/**
 * The nodes selection rectangle gets displayed when a user
 * made a selection with on or several nodes
 */
import { useRef, useEffect, type MouseEvent, type KeyboardEvent } from 'react';
import cc from 'classcat';
import { shallow } from 'zustand/shallow';
import { getNodesBounds } from '@xyflow/system';

import { useStore, useStoreApi } from '../../hooks/useStore';
import { useDrag } from '../../hooks/useDrag';
import { useMoveSelectedNodes } from '../../hooks/useMoveSelectedNodes';
import { arrowKeyDiffs } from '../NodeWrapper/utils';
import type { InternalNode, Node, ReactFlowState } from '../../types';

export type NodesSelectionProps<NodeType> = {
  onSelectionContextMenu?: (event: MouseEvent, nodes: NodeType[]) => void;
  noPanClassName?: string;
  disableKeyboardA11y: boolean;
};

const selector = (s: ReactFlowState) => {
  const selectedNodes: InternalNode[] = [];
  for (const [, node] of s.nodeLookup) {
    if (node.selected) {
      selectedNodes.push(node);
    }
  }

  const { width, height, x, y } = getNodesBounds(selectedNodes, { nodeOrigin: s.nodeOrigin });

  return {
    width,
    height,
    userSelectionActive: s.userSelectionActive,
    transformString: `translate(${s.transform[0]}px,${s.transform[1]}px) scale(${s.transform[2]}) translate(${x}px,${y}px)`,
  };
};

export function NodesSelection<NodeType extends Node>({
  onSelectionContextMenu,
  noPanClassName,
  disableKeyboardA11y,
}: NodesSelectionProps<NodeType>) {
  const store = useStoreApi<NodeType>();
  const { width, height, transformString, userSelectionActive } = useStore(selector, shallow);
  const moveSelectedNodes = useMoveSelectedNodes();

  const nodeRef = useRef<HTMLDivElement>(null);

  useEffect(() => {
    if (!disableKeyboardA11y) {
      nodeRef.current?.focus({
        preventScroll: true,
      });
    }
  }, [disableKeyboardA11y]);

  useDrag({
    nodeRef,
  });

  if (userSelectionActive || !width || !height) {
    return null;
  }

  const onContextMenu = onSelectionContextMenu
    ? (event: MouseEvent) => {
        const selectedNodes = store.getState().nodes.filter((n) => n.selected);
        onSelectionContextMenu(event, selectedNodes);
      }
    : undefined;

  const onKeyDown = (event: KeyboardEvent) => {
    if (Object.prototype.hasOwnProperty.call(arrowKeyDiffs, event.key)) {
      moveSelectedNodes({
        direction: arrowKeyDiffs[event.key],
        factor: event.shiftKey ? 4 : 1,
      });
    }
  };

  return (
    <div
      className={cc(['react-flow__nodesselection', 'react-flow__container', noPanClassName])}
      style={{
        transform: transformString,
      }}
    >
      <div
        ref={nodeRef}
        className="react-flow__nodesselection-rect"
        onContextMenu={onContextMenu}
        tabIndex={disableKeyboardA11y ? undefined : -1}
        onKeyDown={disableKeyboardA11y ? undefined : onKeyDown}
        style={{
          width,
          height,
        }}
      />
    </div>
  );
}
