import { Platform } from 'react-native';
import * as SecureStore from 'expo-secure-store';
import AsyncStorage from '@react-native-async-storage/async-storage';

/**
 * 🚀 Unified Storage System for biiproject
 * Handles both Native (AsyncStorage/SecureStore) and Web (LocalStorage) seamlessly.
 */
const SENSITIVE_KEYS = ['user_token', 'saved_pass', 'biometric_credentials'];

// In-memory fallback for environments where storage is unavailable (e.g. some web modes or broken native modules)
const memoryStorage: Record<string, string> = {};

export const storage = {
  save: async (key: string, value: string) => {
    try {
      if (Platform.OS === 'web') {
        if (typeof localStorage !== 'undefined') {
          localStorage.setItem(key, value);
        } else {
          memoryStorage[key] = value;
        }
      } else {
        if (SENSITIVE_KEYS.includes(key)) {
          // SecureStore might fail if biometrics are not configured or on some Android versions
          try {
            await SecureStore.setItemAsync(key, value);
          } catch (e) {
            console.warn(`[Storage] SecureStore failed for ${key}, falling back to AsyncStorage`, e);
            await AsyncStorage.setItem(key, value);
          }
        } else {
          await AsyncStorage.setItem(key, value);
        }
      }
      return true;
    } catch (error) {
      console.error(`Storage Save Error [${key}]:`, error);
      memoryStorage[key] = value; // Last resort
      return false;
    }
  },

  get: async (key: string) => {
    try {
      if (Platform.OS === 'web') {
        if (typeof localStorage !== 'undefined') {
          return localStorage.getItem(key);
        }
        return memoryStorage[key] || null;
      } else {
        if (SENSITIVE_KEYS.includes(key)) {
          try {
            const val = await SecureStore.getItemAsync(key);
            if (val) return val;
          } catch (e) {
            console.warn(`[Storage] SecureStore read failed for ${key}`, e);
          }
          // Check fallback
          return await AsyncStorage.getItem(key);
        } else {
          return await AsyncStorage.getItem(key);
        }
      }
    } catch (error) {
      console.warn(`Storage Get Error [${key}]:`, error);
      return memoryStorage[key] || null;
    }
  },

  remove: async (key: string) => {
    try {
      if (Platform.OS === 'web') {
        if (typeof localStorage !== 'undefined') {
          localStorage.removeItem(key);
        }
        delete memoryStorage[key];
      } else {
        if (SENSITIVE_KEYS.includes(key)) {
          try {
            await SecureStore.deleteItemAsync(key);
          } catch (e) {
            console.warn(`[Storage] SecureStore delete failed for ${key}`, e);
          }
          await AsyncStorage.removeItem(key);
        } else {
          await AsyncStorage.removeItem(key);
        }
      }
      return true;
    } catch (error) {
      console.error(`Storage Remove Error [${key}]:`, error);
      return false;
    }
  }
};