/** @jest-environment node */

import {
  getExpectedUploadChunkBytes,
  resolveUploadChunkSize,
} from '@/lib/material-upload-chunk-policy'

const MEBIBYTE = 1024 * 1024

describe('material upload chunk policy', () => {
  test('accepts the declared browser layout and calculates the final remainder', () => {
    const fileSize = 25 * MEBIBYTE
    const chunkSize = 10 * MEBIBYTE
    const totalChunks = 3

    expect(resolveUploadChunkSize(fileSize, totalChunks, chunkSize)).toBe(chunkSize)
    expect(getExpectedUploadChunkBytes({
      fileSize,
      totalChunks,
      chunkSize,
      chunkIndex: 0,
    })).toBe(10 * MEBIBYTE)
    expect(getExpectedUploadChunkBytes({
      fileSize,
      totalChunks,
      chunkSize,
      chunkIndex: 2,
    })).toBe(5 * MEBIBYTE)
  })

  test('keeps already-open legacy 10/20MB browser uploads compatible', () => {
    expect(resolveUploadChunkSize(25 * MEBIBYTE, 3)).toBe(10 * MEBIBYTE)
    expect(resolveUploadChunkSize(25 * MEBIBYTE, 2)).toBe(20 * MEBIBYTE)
  })

  test('rejects a tiny declared file spread across many disk-writing chunks', () => {
    expect(resolveUploadChunkSize(1, 1024)).toBeNull()
    expect(resolveUploadChunkSize(1, 1024, 1)).toBeNull()
  })
})