/** @jest-environment node */

import path from 'path'
import { promises as fs } from 'fs'
import sharp from 'sharp'
import {
  buildWhiteBackgroundWebpVariants,
  resolveWhiteBackgroundPreviewFileUrl,
  WHITE_BACKGROUND_PREVIEW_MAX_DIMENSION,
} from '@/lib/white-background-preview'

describe('white-background-preview helpers', () => {
  const tempRoot = path.join(process.cwd(), 'uploads', '__white-background-preview-tests__')
  const originalEnv = { ...process.env }

  beforeEach(() => {
    process.env.S3_PUBLIC_DOMAIN = 'https://s3.jiansun.vip/gongxiangpan'
  })

  afterEach(async () => {
    process.env = { ...originalEnv }
    await fs.rm(tempRoot, { recursive: true, force: true })
  })

  test('builds original and preview webp variants for large transparent images', async () => {
    const source = await sharp({
      create: {
        width: 2200,
        height: 1100,
        channels: 4,
        background: { r: 255, g: 255, b: 255, alpha: 0 },
      },
    })
      .png()
      .toBuffer()

    const { original, preview } = await buildWhiteBackgroundWebpVariants(source)
    const originalMetadata = await sharp(original).metadata()
    const previewMetadata = await sharp(preview).metadata()

    expect(originalMetadata.format).toBe('webp')
    expect(originalMetadata.width).toBe(2200)
    expect(originalMetadata.height).toBe(1100)
    expect(previewMetadata.format).toBe('webp')
    expect(previewMetadata.width).toBe(WHITE_BACKGROUND_PREVIEW_MAX_DIMENSION)
    expect(previewMetadata.height).toBe(750)
    expect(original.length).toBeGreaterThan(preview.length)
  })

  test('preview variant does not enlarge small images', async () => {
    const source = await sharp({
      create: {
        width: 400,
        height: 300,
        channels: 4,
        background: { r: 255, g: 255, b: 255, alpha: 0 },
      },
    })
      .png()
      .toBuffer()

    const { preview } = await buildWhiteBackgroundWebpVariants(source)
    const previewMetadata = await sharp(preview).metadata()

    expect(previewMetadata.width).toBe(400)
    expect(previewMetadata.height).toBe(300)
  })

  test('优先使用本地 preview 文件，否则回退到 public-display 链接', async () => {
    const originalAbsolutePath = path.join(
      tempRoot,
      'material-1',
      'white-background',
      'sku-1',
      'front.webp',
    )
    const previewAbsolutePath = path.join(
      tempRoot,
      'material-1',
      'white-background',
      'sku-1',
      'preview',
      'front.webp',
    )
    const originalRelativePath = path.relative(process.cwd(), originalAbsolutePath).replace(/\\/g, '/')
    const previewRelativePath = path.relative(process.cwd(), previewAbsolutePath).replace(/\\/g, '/')

    await fs.mkdir(path.dirname(originalAbsolutePath), { recursive: true })
    await fs.writeFile(originalAbsolutePath, Buffer.from('original'))

    expect(resolveWhiteBackgroundPreviewFileUrl(originalRelativePath)).toBe(
      'https://s3.jiansun.vip/gongxiangpan/public-display/white-background/material-1/sku-1/front.webp',
    )

    await fs.mkdir(path.dirname(previewAbsolutePath), { recursive: true })
    await fs.writeFile(previewAbsolutePath, Buffer.from('preview'))

    expect(resolveWhiteBackgroundPreviewFileUrl(originalRelativePath)).toBe(`/${previewRelativePath}`)
  })
})