reorganize engine bits into engine package, same with commands, reimplement player state as FSM

src/main/java/gg/malloc/defense/engine/PlayerManager.java

@@ -0,0 +1,113 @@
+package gg.malloc.defense.engine;
+
+import org.bukkit.entity.Player;
+import org.bukkit.Bukkit;
+import org.bukkit.GameMode;
+import org.bukkit.attribute.Attribute;
+import org.bukkit.event.player.PlayerTeleportEvent;
+
+import java.util.HashMap;
+import java.util.Collection;
+
+public class PlayerManager {
+  HashMap<Player, State> m_playerStates = new HashMap<>();
+
+  public enum State {
+    Idle,
+    Playing,
+    Dead
+  }
+
+  public boolean requestTransitionForAll(State toState) {
+    boolean allSuccess = true;
+    for (Player p : getPlayers()) {
+      allSuccess = allSuccess && requestTransition(p, toState);
+    }
+    return allSuccess;
+  }
+
+  public boolean requestTransition(Player player, State toState) {
+    State currentState = m_playerStates.get(player);
+    if (currentState == toState) {
+      return false;
+    }
+    boolean ret = false;
+    switch(toState) {
+      case Idle:
+        ret = enterIdle(player);break;
+      case Playing:
+        ret = enterPlaying(player);break;
+      case Dead:
+        ret = enterDead(player);break;
+    }
+    if (ret) {
+      m_playerStates.put(player, toState);
+    }
+    return ret;
+  }
+
+  public boolean enterIdle(Player player) {
+    // Reset player to non-game state, return control back to Minecraft
+    player.setGameMode(Bukkit.getDefaultGameMode());
+    return true;
+  }
+
+  // Respawn player
+  public boolean enterPlaying(Player player) {
+    //m_log.fine("Respawning player " + player);
+    player.setGameMode(Bukkit.getDefaultGameMode());
+    player.setHealth(player.getAttribute(Attribute.GENERIC_MAX_HEALTH).getValue());
+    player.setFoodLevel(10);
+    return true;
+  }
+
+  public boolean enterDead(Player player) {
+    //m_log.info("Player has died in game" + player);
+    player.setGameMode(GameMode.SPECTATOR);
+    return true;
+  }
+
+  public void addPlayer(Player player) {
+    //m_log.info("Adding player " + player); 
+    m_playerStates.put(player, State.Idle);
+  }
+
+  public boolean removePlayer(Player player) {
+    //m_log.info("Removing player " + player); 
+    requestTransition(player, State.Idle);
+    m_playerStates.remove(player);
+    return true;
+  }
+
+  public boolean isEmpty() {
+    return m_playerStates.size() == 0;
+  }
+
+  public boolean isAlive(Player player) {
+    return m_playerStates.get(player) == State.Playing;
+  }
+
+  public boolean isAnyoneAlive() {
+    for(Player p : m_playerStates.keySet()) {
+      if (m_playerStates.get(p) == State.Playing) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  public int remainingPlayers() {
+    int aliveCount = 0;
+    for(State s : m_playerStates.values()) {
+      if (s == State.Playing) {
+        aliveCount += 1;
+      }
+    }
+    return aliveCount;
+  }
+
+  Collection<Player> getPlayers() {
+    return m_playerStates.keySet();
+  }
+}
+