FileNameConsistent.scala

package fix

import fix.FileNameConsistent._
import scalafix.Diagnostic
import scalafix.Patch
import scalafix.lint.LintSeverity
import scalafix.v1.SyntacticDocument
import scalafix.v1.SyntacticRule
import scala.meta.Defn
import scala.meta.Pkg
import scala.meta.inputs.Input
import scala.meta.inputs.Position
import java.nio.file.Files
import java.nio.file.Paths

class FileNameConsistent extends SyntacticRule("FileNameConsistent") {
  override def isLinter = true

  override def fix(implicit doc: SyntacticDocument): Patch = {
    val defs = doc.tree
      .collect {
        case x: Defn.Trait if x.isTopLevel =>
          TemplateDef(x, x.name.value)
        case x: Defn.Class if x.isTopLevel =>
          TemplateDef(x, x.name.value)
        case x: Defn.Object if x.isTopLevel =>
          TemplateDef(x, x.name.value)
      }
    val scalaSourceOpt = PartialFunction
      .condOpt(doc.input) {
        case f: Input.File =>
          ScalaSource(
            fullPath = f.path.toString,
            name = f.path.toFile.getName.replace(".scala", "")
          )
        case f: Input.VirtualFile =>
          ScalaSource(
            fullPath = f.path,
            name = f.path.split('/').lastOption.getOrElse("").replace(".scala", "")
          )
      }

    scalaSourceOpt match {
      case Some(src) if defs.nonEmpty =>
        val names = defs.map(_.name).distinct
        if (names.contains(src.name)) {
          // correct
          Patch.empty
        } else if (src.name == "package") {
          // exclude `package.scala`
          Patch.empty
        } else {
          val classNameOpt = {
            names match {
              case List(x) =>
                Some(x)
              case _ =>
                // 2つ以上あると、どのclass名に合わせてファイル名を変更すればいいか決められないため、
                // 1つのときはそのまま強制書き換えし、
                // 2つ以上のときは `scala.io.StdIn.readInt` で選択させる
                println(
                  names.zipWithIndex
                    .map {
                      case (name, index) =>
                        s"${index} : $name"
                    }
                    .mkString(s"${src.fullPath}を、どれにrenameするか選択してください\n", "\n", "")
                )
                val input = scala.io.StdIn.readInt()
                val result = names.lift(input)
                if (result.isEmpty) {
                  println(s"invalid input ${input}")
                }
                result
            }
          }

          classNameOpt.foreach { className =>
            val separator = '/'
            val newName = className + ".scala"
            val newPath = src.fullPath.split(separator).init.mkString(separator.toString) + separator + newName
            Files.move(
              Paths.get(src.fullPath),
              Paths.get(newPath)
            )
          }
          Patch.lint(
            FileNameConsistentWaring(
              names = names,
              path = src.fullPath,
              position = defs.head.tree.pos
            )
          )
        }
      case _ =>
        // no classes, traits, objects ???
        Patch.empty
    }
  }
}

object FileNameConsistent {
  case class ScalaSource(fullPath: String, name: String)

  case class TemplateDef(tree: Defn, name: String)

  case class FileNameConsistentWaring(names: List[String], path: String, override val position: Position)
    extends Diagnostic {
    override def message: String = s"file名とclass名が一致しません names = ${names.mkString("[", ", ", "]")}"

    override def severity: LintSeverity = LintSeverity.Warning
  }

  implicit class DefnOps(private val self: Defn) extends AnyVal {
    def isTopLevel: Boolean =
      self.parent.exists(_.is[Pkg])
  }
}

run.sh

echo 'addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.9.24")' > project/scalafix.sbt

sbt "scalafixAll https://gist.githubusercontent.com/xuwei-k/ff0953aeb7624193f02ce26e517075c3/raw/d067a550133d9c34f1c173a82bd6b343f0899fce/FileNameConsistent.scala"

rm project/scalafix.sbt