'use client';

import { useState, MouseEvent } from 'react';
import {
  IconButton,
  Badge,
  Popover,
  Box,
  Typography,
  List,
  ListItem,
  ListItemButton,
  ListItemText,
  Button,
  CircularProgress,
  Alert,
  Divider,
  useTheme,
  useMediaQuery,
} from '@mui/material';
import {
  Notifications as NotificationsIcon,
  Circle,
  Restaurant,
  Bedtime,
  ChildCare,
  Medication,
  EmojiEvents,
  Group,
  Settings,
  NotificationsOff,
} from '@mui/icons-material';
import { formatDistanceToNow } from 'date-fns';
import { useNotifications } from '@/hooks/useNotifications';
import { Notification } from '@/lib/api/notifications';

interface NotificationBellProps {
  variant?: 'default' | 'compact';
}

const notificationIcons: Record<Notification['type'], React.ComponentType> = {
  feeding: Restaurant,
  sleep: Bedtime,
  diaper: ChildCare,
  medication: Medication,
  milestone: EmojiEvents,
  family: Group,
  system: Settings,
  reminder: NotificationsIcon,
};

export function NotificationBell({ variant = 'default' }: NotificationBellProps) {
  const theme = useTheme();
  const isMobile = useMediaQuery(theme.breakpoints.down('sm'));
  const [anchorEl, setAnchorEl] = useState<null | HTMLElement>(null);

  const {
    notifications,
    unreadCount,
    loading,
    error,
    refresh,
    markAsRead,
    markAllAsRead,
  } = useNotifications({ limit: 10 });

  const open = Boolean(anchorEl);

  const handleClick = (event: MouseEvent<HTMLElement>) => {
    setAnchorEl(event.currentTarget);
  };

  const handleClose = () => {
    setAnchorEl(null);
  };

  const handleNotificationClick = async (notification: Notification) => {
    if (!notification.isRead) {
      await markAsRead(notification.id);
    }
    // TODO: Navigate to related content based on notification.data
  };

  const handleMarkAllAsRead = async () => {
    await markAllAsRead();
  };

  const getNotificationIcon = (type: Notification['type']) => {
    const IconComponent = notificationIcons[type] || NotificationsIcon;
    return <IconComponent fontSize="small" />;
  };

  const formatTimestamp = (timestamp: string) => {
    try {
      return formatDistanceToNow(new Date(timestamp), { addSuffix: true });
    } catch {
      return 'Recently';
    }
  };

  const displayCount = unreadCount > 99 ? '99+' : unreadCount;

  return (
    <>
      <IconButton
        onClick={handleClick}
        sx={{
          color: open ? 'primary.main' : 'inherit',
          transition: 'all 0.2s',
          '&:hover': {
            backgroundColor: 'action.hover',
          },
        }}
        aria-label={`${unreadCount} unread notifications`}
      >
        <Badge
          badgeContent={displayCount}
          color="error"
          max={99}
          sx={{
            '& .MuiBadge-badge': {
              animation: unreadCount > 0 ? 'pulse 2s ease-in-out infinite' : 'none',
              '@keyframes pulse': {
                '0%, 100%': {
                  transform: 'scale(1)',
                },
                '50%': {
                  transform: 'scale(1.1)',
                },
              },
            },
          }}
        >
          <NotificationsIcon />
        </Badge>
      </IconButton>

      <Popover
        open={open}
        anchorEl={anchorEl}
        onClose={handleClose}
        anchorOrigin={{
          vertical: 'bottom',
          horizontal: 'right',
        }}
        transformOrigin={{
          vertical: 'top',
          horizontal: 'right',
        }}
        slotProps={{
          paper: {
            sx: {
              width: isMobile ? '100vw' : 400,
              maxHeight: 600,
              mt: 1,
              borderRadius: isMobile ? 0 : 2,
              boxShadow: theme.shadows[8],
            },
          },
        }}
      >
        <Box sx={{ p: 2, borderBottom: 1, borderColor: 'divider' }}>
          <Box sx={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between' }}>
            <Typography variant="h6" fontWeight="600">
              Notifications
            </Typography>
            {unreadCount > 0 && (
              <Button size="small" onClick={handleMarkAllAsRead}>
                Mark all read
              </Button>
            )}
          </Box>
        </Box>

        <Box sx={{ maxHeight: 480, overflowY: 'auto' }}>
          {loading && notifications.length === 0 ? (
            <Box sx={{ display: 'flex', justifyContent: 'center', p: 4 }}>
              <CircularProgress size={32} />
            </Box>
          ) : error ? (
            <Box sx={{ p: 2 }}>
              <Alert severity="error" sx={{ borderRadius: 2 }}>
                {error}
              </Alert>
              <Button onClick={refresh} fullWidth sx={{ mt: 1 }}>
                Retry
              </Button>
            </Box>
          ) : notifications.length === 0 ? (
            <Box
              sx={{
                display: 'flex',
                flexDirection: 'column',
                alignItems: 'center',
                justifyContent: 'center',
                p: 4,
                textAlign: 'center',
              }}
            >
              <NotificationsOff sx={{ fontSize: 64, color: 'text.disabled', mb: 2 }} />
              <Typography variant="body1" color="text.secondary" fontWeight="500">
                No notifications
              </Typography>
              <Typography variant="body2" color="text.disabled" sx={{ mt: 0.5 }}>
                You're all caught up!
              </Typography>
            </Box>
          ) : (
            <List sx={{ p: 0 }}>
              {notifications.map((notification, index) => (
                <Box key={notification.id}>
                  {index > 0 && <Divider />}
                  <ListItem disablePadding>
                    <ListItemButton
                      onClick={() => handleNotificationClick(notification)}
                      sx={{
                        px: 2,
                        py: 1.5,
                        backgroundColor: notification.isRead ? 'transparent' : 'action.hover',
                        '&:hover': {
                          backgroundColor: notification.isRead ? 'action.hover' : 'action.selected',
                        },
                      }}
                    >
                      <Box sx={{ display: 'flex', alignItems: 'flex-start', gap: 2, width: '100%' }}>
                        <Box
                          sx={{
                            display: 'flex',
                            alignItems: 'center',
                            justifyContent: 'center',
                            width: 40,
                            height: 40,
                            borderRadius: '50%',
                            backgroundColor: 'primary.light',
                            color: 'primary.main',
                            flexShrink: 0,
                          }}
                        >
                          {getNotificationIcon(notification.type)}
                        </Box>

                        <Box sx={{ flex: 1, minWidth: 0 }}>
                          <Box sx={{ display: 'flex', alignItems: 'flex-start', gap: 1 }}>
                            {!notification.isRead && (
                              <Circle sx={{ fontSize: 8, color: 'primary.main', mt: 0.75 }} />
                            )}
                            <Box sx={{ flex: 1, minWidth: 0 }}>
                              <Typography
                                variant="body2"
                                fontWeight={notification.isRead ? 400 : 600}
                                sx={{
                                  overflow: 'hidden',
                                  textOverflow: 'ellipsis',
                                  display: '-webkit-box',
                                  WebkitLineClamp: 2,
                                  WebkitBoxOrient: 'vertical',
                                }}
                              >
                                {notification.title}
                              </Typography>
                              <Typography
                                variant="caption"
                                color="text.secondary"
                                sx={{
                                  overflow: 'hidden',
                                  textOverflow: 'ellipsis',
                                  display: '-webkit-box',
                                  WebkitLineClamp: 2,
                                  WebkitBoxOrient: 'vertical',
                                  mt: 0.5,
                                }}
                              >
                                {notification.message}
                              </Typography>
                              <Typography variant="caption" color="text.disabled" sx={{ mt: 0.5, display: 'block' }}>
                                {formatTimestamp(notification.createdAt)}
                              </Typography>
                            </Box>
                          </Box>
                        </Box>
                      </Box>
                    </ListItemButton>
                  </ListItem>
                </Box>
              ))}
            </List>
          )}
        </Box>

        {notifications.length > 0 && (
          <Box sx={{ p: 1.5, borderTop: 1, borderColor: 'divider', textAlign: 'center' }}>
            <Button fullWidth size="small" href="/notifications" onClick={handleClose}>
              View all notifications
            </Button>
          </Box>
        )}
      </Popover>
    </>
  );
}