// Copyright (c) 2026 Gordon Bolton. MIT License.
const { logToFile } = require('./logger');
const {
  getSABnzbdInstances,
  getQbittorrentInstances,
  getTransmissionInstances,
  getRtorrentInstances
} = require('./config');

// Import client classes
const SABnzbdClient = require('../clients/SABnzbdClient');
const QBittorrentClient = require('../clients/QBittorrentClient');
const TransmissionClient = require('../clients/TransmissionClient');
const RTorrentClient = require('../clients/RTorrentClient');

// Client type mapping
const clientClasses = {
  sabnzbd: SABnzbdClient,
  qbittorrent: QBittorrentClient,
  transmission: TransmissionClient,
  rtorrent: RTorrentClient
};

/**
 * Registry and factory for download clients
 */
class DownloadClientRegistry {
  constructor() {
    this.clients = new Map();
    this.initialized = false;
  }

  /**
   * Initialize all configured download clients
   */
  async initialize() {
    if (this.initialized) {
      return;
    }

    logToFile('[DownloadClientRegistry] Initializing download clients...');

    // Get all instance configurations
    const sabnzbdInstances = getSABnzbdInstances();
    const qbittorrentInstances = getQbittorrentInstances();
    const transmissionInstances = getTransmissionInstances();
    const rtorrentInstances = getRtorrentInstances();

    // Create client instances
    const instanceConfigs = [
      ...sabnzbdInstances.map(inst => ({ ...inst, type: 'sabnzbd' })),
      ...qbittorrentInstances.map(inst => ({ ...inst, type: 'qbittorrent' })),
      ...transmissionInstances.map(inst => ({ ...inst, type: 'transmission' })),
      ...rtorrentInstances.map(inst => ({ ...inst, type: 'rtorrent' }))
    ];

    for (const config of instanceConfigs) {
      try {
        const ClientClass = clientClasses[config.type];
        if (!ClientClass) {
          logToFile(`[DownloadClientRegistry] Unknown client type: ${config.type}`);
          continue;
        }

        const client = new ClientClass(config);
        this.clients.set(config.id, client);
        logToFile(`[DownloadClientRegistry] Created ${config.type} client: ${config.name} (${config.id})`);
      } catch (error) {
        logToFile(`[DownloadClientRegistry] Failed to create client ${config.id}: ${error.message}`);
      }
    }

    this.initialized = true;
    logToFile(`[DownloadClientRegistry] Initialized ${this.clients.size} download clients`);
  }

  /**
   * Get all registered clients
   * @returns {Array<DownloadClient>} Array of client instances
   */
  getAllClients() {
    return Array.from(this.clients.values());
  }

  /**
   * Get client by instance ID
   * @param {string} instanceId - The instance ID
   * @returns {DownloadClient|null} Client instance or null if not found
   */
  getClient(instanceId) {
    return this.clients.get(instanceId) || null;
  }

  /**
   * Get clients by type
   * @param {string} type - Client type ('sabnzbd', 'qbittorrent', 'transmission')
   * @returns {Array<DownloadClient>} Array of client instances
   */
  getClientsByType(type) {
    return this.getAllClients().filter(client => client.getClientType() === type);
  }

  /**
   * Get active downloads from all clients
   * @returns {Promise<Array<NormalizedDownload>>} Array of all downloads
   */
  async getAllDownloads() {
    const clients = this.getAllClients();
    if (clients.length === 0) {
      return [];
    }

    // Reset fallback flags for qBittorrent clients
    for (const client of clients) {
      if (client.resetFallbackFlag) {
        client.resetFallbackFlag();
      }
    }

    // Fetch downloads from all clients in parallel
    const results = await Promise.allSettled(
      clients.map(async (client) => {
        try {
          const downloads = await client.getActiveDownloads();
          logToFile(`[DownloadClientRegistry] ${client.name}: ${downloads.length} downloads`);
          return downloads;
        } catch (error) {
          logToFile(`[DownloadClientRegistry] Error fetching from ${client.name}: ${error.message}`);
          return [];
        }
      })
    );

    // Flatten and return all downloads
    const allDownloads = results
      .filter(result => result.status === 'fulfilled')
      .flatMap(result => result.value);

    logToFile(`[DownloadClientRegistry] Total downloads from all clients: ${allDownloads.length}`);
    return allDownloads;
  }

  /**
   * Get downloads grouped by client type (for backward compatibility)
   * @returns {Promise<Object>} Downloads grouped by client type
   */
  async getDownloadsByClientType() {
    const clients = this.getAllClients();
    const result = {};

    // Group by client type
    for (const client of clients) {
      const type = client.getClientType();
      if (!result[type]) {
        result[type] = [];
      }

      try {
        const downloads = await client.getActiveDownloads();
        result[type].push(...downloads);
      } catch (error) {
        logToFile(`[DownloadClientRegistry] Error fetching from ${client.name}: ${error.message}`);
      }
    }

    return result;
  }

  /**
   * Test connection to all clients
   * @returns {Promise<Array<Object>>} Array of connection test results
   */
  async testAllConnections() {
    const clients = this.getAllClients();
    const results = await Promise.allSettled(
      clients.map(async (client) => {
        try {
          const success = await client.testConnection();
          return {
            instanceId: client.getInstanceId(),
            instanceName: client.name,
            clientType: client.getClientType(),
            success,
            error: null
          };
        } catch (error) {
          return {
            instanceId: client.getInstanceId(),
            instanceName: client.name,
            clientType: client.getClientType(),
            success: false,
            error: error.message
          };
        }
      })
    );

    return results
      .filter(result => result.status === 'fulfilled')
      .map(result => result.value);
  }

  /**
   * Get client status information from all clients
   * @returns {Promise<Array<Object>>} Array of client status objects
   */
  async getAllClientStatuses() {
    const clients = this.getAllClients();
    const results = await Promise.allSettled(
      clients.map(async (client) => {
        try {
          const status = await client.getClientStatus();
          return {
            instanceId: client.getInstanceId(),
            instanceName: client.name,
            clientType: client.getClientType(),
            status
          };
        } catch (error) {
          logToFile(`[DownloadClientRegistry] Error getting status from ${client.name}: ${error.message}`);
          return {
            instanceId: client.getInstanceId(),
            instanceName: client.name,
            clientType: client.getClientType(),
            status: null,
            error: error.message
          };
        }
      })
    );

    return results
      .filter(result => result.status === 'fulfilled')
      .map(result => result.value);
  }
}

// Create singleton instance
const registry = new DownloadClientRegistry();

module.exports = {
  DownloadClientRegistry,
  registry,
  
  // Convenience functions
  initializeClients: () => registry.initialize(),
  getAllClients: () => registry.getAllClients(),
  getClient: (instanceId) => registry.getClient(instanceId),
  getClientsByType: (type) => registry.getClientsByType(type),
  getAllDownloads: () => registry.getAllDownloads(),
  getDownloadsByClientType: () => registry.getDownloadsByClientType(),
  testAllConnections: () => registry.testAllConnections(),
  getAllClientStatuses: () => registry.getAllClientStatuses()
};