export const PASCAL_HOST_USER_HEADER = 'x-pascal-user-id'

export interface PascalHostIdentity {
  allowed: boolean
  required: boolean
  userId: string | null
}

export function getPascalHostIdentity(
  headers: Headers,
  env: NodeJS.ProcessEnv = process.env,
): PascalHostIdentity {
  const required =
    env.PASCAL_REQUIRE_HOST_USER === 'true' ||
    (env.NODE_ENV === 'production' && env.PASCAL_REQUIRE_HOST_USER !== 'false')
  const supplied = headers.get(PASCAL_HOST_USER_HEADER)?.trim() ?? ''
  const userId = /^[a-zA-Z0-9_-]{1,128}$/.test(supplied) ? supplied : null

  return {
    allowed: Boolean(userId) || !required,
    required,
    userId,
  }
}