A parboiled2 parser for Discogs track positions

DiscogsTrackPositionParser.scala

package com.elsten.adb.extract.discogs.release

import org.parboiled2._

/*
 * Parses strings according to http://www.discogs.com/help/doc/submission-guidelines-release-trk#Position
 */
class DiscogsTrackPositionParser(val input: ParserInput, val isMultiDisc: Boolean = false, val isAutocoupled: Boolean = false) extends Parser {

  def mediumPrefixKnownFormat = rule { "DVD" | "CD" }
  def mediumPos = rule {
    optional(capture(mediumPrefixKnownFormat)) ~ capture(oneOrMore(CharPredicate.Digit)) ~> ((format, pos) => (format, Some(pos)))
  }
  def mediumPosMandatoryFormat = rule { capture(mediumPrefixKnownFormat) ~ capture(oneOrMore(CharPredicate.Digit)) ~> ((format, pos) => (format, pos)) }

  def subtrackDigit = rule { "." ~ capture(oneOrMore(CharPredicate.Digit)) }
  def subtrackAlpha = rule { optional(".") ~ capture(oneOrMore(CharPredicate.Alpha)) }
  def side = rule { CharPredicate.Alpha }
  def trackWithSubTrackPos = rule {
    capture(optional(side) ~ oneOrMore(CharPredicate.Digit)) ~ subtrackAlpha |
      capture(optional(side) ~ oneOrMore(CharPredicate.Digit)) ~ subtrackDigit |
      capture(oneOrMore(CharPredicate.Digit)) ~ subtrackAlpha
  }

  // a map of auto coupled sides to medium number
  // Commented out further discs. See Songs In The Key Of Life which has 3 media, but trying to auto couple them will give four media, 'E' -> 3, 'H' -> 3, 'F' -> 4, 'G' -> 4
  val autocoupledSeq = Map('A' -> 1, 'D' -> 1, 'B' -> 2, 'C' -> 2)
  def convertToMediumNumber(mediumChar: Char) = {
    def charCodeModulus = ((mediumChar.toUpper - 'A'.toInt) / 2) + 1
    isAutocoupled match {
      case true => autocoupledSeq.get(mediumChar.toUpper).getOrElse(charCodeModulus)
      case false => charCodeModulus
    }
  }

  def trackPosWithSide = rule {
    capture(side) ~ capture(oneOrMore(CharPredicate.Alpha)) ~> ((side, pos) => (convertToMediumNumber(side.head).toString, side + pos)) |
      capture(side) ~ capture(oneOrMore(CharPredicate.Digit)) ~> ((side, pos) => (convertToMediumNumber(side.head).toString, side + pos)) |
      capture(oneOrMore(CharPredicate.Alpha)) ~> ((pos) => (convertToMediumNumber(pos.head).toString, pos))
  }

  def trackPos = rule {
    capture(oneOrMore(CharPredicate.Digit)) |
      capture(oneOrMore(CharPredicate.Alpha))
  }

  def dotSeparator = rule { "." }
  def hyphenSeparator = rule { "-" }

  def mediumAndTrack = isMultiDisc match {
    case true =>
      rule {
        mediumPosMandatoryFormat ~ dotSeparator ~ trackWithSubTrackPos ~> ((mediumPos, trackPos, subTrack) => ParsedTrackPosition(Some(mediumPos._1), Some(mediumPos._2), Some(trackPos), Some(subTrack))) |
          mediumPosMandatoryFormat ~ dotSeparator ~ trackPos ~> ((mediumPos, trackPos) => ParsedTrackPosition(Some(mediumPos._1), Some(mediumPos._2), Some(trackPos), None)) |
          mediumPos ~ dotSeparator ~ trackPos ~> ((mediumPos, trackPos) => ParsedTrackPosition(mediumPos._1, mediumPos._2, Some(trackPos), None)) |
          mediumPos ~ hyphenSeparator ~ trackWithSubTrackPos ~> ((mediumPos, trackPos, subTrack) => ParsedTrackPosition(mediumPos._1, mediumPos._2, Some(trackPos), Some(subTrack))) |
          mediumPos ~ hyphenSeparator ~ trackPos ~> ((mediumPos, trackPos) => ParsedTrackPosition(mediumPos._1, mediumPos._2, Some(trackPos), None)) |
          trackWithSubTrackPos ~> ((trackPos, subTrack) => ParsedTrackPosition(None, None, Some(trackPos), Some(subTrack))) |
          trackPosWithSide ~> ((mediumAndTrackPos) => ParsedTrackPosition(None, Some(mediumAndTrackPos._1), Some(mediumAndTrackPos._2), None)) |
          trackPos ~> (trackPos => ParsedTrackPosition(None, None, Some(trackPos), None))
      }
    case false =>
      rule {
        mediumPosMandatoryFormat ~ dotSeparator ~ trackWithSubTrackPos ~> ((mediumPos, trackPos, subTrack) => ParsedTrackPosition(Some(mediumPos._1), Some(mediumPos._2), Some(trackPos), Some(subTrack))) |
          mediumPosMandatoryFormat ~ dotSeparator ~ trackPos ~> ((mediumPos, trackPos) => ParsedTrackPosition(Some(mediumPos._1), Some(mediumPos._2), Some(trackPos), None)) |
          mediumPos ~ hyphenSeparator ~ trackWithSubTrackPos ~> ((mediumPos, trackPos, subTrack) => ParsedTrackPosition(mediumPos._1, mediumPos._2, Some(trackPos), Some(subTrack))) |
          mediumPos ~ hyphenSeparator ~ trackPos ~> ((mediumPos, trackPos) => ParsedTrackPosition(mediumPos._1, mediumPos._2, Some(trackPos), None)) |
          trackWithSubTrackPos ~> ((trackPos, subTrack) => ParsedTrackPosition(None, None, Some(trackPos), Some(subTrack))) |
          trackPosWithSide ~> ((mediumAndTrackPos) => ParsedTrackPosition(None, Some(mediumAndTrackPos._1), Some(mediumAndTrackPos._2), None)) |
          trackPos ~> (trackPos => ParsedTrackPosition(None, None, Some(trackPos), None))
      }
  }
}

/**
 * The track position that was parsed. "format" is an optional format for the encompassing medium.
 */
case class ParsedTrackPosition(format: Option[String], mediumPosition: Option[String], trackPosition: Option[String], subTrack: Option[String])