Merge PR #120 by @Avalancs - cannot buy same ship.

Author: Cervator

README.markdown

@@ -32,7 +32,7 @@ You can destroy asteroids for easy money, even with the starting ship's ammo-les
 
 Warnings get posted if you get close to dangerous ships or may soon collide with something on your current course. Blue dots along the edge of the screen indicate a planet is nearby.
 
-Watch out about buying a new ship if you can only barely afford it - you might need to buy new compatible weaponry too! Also be careful not to actually re-buy the ship you're already in.
+Watch out about buying a new ship if you can only barely afford it - you might need to buy new compatible weaponry too!
 
 Mercenaries will follow you around and should start with a compatible weapon again in v1.4.1. They'll pick up items as well and keep them, greedy little buggers! But then they drop everything again on death, so ...
 

main/src/org/destinationsol/game/screens/ChangeShip.java

@@ -85,16 +85,46 @@ public void updateCustom(SolApplication cmp, SolInputManager.Ptr[] ptrs, boolean
       return;
     }
     SolItem selItem = is.getSelectedItem();
-    boolean enabled = selItem != null && hero.getMoney() >= selItem.getPrice();
-    myBuyCtrl.setDisplayName(enabled ? "Change" : "---");
-    myBuyCtrl.setEnabled(enabled);
-    if (!enabled) return;
+    if(selItem == null) {
+      myBuyCtrl.setDisplayName("---");
+      myBuyCtrl.setEnabled(false);
+      return;
+    }
+    boolean enabled = hasMoneyToBuyShip(hero, selItem);
+    boolean sameShip = isSameShip(hero, selItem);
+    if(enabled && !sameShip) {
+      myBuyCtrl.setDisplayName("Change");
+      myBuyCtrl.setEnabled(true);
+    } else if(enabled && sameShip) {
+      myBuyCtrl.setDisplayName("Have it");
+      myBuyCtrl.setEnabled(false);
+      return;
+    } else {
+      myBuyCtrl.setDisplayName("---");
+      myBuyCtrl.setEnabled(false);
+      return;
+    }
     if (myBuyCtrl.isJustOff()) {
       hero.setMoney(hero.getMoney() - selItem.getPrice());
       changeShip(game, hero, (ShipItem) selItem);
     }
   }
 
+  private boolean hasMoneyToBuyShip(SolShip hero, SolItem shipToBuy) {
+    return hero.getMoney() >= shipToBuy.getPrice();
+  }
+
+  private boolean isSameShip(SolShip hero, SolItem shipToBuy) {
+    if(shipToBuy instanceof ShipItem) {
+      ShipItem ship = (ShipItem) shipToBuy;
+      HullConfig config1 = ship.getConfig();
+      HullConfig config2 = hero.getHull().getHullConfig();
+      return config1.equals(config2);
+    } else {
+      throw new IllegalArgumentException("ChangeShip:isSameShip received " + shipToBuy.getClass() + " argument instead of ShipItem!");
+    }
+  }
+
   private void changeShip(SolGame game, SolShip hero, ShipItem selected) {
     HullConfig newConfig = selected.getConfig();
     Hull hull = hero.getHull();

main/src/org/destinationsol/game/ship/hulls/Hull.java

@@ -205,4 +205,8 @@ public Fixture getShieldFixture() {
   public float getMass() {
     return myMass;
   }
+
+  public HullConfig getHullConfig() {
+      return config;
+  }
 }