"use strict";
  
  const { domSymbolTree } = require("../helpers/internal-constants");
  const { nodeRoot, isFollowing, isInclusiveAncestor } = require("../helpers/node");
  
  // Returns 0 if equal, +1 for after and -1 for before
  // https://dom.spec.whatwg.org/#concept-range-bp-after
  function compareBoundaryPointsPosition(bpA, bpB) {
    const { node: nodeA, offset: offsetA } = bpA;
    const { node: nodeB, offset: offsetB } = bpB;
  
    if (nodeRoot(nodeA) !== nodeRoot(nodeB)) {
      throw new Error(`Internal Error: Boundary points should have the same root!`);
    }
  
    if (nodeA === nodeB) {
      if (offsetA === offsetB) {
        return 0;
      } else if (offsetA < offsetB) {
        return -1;
      }
  
      return 1;
    }
  
    if (isFollowing(nodeA, nodeB)) {
      return compareBoundaryPointsPosition(bpB, bpA) === -1 ? 1 : -1;
    }
  
    if (isInclusiveAncestor(nodeA, nodeB)) {
      let child = nodeB;
  
      while (domSymbolTree.parent(child) !== nodeA) {
        child = domSymbolTree.parent(child);
      }
  
      if (domSymbolTree.index(child) < offsetA) {
        return 1;
      }
    }
  
    return -1;
  }
  
  module.exports = {
    compareBoundaryPointsPosition
  };