import { describe, expect, it } from 'vitest'
import {
  computeDropPatches,
  computeMovePatches,
  computeReorderPatches,
  sortByOrder,
} from './reorder.js'

const items = [
  { id: 'a', sort_order: 0 },
  { id: 'b', sort_order: 10 },
  { id: 'c', sort_order: 20 },
]

describe('reorder', () => {
  it('sorts by sort_order then id', () => {
    const unsorted = [
      { id: 'c', sort_order: 20 },
      { id: 'a', sort_order: 0 },
      { id: 'b', sort_order: 10 },
    ]
    expect(sortByOrder(unsorted).map((i) => i.id)).toEqual(['a', 'b', 'c'])
  })

  it('computes patches when moving down', () => {
    const patches = computeMovePatches(items, 'a', 'down')
    expect(patches).toEqual(
      expect.arrayContaining([
        { id: 'a', sort_order: 10 },
        { id: 'b', sort_order: 0 },
      ]),
    )
    expect(patches).toHaveLength(2)
  })

  it('computes patches for drag drop', () => {
    const patches = computeDropPatches(items, 'c', 'a')
    expect(patches).toEqual([
      { id: 'c', sort_order: 0 },
      { id: 'a', sort_order: 10 },
      { id: 'b', sort_order: 20 },
    ])
  })

  it('returns empty when indices unchanged', () => {
    expect(computeReorderPatches(items, 1, 1)).toEqual([])
  })
})