package com.ruoyi.buss.common.dynamic;

import javax.tools.*;
import java.util.*;
import java.io.ByteArrayOutputStream;
import java.io.OutputStream;
import java.net.URI;

public class MemoryJavaFileManager extends ForwardingJavaFileManager<JavaFileManager> {
    private final Map<String, byte[]> classBytes = new HashMap<>();
    private final ClassLoader loader;

    public MemoryJavaFileManager(JavaFileManager fileManager) {
        super(fileManager);
        this.loader = new ClassLoader() {
            @Override
            protected Class<?> findClass(String name) throws ClassNotFoundException {
                byte[] buf = classBytes.get(name);
                if (buf == null) throw new ClassNotFoundException(name);
                return defineClass(name, buf, 0, buf.length);
            }
        };
    }

    @Override
    public JavaFileObject getJavaFileForOutput(Location location, String className,
                                               JavaFileObject.Kind kind, FileObject sibling) {
        return new MemoryOutputJavaFileObject(className);
    }

    public ClassLoader getClassLoader() {
        return loader;
    }

    class MemoryOutputJavaFileObject extends SimpleJavaFileObject {
        private final String name;

        MemoryOutputJavaFileObject(String name) {
            super(URI.create("mem:///" + name.replace('.','/') + Kind.CLASS.extension), Kind.CLASS);
            this.name = name;
        }

        @Override
        public OutputStream openOutputStream() {
            return new ByteArrayOutputStream() {
                @Override
                public void close() {
                    classBytes.put(name, toByteArray());
                }
            };
        }
    }
}