package advent

class Day6 {

    open class Planet(
        val name : String,
        val orbits : String?
    ) {
        override fun equals(other : Any?) : Boolean {
            if (this === other) return true
            if (other !is Planet) return false
            if (name != other.name) return false
            return true
        }
        override fun hashCode() = name.hashCode()
        override fun toString() = name
    }

    class CenterOfMass : Planet("COM", null)

    companion object {

        fun getInput() : MutableMap<String, Planet> {
            val planets = mutableMapOf<String, Planet>()
            CenterOfMass().also { planets[it.name] = it }
            javaClass
                .getResource("/Day6Input")
                .readText()
                .lines()
                .forEach {
                    val parts = it.split(")")
                    val planetName = parts[1]
                    val orbits = parts[0]
                    if (!planets.containsKey(planetName)) {
                        planets[planetName] = Planet(planetName, orbits)
                    }
                }
            return planets
        }

        fun getPathToCOM(planets : Map<String, Planet>, planet : Planet) : List<Planet> {
            val path = mutableListOf<Planet>()
            var scannedPlanet : Planet? = planet
            while (scannedPlanet != null && scannedPlanet !is CenterOfMass) {
                scannedPlanet = planets[scannedPlanet.orbits]
                path.add(scannedPlanet ?: planets["COM"]!!)
            }
            return path
        }

        fun part1() {
            val planets = getInput()
            var orbits = 0
            for ((_, planet) in planets) {
                orbits += getPathToCOM(planets, planet).size
            }
            println(orbits)
        }

        fun part2() {
            val planets = getInput()
            val yourPath = getPathToCOM(planets, planets["YOU"]!!).reversed()
            val santasPath = getPathToCOM(planets, planets["SAN"]!!).reversed()
            for (i in yourPath.indices) {
                if (yourPath[i] != santasPath[i]) {
                    val hops = (yourPath.size - i) + (santasPath.size - i)
                    println(hops)
                    return
                }
            }
            println("Path not found")
        }

        @JvmStatic
        fun main(args : Array<String>) {
            part1()
            part2()
        }

    }

}