import { useState, useEffect } from 'react';
import { Link } from 'react-router-dom';
import {
  Users, Scissors, Calendar, FileText, DollarSign,
  TrendingUp, AlertCircle,
} from 'lucide-react';
import { API_URL } from '../config';

interface Stat { label: string; value: number; sublabel: string; icon: any; color: string; path: string }

export default function Dashboard() {
  const stats: Stat[] = [
    { label: 'Active Clients', value: 0, sublabel: '+12 this month', icon: Users, color: 'from-blue-500 to-blue-600', path: '/clients' },
    { label: 'Scheduled', value: 0, sublabel: '3 today', icon: Calendar, color: 'from-amber-500 to-amber-600', path: '/bookings' },
    { label: 'Unpaid', value: 0, sublabel: '4 invoices', icon: FileText, color: 'from-red-500 to-red-600', path: '/invoices' },
    { label: 'Revenue', value: 0, sublabel: 'This month', icon: DollarSign, color: 'from-emerald-500 to-emerald-600', path: '/invoices' },
  ];

  // Fetch stats
  const [statsData, setStatsData] = useState<Stat[]>([]);
  const [recentBookings, setRecentBookings] = useState<any[]>([]);

  useEffect(() => {
    Promise.all([
      fetch(`${API_URL}/clients?limit=1`).then(r => r.json().catch(() => ({ total: 0 }))),
      fetch(`${API_URL}/bookings?status=scheduled`).then(r => r.json().catch(() => ({ items: [] }))),
      fetch(`${API_URL}/invoices`).then(r => r.json().catch(() => ({ items: [] }))),
      fetch(`${API_URL}/services`).then(r => r.json().catch(() => ({ items: [] }))),
      fetch(`${API_URL}/bookings?limit=5`).then(r => r.json().catch(() => ({ items: [] }))),
    ]).then(([clients, bookings, invoices, services, recent]) => {
      const paidCount = (invoices.items || []).filter((x: any) => x.status !== 'paid').length;
      const unpaidTotal = (invoices.items || []).reduce((sum: number, x: any) => sum + (x.total || 0), 0);
      setStatsData([
        { ...stats[0], value: clients.total || 0 },
        { ...stats[1], value: bookings.items?.filter((x: any) => x.status === 'scheduled').length || 0 },
        { ...stats[2], value: paidCount, sublabel: `${paidCount} invoices` },
        { ...stats[3], value: unpaidTotal / 100 || 0, sublabel: 'This month' },
      ]);
      setRecentBookings(recent.items || []);
    }).catch(() => {});
  }, []);

  const statusColors: Record<string, { bg: string; text: string }> = {
    scheduled: { bg: 'bg-amber-100', text: 'text-amber-700' },
    confirmed: { bg: 'bg-blue-100', text: 'text-blue-700' },
    in_progress: { bg: 'bg-purple-100', text: 'text-purple-700' },
    completed: { bg: 'bg-green-100', text: 'text-green-700' },
    cancelled: { bg: 'bg-red-100', text: 'text-red-700' },
  };

  return (
    <div>
      {/* Top Bar */}
      <div className="flex items-center justify-between mb-6">
        <div>
          <h1 className="text-xl font-bold tracking-tight text-slate-800">Dashboard</h1>
          <p className="text-xs text-gray-500 mt-1">
            {new Date().toLocaleDateString('en-US', { weekday: 'long', month: 'long', day: 'numeric', year: 'numeric' })}
          </p>
        </div>
        <Link to="/bookings" className="bg-indigo-600 text-white text-sm font-semibold px-4 py-2 rounded-lg hover:bg-indigo-700 transition-colors flex items-center gap-2">
          <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 4v16m8-8H4" />
          </svg>
          New Booking
        </Link>
      </div>

      {/* Stats Row */}
      <div className="grid grid-cols-4 gap-4 mb-6">
        {statsData.map((s, i) => (
          <Link key={i} to={s.path} className="block">
            <div className="bg-white rounded-xl p-5 border border-gray-200 hover:shadow-md transition-shadow">
              <div className="flex items-center gap-3 mb-3">
                <div className={`w-10 h-10 rounded-xl bg-gradient-to-br ${s.color} flex items-center justify-center`}>
                  <s.icon className="w-5 h-5 text-white" />
                </div>
                <div className="text-[10px] uppercase tracking-wider text-gray-500 font-medium">{s.label}</div>
              </div>
              <div className="text-2xl font-bold text-slate-800">
                {s.label === 'Revenue' ? `$${s.value}` : s.value}
              </div>
              <div className="text-xs text-gray-400 mt-1">{s.sublabel}</div>
            </div>
          </Link>
        ))}
      </div>

      {/* Two Column: Schedule + Alerts */}
      <div className="grid grid-cols-3 gap-4">
        {/* Left: Today's Schedule (2 cols) */}
        <div className="col-span-2 bg-white rounded-xl border border-gray-200">
          <div className="p-4 border-b border-gray-200 flex items-center justify-between">
            <h2 className="text-sm font-bold text-slate-800 flex items-center gap-2">
              <Calendar className="w-4 h-4 text-indigo-600" />
              Today's Schedule
            </h2>
            <Link to="/bookings" className="text-xs text-indigo-600 hover:text-indigo-700 font-medium">
              View Full Calendar →
            </Link>
          </div>
          {recentBookings.length === 0 ? (
            <div className="p-8 text-center">
              <div className="text-4xl mb-3">📅</div>
              <p className="text-sm text-gray-400 font-medium">No bookings today</p>
              <Link to="/bookings" className="text-xs text-indigo-600 hover:text-indigo-700 font-medium mt-2 inline-block">
                Create your first booking →
              </Link>
            </div>
          ) : (
            <div className="divide-y divide-gray-100">
              {recentBookings.map((booking) => {
                const sc = statusColors[booking.status] || statusColors.scheduled;
                return (
                  <Link
                    key={booking.id}
                    to="/bookings"
                    className="p-4 flex items-center gap-4 hover:bg-gray-50 transition-colors"
                  >
                    <div className="text-xs font-mono text-gray-400 w-20">
                      {booking.startAt ? new Date(booking.startAt).toLocaleTimeString('en-US', { hour: 'numeric', minute: '2-digit', hour12: true }) : '—'}
                    </div>
                    <div className="w-8 h-8 rounded-full bg-indigo-100 flex items-center justify-center text-sm">
                      🐾
                    </div>
                    <div className="flex-1 min-w-0">
                      <div className="text-sm font-semibold text-slate-800 truncate">
                        {booking.client?.firstName} {booking.client?.lastName}
                      </div>
                      <div className="text-xs text-gray-500">
                        {booking.service?.name} · {booking.assignedStaff || 'Unassigned'}
                      </div>
                    </div>
                    <span className={`px-2.5 py-1 rounded-full text-[11px] font-semibold ${sc.bg} ${sc.text}`}>
                      {booking.status}
                    </span>
                  </Link>
                );
              })}
            </div>
          )}
        </div>

        {/* Right: Quick Actions + Alerts */}
        <div className="space-y-4">
          <div className="bg-white rounded-xl border border-gray-200">
            <div className="p-4 border-b border-gray-200">
              <h2 className="text-sm font-bold text-slate-800">Quick Actions</h2>
            </div>
            <div className="p-3 space-y-1.5">
              <Link to="/clients" className="flex items-center gap-3 px-3 py-2.5 text-sm rounded-lg hover:bg-gray-50 text-gray-600 transition-colors">
                <div className="w-8 h-8 rounded-lg bg-blue-100 flex items-center justify-center">
                  <Users className="w-4 h-4 text-blue-600" />
                </div>
                Add Client
              </Link>
              <Link to="/bookings" className="flex items-center gap-3 px-3 py-2.5 text-sm rounded-lg hover:bg-gray-50 text-gray-600 transition-colors">
                <div className="w-8 h-8 rounded-lg bg-amber-100 flex items-center justify-center">
                  <Calendar className="w-4 h-4 text-amber-600" />
                </div>
                Create Booking
              </Link>
              <Link to="/invoices" className="flex items-center gap-3 px-3 py-2.5 text-sm rounded-lg hover:bg-gray-50 text-gray-600 transition-colors">
                <div className="w-8 h-8 rounded-lg bg-green-100 flex items-center justify-center">
                  <FileText className="w-4 h-4 text-green-600" />
                </div>
                Generate Invoice
              </Link>
              <Link to="/messages" className="flex items-center gap-3 px-3 py-2.5 text-sm rounded-lg hover:bg-gray-50 text-gray-600 transition-colors">
                <div className="w-8 h-8 rounded-lg bg-purple-100 flex items-center justify-center">
                  <MessageCircle className="w-4 h-4 text-purple-600" />
                </div>
                Send Message
              </Link>
            </div>
          </div>

          <div className="bg-amber-50 rounded-xl border border-amber-200 p-4">
            <h2 className="text-sm font-bold text-amber-800 flex items-center gap-2">
              <AlertCircle className="w-4 h-4" />
              Alerts
            </h2>
            <div className="mt-3 space-y-2">
              <p className="text-xs text-amber-600/80 flex items-start gap-2">
                <span className="mt-1 w-1.5 h-1.5 rounded-full bg-amber-400 flex-shrink-0" />
                2 invoices overdue
              </p>
              <p className="text-xs text-amber-600/80 flex items-start gap-2">
                <span className="mt-1 w-1.5 h-1.5 rounded-full bg-amber-400 flex-shrink-0" />
                1 pet vaccination expiring
              </p>
            </div>
          </div>
        </div>
      </div>
    </div>
  );
}