/**
 * Native libp2p bridge component for React Native
 */

import { NativeEventEmitter, NativeModules } from 'react-native';
import { LIBP2P_CONFIG } from '../utils/constants';
import type { ConnectionStatusEvent, PeerDiscoveredEvent, PeerInfoEvent } from '../utils/types';
import type {
  Connection,
  ILibp2pComponent,
  Libp2pEvents,
  Libp2pOptions,
  Multiaddr,
  PeerId,
  PeerInfo,
} from '../interfaces/ILibp2pComponent';

// Helper class to create PeerId-like objects from strings
export class SimplePeerId implements PeerId {
  constructor(private id: string) {}

  toString(): string {
    return this.id;
  }

  toBytes(): Uint8Array {
    return new TextEncoder().encode(this.id);
  }

  equals(other: PeerId): boolean {
    return this.toString() === other.toString();
  }
}

// Helper class to create Multiaddr-like objects from strings  
export class SimpleMultiaddr implements Multiaddr {
  bytes: Uint8Array;

  constructor(private addr: string) {
    this.bytes = new TextEncoder().encode(addr);
  }

  toString(): string {
    return this.addr;
  }

  protos(): Array<{ code: number; name: string }> {
    // Simple parsing of multiaddr components
    const parts = this.addr.split('/').filter((p) => p);
    const protos = [];

    for (let i = 0; i < parts.length; i += 2) {
      const name = parts[i];
      protos.push({ code: 0, name }); // Simplified - real implementation would have proper codes
    }

    return protos;
  }

  getPeerId(): string | null {
    const match = this.addr.match(/\/p2p\/([^/]+)/);
    return match ? match[1] : null;
  }
}

// Type for event handler functions
type EventHandler<T = unknown> = (evt: T) => void;

// Native implementation that wraps our iOS/Android modules
export class Libp2pComponent implements ILibp2pComponent {
  private nativeModule: any;
  private eventEmitter: NativeEventEmitter;
  private eventHandlers: Map<string, Set<EventHandler>> = new Map();
  private _peerId?: PeerId;
  private _multiaddrs: Multiaddr[] = [];
  private _started: boolean = false;
  private cachedConnections: Connection[] = [];
  private options: Libp2pOptions;

  constructor(options?: Libp2pOptions, nativeModules?: typeof NativeModules) {
    // Allow dependency injection of NativeModules for testing
    const modules = nativeModules || NativeModules;
    this.nativeModule = modules.Libp2pModule;
    this.eventEmitter = new NativeEventEmitter(this.nativeModule);
    this.options = options || {};

    if (!this.nativeModule) {
      throw new Error('Libp2p native module not found');
    }

    this.setupNativeEventListeners();
    this.setupProtocolHandlers();
  }

  get peerId(): PeerId | null {
    return this._peerId || null;
  }

  get multiaddrs(): Multiaddr[] {
    return this._multiaddrs;
  }

  private setupNativeEventListeners(): void {
    // Map native events to js-libp2p style events

    // Peer info update
    this.eventEmitter.addListener('onPeerInfo', ({ peerId, multiaddrs }: PeerInfoEvent) => {
      this._peerId = new SimplePeerId(peerId);
      this._multiaddrs = multiaddrs.map((addr: string) => new SimpleMultiaddr(addr));
      this.emit('self:peer:update', {
        peerId: this._peerId,
        multiaddrs: this._multiaddrs,
      });
    });

    // Peer discovery
    this.eventEmitter.addListener(
      'onPeerDiscovered',
      ({ peerId, addresses, multiaddrs }: PeerDiscoveredEvent) => {
        const addrs = (multiaddrs || addresses || []).map(
          (addr: string) => new SimpleMultiaddr(addr),
        );
        this.emit('peer:discovery', {
          id: new SimplePeerId(peerId),
          multiaddrs: addrs,
        });
      },
    );

    // Peer lost (for mDNS service lost events)
    this.eventEmitter.addListener('onPeerLost', ({ peerId }: { peerId: string }) => {
      this.emit('peer:lost', {
        id: new SimplePeerId(peerId),
      });
    });

    // Connection events
    this.eventEmitter.addListener(
      'onConnectionStatus',
      ({ peerId, status, direction, multiaddr }: ConnectionStatusEvent) => {
        const connection: Connection = {
          id: `${peerId}-${Date.now()}`,
          remotePeer: new SimplePeerId(peerId),
          remoteAddr: new SimpleMultiaddr(multiaddr || ''),
          stat: {
            direction: direction || 'outbound',
            status:
              status === LIBP2P_CONFIG.CONNECTION_STATUS.CONNECTED
                ? 'open'
                : status === LIBP2P_CONFIG.CONNECTION_STATUS.PENDING
                  ? 'pending'
                  : status === LIBP2P_CONFIG.CONNECTION_STATUS.DISCONNECTED
                    ? 'closed'
                    : 'closing',
            timeline: {
              open: Date.now(),
            },
          },
        };

        if (
          status === LIBP2P_CONFIG.CONNECTION_STATUS.CONNECTED ||
          status === LIBP2P_CONFIG.CONNECTION_STATUS.PENDING
        ) {
          // Emit peer:connect for both pending and connected states
          // The UI will differentiate based on connection.stat.status
          this.emit('peer:connect', connection);
          this.emit('connection:open', connection);
        } else if (
          status === LIBP2P_CONFIG.CONNECTION_STATUS.DISCONNECTED ||
          status === LIBP2P_CONFIG.CONNECTION_STATUS.FAILED
        ) {
          connection.stat.timeline.close = Date.now();
          connection.stat.status = 'closed';
          this.emit('peer:disconnect', connection);
          this.emit('connection:close', connection);
        }
      },
    );
  }

  private setupProtocolHandlers(): void {
    // Listen for protocol data events
    this.eventEmitter.addListener(
      'onProtocolData',
      (data: { protocolId: string; peerId: string; data?: number[] }) => {
        // Find matching protocol handler
        const handler = this.options.protocols?.find((p) => p.protocolId === data.protocolId);
        if (handler) {
          // Convert number array to Uint8Array if needed
          const uint8Data = data.data ? new Uint8Array(data.data) : undefined;
          handler.handler({ peerId: data.peerId, data: uint8Data });
        }
      },
    );
  }

  private emit<K extends keyof Libp2pEvents>(event: K, detail: unknown): void {
    const handlers = this.eventHandlers.get(event);
    if (handlers) {
      const customEvent = new CustomEvent(event, { detail });
      for (const handler of handlers) {
        handler(customEvent as Libp2pEvents[K]);
      }
    }
  }

  async start(): Promise<void> {
    // Register protocols if any
    if (this.options.protocols && this.nativeModule.registerProtocolHandler) {
      for (const protocol of this.options.protocols) {
        await this.nativeModule.registerProtocolHandler(protocol.protocolId);
      }
    }

    // Pass configuration options to native module including keypair
    const config = {
      tcpPort: this.options.config?.tcpPort,
      wsPort: this.options.config?.wsPort,
      // Convert Uint8Array to base64 for passing to native module
      // Using Buffer.from for proper encoding of binary data
      privateKey: this.options.keypair?.privateKey
        ? Buffer.from(this.options.keypair.privateKey).toString('base64')
        : undefined,
    };

    await this.nativeModule.startLibp2p(config);
    this._started = true;
  }

  async stop(): Promise<void> {
    try {
      await this.nativeModule.stopLibp2p();
      this._started = false;
    } catch (error) {
      // If libp2p wasn't running, that's okay - just update our state
      const errorMessage = error instanceof Error ? error.message : String(error);
      const errorCode = (error as { code?: string })?.code;
      if (errorMessage.includes('not running') || errorCode === 'LIBP2P_ERROR') {
        this._started = false;
      } else {
        // Re-throw other errors
        throw error;
      }
    }
  }

  async dial(multiaddr: string): Promise<Connection> {
    await this.nativeModule.connectToPeer(multiaddr);

    // Create connection object
    const peerId = multiaddr.match(/\/p2p\/([^/]+)/)?.[1] || '';
    return {
      id: `${peerId}-${Date.now()}`,
      remotePeer: new SimplePeerId(peerId),
      remoteAddr: new SimpleMultiaddr(multiaddr),
      stat: {
        direction: 'outbound',
        status: 'open',
        timeline: {
          open: Date.now(),
        },
      },
    };
  }

  async hangUp(peerId: string): Promise<void> {
    const result = await this.nativeModule.hangUp(peerId);

    if (!result?.success) {
      // No active connections to peer - this is okay
    }
  }

  async getConnections(peerId?: string): Promise<Connection[]> {
    try {
      const rawConnections = await this.nativeModule.getConnections();

      // Transform native connections to match the Connection interface
      this.cachedConnections = (rawConnections || []).map((conn: any) => {
        // Ensure the connection has the expected structure
        // Handle different formats from native modules
        let peerIdStr = conn.peerId || 'unknown';
        if (conn.remotePeer) {
          // If remotePeer is an object with toString property (from native module)
          if (typeof conn.remotePeer.toString === 'string') {
            peerIdStr = conn.remotePeer.toString;
          }
          // If remotePeer is a PeerId object with toString method
          else if (typeof conn.remotePeer.toString === 'function') {
            peerIdStr = conn.remotePeer.toString();
          }
        }

        const connection: Connection = {
          id: conn.id || `${peerIdStr}-${Date.now()}`,
          remotePeer: new SimplePeerId(peerIdStr),
          remoteAddr: conn.remoteAddr?.toString
            ? new SimpleMultiaddr(
                typeof conn.remoteAddr.toString === 'string'
                  ? conn.remoteAddr.toString
                  : conn.remoteAddr.toString(),
              )
            : new SimpleMultiaddr('/unknown'),
          stat: conn.stat || {
            direction: conn.direction || 'outbound',
            status: conn.status || 'open',
            timeline: conn.timeline || {
              open: Date.now(),
            },
          },
        };
        return connection;
      });

      // Filter by peerId if provided
      if (peerId) {
        return this.cachedConnections.filter((conn) => conn.remotePeer.toString() === peerId);
      }

      return this.cachedConnections;
    } catch (_error) {
      // Failed to get connections
      return [];
    }
  }

  addEventListener<K extends keyof Libp2pEvents>(
    event: K,
    handler: (evt: Libp2pEvents[K]) => void,
  ): void {
    if (!this.eventHandlers.has(event)) {
      this.eventHandlers.set(event, new Set());
    }
    this.eventHandlers.get(event)?.add(handler as EventHandler);
  }

  removeEventListener<K extends keyof Libp2pEvents>(
    event: K,
    handler: (evt: Libp2pEvents[K]) => void,
  ): void {
    const handlers = this.eventHandlers.get(event);
    if (handlers) {
      handlers.delete(handler as EventHandler);
    }
  }

  async refreshDiscovery(): Promise<void> {
    if (this.nativeModule.refreshDiscovery) {
      await this.nativeModule.refreshDiscovery();
    }
  }

  async pingPeer(peerId: string): Promise<{ success: boolean; rtt?: number; peerId: string }> {
    if (this.nativeModule.pingPeer) {
      return await this.nativeModule.pingPeer(peerId);
    } else {
      throw new Error('Ping not supported on this platform');
    }
  }

  async sendProtocolData(peerId: string, protocolId: string, data: Uint8Array): Promise<void> {
    if (this.nativeModule.sendProtocolData) {
      // Convert Uint8Array to regular array for native module
      const dataArray = Array.from(data);
      await this.nativeModule.sendProtocolData(peerId, protocolId, dataArray);
    } else {
      throw new Error('Protocol sending not supported on this platform');
    }
  }
}

// Type definition for CustomEventInit
interface CustomEventInit<T = unknown> {
  detail?: T;
  bubbles?: boolean;
  cancelable?: boolean;
}

// Polyfill CustomEvent for React Native
if (typeof CustomEvent === 'undefined') {
  const globalObj = global as typeof globalThis & { CustomEvent: typeof CustomEvent };
  globalObj.CustomEvent = class CustomEvent<T = unknown> {
    readonly type: string;
    readonly detail: T;
    readonly bubbles: boolean;
    readonly cancelable: boolean;

    constructor(type: string, eventInitDict?: CustomEventInit<T>) {
      this.type = type;
      this.detail = eventInitDict?.detail as T;
      this.bubbles = eventInitDict?.bubbles || false;
      this.cancelable = eventInitDict?.cancelable || false;
    }

    preventDefault() {}
    stopPropagation() {}
    stopImmediatePropagation() {}
  } as any;
}