Implement grouping, mapping, and sorting on Nodes
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package moe.kageru.spektacles
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import kotlin.collections.LinkedHashMap
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// maybe try this instead?
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// https://arrow-kt.io/docs/recursion/intro/
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sealed class Node<K, T : Any>(open val value: Any) {
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class Leaf<K, T : Any>(override val value: List<T>) : Node<K, T>(value)
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class Split<K, T : Any>(val children: Map<K, Node<K, T>>) : Node<K, T>(children)
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class Value<K, T : Any>(override val value: T) : Node<K, T>(value)
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fun <R : Any> map(op: (T) -> R): Node<K, R> {
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return when (this) {
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is Leaf -> Leaf(value.map(op))
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is Value -> Value(op(value))
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is Split -> Split(children.mapValues { it.value.map(op) })
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}
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}
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fun groupBy(keyGenerator: (T) -> K): Node<K, T> {
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return when (this) {
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is Leaf -> Split(value.groupBy(keyGenerator).mapValues { Leaf<K, T>(it.value) })
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is Value -> this
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is Split -> Split(children.mapValues { it.value.groupBy(keyGenerator) })
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}
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}
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override fun toString() = asString()
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private fun asString(depth: Int = 0): String {
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return when (this) {
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is Leaf -> value.joinToString(indent(depth), prefix = "\n${indent(depth)}")
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is Value -> value.toString()
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is Split -> children.entries.joinToString("") { "\n${indent(depth)}${it.key}: ${it.value.asString(depth + 1)}" }
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}
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}
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fun countLeafs(): Node<K, Int> {
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return when (this) {
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is Leaf -> Value(value.size)
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is Value -> Value(1)
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is Split -> Split(children.mapValues { it.value.countLeafs() })
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}
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}
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private fun indent(depth: Int) = (0..(depth * 2)).joinToString("") { " " }
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}
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fun <K> Node<K, Int>.sort(): Node<K, Int> {
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return when (this) {
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is Node.Leaf -> this
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is Node.Value -> this
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is Node.Split -> Node.Split(this.children.sortByValues().mapValues { it.value.sort() })
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}
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}
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private fun <K> Map<K, Node<K, Int>>.sortByValues(): Map<K, Node<K, Int>> {
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val sortedEntries = entries.sortedBy {
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when (val v = it.value) {
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is Node.Value -> v.value
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is Node.Leaf -> v.value.size
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is Node.Split -> Int.MAX_VALUE
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}
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}
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return LinkedHashMap<K, Node<K, Int>>().apply {
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for ((key, value) in sortedEntries) {
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this[key] = value
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}
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}
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}
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