/**
 * Holesail tunnel RPC handlers.
 * On by default; opt out with ENABLE_HOLESAIL=0.
 */
import {
  isHolesailEnabled,
  isHolesailAvailable,
  listTunnels,
  getTunnel,
  createTunnel,
  closeTunnel,
  holesailStatus,
} from '../services/holesail-tunnels.js'
import { docker } from '../services/docker.js'
import * as validation from '../utils/validation.js'
import logger from '../utils/logger.js'

function assertHolesail() {
  if (!isHolesailEnabled()) {
    const err = new Error(
      'Holesail tunnels disabled. Remove ENABLE_HOLESAIL=0 (enabled by default).'
    )
    err.code = 'FEATURE_DISABLED'
    throw err
  }
  if (!isHolesailAvailable()) {
    const err = new Error(
      'Holesail package is not available. Ensure dependency "holesail" is installed (required).'
    )
    err.code = 'FEATURE_DISABLED'
    throw err
  }
}

/**
 * Resolve a published container port to host bind address.
 * @param {string} containerId
 * @param {number} containerPort
 * @param {'tcp'|'udp'} [protocol]
 */
async function resolveContainerPublish(containerId, containerPort, protocol = 'tcp') {
  const id = validation.sanitizeString(containerId, 128)
  if (!id) throw Object.assign(new Error('containerId required'), { code: 'INVALID_ARGS' })
  const c = docker.getContainer(id)
  const inspect = await c.inspect()
  const ports = inspect?.NetworkSettings?.Ports || {}
  const key = `${containerPort}/${protocol}`
  const bindings = ports[key]
  if (!bindings?.length) {
    throw Object.assign(
      new Error(
        `Container has no published binding for ${key}. Publish the port (e.g. -p 8080:${containerPort}) first.`
      ),
      { code: 'INVALID_ARGS' }
    )
  }
  const b = bindings[0]
  let host = b.HostIp || '127.0.0.1'
  // Docker often uses 0.0.0.0 for "all interfaces" — tunnel to loopback is safer/default
  if (!host || host === '0.0.0.0' || host === '::') host = '127.0.0.1'
  const hostPort = parseInt(b.HostPort, 10)
  if (!hostPort) {
    throw Object.assign(new Error(`Invalid host port mapping for ${key}`), {
      code: 'INVALID_ARGS',
    })
  }
  const name = (inspect.Name || '').replace(/^\//, '') || id.slice(0, 12)
  return {
    host,
    port: hostPort,
    containerId: inspect.Id,
    containerName: name,
  }
}

export function registerTunnelHandlers(session) {
  // Always register so clients get FEATURE_DISABLED when off.

  session.respond('listTunnels', async () => {
    assertHolesail()
    return {
      success: true,
      tunnels: listTunnels(),
      status: holesailStatus(),
    }
  })

  session.respond('getHolesailStatus', async () => {
    return {
      success: true,
      status: holesailStatus(),
    }
  })

  session.respond('createTunnel', async (args = {}) => {
    assertHolesail()
    const protocol = args.protocol === 'udp' ? 'udp' : 'tcp'
    let host = args.host
    let port = args.port
    let containerId = args.containerId || null
    let containerName = args.containerName || null

    if (args.containerId && args.containerPort != null) {
      const resolved = await resolveContainerPublish(
        args.containerId,
        Number(args.containerPort),
        protocol
      )
      host = resolved.host
      port = resolved.port
      containerId = resolved.containerId
      containerName = resolved.containerName
    }

    if (port == null) {
      throw Object.assign(new Error('port is required (or containerId + containerPort)'), {
        code: 'INVALID_ARGS',
      })
    }

    const tunnel = await createTunnel({
      name: args.name,
      host,
      port: Number(port),
      protocol,
      secure: args.secure !== false,
      containerId,
      containerName,
    })
    const existing = Boolean(tunnel?.existing)
    logger.info(existing ? 'Tunnel reused via RPC' : 'Tunnel created via RPC', {
      id: tunnel.id,
      peerId: session.id?.slice?.(0, 12),
      name: tunnel.name,
      existing,
    })
    // Strip internal flag from tunnel payload but surface on envelope
    const { existing: _e, ...tunnelOut } = tunnel
    return { success: true, tunnel: tunnelOut, existing }
  })

  session.respond('closeTunnel', async (args = {}) => {
    assertHolesail()
    const id = validation.sanitizeString(args.id || args.tunnelId, 64)
    if (!id) throw Object.assign(new Error('id required'), { code: 'INVALID_ARGS' })
    const existing = getTunnel(id)
    if (!existing) {
      throw Object.assign(new Error(`Tunnel not found: ${id}`), { code: 'INVALID_ARGS' })
    }
    await closeTunnel(id)
    return { success: true, id, closed: true }
  })

  session.respond('getTunnel', async (args = {}) => {
    assertHolesail()
    const id = validation.sanitizeString(args.id || args.tunnelId, 64)
    if (!id) throw Object.assign(new Error('id required'), { code: 'INVALID_ARGS' })
    const tunnel = getTunnel(id)
    if (!tunnel) {
      throw Object.assign(new Error(`Tunnel not found: ${id}`), { code: 'INVALID_ARGS' })
    }
    return { success: true, tunnel }
  })
}