From 5531c8a06e15606f70fa7428013bcdc4e721e13e Mon Sep 17 00:00:00 2001
From: yushijinhun <yushijinhun@gmail.com>
Date: Sun, 30 Dec 2018 00:40:49 +0800
Subject: [PATCH] Support Citizens2

---
 .../authlibinjector/AuthlibInjector.java      |  2 +
 .../support/CitizensTransformer.java          | 64 +++++++++++++++++++
 2 files changed, 66 insertions(+)
 create mode 100644 src/main/java/moe/yushi/authlibinjector/transform/support/CitizensTransformer.java

diff --git a/src/main/java/moe/yushi/authlibinjector/AuthlibInjector.java b/src/main/java/moe/yushi/authlibinjector/AuthlibInjector.java
index 664b125..af2445d 100644
--- a/src/main/java/moe/yushi/authlibinjector/AuthlibInjector.java
+++ b/src/main/java/moe/yushi/authlibinjector/AuthlibInjector.java
@@ -31,6 +31,7 @@ import moe.yushi.authlibinjector.transform.ConstantURLTransformUnit;
 import moe.yushi.authlibinjector.transform.DumpClassListener;
 import moe.yushi.authlibinjector.transform.SkinWhitelistTransformUnit;
 import moe.yushi.authlibinjector.transform.YggdrasilKeyTransformUnit;
+import moe.yushi.authlibinjector.transform.support.CitizensTransformer;
 import moe.yushi.authlibinjector.util.Logging;
 
 public final class AuthlibInjector {
@@ -296,6 +297,7 @@ public final class AuthlibInjector {
 		}
 
 		transformer.units.add(new ConstantURLTransformUnit(urlProcessor));
+		transformer.units.add(new CitizensTransformer());
 
 		transformer.units.add(new SkinWhitelistTransformUnit(config.getSkinDomains().toArray(new String[0])));
 
diff --git a/src/main/java/moe/yushi/authlibinjector/transform/support/CitizensTransformer.java b/src/main/java/moe/yushi/authlibinjector/transform/support/CitizensTransformer.java
new file mode 100644
index 0000000..acdc26a
--- /dev/null
+++ b/src/main/java/moe/yushi/authlibinjector/transform/support/CitizensTransformer.java
@@ -0,0 +1,64 @@
+package moe.yushi.authlibinjector.transform.support;
+
+import static org.objectweb.asm.Opcodes.ALOAD;
+import static org.objectweb.asm.Opcodes.ASM6;
+import static org.objectweb.asm.Opcodes.F_SAME;
+import static org.objectweb.asm.Opcodes.GETFIELD;
+import static org.objectweb.asm.Opcodes.IFEQ;
+import static org.objectweb.asm.Opcodes.INVOKEVIRTUAL;
+import static org.objectweb.asm.Opcodes.RETURN;
+
+import java.util.Optional;
+
+import org.objectweb.asm.ClassVisitor;
+import org.objectweb.asm.Label;
+import org.objectweb.asm.MethodVisitor;
+
+import moe.yushi.authlibinjector.transform.TransformUnit;
+
+/**
+ * Support for Citizens2
+ *
+ * In <https://github.com/CitizensDev/Citizens2/commit/28b0c4fdc3b343d4dc14f2a45cff37c0b75ced1d>,
+ * the profile-url that Citizens use became configurable. This class is used to make Citizens ignore
+ * the config property and use authlib-injector's url.
+ */
+public class CitizensTransformer implements TransformUnit {
+
+	@Override
+	public Optional<ClassVisitor> transform(ClassLoader classLoader, String className, ClassVisitor writer, Runnable modifiedCallback) {
+		if ("net.citizensnpcs.Settings$Setting".equals(className)) {
+			return Optional.of(new ClassVisitor(ASM6, writer) {
+				@Override
+				public MethodVisitor visitMethod(int access, String name, String descriptor, String signature, String[] exceptions) {
+					if (("loadFromKey".equals(name) || "setAtKey".equals(name))
+							&& "(Lnet/citizensnpcs/api/util/DataKey;)V".equals(descriptor)) {
+						return new MethodVisitor(ASM6, super.visitMethod(access, name, descriptor, signature, exceptions)) {
+							@Override
+							public void visitCode() {
+								super.visitCode();
+								super.visitLdcInsn("general.authlib.profile-url");
+								super.visitVarInsn(ALOAD, 0);
+								super.visitFieldInsn(GETFIELD, "net/citizensnpcs/Settings$Setting", "path", "Ljava/lang/String;");
+								super.visitMethodInsn(INVOKEVIRTUAL, "java/lang/String", "equals", "(Ljava/lang/Object;)Z", false);
+								Label lbl = new Label();
+								super.visitJumpInsn(IFEQ, lbl);
+								super.visitInsn(RETURN);
+								super.visitLabel(lbl);
+								super.visitFrame(F_SAME, 0, null, 0, null);
+								modifiedCallback.run();
+							}
+						};
+					}
+					return super.visitMethod(access, name, descriptor, signature, exceptions);
+				}
+			});
+		}
+		return Optional.empty();
+	}
+
+	@Override
+	public String toString() {
+		return "Citizens2 Support";
+	}
+}