sbt task to find class in classpath matching a specified name

FindClass.sbt

lazy val allClasses = taskKey[Stream[String]]("Classes in classpath")
lazy val findClass = inputKey[Stream[String]]("Find classes matching name")

findClass := {
  import complete.DefaultParsers._

  val any = ".*"
  val parts: Seq[String] = spaceDelimited("<arg>").parsed
  val caseSensitive: Boolean = parts.exists(_.matches(s"$any[A-Z]$any"))
  val regex: String = (if (caseSensitive) "" else "(?i)") +
    parts.mkString(any, any, any)

  val matches: Stream[String] = allClasses.value.filter(_.matches(regex))
  matches.foreach(println)
  matches
}

allClasses := {
  import java.io.File

  def isClass(path: String): Boolean =
    path.endsWith(".class") && !path.contains("$")

  fullClasspath.in(Compile).value.toStream.flatMap { attr =>
    val file: File = attr.data
    val filePath: String = file.getAbsolutePath

    def clean(path: String): String = path
      .replaceAll(s"^$filePath", "")
      .replaceAll(".class$", "")
      .replaceAll("^/", "")
      .replace("/", ".")

    def getClassFileNames(f: File): Iterable[String] = {
      if (f.isFile) {
        val path: String = f.getAbsolutePath

        if (isClass(path)) {
          Seq(clean(path))
        } else if (path.endsWith(".jar")) {
          // Could do this without an external command, but whatever
          s"jar tf ${f.getAbsolutePath}"
            .lines_!
            .withFilter(isClass)
            .map(clean)
        } else Seq.empty
      } else if (f.isDirectory) {
        f.listFiles.flatMap(getClassFileNames)
      } else {
        Seq.empty
      }
    }

    getClassFileNames(file)
  }
}