/**
 * Settings Service
 *
 * Manages application settings and provides methods to:
 * - Load/save settings
 * - Apply settings to native modules
 * - Reset application data
 */

import { LoggerComponent } from 'ior:gitea:gitea.metatrom.net:universal-components/logger@1.0.0';
import AsyncStorage from '@react-native-async-storage/async-storage';
import { NativeModules, Platform } from 'react-native';

// Storage keys
const SETTINGS_KEY = '@libp2p_settings';

// Default settings
export const DEFAULT_SETTINGS = {
  tcpPort: 10000,
  wsPort: 10005,
  discoveryTimeout: 30000,
  enableDebugLogs: false,
  autoDiscovery: false,
  useCustomPorts: false,
  dhtServerUrl: 'ws://192.168.188.40:3000/ws', // This is the default/fallback DHT server URL
};

export interface AppSettings {
  tcpPort: number;
  wsPort: number;
  discoveryTimeout: number;
  enableDebugLogs: boolean;
  autoDiscovery: boolean;
  useCustomPorts: boolean;
  dhtServerUrl: string;
}

export interface INativeModules {
  Libp2pModule?: any;
  DiscoveryModule?: any;
  SecureStorageModule?: any;
}

export class SettingsService {
  private static instance: SettingsService | null = null;
  private currentSettings: AppSettings = DEFAULT_SETTINGS;
  private logger = new LoggerComponent('SettingsService');
  private nativeModules: INativeModules;

  private constructor(nativeModules?: INativeModules) {
    // Allow dependency injection of native modules
    this.nativeModules = nativeModules || NativeModules;
  }

  public static getInstance(nativeModules?: INativeModules): SettingsService {
    if (!SettingsService.instance) {
      SettingsService.instance = new SettingsService(nativeModules);
    }
    return SettingsService.instance;
  }

  /**
   * Reset the singleton instance (useful for testing)
   */
  public static resetInstance(): void {
    SettingsService.instance = null;
  }

  /**
   * Initialize settings service
   */
  async initialize(): Promise<AppSettings> {
    try {
      const settings = await this.loadSettings();
      this.currentSettings = settings;
      return settings;
    } catch (error) {
      this.logger.error('[SettingsService] Failed to initialize:', error);
      return DEFAULT_SETTINGS;
    }
  }

  /**
   * Load settings from storage
   */
  async loadSettings(): Promise<AppSettings> {
    try {
      const stored = await AsyncStorage.getItem(SETTINGS_KEY);
      if (stored) {
        const parsed = JSON.parse(stored);
        return { ...DEFAULT_SETTINGS, ...parsed };
      }
    } catch (error) {
      this.logger.error('[SettingsService] Failed to load settings:', error);
    }
    return DEFAULT_SETTINGS;
  }

  /**
   * Save settings to storage
   */
  async saveSettings(settings: AppSettings): Promise<void> {
    try {
      await AsyncStorage.setItem(SETTINGS_KEY, JSON.stringify(settings));
      this.currentSettings = settings;

      // Apply settings to native modules if needed
      await this.applySettings(settings);
    } catch (error) {
      this.logger.error('[SettingsService] Failed to save settings:', error);
      throw error;
    }
  }

  /**
   * Apply settings to native modules
   */
  private async applySettings(settings: AppSettings): Promise<void> {
    const { Libp2pModule, DiscoveryModule } = this.nativeModules;

    // Apply port settings if custom ports are enabled
    if (settings.useCustomPorts) {
      // This would need to be passed to the native modules
      // when starting the libp2p node
      this.logger.debug('[SettingsService] Custom ports:', {
        tcp: settings.tcpPort,
        ws: settings.wsPort,
      });
    }

    // Apply debug logging
    if (Libp2pModule?.setDebugConsoleOutput) {
      Libp2pModule.setDebugConsoleOutput(settings.enableDebugLogs);
    }

    // Apply discovery timeout
    if (DiscoveryModule?.setDiscoveryTimeout) {
      DiscoveryModule.setDiscoveryTimeout(settings.discoveryTimeout);
    }
  }

  /**
   * Get current settings
   */
  getSettings(): AppSettings {
    return this.currentSettings;
  }

  /**
   * Get specific setting value
   */
  getSetting<K extends keyof AppSettings>(key: K): AppSettings[K] {
    return this.currentSettings[key];
  }

  /**
   * Update specific setting
   */
  async updateSetting<K extends keyof AppSettings>(key: K, value: AppSettings[K]): Promise<void> {
    const newSettings = { ...this.currentSettings, [key]: value };
    await this.saveSettings(newSettings);
  }

  /**
   * Reset all application data
   */
  async resetAllData(): Promise<void> {
    try {
      this.logger.info('[SettingsService] Starting app reset...');

      // Clear all AsyncStorage (this includes dht_discovered_users)
      const allKeys = await AsyncStorage.getAllKeys();
      this.logger.debug('[SettingsService] Clearing AsyncStorage keys:', allKeys);
      await AsyncStorage.multiRemove(allKeys);

      // Clear native module data
      await this.clearNativeData();

      // Reset settings to defaults
      this.currentSettings = DEFAULT_SETTINGS;

      this.logger.info('[SettingsService] App reset complete');
    } catch (error) {
      this.logger.error('[SettingsService] Failed to reset app data:', error);
      throw error;
    }
  }

  /**
   * Clear native module stored data
   */
  private async clearNativeData(): Promise<void> {
    const { Libp2pModule, DiscoveryModule, SecureStorageModule } = this.nativeModules;

    try {
      if (Platform.OS === 'ios') {
        // Clear iOS UserDefaults
        if (Libp2pModule?.clearStoredData) {
          await Libp2pModule.clearStoredData();
        }
        if (DiscoveryModule?.clearStoredData) {
          await DiscoveryModule.clearStoredData();
        }
        if (SecureStorageModule?.clearAll) {
          await SecureStorageModule.clearAll();
        }
      } else if (Platform.OS === 'android') {
        // Clear Android SharedPreferences
        if (Libp2pModule?.clearStoredData) {
          await Libp2pModule.clearStoredData();
        }
        if (DiscoveryModule?.clearStoredData) {
          await DiscoveryModule.clearStoredData();
        }
        if (SecureStorageModule?.clearAll) {
          await SecureStorageModule.clearAll();
        }
      }
    } catch (error) {
      this.logger.error('[SettingsService] Failed to clear native data:', error);
      // Continue even if native clear fails
    }
  }

  /**
   * Export all app data for debugging
   */
  async exportDebugData(): Promise<object> {
    try {
      const allKeys = await AsyncStorage.getAllKeys();
      const allData: Record<string, unknown> = {};

      for (const key of allKeys) {
        try {
          const value = await AsyncStorage.getItem(key);
          allData[key] = value ? JSON.parse(value) : null;
        } catch {
          // If JSON parse fails, store as string
          allData[key] = await AsyncStorage.getItem(key);
        }
      }

      return {
        settings: this.currentSettings,
        storedData: allData,
        platform: Platform.OS,
        timestamp: new Date().toISOString(),
      };
    } catch (error) {
      this.logger.error('[SettingsService] Failed to export debug data:', error);
      throw error;
    }
  }

  /**
   * Check if this is first app launch
   */
  async isFirstLaunch(): Promise<boolean> {
    try {
      const hasSettings = await AsyncStorage.getItem(SETTINGS_KEY);
      return !hasSettings;
    } catch {
      return true;
    }
  }

  /**
   * Get storage info
   */
  async getStorageInfo(): Promise<{
    keys: string[];
    totalSize: number;
  }> {
    try {
      const allKeys = await AsyncStorage.getAllKeys();
      let totalSize = 0;

      for (const key of allKeys) {
        const value = await AsyncStorage.getItem(key);
        if (value) {
          totalSize += value.length;
        }
      }

      return {
        keys: [...allKeys], // Convert readonly array to mutable array
        totalSize,
      };
    } catch (error) {
      this.logger.error('[SettingsService] Failed to get storage info:', error);
      return { keys: [], totalSize: 0 };
    }
  }
}

// Export singleton getter function instead of instance
export const getSettingsService = (nativeModules?: INativeModules) => 
  SettingsService.getInstance(nativeModules);