/* ─── State ─────────────────────────────────────────── */
let ws = null;
let currentRoom = "general";
let currentUser = "";
let rooms = {};
let reconnectTimer = null;
let reconnectDelay = 1000;

/* ─── DOM refs ──────────────────────────────────────── */
const messagesEl      = document.getElementById("messages");
const msgInput        = document.getElementById("msg-input");
const channelNameEl   = document.getElementById("ch-name");
const channelDescEl   = document.getElementById("ch-desc");
const channelListEl   = document.getElementById("channel-list");
const userDisplayEl   = document.getElementById("user-display");
const connStatus      = document.getElementById("conn-status");
const userModal       = document.getElementById("user-modal-overlay");
const userNameInput   = document.getElementById("username-input");
const typingEl        = document.getElementById("typing-indicator");

/* ─── Init ──────────────────────────────────────────── */
window.addEventListener("DOMContentLoaded", () => {
  const saved = sessionStorage.getItem("guardia_user");
  if (saved) { currentUser = saved; startApp(); }
  else        { userModal.classList.add("show"); userNameInput.focus(); }
});

document.getElementById("username-form").addEventListener("submit", e => {
  e.preventDefault();
  const name = userNameInput.value.trim();
  if (!name) return;
  currentUser = name;
  sessionStorage.setItem("guardia_user", name);
  userModal.classList.remove("show");
  startApp();
});

function startApp() {
  userDisplayEl.textContent = currentUser;
  connect();
}

/* ─── WebSocket ─────────────────────────────────────── */
function connect() {
  const proto = location.protocol === "https:" ? "wss" : "ws";
  const url   = `${proto}://${location.host}/ws/chat/${currentRoom}/${encodeURIComponent(currentUser)}`;
  ws = new WebSocket(url);

  showStatus("reconnecting", "연결 중…");

  ws.onopen = () => {
    showStatus("online", "연결됨");
    reconnectDelay = 1000;
    setTimeout(() => connStatus.classList.remove("show"), 2000);
  };

  ws.onmessage = e => {
    const data = JSON.parse(e.data);
    if (data.type === "init") {
      rooms = data.rooms || {};
      renderChannelList();
      updateChannelHeader();
      messagesEl.innerHTML = "";
      if (data.messages?.length) {
        data.messages.forEach(renderMessage);
        scrollBottom();
      } else {
        renderWelcome();
      }
    } else {
      renderMessage(data);
      scrollBottom();
    }
  };

  ws.onclose = () => {
    showStatus("offline", "연결 끊김 — 재연결 중…");
    reconnectTimer = setTimeout(() => {
      reconnectDelay = Math.min(reconnectDelay * 2, 15000);
      connect();
    }, reconnectDelay);
  };

  ws.onerror = () => ws.close();
}

function sendMessage() {
  const text = msgInput.value.trim();
  if (!text || !ws || ws.readyState !== WebSocket.OPEN) return;
  ws.send(JSON.stringify({ content: text }));
  msgInput.value = "";
  msgInput.style.height = "auto";
}

/* ─── Channel switching ─────────────────────────────── */
function switchRoom(roomId) {
  if (roomId === currentRoom) return;
  currentRoom = roomId;
  if (ws) { ws.onclose = null; ws.close(); }
  clearTimeout(reconnectTimer);
  connect();
  document.querySelectorAll(".channel-item").forEach(el => {
    el.classList.toggle("active", el.dataset.room === roomId);
  });
  updateChannelHeader();
}

function updateChannelHeader() {
  const name = rooms[currentRoom] || currentRoom;
  channelNameEl.textContent = "# " + name;
  channelDescEl.textContent = roomDesc(currentRoom);
}

function roomDesc(id) {
  const descs = {
    general: "팀 전체 공지 및 일반 대화",
    deploy:  "배포 작업 요청 및 진행 현황",
    ops:     "서버 운영 및 장애 대응",
    pm:      "PM 승인 워크플로우 및 진척 관리",
    alerts:  "자동 알림 및 임계치 경보",
  };
  return descs[id] || "";
}

/* ─── Render ────────────────────────────────────────── */
function renderChannelList() {
  channelListEl.innerHTML = "";
  Object.entries(rooms).forEach(([id, label]) => {
    const el = document.createElement("div");
    el.className = "channel-item" + (id === currentRoom ? " active" : "");
    el.dataset.room = id;
    el.innerHTML = `<span class="ch-icon">#</span> ${label}`;
    el.addEventListener("click", () => switchRoom(id));
    channelListEl.appendChild(el);
  });
}

function renderWelcome() {
  const div = document.createElement("div");
  div.className = "date-divider";
  div.textContent = `# ${rooms[currentRoom] || currentRoom} 채널에 오신 것을 환영합니다`;
  messagesEl.appendChild(div);

  const hint = document.createElement("div");
  hint.style.cssText = "padding:8px 0;font-size:13px;color:var(--text-muted)";
  hint.innerHTML = "💡 <code>@bot 도움</code> 을 입력하면 GUARDiA Bot 명령어를 확인할 수 있습니다.";
  messagesEl.appendChild(hint);
}

let lastDate = "";
let lastSender = "";

function renderMessage(msg) {
  const msgDate = new Date(msg.timestamp).toLocaleDateString("ko-KR", {
    month: "long", day: "numeric", weekday: "long"
  });

  if (msgDate !== lastDate) {
    const divider = document.createElement("div");
    divider.className = "date-divider";
    divider.textContent = msgDate;
    messagesEl.appendChild(divider);
    lastDate   = msgDate;
    lastSender = "";
  }

  const isBot  = msg.sender_type === "BOT";
  const isSame = msg.sender === lastSender && !isBot;
  lastSender   = msg.sender;

  const group = document.createElement("div");
  group.className = "msg-group";
  group.dataset.msgId = msg.message_id;

  const initials = msg.sender.slice(0, 2).toUpperCase();
  const time = new Date(msg.timestamp).toLocaleTimeString("ko-KR", {
    hour: "2-digit", minute: "2-digit"
  });

  const avatarHTML = isSame
    ? `<div style="width:36px;flex-shrink:0"></div>`
    : `<div class="avatar ${isBot ? "bot" : "human"}">${initials}</div>`;

  const metaHTML = isSame
    ? ""
    : `<div class="msg-meta">
         <span class="msg-sender ${isBot ? "bot" : ""}">${escHtml(msg.sender)}</span>
         <span class="msg-time">${time}</span>
       </div>`;

  const contentHTML = formatContent(msg.content);

  let widgetHTML = "";
  if (msg.is_widget && msg.interactive_action) {
    const act = msg.interactive_action;
    if (act.type === "BUTTON") {
      widgetHTML = `
        <div class="widget-actions">
          <button class="btn-action btn-primary"
                  onclick="handleAction(this,'${escAttr(act.command_code)}','','')">
            ${escHtml(act.label || "실행")}
          </button>
        </div>`;
    } else if (act.type === "APPROVAL_BUTTONS") {
      widgetHTML = `
        <div class="widget-actions">
          <button class="btn-action btn-approve"
                  onclick="handleAction(this,'APPROVE','${escAttr(act.approve_url)}','승인')">
            ✅ 승인
          </button>
          <button class="btn-action btn-reject"
                  onclick="handleAction(this,'REJECT','${escAttr(act.reject_url)}','반려')">
            ❌ 반려
          </button>
        </div>`;
    }
  }

  const bubbleClass = isBot ? "bot-bubble" : "";

  group.innerHTML = `
    ${avatarHTML}
    <div class="msg-body">
      ${metaHTML}
      <div class="${bubbleClass}">
        <div class="msg-content">${contentHTML}</div>
        ${widgetHTML}
      </div>
    </div>`;

  messagesEl.appendChild(group);
}

/* ─── Interactive actions ───────────────────────────── */
async function handleAction(btn, code, url, label) {
  btn.classList.add("clicked");
  const siblings = btn.closest(".widget-actions")?.querySelectorAll(".btn-action");
  siblings?.forEach(b => b.classList.add("clicked"));

  let resultText = "";
  if (url) {
    try {
      const res  = await fetch(url, { method: "POST" });
      const data = await res.json();
      resultText = data.message || `${label} 처리 완료`;
    } catch {
      resultText = "처리 중 오류가 발생했습니다.";
    }
  } else {
    resultText = `명령 전송됨: ${code}`;
  }

  const result = document.createElement("div");
  result.className = "btn-result";
  result.textContent = "→ " + resultText;
  btn.closest(".widget-actions").insertAdjacentElement("afterend", result);
}

/* ─── Formatting helpers ────────────────────────────── */
function formatContent(text) {
  // Code blocks
  text = text.replace(/```([\s\S]*?)```/g, (_, code) =>
    `<pre>${escHtml(code.trim())}</pre>`
  );
  // Inline code
  text = text.replace(/`([^`]+)`/g, (_, code) =>
    `<code>${escHtml(code)}</code>`
  );
  // Bold
  text = text.replace(/\*\*(.+?)\*\*/g, "<strong>$1</strong>");
  // Remaining escaping for non-tagged parts (basic)
  return text;
}

function escHtml(s) {
  return String(s)
    .replace(/&/g, "&amp;").replace(/</g, "&lt;")
    .replace(/>/g, "&gt;").replace(/"/g, "&quot;");
}

function escAttr(s) {
  return String(s || "").replace(/'/g, "\\'");
}

/* ─── UI helpers ────────────────────────────────────── */
function scrollBottom() {
  requestAnimationFrame(() => {
    messagesEl.scrollTop = messagesEl.scrollHeight;
  });
}

function showStatus(cls, text) {
  connStatus.className = `show ${cls}`;
  connStatus.textContent = text;
}

/* ─── Input events ──────────────────────────────────── */
document.getElementById("send-btn").addEventListener("click", sendMessage);

msgInput.addEventListener("keydown", e => {
  if (e.key === "Enter" && !e.shiftKey) { e.preventDefault(); sendMessage(); }
});

msgInput.addEventListener("input", () => {
  msgInput.style.height = "auto";
  msgInput.style.height = Math.min(msgInput.scrollHeight, 120) + "px";
});