/*
 * Copyright 2002-2015 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.core.type.classreading;

import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.springframework.asm.AnnotationVisitor;
import org.springframework.asm.MethodVisitor;
import org.springframework.asm.Opcodes;
import org.springframework.asm.Type;
import org.springframework.core.annotation.AnnotationAttributes;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.core.type.MethodMetadata;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;

/**
 * ASM class visitor which looks for the class name and implemented types as
 * well as for the annotations defined on the class, exposing them through
 * the {@link org.springframework.core.type.AnnotationMetadata} interface.
 *
 * @author Juergen Hoeller
 * @author Mark Fisher
 * @author Costin Leau
 * @author Phillip Webb
 * @author Sam Brannen
 * @since 2.5
 */
public class AnnotationMetadataReadingVisitor extends ClassMetadataReadingVisitor implements AnnotationMetadata {

        protected final ClassLoader classLoader;

        protected final Set<String> annotationSet = new LinkedHashSet<String>(4);

        protected final Map<String, Set<String>> metaAnnotationMap = new LinkedHashMap<String, Set<String>>(4);

        /**
         * Declared as a {@link LinkedMultiValueMap} instead of a {@link MultiValueMap}
         * to ensure that the hierarchical ordering of the entries is preserved.
         * @see AnnotationReadingVisitorUtils#getMergedAnnotationAttributes
         */
        protected final LinkedMultiValueMap<String, AnnotationAttributes> attributesMap =
                        new LinkedMultiValueMap<String, AnnotationAttributes>(4);

        protected final Set<MethodMetadata> methodMetadataSet = new LinkedHashSet<MethodMetadata>(4);


        public AnnotationMetadataReadingVisitor(ClassLoader classLoader) {
                this.classLoader = classLoader;
        }


        @Override
        public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
                // Skip bridge methods - we're only interested in original annotation-defining user methods.
                // On JDK 8, we'd otherwise run into double detection of the same annotated method...
                if ((access & Opcodes.ACC_BRIDGE) != 0) {
                        return super.visitMethod(access, name, desc, signature, exceptions);
                }
                return new MethodMetadataReadingVisitor(name, access, getClassName(),
                                Type.getReturnType(desc).getClassName(), this.classLoader, this.methodMetadataSet);
        }

        @Override
        public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
                String className = Type.getType(desc).getClassName();
                this.annotationSet.add(className);
                return new AnnotationAttributesReadingVisitor(
                                className, this.attributesMap, this.metaAnnotationMap, this.classLoader);
        }


        @Override
        public Set<String> getAnnotationTypes() {
                return this.annotationSet;
        }

        @Override
        public Set<String> getMetaAnnotationTypes(String annotationName) {
                return this.metaAnnotationMap.get(annotationName);
        }

        @Override
        public boolean hasAnnotation(String annotationName) {
                return this.annotationSet.contains(annotationName);
        }

        @Override
        public boolean hasMetaAnnotation(String metaAnnotationType) {
                Collection<Set<String>> allMetaTypes = this.metaAnnotationMap.values();
                for (Set<String> metaTypes : allMetaTypes) {
                        if (metaTypes.contains(metaAnnotationType)) {
                                return true;
                        }
                }
                return false;
        }

        @Override
        public boolean isAnnotated(String annotationName) {
                return (!AnnotationUtils.isInJavaLangAnnotationPackage(annotationName) &&
                                this.attributesMap.containsKey(annotationName));
        }

        @Override
        public AnnotationAttributes getAnnotationAttributes(String annotationName) {
                return getAnnotationAttributes(annotationName, false);
        }

        @Override
        public AnnotationAttributes getAnnotationAttributes(String annotationName, boolean classValuesAsString) {
                AnnotationAttributes raw = AnnotationReadingVisitorUtils.getMergedAnnotationAttributes(
                                this.attributesMap, this.metaAnnotationMap, annotationName);
                return AnnotationReadingVisitorUtils.convertClassValues(
                                "class '" + getClassName() + "'", this.classLoader, raw, classValuesAsString);
        }

        @Override
        public MultiValueMap<String, Object> getAllAnnotationAttributes(String annotationName) {
                return getAllAnnotationAttributes(annotationName, false);
        }

        @Override
        public MultiValueMap<String, Object> getAllAnnotationAttributes(String annotationName, boolean classValuesAsString) {
                MultiValueMap<String, Object> allAttributes = new LinkedMultiValueMap<String, Object>();
                List<AnnotationAttributes> attributes = this.attributesMap.get(annotationName);
                if (attributes == null) {
                        return null;
                }
                for (AnnotationAttributes raw : attributes) {
                        for (Map.Entry<String, Object> entry : AnnotationReadingVisitorUtils.convertClassValues(
                                        "class '" + getClassName() + "'", this.classLoader, raw, classValuesAsString).entrySet()) {
                                allAttributes.add(entry.getKey(), entry.getValue());
                        }
                }
                return allAttributes;
        }

        @Override
        public boolean hasAnnotatedMethods(String annotationName) {
                for (MethodMetadata methodMetadata : this.methodMetadataSet) {
                        if (methodMetadata.isAnnotated(annotationName)) {
                                return true;
                        }
                }
                return false;
        }

        @Override
        public Set<MethodMetadata> getAnnotatedMethods(String annotationName) {
                Set<MethodMetadata> annotatedMethods = new LinkedHashSet<MethodMetadata>(4);
                for (MethodMetadata methodMetadata : this.methodMetadataSet) {
                        if (methodMetadata.isAnnotated(annotationName)) {
                                annotatedMethods.add(methodMetadata);
                        }
                }
                return annotatedMethods;
        }

}