import type { AnchorHTMLAttributes, ButtonHTMLAttributes, ReactNode } from "react";
import { forwardRef } from "react";
import { cva, type VariantProps } from "class-variance-authority";
import { cn } from "@/lib/utils";
import { Spinner } from "./Spinner";

const buttonVariants = cva(
  "inline-flex items-center justify-center rounded-lg text-sm font-medium transition-all duration-200 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-blue-500 focus-visible:ring-offset-2 disabled:opacity-50 disabled:pointer-events-none ring-offset-background active:scale-[0.98]",
  {
    variants: {
      variant: {
        default: "bg-blue-600 text-white hover:bg-blue-700 shadow-sm hover:shadow-md",
        destructive: "bg-red-600 text-white hover:bg-red-700 shadow-sm hover:shadow-md",
        outline:
          "border border-gray-300 bg-white hover:bg-gray-50 hover:border-gray-400 shadow-sm hover:shadow-md",
        secondary: "bg-gray-100 text-gray-900 hover:bg-gray-200 shadow-sm hover:shadow-md",
        ghost: "hover:bg-gray-100 hover:shadow-sm",
        link: "underline-offset-4 hover:underline text-blue-600",
      },
      size: {
        default: "h-11 py-2.5 px-4",
        sm: "h-9 px-3 text-xs",
        lg: "h-12 px-6 text-base",
      },
    },
    defaultVariants: {
      variant: "default",
      size: "default",
    },
  }
);

interface ButtonExtras {
  leftIcon?: ReactNode;
  rightIcon?: ReactNode;
  loading?: boolean;
  isLoading?: boolean;
  loadingText?: ReactNode;
}

type ButtonAsAnchorProps = {
  as: "a";
  href: string;
} & AnchorHTMLAttributes<HTMLAnchorElement> &
  VariantProps<typeof buttonVariants> &
  ButtonExtras;

type ButtonAsButtonProps = {
  as?: "button";
} & ButtonHTMLAttributes<HTMLButtonElement> &
  VariantProps<typeof buttonVariants> &
  ButtonExtras;

export type ButtonProps = ButtonAsAnchorProps | ButtonAsButtonProps;

const Button = forwardRef<HTMLButtonElement | HTMLAnchorElement, ButtonProps>((props, ref) => {
  const {
    leftIcon,
    rightIcon,
    loading: loadingProp,
    isLoading,
    loadingText,
    children,
    ...rest
  } = props;

  const loading = loadingProp ?? isLoading ?? false;

  if (props.as === "a") {
    const { className, variant, size, as: _as, href, ...anchorProps } = rest as ButtonAsAnchorProps;
    void _as;
    return (
      <a
        className={cn(buttonVariants({ variant, size, className }))}
        href={href}
        ref={ref as React.Ref<HTMLAnchorElement>}
        aria-busy={loading || undefined}
        {...anchorProps}
      >
        <span className="inline-flex items-center justify-center gap-2">
          {loading ? <Spinner size="sm" /> : leftIcon}
          <span className="flex-1">{loading ? (loadingText ?? children) : children}</span>
          {!loading && rightIcon ? (
            <span className="transition-transform duration-200 group-hover:translate-x-0.5">
              {rightIcon}
            </span>
          ) : null}
        </span>
      </a>
    );
  }

  const {
    className,
    variant,
    size,
    as: _as,
    disabled,
    ...buttonProps
  } = rest as ButtonAsButtonProps;
  void _as;
  return (
    <button
      className={cn(buttonVariants({ variant, size, className }))}
      ref={ref as React.Ref<HTMLButtonElement>}
      disabled={loading || disabled}
      aria-busy={loading || undefined}
      {...buttonProps}
    >
      <span className="inline-flex items-center justify-center gap-2">
        {loading ? <Spinner size="sm" /> : leftIcon}
        <span className="flex-1">{loading ? (loadingText ?? children) : children}</span>
        {!loading && rightIcon ? (
          <span className="transition-transform duration-200 group-hover:translate-x-0.5">
            {rightIcon}
          </span>
        ) : null}
      </span>
    </button>
  );
});
Button.displayName = "Button";

export { Button, buttonVariants };