import { useState } from 'react';
import {
  format, startOfMonth, endOfMonth, startOfWeek, endOfWeek,
  eachDayOfInterval, isSameMonth, isSameDay, addMonths, subMonths,
  isWithinInterval, parseISO, isBefore
} from 'date-fns';
import { es } from 'date-fns/locale/es';
import { ChevronLeft, ChevronRight } from 'lucide-react';
import { toast } from 'sonner';
import type { Reservation } from '../types';

interface Props {
  reservations: Reservation[];
  onSelectRange: (start: Date, end: Date) => void;
  onSelectReservation: (reservation: Reservation) => void;
}

export function CustomMobileCalendar({ reservations, onSelectRange, onSelectReservation }: Props) {
  const [currentDate, setCurrentDate] = useState(new Date());
  const [selectionStart, setSelectionStart] = useState<Date | null>(null);

  const monthStart = startOfMonth(currentDate);
  const monthEnd = endOfMonth(monthStart);
  const startDate = startOfWeek(monthStart, { weekStartsOn: 1, locale: es });
  const endDate = endOfWeek(monthEnd, { weekStartsOn: 1, locale: es });

  const days = eachDayOfInterval({ start: startDate, end: endDate });

  const nextMonth = () => setCurrentDate(addMonths(currentDate, 1));
  const prevMonth = () => setCurrentDate(subMonths(currentDate, 1));

  const getReservationForDay = (day: Date) => {
    return reservations.find(res =>
      isWithinInterval(day, { start: parseISO(res.start_date), end: parseISO(res.end_date) })
    );
  };

  const rangeHasOverlap = (start: Date, end: Date) => {
    const rangeDays = eachDayOfInterval({ start, end });
    return rangeDays.some(day => getReservationForDay(day));
  };

  const handleDayClick = (day: Date) => {
    const existingRes = getReservationForDay(day);

    if (existingRes) {
      onSelectReservation(existingRes);
      setSelectionStart(null);
      return;
    }

    if (!selectionStart) {
      setSelectionStart(day);
      return;
    }

    let start = selectionStart;
    let end = day;

    if (isBefore(day, selectionStart)) {
      start = day;
      end = selectionStart;
    }

    if (rangeHasOverlap(start, end)) {
      toast.error("No puedes seleccionar un rango que incluya días ya reservados.");
      setSelectionStart(null);
      return;
    }

    onSelectRange(start, end);
    setSelectionStart(null);
  };

  return (
    <div className="bg-white rounded-3xl overflow-hidden">
      {/* Header */}
      <div className="flex items-center justify-between px-5 py-4 bg-white border-b border-gray-100">
        <h2 className="text-lg font-bold text-gray-900 capitalize">
          {format(currentDate, 'MMMM yyyy', { locale: es })}
        </h2>
        <div className="flex space-x-1">
          <button onClick={prevMonth} className="p-2 rounded-lg hover:bg-gray-50">
            <ChevronLeft size={20} className="text-gray-600" />
          </button>
          <button onClick={nextMonth} className="p-2 rounded-lg hover:bg-gray-50">
            <ChevronRight size={20} className="text-gray-600" />
          </button>
        </div>
      </div>

      {/* Week Days */}
      <div className="grid grid-cols-7 px-3 py-2 bg-gray-50">
        {['Lun', 'Mar', 'Mié', 'Jue', 'Vie', 'Sáb', 'Dom'].map(day => (
          <div key={day} className="text-center text-[11px] font-semibold text-gray-500 uppercase tracking-wide py-1">
            {day}
          </div>
        ))}
      </div>

      {/* Days Grid - NUEVO DISEÑO TIPO AIRBNB */}
      <div className="grid grid-cols-7 gap-0 p-3 bg-white">
        {days.map((day) => {
          const dayRes = getReservationForDay(day);
          const isSelected = selectionStart && isSameDay(day, selectionStart);
          const isCurrentMonth = isSameMonth(day, monthStart);

          // Palette de colores según referencia
          let bgColor = 'bg-white';
          let numberBgColor = '';
          let numberTextColor = 'text-gray-400';

          if (dayRes) {
            if (dayRes.origin === 'Teneriffa2000') {
              bgColor = 'bg-blue-100'; // Fondo azul pastel
              numberBgColor = 'bg-blue-500'; // Círculo azul intenso
              numberTextColor = 'text-white';
            } else {
              bgColor = 'bg-yellow-100'; // Fondo amarillo pastel
              numberBgColor = 'bg-yellow-500'; // Círculo amarillo intenso
              numberTextColor = 'text-white';
            }
          } else if (isSelected) {
            bgColor = 'bg-gray-800';
            numberBgColor = 'bg-white';
            numberTextColor = 'text-gray-800';
          } else if (isCurrentMonth) {
            numberTextColor = 'text-gray-900';
          }

          return (
            <div
              key={day.toString()}
              onClick={() => handleDayClick(day)}
              className={`
                  relative h-12 flex items-center justify-center cursor-pointer
                  transition-all duration-150
                  ${bgColor}
                `}
            >
              <div className={`
                    w-8 h-8 rounded-full flex items-center justify-center
                    text-sm font-semibold
                    ${numberBgColor}
                    ${numberTextColor}
                  `}>
                {format(day, 'd')}
              </div>
            </div>
          );
        })}
      </div>
    </div>
  );
}