/** @jest-environment node */

import sharp from 'sharp'
import {
  assertBrandKnowledgePreviewMetadata,
  prepareBrandKnowledgePreview,
  validateBrandKnowledgeUploadedPreviewSlices,
} from '@/lib/brand-knowledge-preview'

describe('brand knowledge long preview processing', () => {
  test('keeps previews at or below 3000px as one image and slices above the boundary', async () => {
    const exactBoundary = await sharp({
      create: {
        width: 800,
        height: 3_000,
        channels: 3,
        background: { r: 238, g: 241, b: 244 },
      },
    }).png().toBuffer()
    const overBoundary = await sharp({
      create: {
        width: 800,
        height: 3_001,
        channels: 3,
        background: { r: 238, g: 241, b: 244 },
      },
    }).png().toBuffer()

    const exactResult = await prepareBrandKnowledgePreview(exactBoundary, 'image/png')
    const overResult = await prepareBrandKnowledgePreview(overBoundary, 'image/png')

    await expect(sharp(exactResult.slices[0]).metadata()).resolves.toMatchObject({
      format: 'webp', width: 800, height: 3_000,
    })
    expect(exactResult.slices).toHaveLength(1)
    expect(overResult.slices).toHaveLength(3)
  })

  test('still slices images above 3000px when width scaling makes the output shorter than 1500px', async () => {
    const wideOverBoundary = await sharp({
      create: {
        width: 4_000,
        height: 3_001,
        channels: 3,
        background: { r: 238, g: 241, b: 244 },
      },
    }).png().toBuffer()

    const result = await prepareBrandKnowledgePreview(wideOverBoundary, 'image/png')
    const metadata = await Promise.all(result.slices.map((slice) => sharp(slice).metadata()))

    expect(result.slices).toHaveLength(2)
    expect(metadata.map((item) => [item.width, item.height])).toEqual([
      [1_600, 600],
      [1_600, 600],
    ])
  })

  test('slices a long image into ordered WebP segments suitable for seamless rendering', async () => {
    const source = await sharp({
      create: {
        width: 800,
        height: 4_100,
        channels: 3,
        background: { r: 238, g: 241, b: 244 },
      },
    }).png().toBuffer()

    const result = await prepareBrandKnowledgePreview(source, 'image/png')
    const metadata = await Promise.all(result.slices.map((slice) => sharp(slice).metadata()))

    expect(result.source).toMatchObject({ contentType: 'image/png', width: 800, height: 4_100 })
    expect(result.slices).toHaveLength(3)
    expect(metadata.map((item) => item.height)).toEqual([1_500, 1_500, 1_100])
    expect(metadata.every((item) => item.format === 'webp' && item.width === 800)).toBe(true)
  })

  test('rejects MIME mismatches and animated previews', async () => {
    const png = await sharp({
      create: { width: 20, height: 20, channels: 3, background: '#fff' },
    }).png().toBuffer()
    await expect(prepareBrandKnowledgePreview(png, 'image/jpeg')).rejects.toThrow('内容与声明格式不一致')

    expect(() => assertBrandKnowledgePreviewMetadata({
      format: 'webp', width: 20, height: 40, pages: 2,
    }, 'image/webp')).toThrow('不支持动画或多页图片')
  })

  test('enforces the 60 million pixel and long-edge limits before slicing', () => {
    expect(() => assertBrandKnowledgePreviewMetadata({
      format: 'png', width: 10_000, height: 6_001, pages: 1,
    }, 'image/png')).toThrow('6000 万像素')
    expect(() => assertBrandKnowledgePreviewMetadata({
      format: 'webp', width: 800, height: 90_001, pages: 1,
    }, 'image/webp')).toThrow('尺寸过大')
  })

  test('validates ordered browser WebP slices before storage', async () => {
    const first = await sharp({
      create: { width: 1_600, height: 1_500, channels: 3, background: '#fff' },
    }).webp().toBuffer()
    const last = await sharp({
      create: { width: 1_600, height: 800, channels: 3, background: '#fff' },
    }).webp().toBuffer()

    const result = await validateBrandKnowledgeUploadedPreviewSlices([
      { buffer: first, declaredContentType: 'image/webp' },
      { buffer: last, declaredContentType: 'image/webp' },
    ])

    expect(result.slices.map((slice) => [slice.width, slice.height])).toEqual([
      [1_600, 1_500],
      [1_600, 800],
    ])
  })

  test('accepts one browser preview up to 3000px without treating it as a sliced image', async () => {
    const single = await sharp({
      create: { width: 1_000, height: 3_000, channels: 3, background: '#fff' },
    }).webp().toBuffer()

    const result = await validateBrandKnowledgeUploadedPreviewSlices([
      { buffer: single, declaredContentType: 'image/webp' },
    ])

    expect(result.slices.map((slice) => [slice.width, slice.height])).toEqual([[1_000, 3_000]])
  })

  test('accepts a short equal-height pair created after scaling a wide source image', async () => {
    const first = await sharp({
      create: { width: 1_600, height: 600, channels: 3, background: '#fff' },
    }).webp().toBuffer()
    const last = await sharp({
      create: { width: 1_600, height: 600, channels: 3, background: '#fff' },
    }).webp().toBuffer()

    const result = await validateBrandKnowledgeUploadedPreviewSlices([
      { buffer: first, declaredContentType: 'image/webp' },
      { buffer: last, declaredContentType: 'image/webp' },
    ])

    expect(result.slices.map((slice) => [slice.width, slice.height])).toEqual([
      [1_600, 600],
      [1_600, 600],
    ])
  })

  test('rejects forged or geometrically inconsistent browser slices', async () => {
    await expect(validateBrandKnowledgeUploadedPreviewSlices([
      { buffer: Buffer.from('not a webp'), declaredContentType: 'image/webp' },
    ])).rejects.toThrow('无法解码')

    const shortFirst = await sharp({
      create: { width: 1_600, height: 1_000, channels: 3, background: '#fff' },
    }).webp().toBuffer()
    const last = await sharp({
      create: { width: 1_600, height: 800, channels: 3, background: '#fff' },
    }).webp().toBuffer()
    await expect(validateBrandKnowledgeUploadedPreviewSlices([
      { buffer: shortFirst, declaredContentType: 'image/webp' },
      { buffer: last, declaredContentType: 'image/webp' },
    ])).rejects.toThrow('切片高度不一致')

    await expect(validateBrandKnowledgeUploadedPreviewSlices([
      { buffer: shortFirst, declaredContentType: 'image/webp' },
      { buffer: shortFirst, declaredContentType: 'image/webp' },
    ])).rejects.toThrow('切片高度不一致')
  })
})