import { mkdir, readFile, stat, writeFile } from 'node:fs/promises'
import path from 'node:path'

const PRESETS_FILE = path.join(process.cwd(), 'src/lib/3d/material-pbr-presets.ts')
const OUTPUT_ROOT = path.join(process.cwd(), 'public/materials/pbr/polyhaven')
const URL_PATTERN = /https:\/\/(?:dl\.polyhaven\.org|polyhaven\.com|cdn\.polyhaven\.com)\/[^\s'"]+/g

function toLocalFilePath(remoteUrl: string): string | null {
  try {
    const parsed = new URL(remoteUrl)
    const segments = parsed.pathname.split('/').filter(Boolean)
    const fileName = segments.at(-1)
    if (!fileName) return null
    const assetName = segments.at(-2) || 'misc'
    return path.join(OUTPUT_ROOT, assetName, fileName)
  } catch {
    return null
  }
}

async function exists(filePath: string): Promise<boolean> {
  try {
    await stat(filePath)
    return true
  } catch {
    return false
  }
}

async function downloadTexture(remoteUrl: string, localFilePath: string): Promise<void> {
  const response = await fetch(remoteUrl)
  if (!response.ok) {
    throw new Error(`下载失败 ${response.status}: ${remoteUrl}`)
  }
  const buffer = Buffer.from(await response.arrayBuffer())
  await mkdir(path.dirname(localFilePath), { recursive: true })
  await writeFile(localFilePath, buffer)
}

async function main() {
  const source = await readFile(PRESETS_FILE, 'utf8')
  const matches = source.match(URL_PATTERN) || []
  const remoteUrls = Array.from(new Set(matches))

  if (remoteUrls.length === 0) {
    console.log('未发现需要同步的远程贴图 URL。')
    return
  }

  let downloaded = 0
  let skipped = 0
  let failed = 0

  for (const remoteUrl of remoteUrls) {
    const localFilePath = toLocalFilePath(remoteUrl)
    if (!localFilePath) {
      failed += 1
      console.warn(`无法解析路径: ${remoteUrl}`)
      continue
    }

    if (await exists(localFilePath)) {
      skipped += 1
      continue
    }

    try {
      await downloadTexture(remoteUrl, localFilePath)
      downloaded += 1
      console.log(`已下载: ${path.relative(process.cwd(), localFilePath)}`)
    } catch (error) {
      failed += 1
      console.warn(`下载失败: ${remoteUrl}`)
      console.warn(error)
    }
  }

  console.log(`同步完成：下载 ${downloaded}，跳过 ${skipped}，失败 ${failed}`)
}

main().catch((error) => {
  console.error('贴图同步脚本执行失败', error)
  process.exit(1)
})