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package com.firefly.utils.classproxy;

import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

import javassist.ClassClassPath;
import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtConstructor;
import javassist.CtField;
import javassist.CtMethod;

import com.firefly.utils.ReflectUtils.MethodProxy;
import com.firefly.utils.StringUtils;

public class ClassProxyFactoryUsingJavassist implements ClassProxyFactory {
	
	public static final ClassProxyFactoryUsingJavassist INSTANCE = new ClassProxyFactoryUsingJavassist();
	public static ClassLoader classLoader;
	static {
		classLoader = Thread.currentThread().getContextClassLoader();
	}
	
	private ClassProxyFactoryUsingJavassist(){}

	@SuppressWarnings({ "unchecked", "rawtypes" })
	@Override
	public Object createProxy(Object instance, ClassProxy proxy, MethodFilter filter) throws Throwable {
		ClassPool classPool = ClassPool.getDefault();
		classPool.insertClassPath(new ClassClassPath(ClassProxyFactory.class));
		
		Class clazz = instance.getClass();
		// make class
		CtClass cc = classPool.makeClass("com.firefly.utils.ClassProxy" + UUID.randomUUID().toString().replace("-", ""));
		cc.setSuperclass(classPool.get(clazz.getName()));
		
		// make fields
		cc.addField(CtField.make("private " + ClassProxy.class.getCanonicalName() + " classProxy;", cc));
		cc.addField(CtField.make("private " + clazz.getCanonicalName() + " originalInstance;", cc));
		cc.addField(CtField.make("private " + MethodProxy[].class.getCanonicalName() + " methodProxies;", cc));
		
		// make constructor
		CtConstructor empty = new CtConstructor(null, cc);
		empty.setBody("{}");
		CtConstructor constructor = new CtConstructor(new CtClass[]{
				classPool.get(ClassProxy.class.getName()),
				classPool.get(clazz.getName()),
				classPool.get(MethodProxy[].class.getName())
			}, cc);
		constructor.setBody("{"
				+ "this.classProxy = (" + ClassProxy.class.getCanonicalName() + ")$1;"
				+ "this.originalInstance = (" + clazz.getCanonicalName() + ")$2;"
				+ "this.methodProxies = (" + MethodProxy[].class.getCanonicalName() + ")$3;"
				+ "}");
		cc.addConstructor(empty);
		cc.addConstructor(constructor);
		
		// make methods		
		List list = new ArrayList();
		for(Method m : clazz.getMethods()) {
			if(m.getDeclaringClass().equals(Object.class) 
					|| Modifier.isFinal(m.getModifiers()) 
					|| Modifier.isStatic(m.getModifiers())
					|| Modifier.isNative(m.getModifiers()))
				continue;
			if(filter != null && !filter.accept(m))
				continue;
			list.add(m);
		}

		Method[] methods = list.toArray(new Method[0]);
		MethodProxy[] methodProxies = new MethodProxy[methods.length];
		for (int i = 0; i < methods.length; i++) {
			Method m = methods[i];
			methodProxies[i] = MethodProxyFactoryUsingJavassist.INSTANCE.getMethodProxy(m);
			String parameterArray = "Object[] args = new Object[]{";
			String str = "public " + m.getReturnType().getCanonicalName() + " " + m.getName() + "(";
			Class[] parameters = m.getParameterTypes();
			for (int j = 0; j < parameters.length; j++) {
				if(j != 0) {
					str += ", ";
					parameterArray += ", ";
				}
				str += parameters[j].getCanonicalName() + " arg" + j;
				if(parameters[j].isPrimitive()) {
					parameterArray += StringUtils.replace("(Object){}.valueOf(", AbstractProxyFactory.primitiveWrapMap.get(parameters[j]))
									+ "arg" + j + ")";
				} else {
					parameterArray += "(Object)arg" + j;
				}
			}
			str += "){\n";
			parameterArray += "};\n";
			if(parameters.length == 0) {
				parameterArray = Object[].class.getCanonicalName() + " args = new Object[0];\n";
			}
			
			str += "\t" + parameterArray;
			if(!m.getReturnType().equals(void.class)) {
				if(m.getReturnType().isPrimitive()) {
					str += "\t" + m.getReturnType().getCanonicalName() + " ret = (("
							+ AbstractProxyFactory.primitiveWrapMap.get(m.getReturnType()) + ")"
							+ "classProxy.intercept(methodProxies[" + i + "], "
							+ "originalInstance, "
							+ "args"
							+ "))." + m.getReturnType().getCanonicalName() + "Value()"
							+ ";\n"; 
				} else {
					str += "\t" + m.getReturnType().getCanonicalName() + " ret = ("
							+ m.getReturnType().getCanonicalName() + ")"
							+ "classProxy.intercept(methodProxies[" + i + "], "
							+ "originalInstance, "
							+ "args"
							+ ");\n"; 
				}
				str += "\treturn ret;\n";
			} else {
				str += "\tclassProxy.intercept(methodProxies[" + i + "], "
						+ "originalInstance, "
						+ "args"
						+ ");\n"; 
			}
			str += "}";
//			System.out.println(str);
			cc.addMethod(CtMethod.make(str, cc));
		}
		
		// generate proxy instance
		Object ret = cc.toClass(classLoader, null).getConstructor(ClassProxy.class, clazz, MethodProxy[].class).newInstance(proxy, instance, methodProxies);
		return ret;
	}
}