/** @jest-environment node */

import { mkdir, mkdtemp, rm, symlink, writeFile } from 'fs/promises'
import os from 'os'
import path from 'path'

import {
  readBoundedRegularFile,
  readBoundedResponseBuffer,
} from '@/lib/bounded-file-reader'

describe('bounded-file-reader', () => {
  let root: string

  beforeEach(async () => {
    root = await mkdtemp(path.join(os.tmpdir(), 'bounded-file-reader-'))
  })

  afterEach(async () => {
    await rm(root, { recursive: true, force: true })
  })

  test('在分配 Buffer 前拒绝超限、申报不一致和符号链接文件', async () => {
    const filePath = path.join(root, 'source.bin')
    await writeFile(filePath, Buffer.from('12345'))

    await expect(readBoundedRegularFile(filePath, {
      maxBytes: 4,
      label: '测试文件',
    })).rejects.toThrow('超过 1MB 限制')

    await expect(readBoundedRegularFile(filePath, {
      maxBytes: 10,
      expectedBytes: 4,
      label: '测试文件',
    })).rejects.toThrow('实际大小与上传记录不一致')

    const symlinkTarget = path.join(root, 'source-link-target')
    const symlinkPath = path.join(root, 'source-link')
    await mkdir(symlinkTarget)
    await symlink(symlinkTarget, symlinkPath, process.platform === 'win32' ? 'junction' : 'dir')
    await expect(readBoundedRegularFile(symlinkPath, {
      maxBytes: 10,
      expectedBytes: 5,
      label: '测试文件',
    })).rejects.toThrow('不是可读取的普通文件')
  })

  test('普通文件仅在实际大小与申报一致时返回完整内容', async () => {
    const filePath = path.join(root, 'source.bin')
    await writeFile(filePath, Buffer.from('bounded'))

    await expect(readBoundedRegularFile(filePath, {
      maxBytes: 64,
      expectedBytes: 7,
      label: '测试文件',
    })).resolves.toEqual(Buffer.from('bounded'))
  })

  test('远程响应无 Content-Length 时仍按可信大小硬停，且不使用 arrayBuffer', async () => {
    const stream = new ReadableStream<Uint8Array>({
      start(controller) {
        controller.enqueue(new Uint8Array([1, 2]))
        controller.enqueue(new Uint8Array([3, 4]))
        controller.close()
      },
    })
    const response = new Response(stream)

    await expect(readBoundedResponseBuffer(response, {
      maxBytes: 4,
      expectedBytes: 3,
      label: '远程文件',
    })).rejects.toThrow('响应超过申报大小')
  })

  test('远程响应先校验 Content-Length，并按申报大小返回单个 Buffer', async () => {
    const response = new Response(Buffer.from('remote'), {
      headers: { 'Content-Length': '6' },
    })

    await expect(readBoundedResponseBuffer(response, {
      maxBytes: 10,
      expectedBytes: 6,
      label: '远程文件',
    })).resolves.toEqual(Buffer.from('remote'))

    const mismatched = new Response(Buffer.from('remote'), {
      headers: { 'Content-Length': '6' },
    })
    await expect(readBoundedResponseBuffer(mismatched, {
      maxBytes: 10,
      expectedBytes: 5,
      label: '远程文件',
    })).rejects.toThrow('响应大小与上传记录不一致')
  })
})