import scala.io.Source

object Main extends App {

  val pattern = "XXYY"
  val pattern2 = "XYYX"

  val words = Source.fromFile("resources/words.txt").getLines.toList

  val patternWords = groupByPattern(pattern,words)
  val pattern2Words = groupByPattern(pattern2,words)


  println(patternWords.take(10))
  println(pattern2Words.take(10))

  def groupByPattern(pattern: String, words: List[String]): List[String] = {
    words.filter(filterPattern(pattern, _))
  }

  def filterPattern(pattern: String, word: String): Boolean = {
    matchPattern(pattern, pattern, word, word, breakDownPattern(pattern))
  }

  def matchPattern(pattern: String, remainingPattern: String, currentWord: String, matchingWord: String, brokenDownPattern: Map[String, String]): Boolean = {
    if (currentWord.length < pattern.length || matchingWord.isEmpty) false
    else {
      remainingPattern match {
        case "" => true
        case _ =>
          val updatedMap = updateMap(brokenDownPattern, remainingPattern, matchingWord)
          if (matchingWord.head.toString == updatedMap(remainingPattern.head.toString))
            matchPattern(pattern, remainingPattern.tail, currentWord, matchingWord.tail, updatedMap)
          else
            matchPattern(pattern, pattern, currentWord.tail, currentWord.tail, breakDownPattern(pattern))
      }
    }
  }

  def updateMap(brokenDownMap: Map[String, String], remainingPattern: String, matchingWord: String): Map[String, String] = {
    if (brokenDownMap(remainingPattern.head.toString) != "")
      brokenDownMap
    else
      brokenDownMap.updated(remainingPattern.head.toString, matchingWord.head.toString)
  }

  def breakDownPattern(pattern: String): Map[String, String] = {
    pattern.map(letter => (letter.toString, "")).toMap
  }
}