import React, { useState } from 'react';
import { View, Text, StyleSheet, TouchableOpacity, ScrollView } from 'react-native';
import { FontAwesome } from '@expo/vector-icons';
import Colors from '../../../constants';

const days = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'];
const months = [
  'January', 'February', 'March', 'April', 'May', 'June',
  'July', 'August', 'September', 'October', 'November', 'December'
];

const CalendarView = ({ onSelectDate, events = [] }) => {
  const [currentMonth, setCurrentMonth] = useState(new Date());
  const today = new Date();
  
  const getDaysInMonth = (date) => {
    const year = date.getFullYear();
    const month = date.getMonth();
    const daysInMonth = new Date(year, month + 1, 0).getDate();
    const firstDay = new Date(year, month, 1).getDay();
    
    const days = [];
    
    // Add empty days for the start of the month
    for (let i = 0; i < firstDay; i++) {
      days.push({ day: '', date: null });
    }
    
    // Add days of the month
    for (let i = 1; i <= daysInMonth; i++) {
      const date = new Date(year, month, i);
      const hasEvent = events.some(event => {
        const eventDate = new Date(event.startDate);
        return eventDate.getDate() === i && 
               eventDate.getMonth() === month && 
               eventDate.getFullYear() === year;
      });
      
      const isToday = today.getDate() === i && 
                      today.getMonth() === month && 
                      today.getFullYear() === year;

      days.push({
        day: i,
        date,
        hasEvent,
        isToday
      });
    }
    
    return days;
  };
  
  const handlePrevMonth = () => {
    const prevMonth = new Date(currentMonth);
    prevMonth.setMonth(prevMonth.getMonth() - 1);
    setCurrentMonth(prevMonth);
  };
  
  const handleNextMonth = () => {
    const nextMonth = new Date(currentMonth);
    nextMonth.setMonth(nextMonth.getMonth() + 1);
    setCurrentMonth(nextMonth);
  };
  
  const calendarDays = getDaysInMonth(currentMonth);
  
  return (
    <View style={styles.container}>
      <View style={styles.header}>
        <TouchableOpacity 
          onPress={handlePrevMonth} 
          style={styles.navButton}
          hitSlop={{ top: 10, bottom: 10, left: 10, right: 10 }}
        >
          <FontAwesome name="chevron-left" size={14} color={Colors.primary} />
        </TouchableOpacity>
        <Text style={styles.monthYear}>
          {months[currentMonth.getMonth()]} {currentMonth.getFullYear()}
        </Text>
        <TouchableOpacity 
          onPress={handleNextMonth} 
          style={styles.navButton}
          hitSlop={{ top: 10, bottom: 10, left: 10, right: 10 }}
        >
          <FontAwesome name="chevron-right" size={14} color={Colors.primary} />
        </TouchableOpacity>
      </View>
      
      <View style={styles.daysHeader}>
        {days.map(day => (
          <Text key={day} style={styles.dayHeader}>{day}</Text>
        ))}
      </View>
      
      <View style={styles.calendarGrid}>
        {calendarDays.map((item, index) => (
          <TouchableOpacity
            key={index}
            style={[
              styles.day,
              !item.date && styles.emptyDay,
              item.isToday && styles.todayDay,
              item.hasEvent && styles.eventDay
            ]}
            onPress={() => item.date && onSelectDate(item.date)}
            disabled={!item.date}
            activeOpacity={item.date ? 0.7 : 1}
          >
            <Text style={[
              styles.dayText,
              item.isToday && styles.todayText
            ]}>
              {item.day}
            </Text>
            {item.hasEvent && <View style={styles.eventDot} />}
          </TouchableOpacity>
        ))}
      </View>
    </View>
  );
};

const styles = StyleSheet.create({
  container: {
    backgroundColor: Colors.card,
    borderRadius: 10,
    padding: 14,
    margin: 16,
    shadowColor: Colors.cardShadow,
    shadowOffset: { width: 0, height: 3 },
    shadowOpacity: 0.1,
    shadowRadius: 6,
    elevation: 3,
    borderWidth: 1,
    borderColor: Colors.border,
  },
  header: {
    flexDirection: 'row',
    justifyContent: 'space-between',
    alignItems: 'center',
    marginBottom: 16,
    paddingHorizontal: 8,
  },
  navButton: {
    width: 28,
    height: 28,
    borderRadius: 14,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: Colors.background,
    borderWidth: 1,
    borderColor: Colors.border,
  },
  monthYear: {
    fontSize: 16,
    fontWeight: '600',
    color: Colors.text,
  },
  daysHeader: {
    flexDirection: 'row',
    justifyContent: 'space-around',
    marginBottom: 10,
    borderBottomWidth: 1,
    borderBottomColor: Colors.divider,
    paddingBottom: 8,
  },
  dayHeader: {
    width: 36,
    textAlign: 'center',
    fontWeight: '600',
    fontSize: 12,
    color: Colors.secondary,
  },
  calendarGrid: {
    flexDirection: 'row',
    flexWrap: 'wrap',
  },
  day: {
    width: '14.28%',
    height: 44,
    justifyContent: 'center',
    alignItems: 'center',
    marginVertical: 2,
    position: 'relative',
  },
  emptyDay: {
    backgroundColor: 'transparent',
  },
  todayDay: {
    backgroundColor: Colors.primary,
    borderRadius: 22,
  },
  todayText: {
    color: '#fff',
    fontWeight: '600',
  },
  eventDay: {
    position: 'relative',
  },
  dayText: {
    textAlign: 'center',
    fontSize: 14,
    color: Colors.text,
  },
  eventDot: {
    position: 'absolute',
    bottom: 6,
    width: 6,
    height: 6,
    borderRadius: 3,
    backgroundColor: Colors.accent,
  },
});

export default CalendarView;