'use client';

import * as React from 'react';
import { Slot } from '@radix-ui/react-slot';
import { cva, type VariantProps } from 'class-variance-authority';
import { cn } from '@/lib/utils';

const buttonVariants = cva(
  'group inline-flex items-center justify-center gap-2 whitespace-nowrap text-sm font-medium transition-all duration-fast ease-standard disabled:pointer-events-none disabled:opacity-50 disabled:cursor-not-allowed [&_svg]:pointer-events-none [&_svg:not([class*="size-"])]:size-4 shrink-0 [&_svg]:shrink-0 outline-none focus-visible:ring-2 focus-visible:ring-brand focus-visible:ring-offset-2 focus-visible:ring-offset-bg-primary min-h-[44px] min-w-[44px] touch-manipulation relative overflow-hidden select-none',
  {
    variants: {
      variant: {
        primary:
          'bg-brand text-white shadow-sm hover:bg-brand-hover hover:shadow-brand-hover hover:-translate-y-px active:translate-y-0 active:scale-[0.97] active:shadow-sm transition-all duration-fast ease-standard',
        secondary:
          'bg-dark-bg text-white shadow-sm hover:bg-dark-bg-secondary hover:shadow-md hover:-translate-y-px active:translate-y-0 active:scale-[0.97] active:shadow-sm transition-all duration-fast ease-standard',
        outline:
          'border border-border-accent bg-transparent text-text-primary hover:bg-dark-bg hover:text-white hover:border-dark-bg hover:-translate-y-px hover:shadow-md active:translate-y-0 active:scale-[0.97] active:shadow-sm transition-all duration-fast ease-standard',
        ghost:
          'text-text-secondary hover:bg-bg-secondary hover:text-text-primary active:scale-[0.97] transition-all duration-fast ease-standard',
        link:
          'text-text-primary underline-offset-4 hover:text-brand relative after:absolute after:bottom-0 after:left-0 after:h-[2px] after:w-0 hover:after:w-full after:bg-brand after:transition-all after:duration-normal after:ease-standard',
        destructive:
          'bg-error text-white shadow-sm hover:bg-error-hover hover:-translate-y-px active:translate-y-0 active:scale-[0.97] transition-all duration-fast ease-standard',
      },
      size: {
        sm: 'h-9 rounded-full px-3 text-xs font-medium',
        default: 'h-11 rounded-full px-5 py-2 font-medium',
        lg: 'h-12 rounded-full px-6 text-base font-semibold',
        xl: 'h-14 rounded-full px-8 text-base font-semibold',
        icon: 'h-11 w-11 rounded-full',
      },
    },
    defaultVariants: {
      variant: 'primary',
      size: 'default',
    },
  }
);

export interface ButtonProps
  extends React.ButtonHTMLAttributes<HTMLButtonElement>,
    VariantProps<typeof buttonVariants> {
  asChild?: boolean;
  showRipple?: boolean;
}

const Button = React.forwardRef<HTMLButtonElement, ButtonProps>(
  ({ className, variant, size, asChild = false, onClick, children, showRipple = true, ...props }, ref) => {
    const [ripples, setRipples] = React.useState<{ x: number; y: number; id: number }[]>([]);

    const handleClick = (e: React.MouseEvent<HTMLButtonElement>) => {
      if (showRipple && variant !== 'link' && variant !== 'ghost') {
        const button = e.currentTarget;
        const rect = button.getBoundingClientRect();
        const x = e.clientX - rect.left;
        const y = e.clientY - rect.top;
        const id = Date.now();

        setRipples((prev) => [...prev, { x, y, id }]);

        setTimeout(() => {
          setRipples((prev) => prev.filter((r) => r.id !== id));
        }, 600);
      }

      onClick?.(e);
    };

    // asChild 模式：Slot 要求单个 React 元素子节点，因此跳过 ripple 和包裹 span。
    // 直接把 children 交给 Slot，由 Slot 克隆并注入 className/onClick 等 props。
    if (asChild) {
      return (
        <Slot
          className={cn(buttonVariants({ variant, size, className }))}
          ref={ref}
          onClick={onClick}
          {...props}
        >
          {children}
        </Slot>
      );
    }

    return (
      <button
        className={cn(buttonVariants({ variant, size, className }))}
        ref={ref}
        onClick={handleClick}
        {...props}
      >
        {ripples.map((ripple) => (
          <span
            key={ripple.id}
            className="pointer-events-none absolute rounded-full bg-white/25 animate-ripple"
            style={{
              left: ripple.x,
              top: ripple.y,
              transform: 'translate(-50%, -50%)',
            }}
          />
        ))}
        <span className="relative z-10 flex items-center justify-center gap-2">
          {children}
        </span>
      </button>
    );
  }
);
Button.displayName = 'Button';

export { Button, buttonVariants };