signature FILE_THREAD =
sig
  val run: FileMessage.t Mailbox.mbox * InputMessage.t Mailbox.mbox -> unit
end

structure FileThread :> FILE_THREAD =
struct
  open FileMessage
  open InputMessage

  datatype parse_result = OK of unit | PARSE_ERROR

  val structureName = "Green"
  val filename = "green.dsc"
  val exportFilename = "green.sml"

  fun ndcToLerpX num =
    let
      val num = (num + 1.0) / 2.0
      val num = Real32.toString num
      val num =
        (* Problem: It seems that Real32.toString may sometimes return a string
         * that is recognised as an integer, like "1" instead of "1.0".
         * If that happens, we just add a ".0" to the end 
         * so it's recognised as a real. *)
        if String.isSubstring "." num then num
        else num ^ ".0"
    in
      "      (((startX * (1.0 - " ^ num ^ ")) + (endX * " ^ num
      ^ ")) / windowWidth) - 1.0"
    end

  fun ndcToLerpY num =
    let
      val num = (num + 1.0) / 2.0
      val num = Real32.toString num
      val num = if String.isSubstring "." num then num else num ^ ".0"
    in
      "      (((startY * (1.0 - " ^ num ^ ")) + (endY * " ^ num
      ^ ")) / windowHeight) - 1.0"
    end

  fun colToString col =
    let val col = Real32.toString col
    in if String.isSubstring "." col then col else col ^ ".0"
    end

  fun exportSquares squares = ()

  fun parse (io, acc) = ()

  fun loadSquares (path, inputMailbox) = ()

  fun saveSquares squares = ()

  fun getDirList (dir, acc, rootPath) =
    case OS.FileSys.readDir dir of
      SOME path =>
        let
          val folderPath = String.concat [rootPath, "/", path]
        in
          if OS.FileSys.isDir folderPath then
            getDirList (dir, AppType.IS_FOLDER path :: acc, rootPath)
          else if OS.FileSys.isLink folderPath then
            getDirList (dir, acc, rootPath)
          else
            getDirList (dir, AppType.IS_FILE path :: acc, rootPath)
        end
    | NONE => let val acc = List.rev acc in Vector.fromList acc end

  fun loadFiles (path, inputMailbox) =
    let
      val path = if String.size path = 0 then OS.FileSys.getDir () else path
      val dir = OS.FileSys.openDir path
      val dirList = getDirList (dir, [], path)
      val _ = OS.FileSys.closeDir dir
      val inputMsg = FILE_BROWSER_AND_PATH {fileBrowser = dirList, path = path}
    in
      Mailbox.send (inputMailbox, inputMsg)
    end

  fun selectPath (path, inputMailbox) =
    if OS.FileSys.isDir path then loadFiles (path, inputMailbox)
    else loadSquares (path, inputMailbox)

  fun run (fileMailbox, inputMailbox) =
    let
      val _ =
        case Mailbox.recv fileMailbox of
          SAVE_SQUARES triangles => saveSquares triangles
        | LOAD_SQUARES => loadSquares (filename, inputMailbox)
        | EXPORT_SQUARES triangles => exportSquares triangles
        | LOAD_FILES path => loadFiles (path, inputMailbox)
        | SELECT_PATH path => selectPath (path, inputMailbox)
    in
      run (fileMailbox, inputMailbox)
    end
end