import { describe, it, expect } from 'vitest'
import { createRef } from 'react'
import { formulaConfig, formulaDownloadConfig } from './config'

describe('formulaConfig', () => {
  it('returns an empty series array', () => {
    const cfg = formulaConfig()
    expect(cfg.series).toEqual([])
  })
})

describe('formulaDownloadConfig', () => {
  it('returns a two-item download config (PNG + CSV)', () => {
    const refUI = createRef<HTMLDivElement>()
    const cfg = formulaDownloadConfig({ refUI })
    expect(cfg).toHaveLength(2)
  })

  it('CSV modifier maps numeric values out of data items', async () => {
    const refUI = createRef<HTMLDivElement>()
    const cfg = formulaDownloadConfig({ refUI })
    const csvItem = cfg[1]!
    // Spy-style: the underlying downloadToCSV.modifier is the only thing that
    // actually returns. We just confirm `modifier` runs without throwing for
    // both populated and empty inputs — that exercises the `?? []` branch.
    await expect(
      csvItem.modifier([{ value: 1 }, { value: 2 }]),
    ).resolves.not.toThrow()
    await expect(
      csvItem.modifier(
        undefined as unknown as Parameters<
          NonNullable<typeof csvItem.modifier>
        >[0],
      ),
    ).resolves.not.toThrow()
  })
})