<!DOCTYPE html>
<html lang="vi">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Chat - SocialNet</title>
  <link rel="stylesheet" href="/css/style.css">
</head>
<body>
  <%- include('partials/header') %>
  <div class="container">
    <div class="chat-container">
      <div class="chat-sidebar">
        <h3>💬 Tin nhắn</h3>
        <ul class="friend-list">
          <% friends.forEach(friend => { %>
            <li data-userid="<%= friend.id %>" class="chat-friend">
              <img src="/uploads/<%= friend.avatar %>" alt="avatar" class="avatar-sm">
              <div>
                <strong><%= friend.fullname %></strong>
                <p class="last-msg"><%= friend.lastMessage ? friend.lastMessage : 'Chưa có tin nhắn' %></p>
              </div>
            </li>
          <% }) %>
        </ul>
      </div>
      <div class="chat-window">
        <div class="chat-header">
          <span id="chatPartner">Chọn một người bạn để chat</span>
        </div>
        <div class="chat-messages" id="chatMessages">
          <!-- Tin nhắn sẽ hiển thị ở đây -->
        </div>
        <div class="chat-input">
          <input type="text" id="messageInput" placeholder="Nhập tin nhắn..." disabled>
          <button id="sendBtn" disabled>Gửi</button>
        </div>
      </div>
    </div>
  </div>
  <script src="/socket.io/socket.io.js"></script>
  <script>
    const socket = io();
    const userId = '<%= user.id %>';
    socket.emit('join', userId);

    let currentFriendId = null;

    // Chọn bạn để chat
    document.querySelectorAll('.chat-friend').forEach(item => {
      item.addEventListener('click', function() {
        const friendId = this.dataset.userid;
        currentFriendId = friendId;
        document.getElementById('chatPartner').innerText = this.querySelector('strong').innerText;
        document.getElementById('messageInput').disabled = false;
        document.getElementById('sendBtn').disabled = false;
        // Tải lịch sử chat
        fetch(`/message/history/${friendId}`)
          .then(res => res.json())
          .then(messages => {
            const container = document.getElementById('chatMessages');
            container.innerHTML = '';
            messages.forEach(msg => {
              const div = document.createElement('div');
              div.className = msg.fromUserId == userId ? 'msg-sent' : 'msg-received';
              div.innerHTML = `<strong>${msg.fromUser.fullname}:</strong> ${msg.content}`;
              container.appendChild(div);
            });
            container.scrollTop = container.scrollHeight;
          });
      });
    });

    // Gửi tin nhắn
    document.getElementById('sendBtn').addEventListener('click', sendMessage);
    document.getElementById('messageInput').addEventListener('keypress', (e) => {
      if (e.key === 'Enter') sendMessage();
    });

    function sendMessage() {
      const input = document.getElementById('messageInput');
      const content = input.value.trim();
      if (!content || !currentFriendId) return;
      socket.emit('private message', { from: userId, to: currentFriendId, content });
      input.value = '';
    }

    // Nhận tin nhắn realtime
    socket.on('new message', (msg) => {
      if (msg.fromUser.id == currentFriendId || msg.fromUser.id == userId) {
        const container = document.getElementById('chatMessages');
        const div = document.createElement('div');
        div.className = msg.fromUser.id == userId ? 'msg-sent' : 'msg-received';
        div.innerHTML = `<strong>${msg.fromUser.fullname}:</strong> ${msg.content}`;
        container.appendChild(div);
        container.scrollTop = container.scrollHeight;
      }
    });
  </script>
</body>
</html>