usePackage.ts

/** Number of recent versions to include in initial payload */
const RECENT_VERSIONS_COUNT = 5

function hasAttestations(version: PackumentVersion): boolean {
  return Boolean(version.dist.attestations)
}

function hasTrustedPublisher(version: PackumentVersion): boolean {
  return Boolean(version._npmUser?.trustedPublisher)
}

function getTrustLevel(version: PackumentVersion): PublishTrustLevel {
  // trusted publishing automatically generates provenance attestations
  if (hasTrustedPublisher(version)) return 'trustedPublisher'
  if (hasAttestations(version)) return 'provenance'
  return 'none'
}

/**
 * Transform a full Packument into a slimmed version for client-side use.
 * Reduces payload size by:
 * - Removing readme (fetched separately)
 * - Including only: 5 most recent versions + one version per dist-tag + requested version
 * - Stripping unnecessary fields from version objects
 */
export function transformPackument(
  pkg: Packument,
  requestedVersion?: string | null,
): SlimPackument {
  // Get versions pointed to by dist-tags
  const distTagVersions = new Set(Object.values(pkg['dist-tags'] ?? {}))

  // Get 5 most recent versions by publish time
  const recentVersions = Object.keys(pkg.versions)
    .filter(v => pkg.time[v])
    .sort((a, b) => {
      const timeA = pkg.time[a]
      const timeB = pkg.time[b]
      if (!timeA || !timeB) return 0
      return Date.parse(timeB) - Date.parse(timeA)
    })
    .slice(0, RECENT_VERSIONS_COUNT)

  // Combine: recent versions + dist-tag versions + requested version (deduplicated)
  const includedVersions = new Set([...recentVersions, ...distTagVersions])

  // Add the requested version if it exists in the package
  if (requestedVersion && pkg.versions[requestedVersion]) {
    includedVersions.add(requestedVersion)
  }

  // Build security metadata for all versions, but only include in payload
  // when the package has mixed trust levels (i.e. a downgrade could exist)
  const securityVersionEntries = Object.entries(pkg.versions).map(([version, metadata]) => {
    const trustLevel = getTrustLevel(metadata)
    return {
      version,
      time: pkg.time[version],
      hasProvenance: trustLevel !== 'none',
      trustLevel,
      deprecated: metadata.deprecated,
    }
  })

  const trustLevels = new Set(securityVersionEntries.map(v => v.trustLevel))
  const hasMixedTrust = trustLevels.size > 1
  const securityVersions = hasMixedTrust ? securityVersionEntries : undefined

  // Build filtered versions object with install scripts info per version
  const filteredVersions: Record<string, SlimVersion> = {}
  let versionData: SlimPackumentVersion | null = null
  for (const v of includedVersions) {
    const version = pkg.versions[v]
    if (version) {
      if (version.version === requestedVersion) {
        // Strip readme from each version, extract install scripts info
        const { readme: _readme, scripts, ...slimVersion } = version

        // Extract install scripts info (which scripts exist + npx deps)
        const installScripts = scripts ? extractInstallScriptsInfo(scripts) : null
        versionData = {
          ...slimVersion,
          installScripts: installScripts ?? undefined,
        }
      }
      const trustLevel = getTrustLevel(version)
      const hasProvenance = trustLevel !== 'none'

      // Normalize license: some versions use { type: "MIT" } instead of "MIT"
      let versionLicense = version.license
      if (versionLicense && typeof versionLicense === 'object' && 'type' in versionLicense) {
        versionLicense = (versionLicense as { type: string }).type
      }

      filteredVersions[v] = {
        hasProvenance,
        trustLevel,
        version: version.version,
        deprecated: version.deprecated,
        tags: version.tags as string[],
        license: typeof versionLicense === 'string' ? versionLicense : undefined,
        type: typeof version.type === 'string' ? version.type : undefined,
      }
    }
  }

  // Build filtered time object (only for included versions + metadata)
  const filteredTime: Record<string, string> = {}
  if (pkg.time.modified) filteredTime.modified = pkg.time.modified
  if (pkg.time.created) filteredTime.created = pkg.time.created
  for (const v of includedVersions) {
    if (pkg.time[v]) filteredTime[v] = pkg.time[v]
  }

  // Normalize license field
  let license = pkg.license
  if (license && typeof license === 'object' && 'type' in license) {
    license = license.type
  }

  // Extract storybook field from the requested version (custom package.json field)
  const requestedPkgVersion = requestedVersion ? pkg.versions[requestedVersion] : null
  const rawStorybook = requestedPkgVersion?.storybook
  const storybook =
    rawStorybook && typeof rawStorybook === 'object' && 'url' in rawStorybook
      ? ({ url: rawStorybook.url } as { url: string })
      : undefined

  return {
    '_id': pkg._id,
    '_rev': pkg._rev,
    'name': pkg.name,
    'description': pkg.description,
    'dist-tags': pkg['dist-tags'],
    'time': filteredTime,
    'maintainers': pkg.maintainers,
    'author': pkg.author,
    'license': license,
    'homepage': pkg.homepage,
    'keywords': pkg.keywords,
    'repository': pkg.repository,
    'bugs': pkg.bugs,
    ...(storybook && { storybook }),
    'requestedVersion': versionData,
    'versions': filteredVersions,
    'securityVersions': securityVersions,
  }
}

export function usePackage(
  name: MaybeRefOrGetter<string>,
  requestedVersion?: MaybeRefOrGetter<string | null>,
) {
  const asyncData = useLazyAsyncData(
    () => `package:${toValue(name)}:${toValue(requestedVersion) ?? ''}`,
    async ({ $npmRegistry }, { signal }) => {
      const encodedName = encodePackageName(toValue(name))
      const { data: r, isStale } = await $npmRegistry<Packument>(`/${encodedName}`, {
        signal,
      })
      const reqVer = toValue(requestedVersion)
      const pkg = transformPackument(r, reqVer)
      return { ...pkg, isStale }
    },
  )

  if (import.meta.client && asyncData.data.value?.isStale) {
    onMounted(() => {
      asyncData.refresh()
    })
  }

  return asyncData
}