import * as React from 'react';
import useModernLayoutEffect from 'use-isomorphic-layout-effect';

import {useId} from '../hooks/useId';
import type {FloatingNodeType, FloatingTreeType, ReferenceType} from '../types';
import {createPubSub} from '../utils/createPubSub';

const FloatingNodeContext = React.createContext<FloatingNodeType | null>(null);
const FloatingTreeContext = React.createContext<FloatingTreeType | null>(null);

/**
 * Returns the parent node id for nested floating elements, if available.
 * Returns `null` for top-level floating elements.
 */
export const useFloatingParentNodeId = (): string | null =>
  React.useContext(FloatingNodeContext)?.id || null;

/**
 * Returns the nearest floating tree context, if available.
 */
export const useFloatingTree = <
  RT extends ReferenceType = ReferenceType,
>(): FloatingTreeType<RT> | null =>
  React.useContext(FloatingTreeContext) as FloatingTreeType<RT> | null;

/**
 * Registers a node into the `FloatingTree`, returning its id.
 * @see https://floating-ui.com/docs/FloatingTree
 */
export function useFloatingNodeId(customParentId?: string): string {
  const id = useId();
  const tree = useFloatingTree();
  const reactParentId = useFloatingParentNodeId();
  const parentId = customParentId || reactParentId;

  useModernLayoutEffect(() => {
    const node = {id, parentId};
    tree?.addNode(node);
    return () => {
      tree?.removeNode(node);
    };
  }, [tree, id, parentId]);

  return id;
}

export interface FloatingNodeProps {
  children?: React.ReactNode;
  id: string;
}

/**
 * Provides parent node context for nested floating elements.
 * @see https://floating-ui.com/docs/FloatingTree
 */
export function FloatingNode(props: FloatingNodeProps): React.JSX.Element {
  const {children, id} = props;

  const parentId = useFloatingParentNodeId();

  return (
    <FloatingNodeContext.Provider
      value={React.useMemo(() => ({id, parentId}), [id, parentId])}
    >
      {children}
    </FloatingNodeContext.Provider>
  );
}

export interface FloatingTreeProps {
  children?: React.ReactNode;
}

/**
 * Provides context for nested floating elements when they are not children of
 * each other on the DOM.
 * This is not necessary in all cases, except when there must be explicit communication between parent and child floating elements. It is necessary for:
 * - The `bubbles` option in the `useDismiss()` Hook
 * - Nested virtual list navigation
 * - Nested floating elements that each open on hover
 * - Custom communication between parent and child floating elements
 * @see https://floating-ui.com/docs/FloatingTree
 */
export function FloatingTree(props: FloatingTreeProps): React.JSX.Element {
  const {children} = props;

  const nodesRef = React.useRef<Array<FloatingNodeType>>([]);

  const addNode = React.useCallback((node: FloatingNodeType) => {
    nodesRef.current = [...nodesRef.current, node];
  }, []);

  const removeNode = React.useCallback((node: FloatingNodeType) => {
    nodesRef.current = nodesRef.current.filter((n) => n !== node);
  }, []);

  const events = React.useState(() => createPubSub())[0];

  return (
    <FloatingTreeContext.Provider
      value={React.useMemo(
        () => ({
          nodesRef,
          addNode,
          removeNode,
          events,
        }),
        [addNode, removeNode, events],
      )}
    >
      {children}
    </FloatingTreeContext.Provider>
  );
}
