import { useState } from 'react';
import { format, isPast, endOfDay } from 'date-fns';
import { useNavigate } from 'react-router-dom';
import { useMutation, useQueryClient } from '@tanstack/react-query';
import { toast } from 'sonner';
import { CheckCircle2, Check } from 'lucide-react';
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
import { Badge } from '@/components/ui/badge';
import { cn } from '@/lib/utils';
import api from '@/lib/api';

interface DashboardTodo {
  id: number;
  title: string;
  due_date: string;
  priority: string;
  category?: string;
}

interface TodoWidgetProps {
  todos: DashboardTodo[];
}

const priorityColors: Record<string, string> = {
  low: 'bg-green-500/10 text-green-400 border-green-500/20',
  medium: 'bg-yellow-500/10 text-yellow-400 border-yellow-500/20',
  high: 'bg-red-500/10 text-red-400 border-red-500/20',
};

const dotColors: Record<string, string> = {
  high: 'bg-red-400',
  medium: 'bg-yellow-400',
  low: 'bg-green-400',
};

export default function TodoWidget({ todos }: TodoWidgetProps) {
  const navigate = useNavigate();
  const queryClient = useQueryClient();
  const [hoveredId, setHoveredId] = useState<number | null>(null);

  const toggleTodo = useMutation({
    mutationFn: (id: number) => api.patch(`/todos/${id}/toggle`),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['dashboard'] });
      queryClient.invalidateQueries({ queryKey: ['upcoming'] });
      toast.success('Todo completed');
    },
    onError: () => toast.error('Failed to complete todo'),
  });

  const hasOverdue = todos.some((t) => isPast(endOfDay(new Date(t.due_date))));

  return (
    <Card className={cn('h-full hover:shadow-lg hover:shadow-accent/5 hover:border-accent/20 transition-all duration-200', hasOverdue && 'animate-card-breathe')}>
      <CardHeader>
        <CardTitle className="flex items-center gap-2">
          <div className="p-1.5 rounded-md bg-blue-500/10">
            <CheckCircle2 className="h-4 w-4 text-blue-400" />
          </div>
          Upcoming Todos
        </CardTitle>
      </CardHeader>
      <CardContent>
        {todos.length === 0 ? (
          <div className="flex flex-col items-center justify-center py-6 gap-2">
            <div className="rounded-full bg-muted p-4">
              <CheckCircle2 className="h-8 w-8 text-muted-foreground" />
            </div>
            <p className="text-sm text-muted-foreground">Your slate is clean</p>
          </div>
        ) : (
          <div className="space-y-0.5">
            {todos.slice(0, 5).map((todo) => {
              const isOverdue = isPast(endOfDay(new Date(todo.due_date)));
              const isHovered = hoveredId === todo.id;
              return (
                <div
                  key={todo.id}
                  onClick={() => navigate('/todos', { state: { todoId: todo.id } })}
                  onMouseEnter={() => setHoveredId(todo.id)}
                  onMouseLeave={() => setHoveredId(null)}
                  className="flex items-center gap-2 py-1.5 px-2 rounded-md hover:bg-card-elevated transition-colors duration-150 cursor-pointer"
                >
                  <div className={cn('w-1.5 h-1.5 rounded-full shrink-0', dotColors[todo.priority] || dotColors.medium)} />
                  <span className="text-sm font-medium truncate flex-1 min-w-0">{todo.title}</span>
                  <div className="relative flex items-center gap-1.5 shrink-0">
                    <div className={cn('flex items-center gap-1.5', isHovered && 'invisible')}>
                      <span className={cn(
                        'text-xs shrink-0 whitespace-nowrap',
                        isOverdue ? 'text-red-400' : 'text-muted-foreground'
                      )}>
                        {format(new Date(todo.due_date), 'MMM d')}
                        {isOverdue && ' overdue'}
                      </span>
                      <Badge className={cn('text-[9px] shrink-0 py-0', priorityColors[todo.priority] || priorityColors.medium)}>
                        {todo.priority}
                      </Badge>
                    </div>
                    {isHovered && (
                      <div className="absolute inset-0 flex items-center justify-end">
                        <button
                          onClick={(e) => {
                            e.stopPropagation();
                            toggleTodo.mutate(todo.id);
                          }}
                          className="p-1 rounded hover:bg-green-500/15 text-muted-foreground hover:text-green-400 transition-colors"
                          title="Complete todo"
                        >
                          <Check className="h-3.5 w-3.5" />
                        </button>
                      </div>
                    )}
                  </div>
                </div>
              );
            })}
          </div>
        )}
      </CardContent>
    </Card>
  );
}