import { useMemo, useRef } from 'react';
import { Stack, Text, Paper, Group, Button, Box } from '@mantine/core';
import { IconPlus } from '@tabler/icons-react';
import { AnniversaryCard } from './AnniversaryCard';
import { getHolidaysForYear } from '../../constants/holidays';
import { calculateCountdown, formatCountdown } from '../../utils/countdown';
import { useAppStore } from '../../stores';
import type { Event } from '../../types';

interface AnniversaryListProps {
  events: Event[];
  onEventClick: (event: Event) => void;
  onAddClick: () => void;
}

// 内置节假日事件类型
interface BuiltInHolidayEvent {
  id: string;
  title: string;
  date: string;
  is_holiday: boolean;
  is_lunar: boolean;
  repeat_type: 'yearly';
  type: 'anniversary';
  is_builtin: true;
}

export function AnniversaryList({ events, onEventClick, onAddClick }: AnniversaryListProps) {
  const anniversaries = events.filter((e) => e.type === 'anniversary');
  const showHolidays = useAppStore((state) => state.settings?.showHolidays ?? true);
  const scrollContainerRef = useRef<HTMLDivElement>(null);

  // 滚动条样式 - 仅在悬停时显示
  const scrollbarStyle = `
    .anniversary-scroll::-webkit-scrollbar {
      width: 4px;
      height: 4px;
    }
    .anniversary-scroll::-webkit-scrollbar-track {
      background: transparent;
    }
    .anniversary-scroll::-webkit-scrollbar-thumb {
      background: transparent;
      border-radius: 2px;
    }
    .anniversary-scroll:hover::-webkit-scrollbar-thumb {
      background: rgba(0, 0, 0, 0.15);
    }
  `;

  // 处理滚轮事件，实现列表独立滚动
  const handleWheel = (e: React.WheelEvent) => {
    const container = scrollContainerRef.current;
    if (!container) return;

    const { scrollTop, scrollHeight, clientHeight } = container;
    // 使用 1px 缓冲避免浮点数精度问题
    const isAtTop = scrollTop <= 0;
    const isAtBottom = scrollTop + clientHeight >= scrollHeight - 1;

    // 如果已经滚动到顶部且向下滚动，或者已经滚动到底部且向上滚动，则阻止事件冒泡
    if ((isAtTop && e.deltaY > 0) || (isAtBottom && e.deltaY < 0)) {
      e.stopPropagation();
    }
    // 如果在滚动范围内，允许事件继续传递以实现正常滚动
  };

  // 获取内置节假日
  const builtInHolidays = useMemo(() => {
    if (!showHolidays) return [];

    const now = new Date();
    const year = now.getFullYear();
    const holidays = getHolidaysForYear(year);
    const nextYear = getHolidaysForYear(year + 1);

    // 合并今年和明年的节假日，按日期排序
    const allHolidays = [...holidays, ...nextYear].sort(
      (a, b) => a.date.getTime() - b.date.getTime()
    );

    // 只取未来90天内的节假日，显示最近3个
    const cutoffDate = new Date(now);
    cutoffDate.setDate(cutoffDate.getDate() + 90);

    return allHolidays
      .filter((h) => h.date >= now && h.date <= cutoffDate)
      .slice(0, 3)
      .map((h): BuiltInHolidayEvent => ({
        id: `builtin-${h.id}`,
        title: h.name,
        date: h.date.toISOString(),
        is_holiday: true,
        is_lunar: h.isLunar,
        repeat_type: 'yearly',
        type: 'anniversary',
        is_builtin: true,
      }));
  }, [showHolidays]);

  // 合并用户纪念日和内置节假日
  const allAnniversaries = useMemo(() => {
    // 用户创建的节假日按倒计时排序
    const sortedUser = [...anniversaries].sort((a, b) => {
      const countdownA = calculateCountdown(a.date, a.repeat_type, a.is_lunar);
      const countdownB = calculateCountdown(b.date, b.repeat_type, b.is_lunar);
      return countdownA.nextDate.getTime() - countdownB.nextDate.getTime();
    });

    // 内置节假日按日期排序
    const sortedBuiltIn = [...builtInHolidays].sort((a, b) => {
      const countdownA = calculateCountdown(a.date, a.repeat_type, a.is_lunar);
      const countdownB = calculateCountdown(b.date, b.repeat_type, b.is_lunar);
      return countdownA.nextDate.getTime() - countdownB.nextDate.getTime();
    });

    return {
      user: sortedUser,
      builtIn: sortedBuiltIn,
      total: sortedUser.length + sortedBuiltIn.length,
    };
  }, [anniversaries, builtInHolidays]);

  // 空状态
  if (allAnniversaries.total === 0) {
    return (
      <Paper p="md" withBorder radius={4} style={{ display: 'flex', flexDirection: 'column', height: '100%' }}>
        <Stack align="center" justify="center" style={{ flex: 1 }}>
          <style>{scrollbarStyle}</style>
          <Text c="#999" size="sm" style={{ letterSpacing: '0.05em' }}>
            暂无纪念日
          </Text>
          <Button
            variant="outline"
            size="xs"
            leftSection={<IconPlus size={12} />}
            onClick={onAddClick}
            style={{
              borderColor: '#ccc',
              color: '#1a1a1a',
              borderRadius: 2,
            }}
          >
            添加纪念日
          </Button>
        </Stack>
      </Paper>
    );
  }

  return (
    <>
      <style>{scrollbarStyle}</style>
      <Paper p="md" withBorder radius={4} data-scroll-container="anniversary" style={{ display: 'flex', flexDirection: 'column', height: '100%' }}>
      <Group justify="space-between" mb="sm" style={{ flexShrink: 0 }}>
        <Group gap={8}>
          <Text fw={500} size="sm" style={{ letterSpacing: '0.1em', color: '#1a1a1a' }}>
            纪念日
          </Text>
          <Text size="xs" c="#999">
            {anniversaries.length}
          </Text>
        </Group>
        <Button
          variant="subtle"
          size="xs"
          leftSection={<IconPlus size={12} />}
          onClick={onAddClick}
          style={{
            color: '#666',
            borderRadius: 2,
          }}
        >
          添加
        </Button>
      </Group>

      <Box
        ref={scrollContainerRef}
        onWheel={handleWheel}
        className="anniversary-scroll"
        style={{ flex: 1, overflowY: 'auto', minHeight: 0 }}
      >
        <Stack gap="xs">
        {/* 内置节假日 */}
        {allAnniversaries.builtIn.length > 0 && (
          <>
            <Text size="xs" c="#888" fw={400} style={{ letterSpacing: '0.05em' }}>
              即将到来
            </Text>
            {allAnniversaries.builtIn.map((holiday) => {
              const countdown = calculateCountdown(holiday.date, holiday.repeat_type, holiday.is_lunar);
              return (
                <Paper
                  key={holiday.id}
                  p="sm"
                  radius={2}
                  style={{
                    cursor: 'pointer',
                    opacity: 0.7,
                    background: 'rgba(0, 0, 0, 0.02)',
                    border: '1px solid rgba(0, 0, 0, 0.04)',
                  }}
                  onClick={() => onEventClick(holiday as unknown as Event)}
                >
                  <Group justify="space-between" wrap="nowrap">
                    <Group gap={6}>
                      <Text size="xs" c="#666">{holiday.title}</Text>
                    </Group>
                    <Text
                      size="xs"
                      c={countdown.isToday ? '#c41c1c' : '#888'}
                      style={{ letterSpacing: '0.05em' }}
                    >
                      {formatCountdown(countdown)}
                    </Text>
                  </Group>
                </Paper>
              );
            })}
          </>
        )}

        {/* 用户纪念日 */}
        {allAnniversaries.user.length > 0 && (
          <>
            {allAnniversaries.builtIn.length > 0 && (
              <Text size="xs" c="#666" fw={500} style={{ letterSpacing: '0.05em' }} mt="xs">
                我的纪念日
              </Text>
            )}
            {allAnniversaries.user.map((event) => (
              <AnniversaryCard
                key={event.id}
                event={event}
                onClick={() => onEventClick(event)}
              />
            ))}
          </>
        )}
        </Stack>
      </Box>
      </Paper>
    </>
  );
}