/**

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

 *

 * Copyright 2013-2014 Oracle and/or its affiliates. All rights reserved.

 *

 * Oracle and Java are registered trademarks of Oracle and/or its affiliates.

 * Other names may be trademarks of their respective owners.

 *

 * The contents of this file are subject to the terms of either the GNU

 * General Public License Version 2 only ("GPL") or the Common

 * Development and Distribution License("CDDL") (collectively, the

 * "License"). You may not use this file except in compliance with the

 * License. You can obtain a copy of the License at

 * http://www.netbeans.org/cddl-gplv2.html

 * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the

 * specific language governing permissions and limitations under the

 * License.  When distributing the software, include this License Header

 * Notice in each file and include the License file at

 * nbbuild/licenses/CDDL-GPL-2-CP.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the GPL Version 2 section of the License file that

 * accompanied this code. If applicable, add the following below the

 * License Header, with the fields enclosed by brackets [] replaced by

 * your own identifying information:

 * "Portions Copyrighted [year] [name of copyright owner]"

 *

 * Contributor(s):

 *

 * The Original Software is NetBeans. The Initial Developer of the Original

 * Software is Oracle. Portions Copyright 2013-2014 Oracle. All Rights Reserved.

 *

 * If you wish your version of this file to be governed by only the CDDL

 * or only the GPL Version 2, indicate your decision by adding

 * "[Contributor] elects to include this software in this distribution

 * under the [CDDL or GPL Version 2] license." If you do not indicate a

 * single choice of license, a recipient has the option to distribute

 * your version of this file under either the CDDL, the GPL Version 2 or

 * to extend the choice of license to its licensees as provided above.

 * However, if you add GPL Version 2 code and therefore, elected the GPL

 * Version 2 license, then the option applies only if the new code is

 * made subject to such option by the copyright holder.

 */

package org.netbeans.html.boot.impl;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.Reader;

import java.net.URL;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Enumeration;

import java.util.List;

import net.java.html.js.JavaScriptBody;

import net.java.html.js.JavaScriptResource;

import org.netbeans.html.boot.spi.Fn;

import org.objectweb.asm.AnnotationVisitor;

import org.objectweb.asm.ClassReader;

import org.objectweb.asm.ClassVisitor;

import org.objectweb.asm.ClassWriter;

import org.objectweb.asm.FieldVisitor;

import org.objectweb.asm.Label;

import org.objectweb.asm.MethodVisitor;

import org.objectweb.asm.Opcodes;

import org.objectweb.asm.Type;

import org.objectweb.asm.signature.SignatureReader;

import org.objectweb.asm.signature.SignatureVisitor;

import org.objectweb.asm.signature.SignatureWriter;

/** Utilities related to bytecode transformations. Depend on asm.jar which

 * needs to be added to be provided to classpath to make methods in this 

 * class useful.

 *

 * @author Jaroslav Tulach

 */

public final class FnUtils {

    private FnUtils() {

    }

    /** Seeks for {@link JavaScriptBody} and {@link JavaScriptResource} annotations

     * in the bytecode and converts them into real code. Used by Maven plugin

     * postprocessing classes.

     * 

     * @param bytecode the original bytecode with javascript specific annotations

     * @param loader the loader to load resources (scripts and classes) when needed

     * @return the transformed bytecode

     * @since 0.7

     */

    public static byte[] transform(byte[] bytecode, ClassLoader loader) {

        ClassReader cr = new ClassReader(bytecode) {

            // to allow us to compile with -profile compact1 on 

            // JDK8 while processing the class as JDK7, the highest

            // class format asm 4.1 understands to

            @Override

            public short readShort(int index) {

                short s = super.readShort(index);

                if (index == 6 && s > Opcodes.V1_7) {

                    return Opcodes.V1_7;

                }

                return s;

            }

        };

        FindInClass tst = new FindInClass(loader, null);

        cr.accept(tst, 0);

        if (tst.found > 0) {

            ClassWriter w = new ClassWriterEx(loader, cr, ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);

            FindInClass fic = new FindInClass(loader, w);

            cr.accept(fic, 0);

            bytecode = w.toByteArray();

        }

        return bytecode;

    }

    public static ClassLoader newLoader(final FindResources f, final Fn.Presenter d, ClassLoader parent) {

        return new JsClassLoaderImpl(parent, f, d);

    }

    static String callback(final String body) {

        return new JsCallback() {

            @Override

            protected CharSequence callMethod(

                String ident, String fqn, String method, String params

            ) {

                StringBuilder sb = new StringBuilder();

                if (ident != null) {

                    sb.append("vm.raw$");

                } else {

                    sb.append("vm.");

                }

                sb.append(mangle(fqn, method, params));

                sb.append("(");

                if (ident != null) {

                    sb.append(ident);

                }

                return sb;

            }

        }.parse(body);

    }

    private static final class FindInClass extends ClassVisitor {

        private String name;

        private int found;

        private String resource;

        public FindInClass(ClassLoader l, ClassVisitor cv) {

            super(Opcodes.ASM4, cv);

        }

        @Override

        public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {

            this.name = name;

            super.visit(version, access, name, signature, superName, interfaces);

        }

        @Override

        public AnnotationVisitor visitAnnotation(String desc, boolean visible) {

            final AnnotationVisitor del = super.visitAnnotation(desc, visible);

            if ("Lnet/java/html/js/JavaScriptResource;".equals(desc)) {

                return new LoadResource(del);

            }

            return del;

        }

        @Override

        public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {

            return new FindInMethod(access, name, desc,

                    super.visitMethod(access & (~Opcodes.ACC_NATIVE), name, desc, signature, exceptions)

            );

        }

        @Override

        public FieldVisitor visitField(int access, String name, String desc, String signature, Object value) {

            if (name.startsWith("$$fn$$")) {

                return null;

            }

            return superField(access, name, desc, signature, value);

        }

        final FieldVisitor superField(int access, String name, String desc, String signature, Object value) {

            return super.visitField(access, name, desc, signature, value);

        }

        private final class FindInMethod extends MethodVisitor {

            private final String name;

            private final String desc;

            private final int access;

            private FindInAnno fia;

            private boolean bodyGenerated;

            public FindInMethod(int access, String name, String desc, MethodVisitor mv) {

                super(Opcodes.ASM4, mv);

                this.access = access;

                this.name = name;

                this.desc = desc;

            }

            @Override

            public AnnotationVisitor visitAnnotation(String desc, boolean visible) {

                if ("Lnet/java/html/js/JavaScriptBody;".equals(desc)) { // NOI18N

                    found++;

                    return new FindInAnno();

                }

                return super.visitAnnotation(desc, visible);

            }

            private void generateJSBody(FindInAnno fia) {

                this.fia = fia;

            }

            @Override

            public void visitCode() {

                if (fia == null) {

                    return;

                }

                generateBody(true);

            }

            private boolean generateBody(boolean hasCode) {

                if (bodyGenerated) {

                    return false;

                }

                bodyGenerated = true;

                if (mv != null) {

                    AnnotationVisitor va = super.visitAnnotation("Lnet/java/html/js/JavaScriptBody;", false);

                    AnnotationVisitor varr = va.visitArray("args");

                    for (String argName : fia.args) {

                        varr.visit(null, argName);

                    }

                    varr.visitEnd();

                    va.visit("javacall", fia.javacall);

                    va.visit("body", fia.body);

                    va.visitEnd();

                }

                String body;

                List<String> args;

                if (fia.javacall) {

                    body = callback(fia.body);

                    args = new ArrayList<String>(fia.args);

                    args.add("vm");

                } else {

                    body = fia.body;

                    args = fia.args;

                }

                super.visitFieldInsn(

                        Opcodes.GETSTATIC, FindInClass.this.name,

                        "$$fn$$" + name + "_" + found,

                        "Lorg/netbeans/html/boot/spi/Fn;"

                );

                super.visitInsn(Opcodes.DUP);

                super.visitMethodInsn(

                        Opcodes.INVOKESTATIC,

                        "org/netbeans/html/boot/spi/Fn", "isValid",

                        "(Lorg/netbeans/html/boot/spi/Fn;)Z"

                );

                Label ifNotNull = new Label();

                super.visitJumpInsn(Opcodes.IFNE, ifNotNull);

                // init Fn

                super.visitInsn(Opcodes.POP);

                super.visitLdcInsn(Type.getObjectType(FindInClass.this.name));

                super.visitInsn(fia.keepAlive ? Opcodes.ICONST_1 : Opcodes.ICONST_0);

                super.visitLdcInsn(body);

                super.visitIntInsn(Opcodes.SIPUSH, args.size());

                super.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/String");

                boolean needsVM = false;

                for (int i = 0; i < args.size(); i++) {

                    assert !needsVM;

                    String argName = args.get(i);

                    needsVM = "vm".equals(argName);

                    super.visitInsn(Opcodes.DUP);

                    super.visitIntInsn(Opcodes.BIPUSH, i);

                    super.visitLdcInsn(argName);

                    super.visitInsn(Opcodes.AASTORE);

                }

                super.visitMethodInsn(Opcodes.INVOKESTATIC,

                        "org/netbeans/html/boot/spi/Fn", "define",

                        "(Ljava/lang/Class;ZLjava/lang/String;[Ljava/lang/String;)Lorg/netbeans/html/boot/spi/Fn;"

                );

                Label noPresenter = new Label();

                super.visitInsn(Opcodes.DUP);

                super.visitJumpInsn(Opcodes.IFNULL, noPresenter);

                if (resource != null) {

                    super.visitLdcInsn(Type.getObjectType(FindInClass.this.name));

                    super.visitLdcInsn(resource);

                    super.visitMethodInsn(Opcodes.INVOKESTATIC,

                            "org/netbeans/html/boot/spi/Fn", "preload",

                            "(Lorg/netbeans/html/boot/spi/Fn;Ljava/lang/Class;Ljava/lang/String;)Lorg/netbeans/html/boot/spi/Fn;"

                    );

                }

                super.visitInsn(Opcodes.DUP);

                super.visitFieldInsn(

                        Opcodes.PUTSTATIC, FindInClass.this.name,

                        "$$fn$$" + name + "_" + found,

                        "Lorg/netbeans/html/boot/spi/Fn;"

                );

                // end of Fn init

                super.visitLabel(ifNotNull);

                final int offset;

                if ((access & Opcodes.ACC_STATIC) == 0) {

                    offset = 1;

                    super.visitIntInsn(Opcodes.ALOAD, 0);

                } else {

                    offset = 0;

                    super.visitInsn(Opcodes.ACONST_NULL);

                }

                super.visitIntInsn(Opcodes.SIPUSH, args.size());

                super.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");

                class SV extends SignatureVisitor {

                    private boolean nowReturn;

                    private Type returnType;

                    private int index;

                    private int loadIndex = offset;

                    public SV() {

                        super(Opcodes.ASM4);

                    }

                    @Override

                    public void visitBaseType(char descriptor) {

                        final Type t = Type.getType("" + descriptor);

                        if (nowReturn) {

                            returnType = t;

                            return;

                        }

                        FindInMethod.super.visitInsn(Opcodes.DUP);

                        FindInMethod.super.visitIntInsn(Opcodes.SIPUSH, index++);

                        FindInMethod.super.visitVarInsn(t.getOpcode(Opcodes.ILOAD), loadIndex++);

                        String factory;

                        switch (descriptor) {

                            case 'I':

                                factory = "java/lang/Integer";

                                break;

                            case 'J':

                                factory = "java/lang/Long";

                                loadIndex++;

                                break;

                            case 'S':

                                factory = "java/lang/Short";

                                break;

                            case 'F':

                                factory = "java/lang/Float";

                                break;

                            case 'D':

                                factory = "java/lang/Double";

                                loadIndex++;

                                break;

                            case 'Z':

                                factory = "java/lang/Boolean";

                                break;

                            case 'C':

                                factory = "java/lang/Character";

                                break;

                            case 'B':

                                factory = "java/lang/Byte";

                                break;

                            default:

                                throw new IllegalStateException(t.toString());

                        }

                        FindInMethod.super.visitMethodInsn(Opcodes.INVOKESTATIC,

                                factory, "valueOf", "(" + descriptor + ")L" + factory + ";"

                        );

                        FindInMethod.super.visitInsn(Opcodes.AASTORE);

                    }

                    @Override

                    public SignatureVisitor visitArrayType() {

                        if (nowReturn) {

                            return new SignatureVisitor(Opcodes.ASM4) {

                                @Override

                                public void visitClassType(String name) {

                                    returnType = Type.getType("[" + Type.getObjectType(name).getDescriptor());

                                }

                                @Override

                                public void visitBaseType(char descriptor) {

                                    returnType = Type.getType("[" + descriptor);

                                }

                            };

                        }

                        loadObject();

                        return new SignatureWriter();

                    }

                    @Override

                    public void visitClassType(String name) {

                        if (nowReturn) {

                            returnType = Type.getObjectType(name);

                            return;

                        }

                        loadObject();

                    }

                    @Override

                    public SignatureVisitor visitReturnType() {

                        nowReturn = true;

                        return this;

                    }

                    private void loadObject() {

                        FindInMethod.super.visitInsn(Opcodes.DUP);

                        FindInMethod.super.visitIntInsn(Opcodes.SIPUSH, index++);

                        FindInMethod.super.visitVarInsn(Opcodes.ALOAD, loadIndex++);

                        FindInMethod.super.visitInsn(Opcodes.AASTORE);

                    }

                }

                SV sv = new SV();

                SignatureReader sr = new SignatureReader(desc);

                sr.accept(sv);

                if (needsVM) {

                    FindInMethod.super.visitInsn(Opcodes.DUP);

                    FindInMethod.super.visitIntInsn(Opcodes.SIPUSH, sv.index);

                    int lastSlash = FindInClass.this.name.lastIndexOf('/');

                    String jsCallbacks = FindInClass.this.name.substring(0, lastSlash + 1) + "$JsCallbacks$";

                    FindInMethod.super.visitFieldInsn(Opcodes.GETSTATIC, jsCallbacks, "VM", "L" + jsCallbacks + ";");

                    FindInMethod.super.visitMethodInsn(Opcodes.INVOKEVIRTUAL, jsCallbacks, "current", "()L" + jsCallbacks + ";");

                    FindInMethod.super.visitInsn(Opcodes.AASTORE);

                }

                if (fia.wait4js) {

                    super.visitMethodInsn(Opcodes.INVOKEVIRTUAL,

                            "org/netbeans/html/boot/spi/Fn", "invoke", "(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object;"

                    );

                    switch (sv.returnType.getSort()) {

                        case Type.VOID:

                            super.visitInsn(Opcodes.RETURN);

                            break;

                        case Type.ARRAY:

                        case Type.OBJECT:

                            super.visitTypeInsn(Opcodes.CHECKCAST, sv.returnType.getInternalName());

                            super.visitInsn(Opcodes.ARETURN);

                            break;

                        case Type.BOOLEAN:

                            super.visitTypeInsn(Opcodes.CHECKCAST, "java/lang/Boolean");

                            super.visitMethodInsn(Opcodes.INVOKEVIRTUAL,

                                    "java/lang/Boolean", "booleanValue", "()Z"

                            );

                            super.visitInsn(Opcodes.IRETURN);

                            break;

                        default:

                            super.visitTypeInsn(Opcodes.CHECKCAST, "java/lang/Number");

                            super.visitMethodInsn(Opcodes.INVOKEVIRTUAL,

                                    "java/lang/Number", sv.returnType.getClassName() + "Value", "()" + sv.returnType.getDescriptor()

                            );

                            super.visitInsn(sv.returnType.getOpcode(Opcodes.IRETURN));

                    }

                } else {

                    super.visitMethodInsn(Opcodes.INVOKEVIRTUAL,

                            "org/netbeans/html/boot/spi/Fn", "invokeLater", "(Ljava/lang/Object;[Ljava/lang/Object;)V"

                    );

                    super.visitInsn(Opcodes.RETURN);

                }

                super.visitLabel(noPresenter);

                if (hasCode) {

                    super.visitCode();

                } else {

                    super.visitTypeInsn(Opcodes.NEW, "java/lang/IllegalStateException");

                    super.visitInsn(Opcodes.DUP);

                    super.visitLdcInsn("No presenter active. Use BrwsrCtx.execute!");

                    super.visitMethodInsn(Opcodes.INVOKESPECIAL, 

                        "java/lang/IllegalStateException", "<init>", "(Ljava/lang/String;)V"

                    );

                    this.visitInsn(Opcodes.ATHROW);

                }

                return true;

            }

            @Override

            public void visitEnd() {

                super.visitEnd();

                if (fia != null) {

                    if (generateBody(false)) {

                        // native method

                        super.visitMaxs(1, 0);

                    }

                    FindInClass.this.superField(

                            Opcodes.ACC_PRIVATE | Opcodes.ACC_STATIC,

                            "$$fn$$" + name + "_" + found,

                            "Lorg/netbeans/html/boot/spi/Fn;",

                            null, null

                    );

                }

            }

            private final class FindInAnno extends AnnotationVisitor {

                List<String> args = new ArrayList<String>();

                String body;

                boolean javacall = false;

                boolean wait4js = true;

                boolean keepAlive = true;

                public FindInAnno() {

                    super(Opcodes.ASM4);

                }

                @Override

                public void visit(String name, Object value) {

                    if (name == null) {

                        args.add((String) value);

                        return;

                    }

                    if (name.equals("javacall")) { // NOI18N

                        javacall = (Boolean) value;

                        return;

                    }

                    if (name.equals("wait4js")) { // NOI18N

                        wait4js = (Boolean) value;

                        return;

                    }

                    if (name.equals("keepAlive")) { // NOI18N

                        keepAlive = (Boolean) value;

                        return;

                    }

                    assert name.equals("body"); // NOI18N

                    body = (String) value;

                }

                @Override

                public AnnotationVisitor visitArray(String name) {

                    return this;

                }

                @Override

                public void visitEnd() {

                    if (body != null) {

                        generateJSBody(this);

                    }

                }

            }

        }

        private final class LoadResource extends AnnotationVisitor {

            public LoadResource(AnnotationVisitor av) {

                super(Opcodes.ASM4, av);

            }

            @Override

            public void visit(String attrName, Object value) {

                super.visit(attrName, value);

                String relPath = (String) value;

                if (relPath.startsWith("/")) {

                    resource = relPath;

                } else {

                    int last = name.lastIndexOf('/');

                    String fullPath = name.substring(0, last + 1) + relPath;

                    resource = fullPath;

                }

            }

        }

    }

    private static class ClassWriterEx extends ClassWriter {

        private final ClassLoader loader;

        public ClassWriterEx(ClassLoader l, ClassReader classReader, int flags) {

            super(classReader, flags);

            this.loader = l;

        }

        @Override

        protected String getCommonSuperClass(final String type1, final String type2) {

            Class<?> c, d;

            try {

                c = Class.forName(type1.replace('/', '.'), false, loader);

                d = Class.forName(type2.replace('/', '.'), false, loader);

            } catch (Exception e) {

                throw new RuntimeException(e.toString());

            }

            if (c.isAssignableFrom(d)) {

                return type1;

            }

            if (d.isAssignableFrom(c)) {

                return type2;

            }

            if (c.isInterface() || d.isInterface()) {

                return "java/lang/Object";

            } else {

                do {

                    c = c.getSuperclass();

                } while (!c.isAssignableFrom(d));

                return c.getName().replace('.', '/');

            }

        }

    }

    static class JsClassLoaderImpl extends JsClassLoader {

        private final FindResources f;

        private final Fn.Presenter d;

        public JsClassLoaderImpl(ClassLoader parent, FindResources f, Fn.Presenter d) {

            super(parent);

            setDefaultAssertionStatus(JsClassLoader.class.desiredAssertionStatus());

            this.f = f;

            this.d = d;

        }

        @Override

        protected URL findResource(String name) {

            List<URL> l = res(name, true);

            return l.isEmpty() ? null : l.get(0);

        }

        @Override

        protected Enumeration<URL> findResources(String name) {

            return Collections.enumeration(res(name, false));

        }

        private List<URL> res(String name, boolean oneIsEnough) {

            List<URL> l = new ArrayList<URL>();

            f.findResources(name, l, oneIsEnough);

            return l;

        }

        @Override

        protected Class<?> findClass(String name) throws ClassNotFoundException {

            if (name.startsWith("javafx")) {

                return Class.forName(name);

            }

            if (name.startsWith("netscape")) {

                return Class.forName(name);

            }

            if (name.startsWith("com.sun")) {

                return Class.forName(name);

            }

            if (name.startsWith("org.netbeans.html.context.spi")) {

                return Class.forName(name);

            }

            if (name.startsWith("net.java.html.BrwsrCtx")) {

                return Class.forName(name);

            }

            if (name.equals(JsClassLoader.class.getName())) {

                return JsClassLoader.class;

            }

            if (name.equals(Fn.class.getName())) {

                return Fn.class;

            }

            if (name.equals(Fn.Presenter.class.getName())) {

                return Fn.Presenter.class;

            }

            if (name.equals(Fn.ToJavaScript.class.getName())) {

                return Fn.ToJavaScript.class;

            }

            if (name.equals(Fn.FromJavaScript.class.getName())) {

                return Fn.FromJavaScript.class;

            }

            if (name.equals(FnUtils.class.getName())) {

                return FnUtils.class;

            }

            if (

                name.equals("org.netbeans.html.boot.spi.Fn") ||

                name.equals("org.netbeans.html.boot.impl.FnUtils") ||

                name.equals("org.netbeans.html.boot.impl.FnContext")

            ) {

                return Class.forName(name);

            }

            URL u = findResource(name.replace('.', '/') + ".class");

            if (u != null) {

                InputStream is = null;

                try {

                    is = u.openStream();

                    byte[] arr = new byte[is.available()];

                    int len = 0;

                    while (len < arr.length) {

                        int read = is.read(arr, len, arr.length - len);

                        if (read == -1) {

                            throw new IOException("Can't read " + u);

                        }

                        len += read;

                    }

                    is.close();

                    is = null;

                    if (JsPkgCache.process(this, name)) {

                        arr = FnUtils.transform(arr, this);

                    }

                    return defineClass(name, arr, 0, arr.length);

                } catch (IOException ex) {

                    throw new ClassNotFoundException("Can't load " + name, ex);

                } finally {

                    try {

                        if (is != null) is.close();

                    } catch (IOException ex) {

                        throw new ClassNotFoundException(null, ex);

                    }

                }

            }

            return super.findClass(name);

        }

        protected Fn defineFn(String code, String... names) {

            return d.defineFn(code, names);

        }

        protected void loadScript(Reader code) throws Exception {

            d.loadScript(code);

        }

    }

}