import {Edge, Graph} from 'graphlib';
import addSubgraphConstraints from './add-subgraph-constraints';

describe('order/addSubgraphConstraints', function () {
  let g: any;
  let cg: any;

  beforeEach(() => {
    g = new Graph({ compound: true });
    cg = new Graph();
  });

  it('does not change CG for a flat set of nodes', function () {
    const vs = ['a', 'b', 'c', 'd'];
    vs.forEach(v => {
      g.setNode(v);
    });
    addSubgraphConstraints(g, cg, vs);
    expect(cg.nodeCount()).toEqual(0);
    expect(cg.edgeCount()).toEqual(0);
  });

  it("doesn't create a constraint for contiguous subgraph nodes", function () {
    const vs = ['a', 'b', 'c'];
    vs.forEach(v => {
      g.setParent(v, 'sg');
    });
    addSubgraphConstraints(g, cg, vs);
    expect(cg.nodeCount()).toEqual(0);
    expect(cg.edgeCount()).toEqual(0);
  });

  it('adds a constraint when the parents for adjacent nodes are different', function () {
    const vs = ['a', 'b'];
    g.setParent('a', 'sg1');
    g.setParent('b', 'sg2');
    addSubgraphConstraints(g, cg, vs);
    expect(cg.edges()[0]).toEqual({ v: 'sg1', w: 'sg2' });
  });

  it('works for multiple levels', function () {
    const vs = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'];
    vs.forEach(v => {
      g.setNode(v);
    });
    g.setParent('b', 'sg2');
    g.setParent('sg2', 'sg1');
    g.setParent('c', 'sg1');
    g.setParent('d', 'sg3');
    g.setParent('sg3', 'sg1');
    g.setParent('f', 'sg4');
    g.setParent('g', 'sg5');
    g.setParent('sg5', 'sg4');
    addSubgraphConstraints(g, cg, vs);
    expect(cg.edges().sort((a:Edge, b: Edge) => {
      const valueA = a['v'];
      const valueB = b['v'];
      if (valueA < valueB) {
        return -1;
      }
      if (valueA > valueB) {
        return 1;
      }

      // names must be equal
      return 0;
    })).toEqual([
      { v: 'sg1', w: 'sg4' },
      { v: 'sg2', w: 'sg3' },
    ]);
  });
});