Logger with nested contexts

Logger.scala

// Author: github.com/loverdos
// SPDX-License-Identifier: Apache-2.0

import java.io.PrintStream

final class Logger(out: PrintStream = System.out) {
  private var ctx = List[String]()

  private val indent_chunk = "   "
  private def ctx_size = ctx.length

  private def get_log_prefix(
    indent: Int,
    is_context: Boolean,
    is_context_push: Boolean
  ): String = {
    val sb = new StringBuilder

    val indent_chunk_size: Int = indent_chunk.length
    val max_n = indent * indent_chunk_size
    for(n <- 0 to max_n) {
      val s: String =
        (n, is_context, is_context_push) match {
          case (n, true, true) if n == max_n => ">"
          case (n, true, true) if (n % indent_chunk_size) == 0 => "+"
          case (_, true, true) => "-"
          case (n, true, false) if n == max_n => "<"
          case (n, true, false) if (n % indent_chunk_size) == 0 => "+"
          case (_, true, false) => "-"
          case (n, false, _) if (n % indent_chunk_size) == 0 => "|"
          case (_, false, _)  => " "
        }
      sb.append(s)
    }

    sb.toString()
  }

  private def println_raw(s: String): Unit = out.println(s)

  def push_ctx(name: String, info: String = ""): Unit =  {
    ctx = name :: ctx
    val prefix = get_log_prefix(ctx_size, true, true)
    //val msg = prefix + " (" + name + ")"
    val msg = prefix + " " + name
    println_raw(msg)
    if(info.nonEmpty) {
      log(">> " + info)
    }
  }

  def pop_ctx(info: String = ""): Unit = {
    val name = ctx.head
    val prefix = get_log_prefix(ctx_size, true, false)
    //val msg = prefix + " (" + name + ")"
    val msg = prefix + " " + name
    if(info.nonEmpty) {
      log("<< " + info)
    }
    println_raw(msg)

    ctx = ctx.tail
  }

  def log(ss: String*): Unit = {
    val prefix = get_log_prefix(ctx_size, false, false)
    val s = ss.mkString("")

    println_raw(prefix + " " + s)
  }
}