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/*
 * Copyright (c) 2023, 2024 Oracle and/or its affiliates.
 *
 * 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
 *
 *     http://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 io.helidon.codegen.scan;

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import io.helidon.common.types.Annotation;
import io.helidon.common.types.EnumValue;
import io.helidon.common.types.TypeName;

import io.github.classgraph.AnnotationClassRef;
import io.github.classgraph.AnnotationEnumValue;
import io.github.classgraph.AnnotationInfo;
import io.github.classgraph.AnnotationParameterValue;
import io.github.classgraph.AnnotationParameterValueList;

/**
 * Factory for annotations.
 */
final class ScanAnnotationFactory {
    private ScanAnnotationFactory() {
    }

    /**
     * Creates an instance from an annotation mirror during annotation processing.
     *
     * @param ctx processing context
     * @param am  the annotation mirror
     * @return the new instance or empty if the annotation mirror passed is invalid
     */
    public static Annotation createAnnotation(ScanContext ctx,
                                              AnnotationInfo am) {
        TypeName typeName = ScanTypeFactory.create(am.getClassInfo());

        return Annotation.create(typeName, extractAnnotationValues(ctx, am));
    }

    /**
     * Extracts values from the annotation mirror value.
     *
     * @param ctx the processing context
     * @param am  the annotation mirror
     * @return the extracted values
     */
    private static Map extractAnnotationValues(ScanContext ctx,
                                                               AnnotationInfo am) {

        Map result = new LinkedHashMap<>();
        AnnotationParameterValueList parameterValues = am.getParameterValues();
        for (AnnotationParameterValue parameterValue : parameterValues) {
            String name = parameterValue.getName();
            Object value = parameterValue.getValue();
            if (value != null) {
                result.put(name, toAnnotationValue(ctx, value));
            }
        }

        return result;
    }

    private static Object toAnnotationValue(ScanContext ctx, Object scanAnnotationValue) {
        if (scanAnnotationValue.getClass().isArray()) {
            List