Instant AI Agent
for Customer Support

const API = "https://api.expressagent.ai"
const CHAT = `${API}/api/agent-api/chat`
const MESSAGES = `${API}/api/agent-api/messages`
const KEY = "gpta_••••••••••••"

let sessionId = null
let lastAssistantMessageId = 0
let pollTimer = null

async function sendUserMessage(text) {
  const res = await fetch(CHAT, {
    method: "POST",
    headers: { Authorization: `Bearer ${KEY}`, "Content-Type": "application/json" },
    body: JSON.stringify({ message: text + " url: " + window.location.href, sessionId }),
  })
  const json = await res.json()
  if (!json.success) throw new Error(json.error)
  sessionId = json.data.sessionId
  lastAssistantMessageId = json.data.assistantMessageId ?? 0
  startPolling()
  return json.data.reply
}

function startPolling() {
  if (pollTimer) clearInterval(pollTimer)
  pollTimer = setInterval(async () => {
    if (!sessionId) return
    const url = new URL(MESSAGES)
    url.searchParams.set("sessionId", sessionId)
    url.searchParams.set("afterMessageId", String(lastAssistantMessageId))
    const res = await fetch(url.toString(), { headers: { Authorization: `Bearer ${KEY}` } })
    const json = await res.json()
    if (!json.success || !json.data.messages?.length) return
    for (const m of json.data.messages) {
      lastAssistantMessageId = Math.max(lastAssistantMessageId, m.messageId)
      if (!m.isFromUser) console.log("Async assistant (idle, no new user message yet):", m.content)
    }
  }, 8000)
}