[WIP] initial Fabric port

major package refactoring

src/main/kotlin/mods/betterfoliage/util/Collections.kt

@@ -0,0 +1,63 @@
+package mods.betterfoliage.util
+
+import java.util.*
+
+/**
+ * Starting with the second element of this [Iterable] until the last, call the supplied lambda with
+ * the parameters (index, element, previous element).
+ */
+inline fun <reified T> Iterable<T>.forEachPairIndexed(func: (Int, T, T)->Unit) {
+    var previous: T? = null
+    forEachIndexed { idx, current ->
+        if (previous != null) func(idx, current, previous!!)
+        previous = current
+    }
+}
+
+inline fun <T, C: Comparable<C>> Pair<T, T>.minBy(func: (T)->C) =
+    if (func(first) < func(second)) first else second
+
+inline fun <T, C: Comparable<C>> Pair<T, T>.maxBy(func: (T)->C) =
+    if (func(first) > func(second)) first else second
+
+inline fun <T, C: Comparable<C>> Triple<T, T, T>.maxValueBy(func: (T)->C): C {
+    var result = func(first)
+    func(second).let { if (it > result) result = it }
+    func(third).let { if (it > result) result = it }
+    return result
+}
+
+@Suppress("UNCHECKED_CAST")
+inline fun <K, V> Map<K, V?>.filterValuesNotNull() = filterValues { it != null } as Map<K, V>
+
+inline fun <reified T, R> Iterable<T>.findFirst(func: (T)->R?): R? {
+    forEach { func(it)?.let { return it } }
+    return null
+}
+
+inline fun <A1, reified A2, B> List<Pair<A1, B>>.filterIsInstanceFirst(cls: Class<A2>) = filter { it.first is A2 } as List<Pair<A2, B>>
+
+/** Cross product of this [Iterable] with the parameter. */
+fun <A, B> Iterable<A>.cross(other: Iterable<B>) = flatMap { a -> other.map { b -> a to b } }
+
+inline fun <C, R, T> Iterable<T>.mapAs(transform: (C) -> R) = map { transform(it as C) }
+
+inline fun <T1, T2> forEachNested(list1: Iterable<T1>, list2: Iterable<T2>, func: (T1, T2)-> Unit) =
+    list1.forEach { e1 ->
+        list2.forEach { e2 ->
+            func(e1, e2)
+        }
+    }
+
+/** Mutating version of _map_. Replace each element of the list with the result of the given transformation. */
+inline fun <reified T> MutableList<T>.replace(transform: (T) -> T) = forEachIndexed { idx, value -> this[idx] = transform(value) }
+
+/** Exchange the two elements of the list with the given indices */
+inline fun <T> MutableList<T>.exchange(idx1: Int, idx2: Int) {
+    val e = this[idx1]
+    this[idx1] = this[idx2]
+    this[idx2] = e
+}
+
+/** Return a random element from the array using the provided random generator */
+inline operator fun <T> Array<T>.get(random: Random) = get(random.nextInt(Int.MAX_VALUE) % size)