Added GamePhase api

src/main/kotlin/net/axay/kspigot/game/GamePhases.kt

@@ -0,0 +1,53 @@
+@file:Suppress("MemberVisibilityCanBePrivate")
+
+package net.axay.kspigot.game
+
+import net.axay.kspigot.extensions.broadcast
+import net.axay.kspigot.main.KSpigot
+import net.axay.kspigot.runnables.task
+
+class GamePhaseSystem(vararg gamePhases: GamePhase) {
+    val gamePhases = gamePhases.toMutableList()
+    fun begin(kSpigot: KSpigot) = gamePhases.removeAt(0).startIt(kSpigot, gamePhases)
+}
+
+fun counterMessage(prefix: String? = null, beginning: String, seconds: String, second: String): (Long) -> String = {
+    val realPrefix = prefix?.plus(" ") ?: ""
+    if (it <= 1L) "$realPrefix$beginning $it $second" else "$prefix $beginning $it $seconds"
+}
+
+class GamePhase(
+        val length: Long,
+        val start: (() -> Unit)?,
+        val end: (() -> Unit)?,
+        val counterMessage: ((secondsLeft: Long) -> String)?
+) {
+    fun startIt(kSpigot: KSpigot, phaseQueue: MutableList<GamePhase>) {
+        start?.invoke()
+        kSpigot.task(
+                period = 20,
+                howOften = length / 20,
+                endCallback = {
+
+                    end?.invoke()
+
+                    if (phaseQueue.isNotEmpty())
+                        phaseQueue.removeAt(0).startIt(kSpigot, phaseQueue)
+
+                }
+        ) {
+
+            if (counterMessage != null) {
+                val currentCounter = it.counterDown
+                if (currentCounter?.isCounterValue == true)
+                    broadcast(counterMessage.invoke(currentCounter))
+            }
+
+        }
+    }
+}
+
+private val Long.isCounterValue: Boolean get() = when (this) {
+    1L, 2L, 3L, 4L, 5L, 10L, 15L, 20L, 30L -> true
+    else -> this % 60 == 0L
+}