native-module';
  return native.showSession(title, body, endTimeMillis, endLabel, extendLabel);
}

export async function clearSession(): Promise<void> {
  await native?.clearSession();
}

/** Read + clear a notification-button action taken while the app was away. */
export async function consumePendingAction(): Promise<PendingAction> {
  const a = await native?.consumePendingAction();
  return a === 'end' || a === 'extend' ? a : null;
}

export async function hasActiveSession(): Promise<boolean> {
  return (await native?.hasActiveSession()) ?? false;
}