// The order of a section, proposed with a list one clicks (Yvv, 2026-10-30:
// « une simple liste clipable »): an article, then its new place; or its arrows.
import { describe, expect, it } from 'vitest';
import { moved, place, sameOrder, step } from '../../src/lib/order';

const section = ['T1', 'E1', 'E2', 'E3'];

describe('the order of a section, by clicks', () => {
  it('an article chosen takes the place clicked, the others close up', () => {
    expect(place(section, 'E2', 'T1')).toEqual(['E2', 'T1', 'E1', 'E3']);
    expect(place(section, 'T1', 'E3')).toEqual(['E1', 'E2', 'E3', 'T1']);
    expect(place(section, 'E1', 'E2')).toEqual(['T1', 'E2', 'E1', 'E3']);
    // Its own place, or an article not in the list: nothing moves.
    expect(place(section, 'E1', 'E1')).toEqual(section);
    expect(place(section, 'X9', 'E1')).toEqual(section);
    expect(place(section, 'E1', 'X9')).toEqual(section);
  });

  it('the arrows move one place, never beyond the ends', () => {
    expect(step(section, 'E2', -1)).toEqual(['T1', 'E2', 'E1', 'E3']);
    expect(step(section, 'E2', 1)).toEqual(['T1', 'E1', 'E3', 'E2']);
    expect(step(section, 'T1', -1)).toEqual(section);
    expect(step(section, 'E3', 1)).toEqual(section);
  });

  it('a list never loses nor doubles an article', () => {
    const once = place(step(place(section, 'E3', 'T1'), 'T1', 1), 'E1', 'E3');
    expect([...once].sort()).toEqual([...section].sort());
  });

  it('tells the order in force from another, and what moved', () => {
    expect(sameOrder(section, [...section])).toBe(true);
    expect(sameOrder(section, step(section, 'E1', 1))).toBe(false);
    expect(sameOrder(section, section.slice(1))).toBe(false);
    expect([...moved(section, ['E1', 'T1', 'E2', 'E3'])].sort()).toEqual(['E1', 'T1']);
    expect(moved(section, section).size).toBe(0);
  });
});