import { useState, FormEvent } from 'react';
import { useMutation, useQueryClient } from '@tanstack/react-query';
import { toast } from 'sonner';
import api, { getErrorMessage } from '@/lib/api';
import type { Calendar } from '@/types';
import {
  Dialog,
  DialogContent,
  DialogHeader,
  DialogTitle,
  DialogFooter,
  DialogClose,
} from '@/components/ui/dialog';
import { Input } from '@/components/ui/input';
import { Label } from '@/components/ui/label';
import { Button } from '@/components/ui/button';

interface CalendarFormProps {
  calendar: Calendar | null;
  onClose: () => void;
}

const colorSwatches = [
  '#3b82f6', // blue
  '#ef4444', // red
  '#f97316', // orange
  '#eab308', // yellow
  '#22c55e', // green
  '#8b5cf6', // purple
  '#ec4899', // pink
  '#06b6d4', // cyan
];

export default function CalendarForm({ calendar, onClose }: CalendarFormProps) {
  const queryClient = useQueryClient();
  const [name, setName] = useState(calendar?.name || '');
  const [color, setColor] = useState(calendar?.color || '#3b82f6');

  const mutation = useMutation({
    mutationFn: async () => {
      if (calendar) {
        const { data } = await api.put(`/calendars/${calendar.id}`, { name, color });
        return data;
      } else {
        const { data } = await api.post('/calendars', { name, color });
        return data;
      }
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['calendars'] });
      queryClient.invalidateQueries({ queryKey: ['calendar-events'] });
      toast.success(calendar ? 'Calendar updated' : 'Calendar created');
      onClose();
    },
    onError: (error) => {
      toast.error(getErrorMessage(error, 'Failed to save calendar'));
    },
  });

  const deleteMutation = useMutation({
    mutationFn: async () => {
      await api.delete(`/calendars/${calendar?.id}`);
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['calendars'] });
      queryClient.invalidateQueries({ queryKey: ['calendar-events'] });
      toast.success('Calendar deleted');
      onClose();
    },
    onError: (error) => {
      toast.error(getErrorMessage(error, 'Failed to delete calendar'));
    },
  });

  const handleSubmit = (e: FormEvent) => {
    e.preventDefault();
    if (!name.trim()) return;
    mutation.mutate();
  };

  const canDelete = calendar && !calendar.is_default && !calendar.is_system;

  return (
    <Dialog open={true} onOpenChange={onClose}>
      <DialogContent>
        <DialogClose onClick={onClose} />
        <DialogHeader>
          <DialogTitle>{calendar ? 'Edit Calendar' : 'New Calendar'}</DialogTitle>
        </DialogHeader>
        <form onSubmit={handleSubmit} className="space-y-4">
          <div className="space-y-2">
            <Label htmlFor="cal-name" required>Name</Label>
            <Input
              id="cal-name"
              value={name}
              onChange={(e) => setName(e.target.value)}
              placeholder="Calendar name"
              required
              disabled={calendar?.is_system}
            />
          </div>

          <div className="space-y-2">
            <Label>Color</Label>
            <div className="flex gap-2">
              {colorSwatches.map((c) => (
                <button
                  key={c}
                  type="button"
                  onClick={() => setColor(c)}
                  className="h-8 w-8 rounded-full border-2 transition-all duration-150 hover:scale-110"
                  style={{
                    backgroundColor: c,
                    borderColor: color === c ? 'hsl(0 0% 98%)' : 'transparent',
                    boxShadow: color === c ? `0 0 0 2px ${c}40` : 'none',
                  }}
                />
              ))}
            </div>
          </div>

          <DialogFooter>
            {canDelete && (
              <Button
                type="button"
                variant="destructive"
                onClick={() => deleteMutation.mutate()}
                disabled={deleteMutation.isPending}
                className="mr-auto"
              >
                Delete
              </Button>
            )}
            <Button type="button" variant="outline" onClick={onClose}>
              Cancel
            </Button>
            <Button type="submit" disabled={mutation.isPending}>
              {mutation.isPending ? 'Saving...' : calendar ? 'Update' : 'Create'}
            </Button>
          </DialogFooter>
        </form>
      </DialogContent>
    </Dialog>
  );
}