// ============================================================================
// Transport options
// ============================================================================

export interface IVpnTransportStdio {
  transport: 'stdio';
}

export interface IVpnTransportSocket {
  transport: 'socket';
  socketPath: string;
  autoReconnect?: boolean;
  reconnectBaseDelayMs?: number;
  reconnectMaxDelayMs?: number;
  maxReconnectAttempts?: number;
}

export type TVpnTransportOptions = IVpnTransportStdio | IVpnTransportSocket;

// ============================================================================
// Client configuration
// ============================================================================

export interface IVpnClientConfig {
  /** Server WebSocket URL, e.g. wss://vpn.example.com/tunnel */
  serverUrl: string;
  /** Server's static public key (base64) for Noise NK handshake */
  serverPublicKey: string;
  /** Optional DNS servers to use while connected */
  dns?: string[];
  /** Optional MTU for the TUN device */
  mtu?: number;
  /** Keepalive interval in seconds (default: 30) */
  keepaliveIntervalSecs?: number;
}

export interface IVpnClientOptions {
  transport: TVpnTransportOptions;
  config?: IVpnClientConfig;
}

// ============================================================================
// Server configuration
// ============================================================================

export interface IVpnServerConfig {
  /** Listen address for WebSocket, e.g. 0.0.0.0:443 */
  listenAddr: string;
  /** TLS certificate PEM (optional — can be behind reverse proxy) */
  tlsCert?: string;
  /** TLS private key PEM */
  tlsKey?: string;
  /** Server's Noise static private key (base64) */
  privateKey: string;
  /** Server's Noise static public key (base64) */
  publicKey: string;
  /** IP subnet for VPN clients, e.g. 10.8.0.0/24 */
  subnet: string;
  /** DNS servers pushed to clients */
  dns?: string[];
  /** MTU for TUN device */
  mtu?: number;
  /** Keepalive interval in seconds (default: 30) */
  keepaliveIntervalSecs?: number;
  /** Enable NAT/masquerade for client traffic */
  enableNat?: boolean;
  /** Default rate limit for new clients (bytes/sec). Omit for unlimited. */
  defaultRateLimitBytesPerSec?: number;
  /** Default burst size for new clients (bytes). Omit for unlimited. */
  defaultBurstBytes?: number;
}

export interface IVpnServerOptions {
  transport: TVpnTransportOptions;
  config?: IVpnServerConfig;
}

// ============================================================================
// Status and statistics
// ============================================================================

export type TVpnConnectionState =
  | 'disconnected'
  | 'connecting'
  | 'handshaking'
  | 'connected'
  | 'reconnecting'
  | 'error';

export interface IVpnStatus {
  state: TVpnConnectionState;
  assignedIp?: string;
  serverAddr?: string;
  connectedSince?: string;
  lastError?: string;
}

export interface IVpnStatistics {
  bytesSent: number;
  bytesReceived: number;
  packetsSent: number;
  packetsReceived: number;
  keepalivesSent: number;
  keepalivesReceived: number;
  uptimeSeconds: number;
  quality?: IVpnConnectionQuality;
}

export interface IVpnClientInfo {
  clientId: string;
  assignedIp: string;
  connectedSince: string;
  bytesSent: number;
  bytesReceived: number;
  packetsDropped: number;
  bytesDropped: number;
  lastKeepaliveAt?: string;
  keepalivesReceived: number;
  rateLimitBytesPerSec?: number;
  burstBytes?: number;
}

export interface IVpnServerStatistics extends IVpnStatistics {
  activeClients: number;
  totalConnections: number;
}

export interface IVpnKeypair {
  publicKey: string;
  privateKey: string;
}

// ============================================================================
// QoS: Connection quality
// ============================================================================

export type TVpnLinkHealth = 'healthy' | 'degraded' | 'critical';

export interface IVpnConnectionQuality {
  srttMs: number;
  jitterMs: number;
  minRttMs: number;
  maxRttMs: number;
  lossRatio: number;
  consecutiveTimeouts: number;
  linkHealth: TVpnLinkHealth;
  currentKeepaliveIntervalSecs: number;
}

// ============================================================================
// QoS: MTU info
// ============================================================================

export interface IVpnMtuInfo {
  tunMtu: number;
  effectiveMtu: number;
  linkMtu: number;
  overheadBytes: number;
  oversizedPacketsDropped: number;
  icmpTooBigSent: number;
}

// ============================================================================
// QoS: Client telemetry (server-side per-client)
// ============================================================================

export interface IVpnClientTelemetry {
  clientId: string;
  assignedIp: string;
  lastKeepaliveAt?: string;
  keepalivesReceived: number;
  packetsDropped: number;
  bytesDropped: number;
  bytesReceived: number;
  bytesSent: number;
  rateLimitBytesPerSec?: number;
  burstBytes?: number;
}

// ============================================================================
// IPC Command maps (used by smartrust RustBridge<TCommands>)
// ============================================================================

export type TVpnClientCommands = {
  connect: { params: { config: IVpnClientConfig }; result: { assignedIp: string } };
  disconnect: { params: Record<string, never>; result: void };
  getStatus: { params: Record<string, never>; result: IVpnStatus };
  getStatistics: { params: Record<string, never>; result: IVpnStatistics };
  getConnectionQuality: { params: Record<string, never>; result: IVpnConnectionQuality };
  getMtuInfo: { params: Record<string, never>; result: IVpnMtuInfo };
};

export type TVpnServerCommands = {
  start: { params: { config: IVpnServerConfig }; result: void };
  stop: { params: Record<string, never>; result: void };
  getStatus: { params: Record<string, never>; result: IVpnStatus };
  getStatistics: { params: Record<string, never>; result: IVpnServerStatistics };
  listClients: { params: Record<string, never>; result: { clients: IVpnClientInfo[] } };
  disconnectClient: { params: { clientId: string }; result: void };
  generateKeypair: { params: Record<string, never>; result: IVpnKeypair };
  setClientRateLimit: { params: { clientId: string; rateBytesPerSec: number; burstBytes: number }; result: void };
  removeClientRateLimit: { params: { clientId: string }; result: void };
  getClientTelemetry: { params: { clientId: string }; result: IVpnClientTelemetry };
};

// ============================================================================
// Installer
// ============================================================================

export type TVpnPlatform = 'linux' | 'macos' | 'windows' | 'unknown';

export interface IVpnServiceUnit {
  platform: TVpnPlatform;
  content: string;
  installPath: string;
}

// ============================================================================
// Events emitted by VpnClient / VpnServer
// ============================================================================

export interface IVpnEventMap {
  'status': IVpnStatus;
  'error': { message: string; code?: string };
  'client-connected': IVpnClientInfo;
  'client-disconnected': { clientId: string; reason?: string };
  'exit': { code: number | null; signal: string | null };
  'reconnected': void;
}