/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the "Elastic License
 * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
 * Public License v 1"; you may not use this file except in compliance with, at
 * your election, the "Elastic License 2.0", the "GNU Affero General Public
 * License v3.0 only", or the "Server Side Public License, v 1".
 */

package org.elasticsearch.painless;

import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import org.objectweb.asm.commons.Method;
import org.objectweb.asm.util.Printer;
import org.objectweb.asm.util.TraceClassVisitor;

import java.io.Closeable;
import java.lang.reflect.Modifier;
import java.util.BitSet;

/**
 * Manages the top level writers for class and possibly
 * clinit if necessary.
 */
public class ClassWriter implements Closeable {

    /**
     * Converts Java reflection modifiers to ASM access constants.
     * @param modifiers Java reflection {@code Modifiers}
     * @param synthetic {@code true} if the item is synthetically generated
     * @return ASM access constants
     */
    public static int buildAccess(int modifiers, boolean synthetic) {
        int access = synthetic ? Opcodes.ACC_SYNTHETIC : 0;

        if (Modifier.isFinal(modifiers)) access |= Opcodes.ACC_FINAL;
        if (Modifier.isInterface(modifiers)) access |= Opcodes.ACC_INTERFACE;
        if (Modifier.isNative(modifiers)) access |= Opcodes.ACC_NATIVE;
        if (Modifier.isPrivate(modifiers)) access |= Opcodes.ACC_PRIVATE;
        if (Modifier.isProtected(modifiers)) access |= Opcodes.ACC_PROTECTED;
        if (Modifier.isPublic(modifiers)) access |= Opcodes.ACC_PUBLIC;
        if (Modifier.isStatic(modifiers)) access |= Opcodes.ACC_STATIC;
        if (Modifier.isStrict(modifiers)) access |= Opcodes.ACC_STRICT;
        if (Modifier.isSynchronized(modifiers)) access |= Opcodes.ACC_SYNCHRONIZED;
        if (Modifier.isTransient(modifiers)) access |= Opcodes.ACC_TRANSIENT;
        if (Modifier.isVolatile(modifiers)) access |= Opcodes.ACC_VOLATILE;

        return access;
    }

    protected final CompilerSettings compilerSettings;
    protected final BitSet statements;

    protected final org.objectweb.asm.ClassWriter classWriter;
    protected final ClassVisitor classVisitor;

    public ClassWriter(
        CompilerSettings compilerSettings,
        BitSet statements,
        Printer debugStream,
        Class<?> baseClass,
        int classFrames,
        int classAccess,
        String className,
        String[] classInterfaces
    ) {

        this.compilerSettings = compilerSettings;
        this.statements = statements;

        classWriter = new org.objectweb.asm.ClassWriter(classFrames);
        ClassVisitor visitor = classWriter;

        if (compilerSettings.isPicky()) {
            visitor = new SimpleChecksAdapter(visitor);
        }

        if (debugStream != null) {
            visitor = new TraceClassVisitor(visitor, debugStream, null);
        }

        classVisitor = visitor;
        classVisitor.visit(
            WriterConstants.CLASS_VERSION,
            classAccess,
            className,
            null,
            Type.getType(baseClass).getInternalName(),
            classInterfaces
        );
    }

    public ClassVisitor getClassVisitor() {
        return classVisitor;
    }

    public MethodWriter newMethodWriter(int access, Method method) {
        return new MethodWriter(access, method, classVisitor, statements, compilerSettings);
    }

    @Override
    public void close() {
        classVisitor.visitEnd();
    }

    public byte[] getClassBytes() {
        return classWriter.toByteArray();
    }
}