From cde2d368871646bb08934fd6b7f459c1b91d9016 Mon Sep 17 00:00:00 2001
From: pacien
Date: Sun, 4 Feb 2018 19:01:05 +0100
Subject: Implement garbage destruction on trash meeting

Signed-off-by: pacien <pacien.trangirard@pacien.net>
---
 .../java/fr/umlv/java/wallj/block/TrashBlock.java  | 47 ++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/src/main/java/fr/umlv/java/wallj/block/TrashBlock.java b/src/main/java/fr/umlv/java/wallj/block/TrashBlock.java
index 33b5a6b..1f2dfa6 100644
--- a/src/main/java/fr/umlv/java/wallj/block/TrashBlock.java
+++ b/src/main/java/fr/umlv/java/wallj/block/TrashBlock.java
@@ -3,12 +3,17 @@ package fr.umlv.java.wallj.block;
 import fr.umlv.java.wallj.board.TileVec2;
 import fr.umlv.java.wallj.context.Context;
 import fr.umlv.java.wallj.context.Updateables;
+import fr.umlv.java.wallj.event.BlockDestroyEvent;
 import fr.umlv.java.wallj.event.Event;
 import org.jbox2d.common.Vec2;
 import org.jbox2d.dynamics.BodyType;
+import org.jbox2d.dynamics.contacts.ContactEdge;
 
 import java.awt.*;
+import java.util.Spliterator;
+import java.util.function.Consumer;
 import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
 
 /**
  * A trash block.
@@ -23,11 +28,53 @@ public class TrashBlock extends JBoxBlock {
   @Override
   public Stream<Event> update(Context context) {
     return Updateables.updateAll(context,
+    this::handleContacts,
     this::paint);
   }
 
+  private Stream<Event> handleContacts(Context context) {
+    return streamContactEdges()
+           .map(contactEdge -> ((Block) contactEdge.other.getUserData()))
+           .filter(otherBody -> otherBody.getType() == BlockType.GARBAGE)
+           .map(BlockDestroyEvent::new);
+  }
+
   private Stream<Event> paint(Context context) {
     context.getGraphicsContext().paintRectangle(Color.RED, getPos(), TileVec2.TILE_DIM, TileVec2.TILE_DIM);
     return Stream.empty();
   }
+
+  private Stream<ContactEdge> streamContactEdges() {
+    // If only we had (a working) Java 9...
+    // return Stream.iterate(getBody().getContactList(), c -> c.next)
+    //        .takeWhile(Objects::nonNull);
+
+    return StreamSupport.stream(new Spliterator<ContactEdge>() {
+      private ContactEdge contactEdge = getBody().getContactList();
+
+      @Override
+      public boolean tryAdvance(Consumer<? super ContactEdge> consumer) {
+        if (contactEdge == null) return false;
+
+        consumer.accept(contactEdge);
+        contactEdge = contactEdge.next;
+        return true;
+      }
+
+      @Override
+      public Spliterator<ContactEdge> trySplit() {
+        return null;
+      }
+
+      @Override
+      public long estimateSize() {
+        return Long.MAX_VALUE;
+      }
+
+      @Override
+      public int characteristics() {
+        return NONNULL;
+      }
+    }, false);
+  }
 }
-- 
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