package com.mark.b01Operation.service.impl;
import com.mark.b01Operation.service.CreateClassService;
import com.mark.b01Operation.service.operation.AbstractOperation;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.*;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
import javax.tools.*;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URI;
import java.util.Arrays;
@Service
public class CreateClassServiceImpl implements CreateClassService {
    @Resource
    private ConfigurableListableBeanFactory configurableListableBeanFactory;
    @Resource
    private AbstractBeanFactory abstractBeanFactory;
    @Override
    public void CreateClass(String str,String name) throws Exception {
        //1.获取java编程语言编译器
        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
        //2.获取文件管理器
        StandardJavaFileManager standardFileManager = compiler.getStandardFileManager(null, null, null);
        //3.获取class文件管理器
        ClassJavaFileManager classJavaFileManager = new ClassJavaFileManager(standardFileManager);
        //4.获取要加载的.java文件内容
        StringObject stringObject = new StringObject(new URI(name+".java"), JavaFileObject.Kind.SOURCE, str);
        //5.调用编译器，传入参数获取要执行的编译任务
        JavaCompiler.CompilationTask task = compiler.getTask(null, classJavaFileManager,
                null, null, null, Arrays.asList(stringObject));
        //6.执行编译任务
        if (task.call()) {
            //7.获取类文件获取.class文件
            ClassJavaFileObject javaFileObject = classJavaFileManager.getClassJavaFileObject();
            //8.创建类加载器，并将.class文件传入
            ClassLoader classLoader = new MyClassLoader(javaFileObject);
            //9.获得该类的实例
            Object AddFactory = classLoader.loadClass(name).newInstance();
            //10.调用spring管理bean的集合，将实例化的类交给spring管理
            configurableListableBeanFactory.registerSingleton(name,AddFactory);
            //11.通过spring的BeanFactory获取bean验证是否可以获取到
            AbstractOperation abstractOperation =  (AbstractOperation) abstractBeanFactory.getBean(name);
            System.out.println(AddFactory);
        }
    }
    /**
     *自定义fileManager 继承ForwardingJavaFileManager文件管理器
     */
    static class ClassJavaFileManager extends ForwardingJavaFileManager {
        private ClassJavaFileObject classJavaFileObject;
        public ClassJavaFileManager(JavaFileManager fileManager) {
            super(fileManager);
        }
        public ClassJavaFileObject getClassJavaFileObject() {
            return classJavaFileObject;
        }
        //这个方法一定要自定义
        //获取输出的文件对象，它表示给定位置处指定类型的制定类
        @Override
        public JavaFileObject getJavaFileForOutput(Location location, String className, JavaFileObject.Kind kind, FileObject sibling) throws IOException {
            return (classJavaFileObject = new ClassJavaFileObject(className,kind));
        }
    }
    /**
     * 存储源文件   SimpleJavaFileObject：简单的java文件对象
     */
    static class StringObject extends SimpleJavaFileObject {
        private String content;
        public StringObject(URI uri, Kind kind, String content) {
            super(uri, kind);
            this.content = content;
        }
        @Override
        public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {
            return this.content;
        }
    }
    /**
     * class文件（不需要存到文件中）
     */
    static class ClassJavaFileObject extends SimpleJavaFileObject{
        ByteArrayOutputStream outputStream;
        public ClassJavaFileObject(String className, Kind kind) {
            super(URI.create(className + kind.extension), kind);
            this.outputStream = new ByteArrayOutputStream();
        }
        //这个也要实现
        @Override
        public OutputStream openOutputStream() throws IOException {
            return this.outputStream;
        }
        public byte[] getBytes(){
            return this.outputStream.toByteArray();
        }
    }
    //自定义classloader
    static class MyClassLoader extends ClassLoader{
        private ClassJavaFileObject classJavaFileObject;
        public MyClassLoader(ClassJavaFileObject classJavaFileObject){
            this.classJavaFileObject = classJavaFileObject;
        }
        @Override
        protected Class<?> findClass(String name) throws ClassNotFoundException {
            byte[] bytes = this.classJavaFileObject.getBytes();
            return defineClass(name,bytes,0,bytes.length);
        }
    }
}