import { useState, useEffect, useRef } from 'react';
import { useAuth } from '../contexts/AuthContext.jsx';
import { useSocket } from '../contexts/SocketContext.jsx';
import { api, parseTS } from '../utils/api.js';
import { useToast } from '../contexts/ToastContext.jsx';
import Avatar from './Avatar.jsx';
import './Sidebar.css';

function useTheme() {
  const [dark, setDark] = useState(() => localStorage.getItem('jama-theme') === 'dark');
  useEffect(() => {
    document.documentElement.setAttribute('data-theme', dark ? 'dark' : 'light');
    localStorage.setItem('jama-theme', dark ? 'dark' : 'light');
  }, [dark]);
  return [dark, setDark];
}

function useAppSettings() {
  const [settings, setSettings] = useState({ app_name: 'jama', logo_url: '', color_avatar_public: '', color_avatar_dm: '' });
  const fetchSettings = () => {
    api.getSettings().then(({ settings }) => setSettings(settings)).catch(() => {});
  };
  useEffect(() => {
    fetchSettings();
    window.addEventListener('jama:settings-changed', fetchSettings);
    return () => window.removeEventListener('jama:settings-changed', fetchSettings);
  }, []);
  useEffect(() => {
    const name = settings.app_name || 'jama';
    const prefix = document.title.match(/^(\(\d+\)\s*)/)?.[1] || '';
    document.title = prefix + name;
    const faviconUrl = settings.logo_url || '/icons/jama.png';
    let link = document.querySelector("link[rel~='icon']");
    if (!link) { link = document.createElement('link'); link.rel = 'icon'; document.head.appendChild(link); }
    link.href = faviconUrl;
  }, [settings]);
  return settings;
}

function formatTime(dateStr) {
  if (!dateStr) return '';
  const date = parseTS(dateStr);
  const now = new Date();
  const diff = now - date;
  if (diff < 86400000 && date.getDate() === now.getDate()) {
    return date.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' });
  }
  if (diff < 604800000) {
    return date.toLocaleDateString([], { weekday: 'short' });
  }
  return date.toLocaleDateString([], { month: 'short', day: 'numeric' });
}

export default function Sidebar({ groups, activeGroupId, onSelectGroup, notifications, unreadGroups = new Map(), onNewChat, onProfile, onUsers, onSettings: onOpenSettings, onBranding, onGroupManager, onGroupsUpdated, isMobile, onAbout, onHelp, onlineUserIds = new Set(), features = {} }) {
  const { user, logout } = useAuth();
  const { connected } = useSocket();
  const toast = useToast();
  const [showMenu, setShowMenu] = useState(false);
  const settings = useAppSettings();
  const [dark, setDark] = useTheme();
  const menuRef = useRef(null);
  const footerBtnRef = useRef(null);

  useEffect(() => {
    if (!showMenu) return;
    const handler = (e) => {
      if (menuRef.current && !menuRef.current.contains(e.target) &&
          footerBtnRef.current && !footerBtnRef.current.contains(e.target)) {
        setShowMenu(false);
      }
    };
    document.addEventListener('mousedown', handler);
    document.addEventListener('touchstart', handler);
    return () => {
      document.removeEventListener('mousedown', handler);
      document.removeEventListener('touchstart', handler);
    };
  }, [showMenu]);

  const allGroups = [
    ...(groups.publicGroups || []),
    ...(groups.privateGroups || [])
  ];

  const publicFiltered = allGroups.filter(g => g.type === 'public');

  const privateFiltered = [...allGroups.filter(g => g.type === 'private')].sort((a, b) => {
    if (!a.last_message_at && !b.last_message_at) return 0;
    if (!a.last_message_at) return 1;
    if (!b.last_message_at) return -1;
    return new Date(b.last_message_at) - new Date(a.last_message_at);
  });

  const getNotifCount = (groupId) => notifications.filter(n => n.groupId === groupId).length;
  const handleLogout = async () => { await logout(); };

  const GroupItem = ({ group }) => {
    const notifs = getNotifCount(group.id);
    const unreadCount = unreadGroups.get(group.id) || 0;
    const hasUnread = unreadCount > 0;
    const isActive = group.id === activeGroupId;
    const isOnline = !!group.is_direct && !!group.peer_id && (onlineUserIds instanceof Set ? onlineUserIds.has(Number(group.peer_id)) : false);

    return (
      <div
        className={`group-item ${isActive ? 'active' : ''} ${hasUnread ? 'has-unread' : ''}`}
        onClick={() => onSelectGroup(group.id)}
      >
        <div className="group-icon-wrap">
          {group.is_direct && group.peer_avatar && !group.is_managed ? (
            <img src={group.peer_avatar} alt={group.name} className="group-icon" style={{ objectFit: 'cover', padding: 0 }} />
          ) : group.is_managed ? (
            <div className="group-icon" style={{ background: settings.color_avatar_dm || '#a142f4', borderRadius: 8, fontSize: 11, fontWeight: 700 }}>MG</div>
          ) : (
            <div className="group-icon" style={{ background: group.type === 'public' ? (settings.color_avatar_public || '#1a73e8') : (settings.color_avatar_dm || '#a142f4') }}>
              {group.type === 'public' ? '#' : group.is_direct ? (group.peer_real_name || group.name)[0]?.toUpperCase() : group.name[0]?.toUpperCase()}
            </div>
          )}
          {isOnline && <span className="online-dot" />}
        </div>
        <div className="group-info flex-1 overflow-hidden">
          <div className="flex items-center justify-between">
            <span className={`group-name truncate ${hasUnread ? 'unread-name' : ''}`}>
              {group.is_direct && group.peer_display_name
                ? <>{group.peer_display_name}<span className="dm-real-name"> ({group.peer_real_name})</span></>
                : group.is_direct && group.peer_real_name ? group.peer_real_name : group.name}
            </span>
            {group.last_message_at && (
              <span className="group-time">{formatTime(group.last_message_at)}</span>
            )}
          </div>
          <div className="flex items-center justify-between gap-2">
            <span className="group-last-msg truncate">
              {(() => {
                const preview = (group.last_message || '').replace(/@\[([^\]]+)\]/g, '@$1');
                if (!preview) return group.is_readonly ? '📢 Read-only' : 'No messages yet';
                const isOwn = group.last_message_user_id && user && group.last_message_user_id === user.id;
                return isOwn ? <><strong style={{ fontWeight: 600 }}>You:</strong> {preview}</> : preview;
              })()}
            </span>
            {notifs > 0 && <span className="badge shrink-0">{notifs}</span>}
            {hasUnread && notifs === 0 && <span className="badge badge-unread shrink-0">{unreadCount}</span>}
          </div>
        </div>
      </div>
    );
  };

  return (
    <div className="sidebar">
      <div className="sidebar-newchat-bar">
        {!isMobile && (
          <button className="newchat-btn" onClick={onNewChat}>
            <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" strokeWidth={1.5} stroke="currentColor" width="18" height="18">
              <path strokeLinecap="round" strokeLinejoin="round" d="M7.5 8.25h9m-9 3H12m-9.75 1.51c0 1.6 1.123 2.994 2.707 3.227 1.129.166 2.27.293 3.423.379.35.026.67.21.865.501L12 21l2.755-4.133a1.14 1.14 0 0 1 .865-.501 48.172 48.172 0 0 0 3.423-.379c1.584-.233 2.707-1.626 2.707-3.228V6.741c0-1.602-1.123-2.995-2.707-3.228A48.394 48.394 0 0 0 12 3c-2.392 0-4.744.175-7.043.513C3.373 3.746 2.25 5.14 2.25 6.741v6.018Z" />
            </svg>
            New Chat
          </button>
        )}
      </div>

      <div className="groups-list">
        {publicFiltered.length > 0 && (
          <div className="group-section">
            <div className="section-label">PUBLIC MESSAGES</div>
            {publicFiltered.map(g => <GroupItem key={g.id} group={g} />)}
          </div>
        )}
        {privateFiltered.length > 0 && (
          <div className="group-section">
            <div className="section-label">MESSAGES</div>
            {privateFiltered.map(g => <GroupItem key={g.id} group={g} />)}
          </div>
        )}
        {allGroups.length === 0 && (
          <div style={{ textAlign: 'center', padding: '40px 20px', color: 'var(--text-tertiary)', fontSize: 14 }}>
            No chats yet
          </div>
        )}
      </div>

      {isMobile && (
        <button className="newchat-fab" onClick={onNewChat} title="New Chat">
          <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" strokeWidth={1.5} stroke="currentColor" width="24" height="24">
            <path strokeLinecap="round" strokeLinejoin="round" d="M7.5 8.25h9m-9 3H12m-9.75 1.51c0 1.6 1.123 2.994 2.707 3.227 1.129.166 2.27.293 3.423.379.35.026.67.21.865.501L12 21l2.755-4.133a1.14 1.14 0 0 1 .865-.501 48.172 48.172 0 0 0 3.423-.379c1.584-.233 2.707-1.626 2.707-3.228V6.741c0-1.602-1.123-2.995-2.707-3.228A48.394 48.394 0 0 0 12 3c-2.392 0-4.744.175-7.043.513C3.373 3.746 2.25 5.14 2.25 6.741v6.018Z" />
          </svg>
        </button>
      )}

      <div className="sidebar-footer">
        <div style={{ display: 'flex', alignItems: 'center', gap: 4 }}>
          <button ref={footerBtnRef} className="user-footer-btn" style={{ flex: 1 }} onClick={() => setShowMenu(!showMenu)}>
            <Avatar user={user} size="sm" />
            <div className="flex-col flex-1 overflow-hidden" style={{ textAlign: 'left' }}>
              <span className="font-medium text-sm truncate">{user?.display_name || user?.name}</span>
              <span className="text-xs truncate" style={{ color: 'var(--text-secondary)' }}>{user?.role}</span>
            </div>
            <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2">
              <circle cx="12" cy="12" r="1"/><circle cx="19" cy="12" r="1"/><circle cx="5" cy="12" r="1"/>
            </svg>
          </button>
          <button
            className="btn-icon"
            onClick={() => setDark(d => !d)}
            title={dark ? 'Switch to light mode' : 'Switch to dark mode'}
            style={{ flexShrink: 0, padding: 8 }}
          >
            {dark ? (
              <svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
                <circle cx="12" cy="12" r="5"/>
                <line x1="12" y1="1" x2="12" y2="3"/><line x1="12" y1="21" x2="12" y2="23"/>
                <line x1="4.22" y1="4.22" x2="5.64" y2="5.64"/><line x1="18.36" y1="18.36" x2="19.78" y2="19.78"/>
                <line x1="1" y1="12" x2="3" y2="12"/><line x1="21" y1="12" x2="23" y2="12"/>
                <line x1="4.22" y1="19.78" x2="5.64" y2="18.36"/><line x1="18.36" y1="5.64" x2="19.78" y2="4.22"/>
              </svg>
            ) : (
              <svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
                <path d="M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z"/>
              </svg>
            )}
          </button>
        </div>

        {showMenu && (
          <div ref={menuRef} className="footer-menu">
            <button className="footer-menu-item" onClick={() => { setShowMenu(false); onProfile(); }}>
              <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2"><path d="M20 21v-2a4 4 0 0 0-4-4H8a4 4 0 0 0-4 4v2"/><circle cx="12" cy="7" r="4"/></svg>
              Profile
            </button>
            <button className="footer-menu-item" onClick={() => { setShowMenu(false); onHelp && onHelp(); }}>
              <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2"><path d="M2 3h6a4 4 0 0 1 4 4v14a3 3 0 0 0-3-3H2z"/><path d="M22 3h-6a4 4 0 0 0-4 4v14a3 3 0 0 1 3-3h7z"/></svg>
              Help
            </button>
            <button className="footer-menu-item" onClick={() => { setShowMenu(false); onAbout && onAbout(); }}>
              <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2"><circle cx="12" cy="12" r="10"/><line x1="12" y1="8" x2="12" y2="12"/><line x1="12" y1="16" x2="12.01" y2="16"/></svg>
              About
            </button>
            <hr className="divider" style={{ margin: '4px 0' }} />
            <button className="footer-menu-item danger" onClick={handleLogout}>
              <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2"><path d="M9 21H5a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h4"/><polyline points="16 17 21 12 16 7"/><line x1="21" y1="12" x2="9" y2="12"/></svg>
              Sign out
            </button>
          </div>
        )}
      </div>
    </div>
  );
}
