import { useEffect, useState, useMemo } from 'react';
import {
  Container,
  Title,
  Text,
  Switch,
  Stack,
  Paper,
  Group,
  Button,
  Loader,
  Select,
  Divider,
  Checkbox,
  ScrollArea,
} from '@mantine/core';
import { IconArrowLeft, IconSettings, IconBell, IconRefresh, IconBellCheck, IconChevronDown } from '@tabler/icons-react';
import { useNavigate } from 'react-router-dom';
import { useAppStore } from '../stores';
import { requestNotificationPermission, getNotificationPermission, isNotificationSupported } from '../services/notification';
import { syncRemindersToSW, triggerSWCheck } from '../services/swSync';
import { notifications } from '@mantine/notifications';
import { getBuiltInHolidays } from '../constants/holidays';

export function SettingsPage() {
  const navigate = useNavigate();
  const settings = useAppStore((state) => state.settings);
  const updateSettings = useAppStore((state) => state.updateSettings);
  const [permissionStatus, setPermissionStatus] = useState<'granted' | 'denied' | 'default'>('default');
  const [isRequesting, setIsRequesting] = useState(false);
  const [holidayFilterExpanded, setHolidayFilterExpanded] = useState(false);

  // 获取所有节假日列表
  const allHolidays = useMemo(() => getBuiltInHolidays(), []);

  // 法定节假日
  const statutoryHolidays = useMemo(
    () => allHolidays.filter((h) => h.isStatutory),
    [allHolidays]
  );

  // 非法定节假日
  const nonStatutoryHolidays = useMemo(
    () => allHolidays.filter((h) => !h.isStatutory),
    [allHolidays]
  );

  // 处理节假日开关
  const handleHolidayToggle = (checked: boolean) => {
    updateSettings({ showHolidays: checked });
    if (!checked) {
      // 关闭时也可以收起筛选面板
      setHolidayFilterExpanded(false);
    }
  };

  // 处理显示数量变化
  const handleDisplayCountChange = (value: string | null) => {
    updateSettings({ holidayDisplayCount: value ? parseInt(value, 10) : 3 });
  };

  // 处理仅显示法定节假日变化
  const handleStatutoryOnlyChange = (checked: boolean) => {
    updateSettings({ showStatutoryOnly: checked });
  };

  // 处理特定节假日选择
  const handleHolidaySelection = (holidayId: string, checked: boolean) => {
    const currentEnabled = settings.enabledHolidays || [];
    let newEnabled: string[];

    if (checked) {
      newEnabled = [...currentEnabled, holidayId];
    } else {
      newEnabled = currentEnabled.filter((id) => id !== holidayId);
    }

    updateSettings({ enabledHolidays: newEnabled });
  };

  // 检查节假日是否被选中
  const isHolidaySelected = (holidayId: string) => {
    const enabled = settings.enabledHolidays || [];
    return enabled.includes(holidayId);
  };

  // 全选/取消全选
  const handleSelectAll = (checked: boolean) => {
    if (checked) {
      updateSettings({ enabledHolidays: allHolidays.map((h) => h.id) });
    } else {
      updateSettings({ enabledHolidays: [] });
    }
  };

  // 选择所有法定节假日
  const handleSelectStatutory = (checked: boolean) => {
    if (checked) {
      const statutoryIds = statutoryHolidays.map((h) => h.id);
      const currentEnabled = settings.enabledHolidays || [];
      // 合并现有选择和法定节假日
      const newEnabled = [...new Set([...currentEnabled, ...statutoryIds])];
      updateSettings({ enabledHolidays: newEnabled });
    } else {
      // 移除所有法定节假日
      const statutoryIds = new Set(statutoryHolidays.map((h) => h.id));
      const newEnabled = (settings.enabledHolidays || []).filter(
        (id) => !statutoryIds.has(id)
      );
      updateSettings({ enabledHolidays: newEnabled });
    }
  };

  // 页面加载时检查登录状态
  useEffect(() => {
    const isAuthenticated = useAppStore.getState().isAuthenticated;
    if (!isAuthenticated) {
      navigate('/login', { replace: true });
    }
  }, [navigate]);

  // 初始化权限状态
  useEffect(() => {
    if (isNotificationSupported()) {
      setPermissionStatus(getNotificationPermission());
    }
  }, []);

  // 处理浏览器通知开关
  const handleBrowserNotificationToggle = async (enabled: boolean) => {
    if (!isNotificationSupported()) {
      notifications.show({
        title: '不支持通知',
        message: '您的浏览器不支持通知功能',
        color: 'red',
      });
      return;
    }

    if (enabled) {
      // 请求权限
      setIsRequesting(true);
      const permission = await requestNotificationPermission();
      setIsRequesting(false);
      setPermissionStatus(permission);

      if (permission === 'granted') {
        updateSettings({ browserNotifications: true });
        // 同步所有提醒到 Service Worker
        await syncRemindersToSW();
        notifications.show({
          title: '通知已开启',
          message: '您将收到浏览器的提醒通知',
          color: 'green',
        });
      } else {
        // 权限被拒绝
        notifications.show({
          title: '无法开启通知',
          message: '请在浏览器设置中允许通知权限',
          color: 'red',
        });
      }
    } else {
      updateSettings({ browserNotifications: false });
    }
  };

  // 同步提醒到 SW
  const handleSyncReminders = async () => {
    await syncRemindersToSW();
    notifications.show({
      title: '同步完成',
      message: '提醒已同步到 Service Worker',
      color: 'green',
    });
  };

  // 手动触发 SW 检查
  const handleTriggerCheck = async () => {
    await triggerSWCheck();
    notifications.show({
      title: '检查已触发',
      message: 'Service Worker 将立即检查提醒',
      color: 'blue',
    });
  };

  // 发送测试通知
  const handleTestNotification = async () => {
    if (Notification.permission !== 'granted') {
      notifications.show({
        title: '请先开启通知',
        message: '需要先允许通知权限',
        color: 'yellow',
      });
      return;
    }

    new Notification('测试通知', {
      body: '这是一条测试通知，通知功能正常工作',
      icon: '/favicon.png',
      tag: 'test-notification',
    });

    notifications.show({
      title: '测试通知已发送',
      message: '请查看浏览器通知',
      color: 'blue',
    });
  };

  return (
    <div
      style={{
        minHeight: '100vh',
        background: '#faf9f7',
      }}
    >
      <Container size="xl" py="md">
        {/* Header */}
        <Group mb="lg" style={{ flexShrink: 0 }}>
          <Button
            variant="subtle"
            color="gray"
            size="xs"
            leftSection={<IconArrowLeft size={14} />}
            onClick={() => navigate(-1)}
            style={{
              letterSpacing: '0.1em',
              borderRadius: 2,
            }}
          >
            返回
          </Button>
          <Title
            order={2}
            style={{
              fontWeight: 300,
              fontSize: '1.25rem',
              letterSpacing: '0.15em',
              color: '#1a1a1a',
            }}
          >
            设置
          </Title>
        </Group>

        <Paper p="lg" withBorder radius={4} style={{ maxWidth: 500 }}>
          <Stack gap="lg">
            {/* 节假日设置 */}
            <Group justify="space-between">
              <Group gap="sm">
                <IconSettings size={18} color="#666" />
                <Stack gap={2}>
                  <Text size="sm" fw={400} style={{ letterSpacing: '0.05em', color: '#1a1a1a' }}>
                    显示节假日
                  </Text>
                  <Text size="xs" c="#999" style={{ letterSpacing: '0.03em' }}>
                    在纪念日列表中显示即将到来的节假日
                  </Text>
                </Stack>
              </Group>
              <Switch
                checked={settings.showHolidays}
                onChange={(e) => handleHolidayToggle(e.currentTarget.checked)}
                size="sm"
                color="#1a1a1a"
              />
            </Group>

            {/* 节假日显示数量 */}
            {settings.showHolidays && (
              <Group justify="space-between">
                <Text size="sm" c="#666" style={{ letterSpacing: '0.03em' }}>
                  显示数量
                </Text>
                <Select
                  value={String(settings.holidayDisplayCount)}
                  onChange={handleDisplayCountChange}
                  data={[
                    { value: '1', label: '1个' },
                    { value: '3', label: '3个' },
                    { value: '5', label: '5个' },
                    { value: '10', label: '10个' },
                  ]}
                  size="xs"
                  style={{ width: 100 }}
                  styles={{
                    input: {
                      background: 'transparent',
                      borderColor: '#e0e0e0',
                    },
                  }}
                />
              </Group>
            )}

            {/* 仅显示法定节假日 */}
            {settings.showHolidays && (
              <Group justify="space-between">
                <Text size="sm" c="#666" style={{ letterSpacing: '0.03em' }}>
                  仅显示法定节假日
                </Text>
                <Switch
                  checked={settings.showStatutoryOnly}
                  onChange={(e) => handleStatutoryOnlyChange(e.currentTarget.checked)}
                  size="sm"
                  color="#1a1a1a"
                />
              </Group>
            )}

            {/* 节假日筛选 */}
            {settings.showHolidays && (
              <>
                <Divider />
                <Stack gap="sm">
                  <Group justify="space-between">
                    <Text size="sm" fw={400} style={{ letterSpacing: '0.05em', color: '#1a1a1a' }}>
                      筛选节假日
                    </Text>
                    <Button
                      variant="subtle"
                      size="xs"
                      rightSection={<IconChevronDown size={14} />}
                      onClick={() => setHolidayFilterExpanded(!holidayFilterExpanded)}
                      style={{
                        color: '#666',
                        letterSpacing: '0.03em',
                      }}
                    >
                      {holidayFilterExpanded ? '收起' : '展开'}
                    </Button>
                  </Group>

                  {holidayFilterExpanded && (
                    <Stack gap="xs">
                      <Group gap="lg">
                        <Checkbox
                          label="全选"
                          checked={(settings.enabledHolidays || []).length === allHolidays.length}
                          onChange={(e) => handleSelectAll(e.currentTarget.checked)}
                          size="xs"
                        />
                        <Checkbox
                          label="法定节假日"
                          checked={statutoryHolidays.every((h) => isHolidaySelected(h.id))}
                          indeterminate={
                            statutoryHolidays.some((h) => isHolidaySelected(h.id)) &&
                            !statutoryHolidays.every((h) => isHolidaySelected(h.id))
                          }
                          onChange={(e) => handleSelectStatutory(e.currentTarget.checked)}
                          size="xs"
                        />
                      </Group>

                      <Divider my="xs" />

                      <Text size="xs" c="#888" fw={400}>
                        法定节日
                      </Text>
                      <ScrollArea h={120}>
                        <Group gap="xs">
                          {statutoryHolidays.map((holiday) => (
                            <Checkbox
                              key={holiday.id}
                              label={holiday.name}
                              checked={isHolidaySelected(holiday.id)}
                              onChange={(e) => handleHolidaySelection(holiday.id, e.currentTarget.checked)}
                              size="xs"
                            />
                          ))}
                        </Group>
                      </ScrollArea>

                      <Text size="xs" c="#888" fw={400} mt="xs">
                        传统节日
                      </Text>
                      <ScrollArea h={100}>
                        <Group gap="xs">
                          {nonStatutoryHolidays.map((holiday) => (
                            <Checkbox
                              key={holiday.id}
                              label={holiday.name}
                              checked={isHolidaySelected(holiday.id)}
                              onChange={(e) => handleHolidaySelection(holiday.id, e.currentTarget.checked)}
                              size="xs"
                            />
                          ))}
                        </Group>
                      </ScrollArea>
                    </Stack>
                  )}
                </Stack>
              </>
            )}

            {/* 浏览器通知设置 */}
            {isNotificationSupported() && (
              <Group justify="space-between" style={{ marginTop: 16 }}>
                <Group gap="sm">
                  <IconBell size={18} color="#666" />
                  <Stack gap={2}>
                    <Text size="sm" fw={400} style={{ letterSpacing: '0.05em', color: '#1a1a1a' }}>
                      浏览器通知
                    </Text>
                    <Text size="xs" c="#999" style={{ letterSpacing: '0.03em' }}>
                      {permissionStatus === 'granted'
                        ? '已开启 - 通过系统通知提醒您的重要事项'
                        : permissionStatus === 'denied'
                        ? '已拒绝 - 请在浏览器设置中允许通知'
                        : '通过系统通知提醒您的重要事项'}
                    </Text>
                  </Stack>
                </Group>
                {isRequesting ? (
                  <Loader size="xs" />
                ) : (
                  <Switch
                    checked={settings.browserNotifications && permissionStatus === 'granted'}
                    onChange={(e) => handleBrowserNotificationToggle(e.currentTarget.checked)}
                    disabled={permissionStatus === 'denied'}
                    size="sm"
                    color="#1a1a1a"
                  />
                )}
              </Group>
            )}

            {/* 通知功能测试按钮 */}
            {settings.browserNotifications && permissionStatus === 'granted' && (
              <Stack gap="sm" style={{ marginTop: 16 }}>
                <Text size="sm" fw={400} style={{ letterSpacing: '0.05em', color: '#1a1a1a' }}>
                  通知测试
                </Text>
                <Group>
                  <Button
                    variant="light"
                    size="xs"
                    leftSection={<IconRefresh size={14} />}
                    onClick={handleSyncReminders}
                    style={{ letterSpacing: '0.05em' }}
                  >
                    同步提醒
                  </Button>
                  <Button
                    variant="light"
                    size="xs"
                    leftSection={<IconBellCheck size={14} />}
                    onClick={handleTriggerCheck}
                    style={{ letterSpacing: '0.05em' }}
                  >
                    立即检查
                  </Button>
                  <Button
                    variant="light"
                    size="xs"
                    leftSection={<IconBell size={14} />}
                    onClick={handleTestNotification}
                    style={{ letterSpacing: '0.05em' }}
                  >
                    测试通知
                  </Button>
                </Group>
              </Stack>
            )}
          </Stack>
        </Paper>
      </Container>
    </div>
  );
}