import { orderSlotsByWagonSequence } from './train-builder.service';

describe('orderSlotsByWagonSequence', () => {
  const slot = (sequenceNo: number, physicalWagonId: string | null) => ({
    sequenceNo,
    physicalWagonId,
  });

  it('reorders pinned slots to the wagons’ new positions, unpinned trail in old order', () => {
    // Built train reordered to w3, w1, w2. Slots 1..5: three pinned + two empty.
    const newSeq = new Map([
      ['w3', 1],
      ['w1', 2],
      ['w2', 3],
    ]);
    const slots = [
      slot(1, 'w1'),
      slot(2, 'w2'),
      slot(3, 'w3'),
      slot(4, null),
      slot(5, null),
    ];
    expect(orderSlotsByWagonSequence(slots, newSeq).map((s) => s.physicalWagonId)).toEqual([
      'w3',
      'w1',
      'w2',
      null,
      null,
    ]);
    // Unpinned keep their old relative order (4 before 5).
    expect(orderSlotsByWagonSequence(slots, newSeq).map((s) => s.sequenceNo)).toEqual([
      3, 1, 2, 4, 5,
    ]);
  });

  it('slots pinned to wagons outside the reorder trail like unpinned ones', () => {
    const newSeq = new Map([['w2', 1]]);
    const slots = [slot(1, 'w-foreign'), slot(2, 'w2')];
    expect(orderSlotsByWagonSequence(slots, newSeq).map((s) => s.physicalWagonId)).toEqual([
      'w2',
      'w-foreign',
    ]);
  });
});