/*

 * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved.

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

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

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

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.reflect.annotation;

import java.io.ObjectInputStream;

import java.lang.annotation.*;

import java.lang.reflect.*;

import java.io.Serializable;

import java.util.*;

import java.util.stream.*;

import java.security.AccessController;

import java.security.PrivilegedAction;

/**

 * InvocationHandler for dynamic proxy implementation of Annotation.

 *

 * @author  Josh Bloch

 * @since   1.5

 */

class AnnotationInvocationHandler implements InvocationHandler, Serializable {

    private static final long serialVersionUID = 6182022883658399397L;

    private final Class<? extends Annotation> type;

    private final Map<String, Object> memberValues;

    AnnotationInvocationHandler(Class<? extends Annotation> type, Map<String, Object> memberValues) {

        Class<?>[] superInterfaces = type.getInterfaces();

        if (!type.isAnnotation() ||

            superInterfaces.length != 1 ||

            superInterfaces[0] != java.lang.annotation.Annotation.class)

            throw new AnnotationFormatError("Attempt to create proxy for a non-annotation type.");

        this.type = type;

        this.memberValues = memberValues;

    }

    public Object invoke(Object proxy, Method method, Object[] args) {

        String member = method.getName();

        Class<?>[] paramTypes = method.getParameterTypes();

        // Handle Object and Annotation methods

        if (member.equals("equals") && paramTypes.length == 1 &&

            paramTypes[0] == Object.class)

            return equalsImpl(proxy, args[0]);

        if (paramTypes.length != 0)

            throw new AssertionError("Too many parameters for an annotation method");

        switch(member) {

        case "toString":

            return toStringImpl();

        case "hashCode":

            return hashCodeImpl();

        case "annotationType":

            return type;

        }

        // Handle annotation member accessors

        Object result = memberValues.get(member);

        if (result == null)

            throw new IncompleteAnnotationException(type, member);

        if (result instanceof ExceptionProxy)

            throw ((ExceptionProxy) result).generateException();

        if (result.getClass().isArray() && Array.getLength(result) != 0)

            result = cloneArray(result);

        return result;

    }

    /**

     * This method, which clones its array argument, would not be necessary

     * if Cloneable had a public clone method.

     */

    private Object cloneArray(Object array) {

        Class<?> type = array.getClass();

        if (type == byte[].class) {

            byte[] byteArray = (byte[])array;

            return byteArray.clone();

        }

        if (type == char[].class) {

            char[] charArray = (char[])array;

            return charArray.clone();

        }

        if (type == double[].class) {

            double[] doubleArray = (double[])array;

            return doubleArray.clone();

        }

        if (type == float[].class) {

            float[] floatArray = (float[])array;

            return floatArray.clone();

        }

        if (type == int[].class) {

            int[] intArray = (int[])array;

            return intArray.clone();

        }

        if (type == long[].class) {

            long[] longArray = (long[])array;

            return longArray.clone();

        }

        if (type == short[].class) {

            short[] shortArray = (short[])array;

            return shortArray.clone();

        }

        if (type == boolean[].class) {

            boolean[] booleanArray = (boolean[])array;

            return booleanArray.clone();

        }

        Object[] objectArray = (Object[])array;

        return objectArray.clone();

    }

    /**

     * Implementation of dynamicProxy.toString()

     */

    private String toStringImpl() {

        StringBuilder result = new StringBuilder(128);

        result.append('@');

        result.append(type.getName());

        result.append('(');

        boolean firstMember = true;

        for (Map.Entry<String, Object> e : memberValues.entrySet()) {

            if (firstMember)

                firstMember = false;

            else

                result.append(", ");

            result.append(e.getKey());

            result.append('=');

            result.append(memberValueToString(e.getValue()));

        }

        result.append(')');

        return result.toString();

    }

    /**

     * Translates a member value (in "dynamic proxy return form") into a string.

     */

    private static String memberValueToString(Object value) {

        Class<?> type = value.getClass();

        if (!type.isArray()) {

            // primitive value, string, class, enum const, or annotation

            if (type == Class.class)

                return toSourceString((Class<?>) value);

            else if (type == String.class)

                return  toSourceString((String) value);

            if (type == Character.class)

                return toSourceString((char) value);

            else if (type == Double.class)

                return  toSourceString((double) value);

            else if (type == Float.class)

                return  toSourceString((float) value);

            else if (type == Long.class)

                return  toSourceString((long) value);

            else

                return value.toString();

        } else {

            Stream<String> stringStream;

            if (type == byte[].class)

                stringStream = convert((byte[]) value);

            else if (type == char[].class)

                stringStream = convert((char[]) value);

            else if (type == double[].class)

                stringStream = DoubleStream.of((double[]) value)

                    .mapToObj(AnnotationInvocationHandler::toSourceString);

            else if (type == float[].class)

                stringStream = convert((float[]) value);

            else if (type == int[].class)

                stringStream = IntStream.of((int[]) value).mapToObj(String::valueOf);

            else if (type == long[].class) {

                stringStream = LongStream.of((long[]) value)

                    .mapToObj(AnnotationInvocationHandler::toSourceString);

            } else if (type == short[].class)

                stringStream = convert((short[]) value);

            else if (type == boolean[].class)

                stringStream = convert((boolean[]) value);

            else if (type == Class[].class)

                stringStream =

                    Arrays.stream((Class<?>[]) value).

                    map(AnnotationInvocationHandler::toSourceString);

            else if (type == String[].class)

                stringStream =

                    Arrays.stream((String[])value).

                    map(AnnotationInvocationHandler::toSourceString);

            else

                stringStream = Arrays.stream((Object[])value).map(Objects::toString);

            return stringStreamToString(stringStream);

        }

    }

    /**

     * Translates a Class value to a form suitable for use in the

     * string representation of an annotation.

     */

    private static String toSourceString(Class<?> clazz) {

        Class<?> finalComponent = clazz;

        StringBuilder arrayBackets = new StringBuilder();

        while(finalComponent.isArray()) {

            finalComponent = finalComponent.getComponentType();

            arrayBackets.append("[]");

        }

        return finalComponent.getName() + arrayBackets.toString() + ".class" ;

    }

    private static String toSourceString(float f) {

        if (Float.isFinite(f))

            return Float.toString(f) + "f" ;

        else {

            if (Float.isInfinite(f)) {

                return (f < 0.0f) ? "-1.0f/0.0f": "1.0f/0.0f";

            } else

                return "0.0f/0.0f";

        }

    }

    private static String toSourceString(double d) {

        if (Double.isFinite(d))

            return Double.toString(d);

        else {

            if (Double.isInfinite(d)) {

                return (d < 0.0f) ? "-1.0/0.0": "1.0/0.0";

            } else

                return "0.0/0.0";

        }

    }

    private static String toSourceString(char c) {

        if (c == '\'')

            sb.append("\\'");

        else

            sb.append(c);

    }

    private static String toSourceString(long ell) {

    }

    /**

     * Return a string suitable for use in the string representation

     * of an annotation.

     */

    private static String toSourceString(String s) {

        StringBuilder sb = new StringBuilder();

        sb.append('"');

        // Escape embedded quote characters, if present, but don't do

        // anything more heroic.

        sb.append('"');

        return sb.toString();

    }

    private static Stream<String> convert(byte[] values) {

        List<String> list = new ArrayList<>(values.length);

        for (byte b : values)

            list.add(Byte.toString(b));

        return list.stream();

    }

    private static Stream<String> convert(char[] values) {

        List<String> list = new ArrayList<>(values.length);

        for (char c : values)

            list.add(toSourceString(c));

        return list.stream();

    }

    private static Stream<String> convert(float[] values) {

        List<String> list = new ArrayList<>(values.length);

        for (float f : values) {

            list.add(toSourceString(f));

        }

        return list.stream();

    }

    private static Stream<String> convert(short[] values) {

        List<String> list = new ArrayList<>(values.length);

        for (short s : values)

            list.add(Short.toString(s));

        return list.stream();

    }

    private static Stream<String> convert(boolean[] values) {

        List<String> list = new ArrayList<>(values.length);

        for (boolean b : values)

            list.add(Boolean.toString(b));

        return list.stream();

    }

    private static String stringStreamToString(Stream<String> stream) {

        return stream.collect(Collectors.joining(", ", "{", "}"));

    }

    /**

     * Implementation of dynamicProxy.equals(Object o)

     */

    private Boolean equalsImpl(Object proxy, Object o) {

        if (o == proxy)

            return true;

        if (!type.isInstance(o))

            return false;

        for (Method memberMethod : getMemberMethods()) {

            String member = memberMethod.getName();

            Object ourValue = memberValues.get(member);

            Object hisValue = null;

            AnnotationInvocationHandler hisHandler = asOneOfUs(o);

            if (hisHandler != null) {

                hisValue = hisHandler.memberValues.get(member);

            } else {

                try {

                    hisValue = memberMethod.invoke(o);

                } catch (InvocationTargetException e) {

                    return false;

                } catch (IllegalAccessException e) {

                    throw new AssertionError(e);

                }

            }

            if (!memberValueEquals(ourValue, hisValue))

                return false;

        }

        return true;

    }

    /**

     * Returns an object's invocation handler if that object is a dynamic

     * proxy with a handler of type AnnotationInvocationHandler.

     * Returns null otherwise.

     */

    private AnnotationInvocationHandler asOneOfUs(Object o) {

        if (Proxy.isProxyClass(o.getClass())) {

            InvocationHandler handler = Proxy.getInvocationHandler(o);

            if (handler instanceof AnnotationInvocationHandler)

                return (AnnotationInvocationHandler) handler;

        }

        return null;

    }

    /**

     * Returns true iff the two member values in "dynamic proxy return form"

     * are equal using the appropriate equality function depending on the

     * member type.  The two values will be of the same type unless one of

     * the containing annotations is ill-formed.  If one of the containing

     * annotations is ill-formed, this method will return false unless the

     * two members are identical object references.

     */

    private static boolean memberValueEquals(Object v1, Object v2) {

        Class<?> type = v1.getClass();

        // Check for primitive, string, class, enum const, annotation,

        // or ExceptionProxy

        if (!type.isArray())

            return v1.equals(v2);

        // Check for array of string, class, enum const, annotation,

        // or ExceptionProxy

        if (v1 instanceof Object[] && v2 instanceof Object[])

            return Arrays.equals((Object[]) v1, (Object[]) v2);

        // Check for ill formed annotation(s)

        if (v2.getClass() != type)

            return false;

        // Deal with array of primitives

        if (type == byte[].class)

            return Arrays.equals((byte[]) v1, (byte[]) v2);

        if (type == char[].class)

            return Arrays.equals((char[]) v1, (char[]) v2);

        if (type == double[].class)

            return Arrays.equals((double[]) v1, (double[]) v2);

        if (type == float[].class)

            return Arrays.equals((float[]) v1, (float[]) v2);

        if (type == int[].class)

            return Arrays.equals((int[]) v1, (int[]) v2);

        if (type == long[].class)

            return Arrays.equals((long[]) v1, (long[]) v2);

        if (type == short[].class)

            return Arrays.equals((short[]) v1, (short[]) v2);

        assert type == boolean[].class;

        return Arrays.equals((boolean[]) v1, (boolean[]) v2);

    }

    /**

     * Returns the member methods for our annotation type.  These are

     * obtained lazily and cached, as they're expensive to obtain

     * and we only need them if our equals method is invoked (which should

     * be rare).

     */

    private Method[] getMemberMethods() {

        Method[] value = memberMethods;

        if (value == null) {

            value = computeMemberMethods();

            memberMethods = value;

        }

        return value;

    }

    private Method[] computeMemberMethods() {

        return AccessController.doPrivileged(

            new PrivilegedAction<Method[]>() {

                public Method[] run() {

                    final Method[] methods = type.getDeclaredMethods();

                    validateAnnotationMethods(methods);

                    AccessibleObject.setAccessible(methods, true);

                    return methods;

                }});

    }

    private transient volatile Method[] memberMethods;

    /**

     * Validates that a method is structurally appropriate for an

     * annotation type. As of Java SE 8, annotation types cannot

     * contain static methods and the declared methods of an

     * annotation type must take zero arguments and there are

     * restrictions on the return type.

     */

    private void validateAnnotationMethods(Method[] memberMethods) {

        /*

         * Specification citations below are from JLS

         * 9.6.1. Annotation Type Elements

         */

        boolean valid = true;

        for(Method method : memberMethods) {

            /*

             * "By virtue of the AnnotationTypeElementDeclaration

             * production, a method declaration in an annotation type

             * declaration cannot have formal parameters, type

             * parameters, or a throws clause.

             *

             * "By virtue of the AnnotationTypeElementModifier

             * production, a method declaration in an annotation type

             * declaration cannot be default or static."

             */

            if (method.getModifiers() != (Modifier.PUBLIC | Modifier.ABSTRACT) ||

                method.isDefault() ||

                method.getParameterCount() != 0 ||

                method.getExceptionTypes().length != 0) {

                valid = false;

                break;

            }

            /*

             * "It is a compile-time error if the return type of a

             * method declared in an annotation type is not one of the

             * following: a primitive type, String, Class, any

             * parameterized invocation of Class, an enum type

             * (section 8.9), an annotation type, or an array type

             * (chapter 10) whose element type is one of the preceding

             * types."

             */

            Class<?> returnType = method.getReturnType();

            if (returnType.isArray()) {

                returnType = returnType.getComponentType();

                if (returnType.isArray()) { // Only single dimensional arrays

                    valid = false;

                    break;

                }

            }

            if (!((returnType.isPrimitive() && returnType != void.class) ||

                  returnType == java.lang.String.class ||

                  returnType == java.lang.Class.class ||

                  returnType.isEnum() ||

                  returnType.isAnnotation())) {

                valid = false;

                break;

            }

            /*

             * "It is a compile-time error if any method declared in an

             * annotation type has a signature that is

             * override-equivalent to that of any public or protected

             * method declared in class Object or in the interface