import { useState, useMemo } from 'react';
import { Plus, Bell, BellOff, AlertCircle, Search } from 'lucide-react';
import { useQuery } from '@tanstack/react-query';
import { isPast, isToday, parseISO } from 'date-fns';
import api from '@/lib/api';
import type { Reminder } from '@/types';
import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { Card, CardContent } from '@/components/ui/card';
import { ListSkeleton } from '@/components/ui/skeleton';
import ReminderList from './ReminderList';
import ReminderForm from './ReminderForm';

const statusFilters = [
  { value: 'active', label: 'Active' },
  { value: 'dismissed', label: 'Dismissed' },
  { value: 'all', label: 'All' },
] as const;

type StatusFilter = (typeof statusFilters)[number]['value'];

export default function RemindersPage() {
  const [showForm, setShowForm] = useState(false);
  const [editingReminder, setEditingReminder] = useState<Reminder | null>(null);
  const [filter, setFilter] = useState<StatusFilter>('active');
  const [search, setSearch] = useState('');

  const { data: reminders = [], isLoading } = useQuery({
    queryKey: ['reminders'],
    queryFn: async () => {
      const { data } = await api.get<Reminder[]>('/reminders');
      return data;
    },
  });

  const filteredReminders = useMemo(
    () =>
      reminders.filter((r) => {
        if (filter === 'active' && r.is_dismissed) return false;
        if (filter === 'dismissed' && !r.is_dismissed) return false;
        if (search && !r.title.toLowerCase().includes(search.toLowerCase())) return false;
        return true;
      }),
    [reminders, filter, search]
  );

  const activeCount = reminders.filter((r) => !r.is_dismissed).length;
  const overdueCount = reminders.filter(
    (r) => !r.is_dismissed && r.remind_at && isPast(parseISO(r.remind_at)) && !isToday(parseISO(r.remind_at))
  ).length;
  const dismissedCount = reminders.filter((r) => r.is_dismissed).length;

  const handleEdit = (reminder: Reminder) => {
    setEditingReminder(reminder);
    setShowForm(true);
  };

  const handleCloseForm = () => {
    setShowForm(false);
    setEditingReminder(null);
  };

  return (
    <div className="flex flex-col h-full animate-fade-in">
      {/* Header */}
      <div className="border-b bg-card px-6 h-16 flex items-center gap-4 shrink-0">
        <h1 className="font-heading text-2xl font-bold tracking-tight">Reminders</h1>

        <div className="flex items-center rounded-md border border-border overflow-hidden ml-4">
          {statusFilters.map((sf) => (
            <button
              key={sf.value}
              onClick={() => setFilter(sf.value)}
              className={`px-3 py-1.5 text-sm font-medium transition-colors duration-150 ${
                filter === sf.value
                  ? 'bg-accent/15 text-accent'
                  : 'text-muted-foreground hover:text-foreground hover:bg-card-elevated'
              }`}
              style={{
                backgroundColor:
                  filter === sf.value ? 'hsl(var(--accent-color) / 0.15)' : undefined,
                color: filter === sf.value ? 'hsl(var(--accent-color))' : undefined,
              }}
            >
              {sf.label}
            </button>
          ))}
        </div>

        <div className="flex-1" />

        <div className="relative">
          <Search className="absolute left-2.5 top-1/2 -translate-y-1/2 h-3.5 w-3.5 text-muted-foreground" />
          <Input
            placeholder="Search..."
            value={search}
            onChange={(e) => setSearch(e.target.value)}
            className="w-52 h-8 pl-8 text-sm"
          />
        </div>

        <Button onClick={() => setShowForm(true)} size="sm">
          <Plus className="mr-2 h-4 w-4" />
          Add Reminder
        </Button>
      </div>

      <div className="flex-1 overflow-y-auto px-6 py-5">
        {/* Summary stats */}
        {!isLoading && reminders.length > 0 && (
          <div className="grid gap-2.5 grid-cols-3 mb-5">
            <Card className="bg-gradient-to-br from-accent/[0.03] to-transparent">
              <CardContent className="p-4 flex items-center gap-3">
                <div className="p-1.5 rounded-md bg-orange-500/10">
                  <Bell className="h-4 w-4 text-orange-400" />
                </div>
                <div>
                  <p className="text-[10px] tracking-wider uppercase text-muted-foreground">
                    Active
                  </p>
                  <p className="font-heading text-xl font-bold tabular-nums">{activeCount}</p>
                </div>
              </CardContent>
            </Card>
            <Card className="bg-gradient-to-br from-accent/[0.03] to-transparent">
              <CardContent className="p-4 flex items-center gap-3">
                <div className="p-1.5 rounded-md bg-red-500/10">
                  <AlertCircle className="h-4 w-4 text-red-400" />
                </div>
                <div>
                  <p className="text-[10px] tracking-wider uppercase text-muted-foreground">
                    Overdue
                  </p>
                  <p className="font-heading text-xl font-bold tabular-nums">{overdueCount}</p>
                </div>
              </CardContent>
            </Card>
            <Card className="bg-gradient-to-br from-accent/[0.03] to-transparent">
              <CardContent className="p-4 flex items-center gap-3">
                <div className="p-1.5 rounded-md bg-gray-500/10">
                  <BellOff className="h-4 w-4 text-gray-400" />
                </div>
                <div>
                  <p className="text-[10px] tracking-wider uppercase text-muted-foreground">
                    Dismissed
                  </p>
                  <p className="font-heading text-xl font-bold tabular-nums">{dismissedCount}</p>
                </div>
              </CardContent>
            </Card>
          </div>
        )}

        {isLoading ? (
          <ListSkeleton rows={6} />
        ) : (
          <ReminderList
            reminders={filteredReminders}
            onEdit={handleEdit}
            onAdd={() => setShowForm(true)}
          />
        )}
      </div>

      {showForm && <ReminderForm reminder={editingReminder} onClose={handleCloseForm} />}
    </div>
  );
}