import { useCallback } from 'react';
import { calcNextPosition, snapPosition } from '@xyflow/system';

import { Node } from '../types';
import { useStoreApi } from '../hooks/useStore';

const selectedAndDraggable = (nodesDraggable: boolean) => (n: Node) =>
  n.selected && (n.draggable || (nodesDraggable && typeof n.draggable === 'undefined'));

function useUpdateNodePositions() {
  const store = useStoreApi();

  const updatePositions = useCallback((params: { x: number; y: number; isShiftPressed: boolean }) => {
    const { nodeExtent, nodes, snapToGrid, snapGrid, nodesDraggable, onError, updateNodePositions } = store.getState();
    const selectedNodes = nodes.filter(selectedAndDraggable(nodesDraggable));
    // by default a node moves 5px on each key press, or 20px if shift is pressed
    // if snap grid is enabled, we use that for the velocity.
    const xVelo = snapToGrid ? snapGrid[0] : 5;
    const yVelo = snapToGrid ? snapGrid[1] : 5;
    const factor = params.isShiftPressed ? 4 : 1;

    const xDiff = params.x * xVelo * factor;
    const yDiff = params.y * yVelo * factor;

    const nodeUpdates = selectedNodes.map((node) => {
      if (node.computed?.positionAbsolute) {
        let nextPosition = {
          x: node.computed?.positionAbsolute.x + xDiff,
          y: node.computed?.positionAbsolute.y + yDiff,
        };

        if (snapToGrid) {
          nextPosition = snapPosition(nextPosition, snapGrid);
        }

        const { positionAbsolute, position } = calcNextPosition(
          node,
          nextPosition,
          nodes,
          nodeExtent,
          undefined,
          onError
        );

        node.position = position;
        if (!node.computed) {
          node.computed = {};
        }
        node.computed.positionAbsolute = positionAbsolute;
      }

      return node;
    });

    updateNodePositions(nodeUpdates, true, false);
  }, []);

  return updatePositions;
}

export default useUpdateNodePositions;