Coverage Summary for Class: RateCategory (day19p1)

 package day19p1
 
 fun String.sumOfRatingsOfSortedParts(): Long {
   val (workflows, parts) = toWorkflowsAndParts()
   return parts.asSequence()
     .map { it to workflows.sortPart(it) }
     .filter { it.second == Workflow.A }
     .sumOf { it.first.total }
 }
 
 fun String.toWorkflowsAndParts(): Pair<Workflows, List<Part>> {
   val (workflows, parts) = split("\n\n")
   return workflows.toWorkflows() to parts.toParts()
 }
 
 fun String.toWorkflows(): Workflows = Workflows(lineSequence().map { it.toWorkflow() }.associateBy { it.name })
 
 data class Workflows(val workflows: Map<WorkflowName, Workflow>) {
   private val start = workflows.getValue(WorkflowName("in"))
   fun sortPart(part: Part): EndState {
     var current = start
     while (true) {
       val outcome = current.sortPart(part)
       if (outcome is EndState) return outcome
       require(outcome is WorkflowName)
       current = workflows.getValue(outcome)
     }
   }
 }
 
 private val workflowRegex = """(\w+)\{(.+)}""".toRegex()
 fun String.toWorkflow(): RuleBasedWorkflow = workflowRegex.matchEntire(this)!!.destructured.let { (name, rules) ->
   RuleBasedWorkflow(
     WorkflowName(name),
     rules.split(',').map { it.toRule() }
   )
 }
 
 private val ruleRegex = """([xmas])([><])(\d+):(\w+)""".toRegex()
 fun String.toRule(): Rule = when (this) {
   "A" -> Workflow.A
   "R" -> Workflow.R
   else -> {
     ruleRegex.matchEntire(this)?.destructured?.let { (cat, op, limit, next) ->
       Rule.IntervalRule(
         cat.toRateCategory(),
         when (op) {
           ">" -> limit.toInt() + 1..MAX_RATING_VALUE
           else -> {
             require(op == "<")
             1..<limit.toInt()
           }
         },
         next.toRuleOutcome()
       )
     } ?: this.toRuleOutcome()
   }
 }
 
 private fun String.toRateCategory(): RateCategory = when (this) {
   "x" -> RateCategory.X
   "m" -> RateCategory.M
   "a" -> RateCategory.A
   else -> {
     require(this == "s")
     RateCategory.S
   }
 }
 
 sealed interface Workflow {
   fun sortPart(part: Part): RuleOutcome
 
   data object A : Workflow, Rule, RuleOutcome, EndState {
     override fun sortPart(part: Part): RuleOutcome = this
   }
 
   data object R : Workflow, Rule, RuleOutcome, EndState {
     override fun sortPart(part: Part): RuleOutcome = this
   }
 }
 
 data class RuleBasedWorkflow(val name: WorkflowName, val rules: List<Rule>) : Workflow {
   override fun sortPart(part: Part): RuleOutcome = rules.asSequence().mapNotNull { it.sortPart(part) }.first()
 }
 
 sealed interface RuleOutcome : Rule
 
 sealed interface EndState : RuleOutcome
 
 sealed interface Rule {
   fun sortPart(part: Part): RuleOutcome?
 
   data class IntervalRule(val category: RateCategory, val range: IntRange, val next: RuleOutcome) : Rule {
     override fun sortPart(part: Part): RuleOutcome? = if (range.contains(category(part).value)) next else null
   }
 
   companion object {
     fun xGt(limit: Int, next: String): Rule =
       IntervalRule(RateCategory.X, limit + 1..MAX_RATING_VALUE, next.toRuleOutcome())
 
     fun mLt(limit: Int, next: String): Rule = IntervalRule(RateCategory.M, 1..<limit, next.toRuleOutcome())
 
     fun aGt(limit: Int, next: String): Rule =
       IntervalRule(RateCategory.A, limit + 1..MAX_RATING_VALUE, next.toRuleOutcome())
 
     fun aLt(limit: Int, next: String): Rule =
       IntervalRule(RateCategory.A, 1..<limit, next.toRuleOutcome())
 
     fun mGt(limit: Int, next: String): Rule =
       IntervalRule(RateCategory.M, limit + 1..MAX_RATING_VALUE, next.toRuleOutcome())
   }
 }
 
 private fun String.toRuleOutcome(): RuleOutcome = when (this) {
   "A" -> Workflow.A
   "R" -> Workflow.R
   else -> WorkflowName(this)
 }
 
 data class WorkflowName(val name: String) : Rule, RuleOutcome {
   override fun sortPart(part: Part): RuleOutcome = this
 }
 
 enum class RateCategory {
   X {
     override fun invoke(part: Part) = part.x
   },
   M {
     override fun invoke(part: Part) = part.m
   },
   A {
     override fun invoke(part: Part) = part.a
   },
   S {
     override fun invoke(part: Part) = part.s
   };
 
   abstract operator fun invoke(part: Part): Rating
 }
 
 fun List<Part>.sumOfRatings(): Long = sumOf { it.total }
 
 fun String.toParts(): List<Part> = lines().map { it.toPart() }
 
 val partRegex = """\{x=(\d+),m=(\d+),a=(\d+),s=(\d+)}""".toRegex()
 
 fun String.toPart(): Part {
   val (x, m, a, s) = partRegex.find(this)!!.destructured
   return Part(x.toInt(), m.toInt(), a.toInt(), s.toInt())
 }
 
 const val MAX_RATING_VALUE = 9999
 
 data class Rating(val value: Int) {
   init {
     require(value in 1..MAX_RATING_VALUE)
   }
 
   operator fun plus(other: Rating): Long = this.value.toLong() + other.value
 }
 
 data class Part(val x: Rating, val m: Rating, val a: Rating, val s: Rating) {
   constructor(x: Int, m: Int, a: Int, s: Int) : this(Rating(x), Rating(m), Rating(a), Rating(s))
 
   val total = x + m + a + s
 }
 
 private operator fun Long.plus(rating: Rating): Long = this + rating.value