import { useState, useEffect, useMemo, useRef, useCallback } from 'react';
import { motion, AnimatePresence } from 'framer-motion';
import { Clock, Tag, Link2, ChevronLeft, ChevronRight, ChevronDown, Search, X, Calendar } from 'lucide-react';
import { useInfiniteQuery } from '@tanstack/react-query';
import { useInView } from 'react-intersection-observer';

// 모바일 일정 페이지
function MobileSchedule() {
    const [selectedDate, setSelectedDate] = useState(new Date());
    const [schedules, setSchedules] = useState([]);
    const [categories, setCategories] = useState([]);
    const [loading, setLoading] = useState(true);
    const [isSearchMode, setIsSearchMode] = useState(false);
    const [searchTerm, setSearchTerm] = useState('');
    const [showCalendar, setShowCalendar] = useState(false);
    const [calendarViewDate, setCalendarViewDate] = useState(() => new Date(selectedDate));  // 달력 뷰 날짜
    const [calendarShowYearMonth, setCalendarShowYearMonth] = useState(false);  // 달력 년월 선택 모드
    const contentRef = useRef(null);  // 스크롤 초기화용
    
    // 달력 월 변경 함수
    const changeCalendarMonth = (delta) => {
        const newDate = new Date(calendarViewDate);
        newDate.setMonth(newDate.getMonth() + delta);
        setCalendarViewDate(newDate);
    };
    
    const SEARCH_LIMIT = 10;
    const { ref: loadMoreRef, inView } = useInView({ threshold: 0, rootMargin: '100px' });

    // 검색 무한 스크롤
    const {
        data: searchData,
        fetchNextPage,
        hasNextPage,
        isFetchingNextPage,
        isLoading: searchLoading,
    } = useInfiniteQuery({
        queryKey: ['mobileScheduleSearch', searchTerm],
        queryFn: async ({ pageParam = 0 }) => {
            const response = await fetch(
                `/api/schedules?search=${encodeURIComponent(searchTerm)}&offset=${pageParam}&limit=${SEARCH_LIMIT}`
            );
            if (!response.ok) throw new Error('Search failed');
            return response.json();
        },
        getNextPageParam: (lastPage) => {
            if (lastPage.hasMore) {
                return lastPage.offset + lastPage.schedules.length;
            }
            return undefined;
        },
        enabled: !!searchTerm && isSearchMode,
    });

    const searchResults = useMemo(() => {
        if (!searchData?.pages) return [];
        return searchData.pages.flatMap(page => page.schedules);
    }, [searchData]);

    useEffect(() => {
        if (inView && hasNextPage && !isFetchingNextPage && isSearchMode && searchTerm) {
            fetchNextPage();
        }
    }, [inView, hasNextPage, isFetchingNextPage, fetchNextPage, isSearchMode, searchTerm]);

    // 일정 및 카테고리 로드 (월이 변경될 때만 실행)
    const viewMonth = `${selectedDate.getFullYear()}-${selectedDate.getMonth()}`;
    
    useEffect(() => {
        const year = selectedDate.getFullYear();
        const month = selectedDate.getMonth() + 1;
        
        setLoading(true);
        Promise.all([
            fetch(`/api/schedules?year=${year}&month=${month}`).then(res => res.json()),
            fetch('/api/schedules/categories').then(res => res.json())
        ]).then(([schedulesData, categoriesData]) => {
            setSchedules(schedulesData);
            setCategories(categoriesData);
            setLoading(false);
        }).catch(console.error);
    }, [viewMonth]);

    // 월 변경
    const changeMonth = (delta) => {
        const newDate = new Date(selectedDate);
        newDate.setMonth(newDate.getMonth() + delta);
        
        // 이번 달이면 오늘 날짜, 다른 달이면 1일 선택
        const today = new Date();
        if (newDate.getFullYear() === today.getFullYear() && newDate.getMonth() === today.getMonth()) {
            newDate.setDate(today.getDate());
        } else {
            newDate.setDate(1);
        }
        
        setSelectedDate(newDate);
        setCalendarViewDate(newDate);
    };

    // 날짜 변경 시 스크롤 맨 위로 초기화
    useEffect(() => {
        if (contentRef.current) {
            contentRef.current.scrollTop = 0;
        }
    }, [selectedDate]);


    // 캘린더가 열릴 때 배경 스크롤 방지
    useEffect(() => {
        const preventScroll = (e) => e.preventDefault();
        
        if (showCalendar) {
            document.addEventListener('touchmove', preventScroll, { passive: false });
        } else {
            document.removeEventListener('touchmove', preventScroll);
        }
        return () => {
            document.removeEventListener('touchmove', preventScroll);
        };
    }, [showCalendar]);

    // 카테고리 색상
    const getCategoryColor = (categoryId) => {
        const category = categories.find(c => c.id === categoryId);
        return category?.color || '#6b7280';
    };

    // 날짜별 일정 그룹화
    const groupedSchedules = useMemo(() => {
        const groups = {};
        schedules.forEach(schedule => {
            const date = schedule.date;
            if (!groups[date]) groups[date] = [];
            groups[date].push(schedule);
        });
        return Object.entries(groups).sort((a, b) => a[0].localeCompare(b[0]));
    }, [schedules]);

    // 해당 달의 모든 날짜 배열
    const daysInMonth = useMemo(() => {
        const year = selectedDate.getFullYear();
        const month = selectedDate.getMonth();
        const lastDay = new Date(year, month + 1, 0).getDate();
        const days = [];
        for (let d = 1; d <= lastDay; d++) {
            days.push(new Date(year, month, d));
        }
        return days;
    }, [selectedDate]);

    // 선택된 날짜의 일정
    const selectedDateSchedules = useMemo(() => {
        // KST 기준 날짜 문자열 생성
        const year = selectedDate.getFullYear();
        const month = String(selectedDate.getMonth() + 1).padStart(2, '0');
        const day = String(selectedDate.getDate()).padStart(2, '0');
        const dateStr = `${year}-${month}-${day}`;
        // API 응답의 date는 ISO 형식이므로 T 이전 부분만 비교
        return schedules.filter(s => s.date.split('T')[0] === dateStr);
    }, [schedules, selectedDate]);

    // 요일 이름
    const getDayName = (date) => {
        return ['일', '월', '화', '수', '목', '금', '토'][date.getDay()];
    };

    // 오늘 여부
    const isToday = (date) => {
        const today = new Date();
        return date.getDate() === today.getDate() && 
               date.getMonth() === today.getMonth() && 
               date.getFullYear() === today.getFullYear();
    };

    // 선택된 날짜 여부
    const isSelected = (date) => {
        return date.getDate() === selectedDate.getDate() && 
               date.getMonth() === selectedDate.getMonth() && 
               date.getFullYear() === selectedDate.getFullYear();
    };

    // 날짜 선택 컨테이너 ref
    const dateScrollRef = useRef(null);

    // 선택된 날짜로 자동 스크롤 + 페이지 스크롤 초기화
    useEffect(() => {
        // 페이지 스크롤을 맨 위로 즉시 이동
        window.scrollTo(0, 0);
        
        if (dateScrollRef.current) {
            const selectedDay = selectedDate.getDate();
            const buttons = dateScrollRef.current.querySelectorAll('button');
            if (buttons[selectedDay - 1]) {
                buttons[selectedDay - 1].scrollIntoView({ behavior: 'smooth', inline: 'center', block: 'nearest' });
            }
        }
    }, [selectedDate]);

    return (
        <>
            {/* 툴바 (헤더 + 날짜 선택기) */}
            <div className="mobile-toolbar-schedule shadow-sm z-50">
                {isSearchMode ? (
                    <div className="flex items-center gap-2 px-4 py-3">
                        <div className="flex-1 flex items-center gap-2 bg-gray-100 rounded-full px-4 py-2">
                            <Search size={18} className="text-gray-400" />
                            <input
                                type="text"
                                placeholder="일정 검색..."
                                value={searchTerm}
                                onChange={(e) => setSearchTerm(e.target.value)}
                                className="flex-1 bg-transparent outline-none text-sm"
                                autoFocus
                            />
                            {searchTerm && (
                                <button onClick={() => setSearchTerm('')}>
                                    <X size={18} className="text-gray-400" />
                                </button>
                            )}
                        </div>
                        <button 
                            onClick={() => { setIsSearchMode(false); setSearchTerm(''); }}
                            className="text-sm text-gray-500 flex-shrink-0 whitespace-nowrap"
                        >
                            취소
                        </button>
                    </div>
                ) : (
                    <div className="relative flex items-center justify-between px-4 py-3">
                        {showCalendar ? (
                            // 달력 열렸을 때: 년월은 absolute로 가운데 고정, 드롭다운은 바로 옆에
                            <>
                                <div className="flex items-center gap-1">
                                    <button 
                                        onClick={() => {
                                            setShowCalendar(false);
                                            setCalendarShowYearMonth(false);
                                        }} 
                                        className="p-2 rounded-lg hover:bg-gray-100"
                                    >
                                        <Calendar size={20} className="text-primary" />
                                    </button>
                                    <button onClick={() => changeCalendarMonth(-1)} className="p-2">
                                        <ChevronLeft size={20} />
                                    </button>
                                </div>
                                
                                {/* 년월 텍스트: absolute로 정확히 가운데 고정, 클릭하면 드롭다운 토글 */}
                                <button 
                                    onClick={() => setCalendarShowYearMonth(!calendarShowYearMonth)}
                                    className={`absolute left-1/2 -translate-x-1/2 font-bold transition-colors ${
                                        calendarShowYearMonth ? 'text-primary' : ''
                                    }`}
                                >
                                    {calendarViewDate.getFullYear()}년 {calendarViewDate.getMonth() + 1}월
                                </button>
                                
                                {/* 드롭다운 버튼: 년월 텍스트 바로 옆에 위치하도록 가운데 배치 */}
                                <button 
                                    onClick={() => setCalendarShowYearMonth(!calendarShowYearMonth)}
                                    className={`absolute transition-colors ${
                                        calendarShowYearMonth ? 'text-primary' : ''
                                    }`}
                                    style={{ left: 'calc(50% + 52px)' }}
                                >
                                    <ChevronDown 
                                        size={16} 
                                        className={`transition-transform duration-200 ${calendarShowYearMonth ? 'rotate-180' : ''}`}
                                    />
                                </button>
                                
                                <div className="flex items-center gap-1">
                                    <button onClick={() => changeCalendarMonth(1)} className="p-2">
                                        <ChevronRight size={20} />
                                    </button>
                                    <button onClick={() => setIsSearchMode(true)} className="p-2">
                                        <Search size={20} />
                                    </button>
                                </div>
                            </>
                        ) : (
                            // 달력 닫혔을 때: 기존 UI
                            <>
                                <div className="flex items-center gap-1">
                                    <button 
                                        onClick={() => {
                                            setCalendarViewDate(selectedDate);
                                            setShowCalendar(true);
                                        }} 
                                        className="p-2 rounded-lg hover:bg-gray-100"
                                    >
                                        <Calendar size={20} className="text-gray-600" />
                                    </button>
                                    <button onClick={() => changeMonth(-1)} className="p-2">
                                        <ChevronLeft size={20} />
                                    </button>
                                </div>
                                <span className="font-bold">
                                    {selectedDate.getFullYear()}년 {selectedDate.getMonth() + 1}월
                                </span>
                                <div className="flex items-center gap-1">
                                    <button onClick={() => changeMonth(1)} className="p-2">
                                        <ChevronRight size={20} />
                                    </button>
                                    <button onClick={() => setIsSearchMode(true)} className="p-2">
                                        <Search size={20} />
                                    </button>
                                </div>
                            </>
                        )}
                    </div>
                )}

                {/* 가로 스크롤 날짜 선택기 */}
                {!isSearchMode && (
                    <div 
                        ref={dateScrollRef}
                        className="flex overflow-x-auto scrollbar-hide px-2 py-2 gap-1"
                        style={{ scrollbarWidth: 'none', msOverflowStyle: 'none' }}
                    >
                        {daysInMonth.map((date) => {
                            const dayOfWeek = date.getDay();
                            const year = date.getFullYear();
                            const month = String(date.getMonth() + 1).padStart(2, '0');
                            const day = String(date.getDate()).padStart(2, '0');
                            const dateStr = `${year}-${month}-${day}`;
                            
                            // 해당 날짜의 일정 목록 (최대 3개)
                            const daySchedules = schedules
                                .filter(s => s.date?.split('T')[0] === dateStr)
                                .slice(0, 3);
                            
                            return (
                                <button
                                    key={date.getDate()}
                                    onClick={() => {
                                        setSelectedDate(date);
                                        setCalendarViewDate(date);
                                    }}
                                    className={`flex flex-col items-center min-w-[44px] h-[64px] py-2 px-1 rounded-xl transition-all ${
                                        isSelected(date)
                                            ? 'bg-primary text-white'
                                            : 'hover:bg-gray-100'
                                    }`}
                                >
                                    <span className={`text-[10px] font-medium ${
                                        isSelected(date) 
                                            ? 'text-white/80' 
                                            : dayOfWeek === 0 
                                                ? 'text-red-400' 
                                                : dayOfWeek === 6 
                                                    ? 'text-blue-400' 
                                                    : 'text-gray-400'
                                    }`}>
                                        {getDayName(date)}
                                    </span>
                                    <span className={`text-sm font-semibold mt-0.5 ${
                                        isSelected(date) 
                                            ? 'text-white' 
                                            : isToday(date) 
                                                ? 'text-primary' 
                                                : 'text-gray-700'
                                    }`}>
                                        {date.getDate()}
                                    </span>
                                    {/* 일정 점 (최대 3개) */}
                                    <div className="flex gap-0.5 mt-1 h-1.5">
                                        {!isSelected(date) && daySchedules.map((schedule, i) => {
                                            const cat = categories.find(c => c.id === schedule.category_id);
                                            const color = cat?.color || '#6b7280';
                                            return (
                                                <div 
                                                    key={i}
                                                    className="w-1 h-1 rounded-full"
                                                    style={{ backgroundColor: color }}
                                                />
                                            );
                                        })}
                                    </div>
                                </button>
                            );
                        })}
                    </div>
                )}
            </div>

            {/* 달력 팝업 - fixed로 위에 띄우기 */}
            <AnimatePresence>
                {showCalendar && !isSearchMode && (
                    <motion.div
                        initial={{ height: 0, opacity: 0 }}
                        animate={{ height: 'auto', opacity: 1 }}
                        exit={{ height: 0, opacity: 0 }}
                        className="fixed left-0 right-0 bg-white shadow-lg z-50 border-b overflow-hidden"
                        style={{ top: '56px' }}
                    >
                        <CalendarPicker 
                            selectedDate={selectedDate} 
                            schedules={schedules}
                            categories={categories}
                            hideHeader={true}
                            externalViewDate={calendarViewDate}
                            onViewDateChange={setCalendarViewDate}
                            externalShowYearMonth={calendarShowYearMonth}
                            onShowYearMonthChange={setCalendarShowYearMonth}
                            onSelectDate={(date) => {
                                setSelectedDate(date);
                                setCalendarViewDate(date);
                                setCalendarShowYearMonth(false);
                                setShowCalendar(false);
                            }}
                        />
                    </motion.div>
                )}
            </AnimatePresence>

            {/* 캘린더 배경 오버레이 */}
            <AnimatePresence>
                {showCalendar && !isSearchMode && (
                    <motion.div
                        initial={{ opacity: 0 }}
                        animate={{ opacity: 1 }}
                        exit={{ opacity: 0 }}
                        onClick={() => setShowCalendar(false)}
                        className="fixed inset-0 bg-black/40 z-40"
                        style={{ top: 0 }}
                    />
                )}
            </AnimatePresence>

            {/* 컨텐츠 영역 */}
            <div className="mobile-content" ref={contentRef}>
            <div className="px-4 pt-4 pb-4">
                {isSearchMode && searchTerm ? (
                    // 검색 결과
                    <div className="space-y-3">
                        {searchLoading ? (
                            <div className="flex justify-center py-8">
                                <div className="w-8 h-8 border-2 border-primary border-t-transparent rounded-full animate-spin" />
                            </div>
                        ) : searchResults.length === 0 ? (
                            <div className="text-center py-8 text-gray-400">
                                검색 결과가 없습니다
                            </div>
                        ) : (
                            <>
                                {searchResults.map((schedule, index) => (
                                    <ScheduleCard 
                                        key={`${schedule.id}-search-${index}`}
                                        schedule={schedule}
                                        categoryColor={getCategoryColor(schedule.category_id)}
                                        categories={categories}
                                    />
                                ))}
                                <div ref={loadMoreRef} className="py-4">
                                    {isFetchingNextPage && (
                                        <div className="flex justify-center">
                                            <div className="w-6 h-6 border-2 border-primary border-t-transparent rounded-full animate-spin" />
                                        </div>
                                    )}
                                </div>
                            </>
                        )}
                    </div>
                ) : loading ? (
                    <div className="flex justify-center py-8">
                        <div className="w-8 h-8 border-2 border-primary border-t-transparent rounded-full animate-spin" />
                    </div>
                ) : selectedDateSchedules.length === 0 ? (
                    <div className="text-center py-8 text-gray-400">
                        {selectedDate.getMonth() + 1}월 {selectedDate.getDate()}일 일정이 없습니다
                    </div>
                ) : (
                    // 선택된 날짜의 일정
                    <div className="space-y-3">
                        {selectedDateSchedules.map((schedule, index) => (
                            <TimelineScheduleCard 
                                key={schedule.id}
                                schedule={schedule}
                                categoryColor={getCategoryColor(schedule.category_id)}
                                categories={categories}
                                delay={index * 0.05}
                            />
                        ))}
                    </div>
                )}
            </div>
            </div>
        </>
    );
}

// 일정 카드 컴포넌트 (검색용)
function ScheduleCard({ schedule, categoryColor, categories, delay = 0 }) {
    const categoryName = categories.find(c => c.id === schedule.category_id)?.name || '미분류';
    const memberNames = schedule.member_names || schedule.members?.map(m => m.name).join(',') || '';
    const memberList = memberNames.split(',').filter(name => name.trim());

    return (
        <motion.div
            initial={{ opacity: 0, y: 10 }}
            animate={{ opacity: 1, y: 0 }}
            transition={{ delay }}
            className="bg-white rounded-xl p-4 shadow-sm"
        >
            <div className="flex gap-3">
                <div 
                    className="w-1 rounded-full flex-shrink-0"
                    style={{ backgroundColor: categoryColor }}
                />
                <div className="flex-1 min-w-0">
                    <h3 className="font-semibold text-sm">{schedule.title}</h3>
                    <div className="flex flex-wrap items-center gap-2 mt-1 text-xs text-gray-500">
                        {schedule.time && (
                            <span className="flex items-center gap-1">
                                <Clock size={12} />
                                {schedule.time.slice(0, 5)}
                            </span>
                        )}
                        <span className="flex items-center gap-1">
                            <Tag size={12} />
                            {categoryName}
                        </span>
                        {schedule.source_name && (
                            <span className="flex items-center gap-1">
                                <Link2 size={12} />
                                {schedule.source_name}
                            </span>
                        )}
                    </div>
                    {memberList.length > 0 && (
                        <div className="flex flex-wrap gap-1 mt-2">
                            {memberList.length >= 5 ? (
                                <span className="px-2 py-0.5 bg-gradient-to-r from-primary to-primary-dark text-white text-xs rounded-full shadow-sm">
                                    프로미스나인
                                </span>
                            ) : (
                                memberList.map((name, i) => (
                                    <span key={i} className="px-2 py-0.5 bg-primary/10 text-primary text-xs rounded-full">
                                        {name.trim()}
                                    </span>
                                ))
                            )}
                        </div>
                    )}
                </div>
            </div>
        </motion.div>
    );
}

// 타임라인용 일정 카드 컴포넌트 - 모던 디자인
function TimelineScheduleCard({ schedule, categoryColor, categories, delay = 0 }) {
    const categoryName = categories.find(c => c.id === schedule.category_id)?.name || '미분류';
    const memberNames = schedule.member_names || schedule.members?.map(m => m.name).join(',') || '';
    const memberList = memberNames.split(',').filter(name => name.trim());

    return (
        <motion.div
            initial={{ opacity: 0, x: -10 }}
            animate={{ opacity: 1, x: 0 }}
            transition={{ delay, type: "spring", stiffness: 300, damping: 30 }}
        >
            {/* 카드 본체 */}
            <div className="relative bg-white rounded-md shadow-[0_2px_12px_rgba(0,0,0,0.06)] border border-gray-100/50 overflow-hidden">
                <div className="p-4">
                
                {/* 시간 뱃지 */}
                {schedule.time && (
                    <div className="flex items-center gap-1.5 mb-2">
                        <div 
                            className="flex items-center gap-1 px-2 py-0.5 rounded-full text-white text-xs font-medium"
                            style={{ backgroundColor: categoryColor }}
                        >
                            <Clock size={10} />
                            {schedule.time.slice(0, 5)}
                        </div>
                        <span 
                            className="px-2 py-0.5 rounded-full text-xs font-medium"
                            style={{ 
                                backgroundColor: `${categoryColor}15`,
                                color: categoryColor 
                            }}
                        >
                            {categoryName}
                        </span>
                    </div>
                )}
                
                {/* 제목 */}
                <h3 className="font-bold text-[15px] text-gray-800 leading-snug">
                    {schedule.title}
                </h3>
                
                {/* 출처 */}
                {schedule.source_name && (
                    <div className="flex items-center gap-1 mt-1.5 text-xs text-gray-400">
                        <Link2 size={11} />
                        <span>{schedule.source_name}</span>
                    </div>
                )}
                
                {/* 멤버 */}
                {memberList.length > 0 && (
                    <div className="flex flex-wrap gap-1.5 mt-3 pt-3 border-t border-gray-100">
                        {memberList.length >= 5 ? (
                            <span className="px-2.5 py-1 bg-gradient-to-r from-primary to-primary-dark text-white text-xs rounded-lg font-semibold shadow-sm">
                                프로미스나인
                            </span>
                        ) : (
                            memberList.map((name, i) => (
                                <span 
                                    key={i} 
                                    className="px-2.5 py-1 bg-gradient-to-r from-primary to-primary-dark text-white text-xs rounded-lg font-semibold shadow-sm"
                                >
                                    {name.trim()}
                                </span>
                            ))
                        )}
                    </div>
                )}
                </div>
            </div>
        </motion.div>
    );
}

// 달력 선택기 컴포넌트
function CalendarPicker({ 
    selectedDate, 
    schedules = [], 
    categories = [], 
    onSelectDate,
    hideHeader = false,           // 헤더 숨김 여부
    externalViewDate,             // 외부에서 제어하는 viewDate
    onViewDateChange,             // viewDate 변경 콜백
    externalShowYearMonth,        // 외부에서 제어하는 년월 선택 모드
    onShowYearMonthChange         // 년월 선택 모드 변경 콜백
}) {
    const [internalViewDate, setInternalViewDate] = useState(new Date(selectedDate));
    
    // 외부 viewDate가 있으면 사용, 없으면 내부 상태 사용
    const viewDate = externalViewDate || internalViewDate;
    const setViewDate = (date) => {
        if (onViewDateChange) {
            onViewDateChange(date);
        } else {
            setInternalViewDate(date);
        }
    };
    
    // 터치 스와이프 핸들링
    const touchStartX = useRef(0);
    const touchEndX = useRef(0);
    
    // 날짜별 일정 존재 여부 및 카테고리 색상
    const scheduleDates = useMemo(() => {
        const dateMap = {};
        schedules.forEach(schedule => {
            const date = schedule.date.split('T')[0];  // YYYY-MM-DD 형식으로 통일
            if (!dateMap[date]) {
                dateMap[date] = [];
            }
            const category = categories.find(c => c.id === schedule.category_id);
            dateMap[date].push(category?.color || '#6b7280');
        });
        return dateMap;
    }, [schedules, categories]);
    
    // 날짜별 일정 목록 가져오기 (점 표시용, 최대 3개)
    const getDaySchedules = (date) => {
        const y = date.getFullYear();
        const m = String(date.getMonth() + 1).padStart(2, '0');
        const d = String(date.getDate()).padStart(2, '0');
        const dateStr = `${y}-${m}-${d}`;
        return schedules.filter(s => s.date?.split('T')[0] === dateStr).slice(0, 3);
    };
    
    const year = viewDate.getFullYear();
    const month = viewDate.getMonth();
    
    // 달력 데이터 생성 함수
    const getCalendarDays = useCallback((y, m) => {
        const firstDay = new Date(y, m, 1);
        const lastDay = new Date(y, m + 1, 0);
        const startDay = firstDay.getDay();
        const daysInMonth = lastDay.getDate();
        
        const days = [];
        
        // 이전 달 날짜
        const prevMonth = new Date(y, m, 0);
        for (let i = startDay - 1; i >= 0; i--) {
            days.push({ 
                day: prevMonth.getDate() - i, 
                isCurrentMonth: false,
                date: new Date(y, m - 1, prevMonth.getDate() - i)
            });
        }
        
        // 현재 달 날짜
        for (let i = 1; i <= daysInMonth; i++) {
            days.push({ 
                day: i, 
                isCurrentMonth: true,
                date: new Date(y, m, i)
            });
        }
        
        // 다음 달 날짜 (현재 줄만 채우기)
        const remaining = (7 - (days.length % 7)) % 7;
        for (let i = 1; i <= remaining; i++) {
            days.push({ 
                day: i, 
                isCurrentMonth: false,
                date: new Date(y, m + 1, i)
            });
        }
        
        return days;
    }, []);
    
    const changeMonth = useCallback((delta) => {
        const newDate = new Date(viewDate);
        newDate.setMonth(newDate.getMonth() + delta);
        setViewDate(newDate);
    }, [viewDate]);
    
    const isToday = (date) => {
        const today = new Date();
        return date.getDate() === today.getDate() && 
               date.getMonth() === today.getMonth() && 
               date.getFullYear() === today.getFullYear();
    };
    
    // 선택된 날짜인지 확인
    const isSelected = (date) => {
        return date.getDate() === selectedDate.getDate() && 
               date.getMonth() === selectedDate.getMonth() && 
               date.getFullYear() === selectedDate.getFullYear();
    };
    
    // 년월 선택 모드 - 외부에서 제어 가능
    const [internalShowYearMonth, setInternalShowYearMonth] = useState(false);
    const showYearMonth = externalShowYearMonth !== undefined ? externalShowYearMonth : internalShowYearMonth;
    const setShowYearMonth = (value) => {
        if (onShowYearMonthChange) {
            onShowYearMonthChange(value);
        } else {
            setInternalShowYearMonth(value);
        }
    };
    
    const [yearRangeStart, setYearRangeStart] = useState(Math.floor(year / 12) * 12);
    const yearRange = Array.from({ length: 12 }, (_, i) => yearRangeStart + i);
    
    // 배경 스크롤 막기
    useEffect(() => {
        document.body.style.overflow = 'hidden';
        return () => { document.body.style.overflow = ''; };
    }, []);
    
    // 현재 달 캘린더 데이터
    const currentMonthDays = useMemo(() => {
        return getCalendarDays(year, month);
    }, [year, month, getCalendarDays]);
    
    // 터치 핸들러
    const handleTouchStart = (e) => {
        touchStartX.current = e.touches[0].clientX;
    };
    
    const handleTouchMove = (e) => {
        touchEndX.current = e.touches[0].clientX;
    };
    
    const handleTouchEnd = () => {
        const diff = touchStartX.current - touchEndX.current;
        const threshold = 50;
        
        if (Math.abs(diff) > threshold) {
            if (diff > 0) {
                changeMonth(1);
            } else {
                changeMonth(-1);
            }
        }
        touchStartX.current = 0;
        touchEndX.current = 0;
    };
    
    // 월 렌더링 컴포넌트
    const renderMonth = (days) => (
        <div
            onTouchStart={handleTouchStart}
            onTouchMove={handleTouchMove}
            onTouchEnd={handleTouchEnd}
        >
            {/* 요일 헤더 */}
            <div className="grid grid-cols-7 gap-1 mb-2">
                {['일', '월', '화', '수', '목', '금', '토'].map((day, i) => (
                    <div 
                        key={day} 
                        className={`text-center text-xs font-medium py-1 ${
                            i === 0 ? 'text-red-400' : i === 6 ? 'text-blue-400' : 'text-gray-500'
                        }`}
                    >
                        {day}
                    </div>
                ))}
            </div>
            
            {/* 날짜 그리드 */}
            <div className="grid grid-cols-7 gap-1">
                {days.map((item, index) => {
                    const dayOfWeek = index % 7;
                    const isSunday = dayOfWeek === 0;
                    const isSaturday = dayOfWeek === 6;
                    const daySchedules = item.isCurrentMonth ? getDaySchedules(item.date) : [];
                    
                    return (
                        <button
                            key={index}
                            onClick={() => onSelectDate(item.date)}
                            className="flex flex-col items-center py-2"
                        >
                            <span className={`w-9 h-9 flex items-center justify-center text-sm font-medium rounded-full transition-all ${
                                !item.isCurrentMonth 
                                    ? 'text-gray-300' 
                                    : isSelected(item.date)
                                        ? 'bg-primary text-white font-bold shadow-lg'
                                        : isToday(item.date)
                                            ? 'text-primary font-bold'
                                            : isSunday 
                                                ? 'text-red-500 hover:bg-red-50' 
                                                : isSaturday 
                                                    ? 'text-blue-500 hover:bg-blue-50'
                                                    : 'text-gray-700 hover:bg-gray-100'
                            }`}>
                                {item.day}
                            </span>
                            {/* 일정 점 - 선택된 날짜에는 표시하지 않음, 최대 3개 */}
                            {!isSelected(item.date) && daySchedules.length > 0 && (
                                <div className="flex gap-0.5 mt-0.5 h-1.5">
                                    {daySchedules.map((schedule, i) => {
                                        const cat = categories.find(c => c.id === schedule.category_id);
                                        const color = cat?.color || '#6b7280';
                                        return (
                                            <div 
                                                key={i} 
                                                className="w-1 h-1 rounded-full"
                                                style={{ backgroundColor: color }}
                                            />
                                        );
                                    })}
                                </div>
                            )}
                        </button>
                    );
                })}
            </div>
        </div>
    );

    return (
        <div className="p-4">
            <AnimatePresence mode="wait">
                {showYearMonth ? (
                    // 년월 선택 UI
                    <motion.div
                        key="yearMonth"
                        initial={{ opacity: 0, y: -10 }}
                        animate={{ opacity: 1, y: 0 }}
                        exit={{ opacity: 0, y: -10 }}
                        transition={{ duration: 0.15 }}
                    >
                        {/* 년도 범위 헤더 */}
                        <div className="flex items-center justify-between mb-3">
                            <button 
                                onClick={() => setYearRangeStart(yearRangeStart - 12)}
                                className="p-1"
                            >
                                <ChevronLeft size={18} />
                            </button>
                            <span className="font-semibold text-sm">
                                {yearRangeStart} - {yearRangeStart + 11}
                            </span>
                            <button 
                                onClick={() => setYearRangeStart(yearRangeStart + 12)}
                                className="p-1"
                            >
                                <ChevronRight size={18} />
                            </button>
                        </div>
                        
                        {/* 년도 선택 */}
                        <div className="text-center text-xs text-gray-400 mb-2">년도</div>
                        <div className="grid grid-cols-4 gap-2 mb-4">
                            {yearRange.map(y => (
                                <button
                                    key={y}
                                    onClick={() => {
                                        const newDate = new Date(viewDate);
                                        newDate.setFullYear(y);
                                        setViewDate(newDate);
                                    }}
                                    className={`py-2 text-sm rounded-lg transition-colors ${
                                        y === year 
                                            ? 'bg-primary text-white' 
                                            : 'text-gray-600 hover:bg-gray-100'
                                    }`}
                                >
                                    {y}
                                </button>
                            ))}
                        </div>
                        
                        {/* 월 선택 */}
                        <div className="text-center text-xs text-gray-400 mb-2">월</div>
                        <div className="grid grid-cols-4 gap-2">
                            {Array.from({ length: 12 }, (_, i) => i + 1).map(m => (
                                <button
                                    key={m}
                                    onClick={() => {
                                        const newDate = new Date(year, m - 1, 1);
                                        setViewDate(newDate);
                                        setShowYearMonth(false);
                                    }}
                                    className={`py-2 text-sm rounded-lg transition-colors ${
                                        m === month + 1 
                                            ? 'bg-primary text-white' 
                                            : 'text-gray-600 hover:bg-gray-100'
                                    }`}
                                >
                                    {m}월
                                </button>
                            ))}
                        </div>
                    </motion.div>
                ) : (
                    <motion.div
                        key={`calendar-${year}-${month}`}
                        initial={{ opacity: 0 }}
                        animate={{ opacity: 1 }}
                        exit={{ opacity: 0 }}
                        transition={{ duration: 0.15 }}
                    >
                        {/* 달력 헤더 - hideHeader일 때 숨김 */}
                        {!hideHeader && (
                            <div className="flex items-center justify-between mb-4">
                                <button 
                                    onClick={() => changeMonth(-1)}
                                    className="p-1"
                                >
                                    <ChevronLeft size={18} />
                                </button>
                                <button 
                                    onClick={() => setShowYearMonth(true)}
                                    className="flex items-center gap-1 font-semibold text-sm hover:text-primary transition-colors"
                                >
                                    {year}년 {month + 1}월
                                    <ChevronDown size={16} />
                                </button>
                                <button 
                                    onClick={() => changeMonth(1)}
                                    className="p-1"
                                >
                                    <ChevronRight size={18} />
                                </button>
                            </div>
                        )}
            
                        {/* 달력 (터치 스와이프 지원) */}
                        {renderMonth(currentMonthDays)}
                        
                        {/* 오늘 버튼 */}
                        <div className="mt-3 flex justify-center">
                            <button
                                onClick={() => onSelectDate(new Date())}
                                className="text-xs text-primary font-medium px-4 py-1.5 bg-primary/10 rounded-full"
                            >
                                오늘
                            </button>
                        </div>
                    </motion.div>
                )}
            </AnimatePresence>
        </div>
    );
}

export default MobileSchedule;