"use client";

import type { HTMLMotionProps } from "motion/react";

import { isMotionComponent, motion } from "motion/react";
import * as React from "react";

import { cn } from "@/lib/utils";

type AnyProps = Record<string, unknown>;

type DOMMotionProps<T extends HTMLElement = HTMLElement> = Omit<
  HTMLMotionProps<keyof HTMLElementTagNameMap>,
  "ref"
> & { ref?: React.Ref<T> };

type WithAsChild<Base extends object>
  = | (Base & { asChild: true; children: React.ReactElement })
    | (Base & { asChild?: false | undefined });

type SlotProps<T extends HTMLElement = HTMLElement> = {
  children?: any;
} & DOMMotionProps<T>;

function mergeRefs<T>(
  ...refs: (React.Ref<T> | undefined)[]
): React.RefCallback<T> {
  return (node) => {
    refs.forEach((ref) => {
      if (!ref)
        return;
      if (typeof ref === "function") {
        ref(node);
      }
      else {
        (ref as React.RefObject<T | null>).current = node;
      }
    });
  };
}

function mergeProps<T extends HTMLElement>(
  childProps: AnyProps,
  slotProps: DOMMotionProps<T>,
): AnyProps {
  const merged: AnyProps = { ...childProps, ...slotProps };

  if (childProps.className || slotProps.className) {
    merged.className = cn(
      childProps.className as string,
      slotProps.className as string,
    );
  }

  if (childProps.style || slotProps.style) {
    merged.style = {
      ...(childProps.style as React.CSSProperties),
      ...(slotProps.style as React.CSSProperties),
    };
  }

  return merged;
}

function Slot<T extends HTMLElement = HTMLElement>({
  children,
  ref,
  ...props
}: SlotProps<T>) {
  const isAlreadyMotion
    = typeof children.type === "object"
      && children.type !== null
      && isMotionComponent(children.type);

  const Base = React.useMemo(
    () =>
      isAlreadyMotion
        ? (children.type as React.ElementType)
        : motion.create(children.type as React.ElementType),
    [isAlreadyMotion, children.type],
  );

  if (!React.isValidElement(children))
    return null;

  const { ref: childRef, ...childProps } = children.props as AnyProps;

  const mergedProps = mergeProps(childProps, props);

  return (
    <Base {...mergedProps} ref={mergeRefs(childRef as React.Ref<T>, ref)} />
  );
}

export {
  type AnyProps,
  type DOMMotionProps,
  Slot,
  type SlotProps,
  type WithAsChild,
};
