import React, { useState, useEffect } from 'react';
import { Link, useSearchParams } from 'react-router-dom';
import { appointmentService } from '../../services/appointmentService';
import Loading from '../../components/Loading';
import ErrorAlert from '../../components/ErrorAlert';

function AppointmentList() {
  const [appointments, setAppointments] = useState([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState(null);
  const [searchParams] = useSearchParams();
  const doctorId = searchParams.get('doctorId');
  const patientId = searchParams.get('patientId');
  const user = JSON.parse(localStorage.getItem('user') || '{}');

  useEffect(() => {
    const fetchAppointmentsData = async () => {
      try {
        setLoading(true);
        let response;
        if (patientId) {
          response = await appointmentService.getAppointmentsForPatient(patientId);
        } else if (doctorId) {
          response = await appointmentService.getAppointmentsForDoctor(doctorId);
        } else {
          response = await appointmentService.getAllAppointments();
        }
        setAppointments(response.data || []);
      } catch (err) {
        setError('Failed to fetch appointments');
        console.error(err);
      } finally {
        setLoading(false);
      }
    };

    fetchAppointmentsData();
  }, [doctorId, patientId]);

  const handleCancelAppointment = async (id) => {
    if (window.confirm('Are you sure you want to cancel this appointment?')) {
      try {
        await appointmentService.cancelAppointment(id);
        setAppointments(appointments.map(apt =>
          apt.appointmentId === id ? { ...apt, status: 'CANCELLED' } : apt
        ));
      } catch (err) {
        setError('Failed to cancel appointment');
      }
    }
  };

  if (loading) return <Loading />;

  return (
    <div>
      <div className="flex justify-between items-center mb-6">
        <h1 className="text-3xl font-bold" style={{ color: '#7c3aed' }}>
          {patientId ? 'Patient Appointments' : doctorId ? 'My Appointments' : 'All Appointments'}
        </h1>
        <Link to="/appointments/new" style={{
          display: 'inline-block',
          background: '#bfdbfe',
          color: '#1e1035',
          padding: '8px 16px',
          borderRadius: '6px',
          textDecoration: 'none',
          fontSize: '14px',
          fontWeight: '400'
        }} onMouseEnter={(e) => e.currentTarget.style.background = '#93c5fd'} onMouseLeave={(e) => e.currentTarget.style.background = '#bfdbfe'}>
          New Appointment
        </Link>
      </div>

      {error && <ErrorAlert message={error} onClose={() => setError(null)} />}

      <div className="bg-white rounded-lg shadow overflow-hidden">
        <table className="w-full">
          <thead className="bg-gray-100">
            <tr>
              <th className="px-6 py-3 text-left text-sm font-semibold">Patient</th>
              <th className="px-6 py-3 text-left text-sm font-semibold">Doctor</th>
              <th className="px-6 py-3 text-left text-sm font-semibold">Date</th>
              <th className="px-6 py-3 text-left text-sm font-semibold">Time</th>
              <th className="px-6 py-3 text-left text-sm font-semibold">Status</th>
              <th className="px-6 py-3 text-left text-sm font-semibold">Actions</th>
            </tr>
          </thead>
          <tbody>
            {appointments.map(appointment => (
              <tr key={appointment.appointmentId} className="border-t hover:bg-gray-50">
                <td className="px-6 py-3">{appointment.patient?.firstName} {appointment.patient?.lastName}</td>
                <td className="px-6 py-3">Dr. {appointment.doctor?.firstName} {appointment.doctor?.lastName}</td>
                <td className="px-6 py-3">{appointment.appointmentDate}</td>
                <td className="px-6 py-3">{appointment.appointmentTime}</td>
                <td className="px-6 py-3">
                  <span className={`px-3 py-1 rounded text-sm font-semibold ${
                    appointment.status === 'SCHEDULED' ? 'bg-purple-100 text-purple-800' :
                    appointment.status === 'COMPLETED' ? 'bg-green-100 text-green-800' :
                    'bg-red-100 text-red-800'
                  }`}>
                    {appointment.status}
                  </span>
                </td>
                <td className="px-6 py-3">
                  {appointment.status === 'SCHEDULED' && (
                    (user.role === 'DOCTOR' && appointment.doctor?.doctorId !== user.doctorId) ? null : (
                      <button
                        onClick={() => handleCancelAppointment(appointment.appointmentId)}
                        className="text-red-600 hover:underline px-3 py-2 text-sm font-medium"
                      >
                        Cancel
                      </button>
                    )
                  )}
                </td>
              </tr>
            ))}
          </tbody>
        </table>
      </div>
    </div>
  );
}

export default AppointmentList;