From 8c7522e1d3845ab1661a58edb5842a26d8d85699 Mon Sep 17 00:00:00 2001
From: Yohann D'ANELLO <yohann.danello@gmail.com>
Date: Tue, 25 Feb 2020 12:11:58 +0100
Subject: [PATCH] Path finding

---
 .../leveleditor/api/editor/RawMap.java        | 11 +++++
 .../java/fr/ynerant/leveleditor/game/Mob.java | 47 +++++++++++++++----
 2 files changed, 50 insertions(+), 8 deletions(-)

diff --git a/src/main/java/fr/ynerant/leveleditor/api/editor/RawMap.java b/src/main/java/fr/ynerant/leveleditor/api/editor/RawMap.java
index 6cfe48d..10af484 100644
--- a/src/main/java/fr/ynerant/leveleditor/api/editor/RawMap.java
+++ b/src/main/java/fr/ynerant/leveleditor/api/editor/RawMap.java
@@ -4,8 +4,10 @@ import fr.ynerant.leveleditor.editor.Map;
 
 import java.awt.image.BufferedImage;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
+import java.util.stream.Collectors;
 
 public class RawMap {
     private List<RawCase> cases;
@@ -48,6 +50,15 @@ public class RawMap {
         return cases_map.get(y * getWidth() + x);
     }
 
+    public Collection<RawCase> getNeighbours(RawCase c) {
+        List<RawCase> list = new ArrayList<>();
+        list.add(getCase(c.getPosX() - 1, c.getPosY()));
+        list.add(getCase(c.getPosX(), c.getPosY() - 1));
+        list.add(getCase(c.getPosX() + 1, c.getPosY()));
+        list.add(getCase(c.getPosX(), c.getPosY() + 1));
+        return list.stream().filter(_c -> _c != null && _c.getCollision() == Collision.ANY).collect(Collectors.toList());
+    }
+
     public int getWidth() {
         return width;
     }
diff --git a/src/main/java/fr/ynerant/leveleditor/game/Mob.java b/src/main/java/fr/ynerant/leveleditor/game/Mob.java
index 187f279..4f143af 100644
--- a/src/main/java/fr/ynerant/leveleditor/game/Mob.java
+++ b/src/main/java/fr/ynerant/leveleditor/game/Mob.java
@@ -5,7 +5,7 @@ import fr.ynerant.leveleditor.api.editor.RawCase;
 import fr.ynerant.leveleditor.api.editor.sprites.Sprite;
 import fr.ynerant.leveleditor.api.editor.sprites.SpriteRegister;
 
-import java.util.Random;
+import java.util.*;
 
 public abstract class Mob {
     private static final Random RANDOM = new Random();
@@ -73,13 +73,44 @@ public abstract class Mob {
             --tickRemains;
         else {
             tickRemains = getSlowness();
-            RawCase c = game.getMap().getCase(getX(), getY());
-            RawCase other = game.getMap().getCase(getX() - 1, getY());
-            if (other == null || other.getCollision() == Collision.ANY) {
-                c.setCollision(Collision.ANY);
-                if (other != null)
-                    other.setCollision(Collision.PARTIAL);
-                move(getX() - 1, getY());
+            RawCase current = game.getMap().getCase(getX(), getY());
+            current.setCollision(Collision.ANY);
+
+            if (current.getPosX() == 0) {
+                move(-1, getY());
+                return;
+            }
+
+            List<RawCase> visited = new ArrayList<>();
+            Queue<RawCase> queue = new ArrayDeque<>();
+            Map<RawCase, RawCase> pred = new HashMap<>();
+            RawCase last = null;
+            queue.add(current);
+            while (!queue.isEmpty()) {
+                RawCase visiting = queue.poll();
+                visited.add(visiting);
+                for (RawCase neighbour : game.getMap().getNeighbours(visiting)) {
+                    if (visited.contains(neighbour))
+                        continue;
+
+                    pred.put(neighbour, visiting);
+                    queue.add(neighbour);
+
+                    if (neighbour.getPosX() == 0) {
+                        last = neighbour;
+                        queue.clear();
+                        break;
+                    }
+                }
+
+                if (last == null) {
+                    current.setCollision(Collision.PARTIAL);
+                }
+                else {
+                    while (pred.get(last) != current)
+                        last = pred.get(last);
+                    move(last.getPosX(), last.getPosY());
+                }
             }
         }
     }