app.js

const clientId = "your_client_id";
const organizationId = "your_organization_id";
let customerToken = null;
let customerId = null;
let currentChatId = null;
let currentThreadId = null;
let isChatActive = false;
let lastEventIds = new Set();
let pollingIntervalId = null;

// ------------------------
// Authorize Customer
// ------------------------

async function authorizeCustomer() {
  const url = "https://accounts.livechat.com/v2/customer/token";
  const payload = {
    grant_type: "cookie",
    client_id: clientId,
    organization_id: organizationId,
    response_type: "token",
    redirect_uri: window.location.origin,
  };

  try {
    const response = await fetch(url, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      credentials: "include",
      body: JSON.stringify(payload),
    });
    if (!response.ok) throw new Error(`Auth failed: ${response.status}`);
    const data = await response.json();
    customerToken = data.access_token;
    customerId = data.entity_id;
    console.log("✅ Customer authorized:", customerId);
    await listChats();
    if (customerToken) startPolling();
  } catch (error) {
    console.error("❌ Authorization error:", error);
  }
}

// ------------------------
// List Existing Chats
// ------------------------

async function listChats() {
  try {
    const res = await fetch(
      `https://api.livechatinc.com/v3.5/customer/action/list_chats?organization_id=${organizationId}`,
      {
        method: "POST",
        headers: {
          Authorization: `Bearer ${customerToken}`,
          "Content-Type": "application/json",
        },
        body: JSON.stringify({}),
      }
    );
    const data = await res.json();
    const chat = data.chats_summary?.[0];
    if (chat) {
      currentChatId = chat.id;
      currentThreadId = chat.last_thread_id;
      isChatActive = chat.active;
      console.log("💬 Existing chat:", currentChatId, "Active:", isChatActive);
    } else {
      currentChatId = null;
      currentThreadId = null;
      isChatActive = false;
      console.log("💬 No existing chat.");
      updateCloseButtonState();
    }
  } catch (err) {
    console.error("Failed to list chats:", err);
  }
}

// ------------------------
// Start Chat
// ------------------------

async function startChat(initialMessage) {
  const res = await fetch(
    `https://api.livechatinc.com/v3.5/customer/action/start_chat?organization_id=${organizationId}`,
    {
      method: "POST",
      headers: {
        Authorization: `Bearer ${customerToken}`,
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        chat: {
          thread: {
            events: [
              {
                type: "message",
                text: initialMessage,
                recipients: "all",
              },
            ],
          },
        },
      }),
    }
  );

  const data = await res.json();
  currentChatId = data.chat_id;
  currentThreadId = data.thread_id;
  isChatActive = true;
  lastEventIds.add(data.event_id); // ✅ prevent polling dupes
  appendMessageToChat("You", initialMessage);
  console.log("✅ Chat started:", currentChatId);
  isChatActive = true;
  updateCloseButtonState();
}

// ------------------------
// Resume Chat
// ------------------------

async function resumeChat() {
  const res = await fetch(
    `https://api.livechatinc.com/v3.5/customer/action/resume_chat?organization_id=${organizationId}`,
    {
      method: "POST",
      headers: {
        Authorization: `Bearer ${customerToken}`,
        "Content-Type": "application/json",
      },
      body: JSON.stringify({ chat: { id: currentChatId } }),
    }
  );
  const data = await res.json();
  currentThreadId = data.thread_id;
  isChatActive = true;
  console.log("🔁 Chat resumed:", currentChatId);
  isChatActive = true;
  updateCloseButtonState();
}

// ------------------------
// Send Message
// ------------------------

async function sendMessage(messageText) {
  if (!customerToken) return;

  if (!currentChatId) {
    await startChat(messageText);
    return;
  }

  if (!isChatActive) {
    await resumeChat();
  }

  const res = await fetch(
    `https://api.livechatinc.com/v3.5/customer/action/send_event?organization_id=${organizationId}`,
    {
      method: "POST",
      headers: {
        Authorization: `Bearer ${customerToken}`,
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        chat_id: currentChatId,
        event: {
          type: "message",
          text: messageText,
          recipients: "all",
        },
      }),
    }
  );

  const data = await res.json();
  lastEventIds.add(data.event_id); // ✅ track for deduping
  appendMessageToChat("You", messageText);
}

// ------------------------
// Deactivate Chat
// ------------------------

async function deactivateChat() {
  if (!currentChatId) return;

  try {
    const res = await fetch(
      `https://api.livechatinc.com/v3.5/customer/action/deactivate_chat?organization_id=${organizationId}`,
      {
        method: "POST",
        headers: {
          Authorization: `Bearer ${customerToken}`,
          "Content-Type": "application/json",
        },
        body: JSON.stringify({ id: currentChatId }),
      }
    );
    if (res.ok) {
      isChatActive = false;
      appendMessageToChat("System", "The chat has been closed.");
      console.log("🚫 Chat deactivated:", currentChatId);
      stopPolling();
      updateCloseButtonState();
    }
  } catch (e) {
    console.error("Deactivate failed:", e);
  }
}

// ------------------------
// Polling Logic
// ------------------------

function startPolling() {
  if (pollingIntervalId) clearInterval(pollingIntervalId);
  pollingIntervalId = setInterval(pollForMessages, 3000);
}

function stopPolling() {
  if (pollingIntervalId) clearInterval(pollingIntervalId);
  pollingIntervalId = null;
}

async function pollForMessages() {
  if (!customerToken || !currentChatId || !currentThreadId) return;

  try {
    const res = await fetch(
      `https://api.livechatinc.com/v3.5/customer/action/list_threads?organization_id=${organizationId}`,
      {
        method: "POST",
        headers: {
          Authorization: `Bearer ${customerToken}`,
          "Content-Type": "application/json",
        },
        body: JSON.stringify({ chat_id: currentChatId }),
      }
    );
    const data = await res.json();
    const thread = data.threads?.find((t) => t.id === currentThreadId);
    if (!thread?.events) return;

    for (const event of thread.events) {
      if (event.type === "message" && !lastEventIds.has(event.id)) {
        const sender = event.author_id === customerId ? "You" : "Agent";
        appendMessageToChat(sender, event.text);
        lastEventIds.add(event.id);
      }
    }
  } catch (e) {
    console.error("Polling error:", e);
  }
}

// ------------------------
// UI Helpers
// ------------------------

function appendMessageToChat(sender, text) {
  const chatBox = document.getElementById("chat-box");
  const div = document.createElement("div");
  div.className = `chat-message ${sender.toLowerCase()}`;
  div.textContent = `${sender}: ${text}`;
  chatBox.appendChild(div);
}

function updateCloseButtonState() {
  const btn = document.getElementById("close-btn");
  if (isChatActive) {
    btn.disabled = false;
    btn.style.opacity = "1";
    btn.style.cursor = "pointer";
  } else {
    btn.disabled = true;
    btn.style.opacity = "0.5";
    btn.style.cursor = "not-allowed";
  }
}

// ------------------------
// DOM Ready
// ------------------------

window.addEventListener("DOMContentLoaded", async () => {
  await authorizeCustomer();

  document.getElementById("send-btn").addEventListener("click", async () => {
    const input = document.getElementById("message-input");
    const text = input.value.trim();
    if (text) {
      await sendMessage(text);
      input.value = "";
    }
  });

  document.getElementById("close-btn").addEventListener("click", async () => {
    await deactivateChat();
  });
});