/**
 * Proxy engine bridge — manages the Rust proxy-engine subprocess.
 *
 * The proxy-engine handles ALL SIP protocol mechanics. TypeScript only:
 * - Sends configuration
 * - Receives high-level events (incoming_call, call_ended, etc.)
 * - Sends high-level commands (hangup, make_call, play_audio)
 *
 * No raw SIP ever touches TypeScript.
 */

import path from 'node:path';
import { RustBridge } from '@push.rocks/smartrust';

// ---------------------------------------------------------------------------
// Command type map for smartrust
// ---------------------------------------------------------------------------

type TProxyCommands = {
  configure: {
    params: Record<string, unknown>;
    result: { bound: string };
  };
  hangup: {
    params: { call_id: string };
    result: Record<string, never>;
  };
  make_call: {
    params: { number: string; device_id?: string; provider_id?: string };
    result: { call_id: string };
  };
  play_audio: {
    params: { call_id: string; leg_id?: string; file_path: string; codec?: number };
    result: Record<string, never>;
  };
  start_recording: {
    params: { call_id: string; file_path: string; max_duration_ms?: number };
    result: Record<string, never>;
  };
  stop_recording: {
    params: { call_id: string };
    result: { file_path: string; duration_ms: number };
  };
};

// ---------------------------------------------------------------------------
// Event types from Rust
// ---------------------------------------------------------------------------

export interface IIncomingCallEvent {
  call_id: string;
  from_uri: string;
  to_number: string;
  provider_id: string;
}

export interface IOutboundCallEvent {
  call_id: string;
  from_device: string | null;
  to_number: string;
}

export interface ICallEndedEvent {
  call_id: string;
  reason: string;
  duration: number;
  from_side?: string;
}

export interface IProviderRegisteredEvent {
  provider_id: string;
  registered: boolean;
  public_ip: string | null;
}

export interface IDeviceRegisteredEvent {
  device_id: string;
  display_name: string;
  address: string;
  port: number;
  aor: string;
  expires: number;
}

// ---------------------------------------------------------------------------
// Bridge singleton
// ---------------------------------------------------------------------------

let bridge: RustBridge<TProxyCommands> | null = null;
let initialized = false;
let logFn: ((msg: string) => void) | undefined;

function buildLocalPaths(): string[] {
  const root = process.cwd();
  return [
    path.join(root, 'dist_rust', 'proxy-engine'),
    path.join(root, 'rust', 'target', 'release', 'proxy-engine'),
    path.join(root, 'rust', 'target', 'debug', 'proxy-engine'),
  ];
}

/**
 * Initialize the proxy engine — spawn the Rust binary.
 * Call configure() separately to push config and start SIP.
 */
export async function initProxyEngine(log?: (msg: string) => void): Promise<boolean> {
  if (initialized && bridge) return true;
  logFn = log;

  try {
    bridge = new RustBridge<TProxyCommands>({
      binaryName: 'proxy-engine',
      localPaths: buildLocalPaths(),
    });

    const spawned = await bridge.spawn();
    if (!spawned) {
      log?.('[proxy-engine] failed to spawn binary');
      bridge = null;
      return false;
    }

    bridge.on('exit', () => {
      logFn?.('[proxy-engine] process exited — will need re-init');
      bridge = null;
      initialized = false;
    });

    // Forward stderr for debugging.
    bridge.on('stderr', (line: string) => {
      logFn?.(`[proxy-engine:stderr] ${line}`);
    });

    initialized = true;
    log?.('[proxy-engine] spawned and ready');
    return true;
  } catch (e: any) {
    log?.(`[proxy-engine] init error: ${e.message}`);
    bridge = null;
    return false;
  }
}

/**
 * Send the full app config to the proxy engine.
 * This binds the SIP socket, starts provider registrations, etc.
 */
export async function configureProxyEngine(config: Record<string, unknown>): Promise<boolean> {
  if (!bridge || !initialized) return false;
  try {
    const result = await bridge.sendCommand('configure', config as any);
    logFn?.(`[proxy-engine] configured, SIP bound on ${(result as any)?.bound || '?'}`);
    return true;
  } catch (e: any) {
    logFn?.(`[proxy-engine] configure error: ${e.message}`);
    return false;
  }
}

/**
 * Initiate an outbound call via Rust. Returns the call ID or null on failure.
 */
export async function makeCall(number: string, deviceId?: string, providerId?: string): Promise<string | null> {
  if (!bridge || !initialized) return null;
  try {
    const result = await bridge.sendCommand('make_call', {
      number,
      device_id: deviceId,
      provider_id: providerId,
    } as any);
    return (result as any)?.call_id || null;
  } catch (e: any) {
    logFn?.(`[proxy-engine] make_call error: ${e?.message || e}`);
    return null;
  }
}

/**
 * Send a hangup command.
 */
export async function hangupCall(callId: string): Promise<boolean> {
  if (!bridge || !initialized) return false;
  try {
    await bridge.sendCommand('hangup', { call_id: callId } as any);
    return true;
  } catch {
    return false;
  }
}

/**
 * Send a WebRTC offer to the proxy engine. Returns the SDP answer.
 */
export async function webrtcOffer(sessionId: string, sdp: string): Promise<{ sdp: string } | null> {
  if (!bridge || !initialized) return null;
  try {
    const result = await bridge.sendCommand('webrtc_offer', { session_id: sessionId, sdp } as any);
    return result as any;
  } catch (e: any) {
    logFn?.(`[proxy-engine] webrtc_offer error: ${e?.message || e}`);
    return null;
  }
}

/**
 * Forward an ICE candidate to the proxy engine.
 */
export async function webrtcIce(sessionId: string, candidate: any): Promise<void> {
  if (!bridge || !initialized) return;
  try {
    await bridge.sendCommand('webrtc_ice', {
      session_id: sessionId,
      candidate: candidate?.candidate || candidate,
      sdp_mid: candidate?.sdpMid,
      sdp_mline_index: candidate?.sdpMLineIndex,
    } as any);
  } catch { /* ignore */ }
}

/**
 * Link a WebRTC session to a SIP call — enables audio bridging.
 * The browser's Opus audio will be transcoded and sent to the provider.
 */
export async function webrtcLink(sessionId: string, callId: string, providerMediaAddr: string, providerMediaPort: number, sipPt: number = 9): Promise<boolean> {
  if (!bridge || !initialized) return false;
  try {
    await bridge.sendCommand('webrtc_link', {
      session_id: sessionId,
      call_id: callId,
      provider_media_addr: providerMediaAddr,
      provider_media_port: providerMediaPort,
      sip_pt: sipPt,
    } as any);
    return true;
  } catch (e: any) {
    logFn?.(`[proxy-engine] webrtc_link error: ${e?.message || e}`);
    return false;
  }
}

/**
 * Close a WebRTC session.
 */
export async function webrtcClose(sessionId: string): Promise<void> {
  if (!bridge || !initialized) return;
  try {
    await bridge.sendCommand('webrtc_close', { session_id: sessionId } as any);
  } catch { /* ignore */ }
}

/**
 * Subscribe to an event from the proxy engine.
 * Event names: incoming_call, outbound_device_call, call_ringing,
 * call_answered, call_ended, provider_registered, device_registered,
 * dtmf_digit, recording_done, sip_unhandled
 */
export function onProxyEvent(event: string, handler: (data: any) => void): void {
  if (!bridge) throw new Error('proxy engine not initialized');
  bridge.on(`management:${event}`, handler);
}

/** Check if the proxy engine is ready. */
export function isProxyReady(): boolean {
  return initialized && bridge !== null;
}

/** Shut down the proxy engine. */
export function shutdownProxyEngine(): void {
  if (bridge) {
    try { bridge.kill(); } catch { /* ignore */ }
    bridge = null;
    initialized = false;
  }
}