hermes-agent/apps/desktop/src/app/gateway/hooks/use-gateway-request.ts

import { useStore } from '@nanostores/react'
import { useCallback, useEffect, useRef } from 'react'

import type { HermesGateway } from '@/hermes'
import { $gatewayState, setConnection } from '@/store/session'

export function useGatewayRequest() {
  const gatewayState = useStore($gatewayState)
  const gatewayRef = useRef<HermesGateway | null>(null)

  const connectionRef = useRef<Awaited<ReturnType<NonNullable<typeof window.hermesDesktop>['getConnection']>> | null>(
    null
  )

  const gatewayStateRef = useRef(gatewayState)
  const reconnectingRef = useRef<Promise<HermesGateway | null> | null>(null)

  useEffect(() => {
    gatewayStateRef.current = gatewayState
  }, [gatewayState])

  const ensureGatewayOpen = useCallback(async () => {
    const existing = gatewayRef.current

    if (!existing) {
      return null
    }

    if (gatewayStateRef.current === 'open') {
      return existing
    }

    if (reconnectingRef.current) {
      return reconnectingRef.current
    }

    reconnectingRef.current = (async () => {
      const desktop = window.hermesDesktop

      if (!desktop) {
        return null
      }

      try {
        const conn = await desktop.getConnection()
        connectionRef.current = conn
        setConnection(conn)
        // Re-mint the WS URL before reconnecting — OAuth tickets are single-use
        // and short-lived, so the cached conn.wsUrl ticket is stale here.
        const wsUrl = (await desktop.getGatewayWsUrl?.().catch(() => null)) || conn.wsUrl
        await existing.connect(wsUrl)

        return existing
      } catch {
        connectionRef.current = null
        setConnection(null)

        return null
      } finally {
        reconnectingRef.current = null
      }
    })()

    return reconnectingRef.current
  }, [])

  const requestGateway = useCallback(
    async <T>(method: string, params: Record<string, unknown> = {}) => {
      const gateway = gatewayRef.current

      if (!gateway) {
        throw new Error('Hermes gateway unavailable')
      }

      try {
        return await gateway.request<T>(method, params)
      } catch (error) {
        const message = error instanceof Error ? error.message : String(error)

        if (!/not connected|connection closed/i.test(message)) {
          throw error
        }

        const recovered = await ensureGatewayOpen()

        if (!recovered) {
          throw error
        }

        return recovered.request<T>(method, params)
      }
    },
    [ensureGatewayOpen]
  )

  return { connectionRef, gatewayRef, requestGateway }
}