/**
 * ESP32 WiFi Provisioning Service
 *
 * Handles BLE communication with WellNuo ESP32 sensors (WP_xxx_xxxxxx)
 * for WiFi configuration and provisioning.
 *
 * Uses @orbital-systems/react-native-esp-idf-provisioning which wraps
 * Espressif's official provisioning libraries.
 *
 * NOTE: This module requires a development build. In Expo Go, a mock
 * implementation is used that returns empty results.
 */

import { Platform, PermissionsAndroid, Alert } from 'react-native';
import Constants from 'expo-constants';

// Check if we're running in Expo Go (no native modules available)
const isExpoGo = Constants.appOwnership === 'expo';

// WellNuo device prefix (matches WP_xxx_xxxxxx pattern)
const WELLNUO_DEVICE_PREFIX = 'WP_';

export interface WellNuoDevice {
  name: string;
  device: any; // ESPDevice when native module available
  wellId?: string;      // Extracted from name: WP_<wellId>_<mac>
  macPart?: string;     // Last part of MAC address
}

export interface WifiNetwork {
  ssid: string;
  rssi: number;
  auth: string;
}

// Dynamic import types - will be null in Expo Go
let ESPProvisionManager: any = null;
let ESPTransport: any = null;
let ESPSecurity: any = null;

// Try to load native module only in development builds
if (!isExpoGo) {
  try {
    const espModule = require('@orbital-systems/react-native-esp-idf-provisioning');
    ESPProvisionManager = espModule.ESPProvisionManager;
    ESPTransport = espModule.ESPTransport;
    ESPSecurity = espModule.ESPSecurity;
  } catch (e) {
    // Native provisioning module not available
  }
}

class ESPProvisioningService {
  private connectedDevice: any | null = null;
  private isScanning = false;

  /**
   * Check if ESP provisioning is available (development build only)
   */
  isAvailable(): boolean {
    return ESPProvisionManager !== null;
  }

  /**
   * Request necessary permissions for BLE on Android
   */
  async requestPermissions(): Promise<boolean> {
    if (!this.isAvailable()) {
      return false;
    }

    if (Platform.OS !== 'android') {
      return true;
    }

    try {
      const granted = await PermissionsAndroid.requestMultiple([
        PermissionsAndroid.PERMISSIONS.BLUETOOTH_SCAN,
        PermissionsAndroid.PERMISSIONS.BLUETOOTH_CONNECT,
        PermissionsAndroid.PERMISSIONS.ACCESS_FINE_LOCATION,
      ]);

      const allGranted = Object.values(granted).every(
        (status) => status === PermissionsAndroid.RESULTS.GRANTED
      );

      return allGranted;
    } catch (error) {
      return false;
    }
  }

  /**
   * Scan for WellNuo ESP32 devices
   * Returns list of devices matching WP_xxx_xxxxxx pattern
   */
  async scanForDevices(timeoutMs = 10000): Promise<WellNuoDevice[]> {
    if (!this.isAvailable()) {
      Alert.alert(
        'Development Build Required',
        'WiFi provisioning requires a development build. This feature is not available in Expo Go.',
        [{ text: 'OK' }]
      );
      return [];
    }

    if (this.isScanning) {
      return [];
    }

    const hasPermissions = await this.requestPermissions();
    if (!hasPermissions) {
      throw new Error('Bluetooth permissions not granted');
    }

    this.isScanning = true;

    try {
      const devices = await ESPProvisionManager.searchESPDevices(
        WELLNUO_DEVICE_PREFIX,
        ESPTransport.ble,
        ESPSecurity.unsecure
      );

      return devices.map((device: any) => {
        // Parse device name: WP_<wellId>_<macPart>
        const parts = device.name?.split('_') || [];
        return {
          name: device.name || 'Unknown',
          device,
          wellId: parts[1],
          macPart: parts[2],
        };
      });
    } catch (error) {
      throw error;
    } finally {
      this.isScanning = false;
    }
  }

  /**
   * Connect to a WellNuo device
   * @param device - The device to connect to
   * @param proofOfPossession - Optional PoP for secure devices
   */
  async connect(
    device: any,
    proofOfPossession?: string
  ): Promise<boolean> {
    if (!this.isAvailable()) {
      return false;
    }

    if (this.connectedDevice) {
      await this.disconnect();
    }

    try {
      // Try without PoP first (unsecure mode)
      await device.connect(proofOfPossession || null);
      this.connectedDevice = device;
      return true;
    } catch (error) {
      throw error;
    }
  }

  /**
   * Scan for available WiFi networks through connected device
   */
  async scanWifiNetworks(): Promise<WifiNetwork[]> {
    if (!this.isAvailable()) {
      return [];
    }

    if (!this.connectedDevice) {
      throw new Error('Not connected to any device');
    }

    try {
      const wifiList = await this.connectedDevice.scanWifiList();

      return wifiList.map((wifi: any) => ({
        ssid: wifi.ssid,
        rssi: wifi.rssi,
        auth: this.getAuthModeName(wifi.auth),
      }));
    } catch (error) {
      throw error;
    }
  }

  /**
   * Provision device with WiFi credentials
   * @param ssid - WiFi network name
   * @param password - WiFi password
   */
  async provisionWifi(ssid: string, password: string): Promise<boolean> {
    if (!this.isAvailable()) {
      return false;
    }

    if (!this.connectedDevice) {
      throw new Error('Not connected to any device');
    }

    try {
      await this.connectedDevice.provision(ssid, password);
      return true;
    } catch (error) {
      throw error;
    }
  }

  /**
   * Disconnect from current device
   */
  async disconnect(): Promise<void> {
    if (!this.connectedDevice) {
      return;
    }

    try {
      this.connectedDevice.disconnect();
      this.connectedDevice = null;
    } catch (error) {
      this.connectedDevice = null;
    }
  }

  /**
   * Check if currently connected to a device
   */
  isConnected(): boolean {
    return this.connectedDevice !== null;
  }

  /**
   * Get currently connected device name
   */
  getConnectedDeviceName(): string | null {
    return this.connectedDevice?.name || null;
  }

  /**
   * Convert auth mode number to human-readable string
   */
  private getAuthModeName(authMode: number): string {
    const modes: Record<number, string> = {
      0: 'Open',
      1: 'WEP',
      2: 'WPA2 Enterprise',
      3: 'WPA2 PSK',
      4: 'WPA PSK',
      5: 'WPA/WPA2 PSK',
    };
    return modes[authMode] || `Unknown (${authMode})`;
  }
}

// Export singleton instance
export const espProvisioning = new ESPProvisioningService();

// Export types for components
export type ESPDevice = any;