/*
 * Copyright 2017-2020 original 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 io.micronaut.inject.ast;

import io.micronaut.core.annotation.AnnotationMetadata;
import io.micronaut.core.annotation.NonNull;
import io.micronaut.core.annotation.ReflectiveAccess;

import java.util.Collections;
import java.util.Set;

/**
 * A member element is an element that is contained within a {@link ClassElement}.
 * The {@link #getDeclaringType()} method returns the class that declares the element.
 *
 * @author graemerocher
 * @since 1.0
 */
public interface MemberElement extends Element {

    /**
     * @return The declaring type of the element.
     */
    ClassElement getDeclaringType();

    /**
     * The owing type is the type that owns this element. This can differ from {@link #getDeclaringType()}
     * in the case of inheritance since this method will return the subclass that owners the inherited member,
     * whilst {@link #getDeclaringType()} will return the super class that declares the type.
     *
     * @return The owning type.
     */
    default ClassElement getOwningType() {
        return getDeclaringType();
    }

    /**
     * @return The {@link ElementModifier} types for this class element
     * @since 3.0.0
     */
    default Set<ElementModifier> getModifiers() {
        return Collections.emptySet();
    }

    /**
     * Returns whether this member element will require reflection to invoke or retrieve at runtime.
     *
     * <p>This method uses {@link #getOwningType()} as the calling type for this method.</p>
     *
     * @return Will return {@code true} if reflection is required.
     * @since 3.4.0
     */
    default boolean isReflectionRequired() {
        return isReflectionRequired(getOwningType());
    }

    /**
     * Returns whether this member element will require reflection to invoke or retrieve at runtime.
     *
     * @param callingType The calling type
     * @return Will return {@code true} if reflection is required.
     * @since 3.4.0
     */
    default boolean isReflectionRequired(@NonNull ClassElement callingType) {
        if (isPublic()) {
            return false;
        }
        if (isPackagePrivate() || isProtected()) {
            // the declaring type might be a super class in which
            // case if the super class is in a different package then
            // the method or field is not visible and hence reflection is required
            final ClassElement declaringType = getDeclaringType();
            return !declaringType.getPackageName().equals(callingType.getPackageName());
        }
        return isPrivate();
    }

    /**
     * Returns whether this member element can be invoked or retrieved at runtime.
     * It can be accessible by a simple invocation or a reflection invocation.
     *
     * <p>This method uses {@link #isReflectionRequired()} with a checks if the reflection access is allowed.
     * By checking for {@link io.micronaut.core.annotation.ReflectiveAccess} annotation.
     * </p>
     *
     * @return Will return {@code true} if is accessible.
     * @since 3.7.0
     */
    default boolean isAccessible() {
        return isAccessible(getOwningType());
    }

    /**
     * Returns whether this member element can be invoked or retrieved at runtime.
     * It can be accessible by a simple invocation or a reflection invocation.
     *
     * <p>This method uses {@link #isReflectionRequired()} with a checks if the reflection access is allowed.
     * By checking for {@link io.micronaut.core.annotation.ReflectiveAccess} annotation.
     * </p>
     *
     * @param callingType The calling type
     * @return Will return {@code true} if is accessible.
     * @since 3.7.0
     */
    default boolean isAccessible(@NonNull ClassElement callingType) {
        return !isReflectionRequired(callingType) || hasAnnotation(ReflectiveAccess.class);
    }

    @Override
    default MemberElement withAnnotationMetadata(AnnotationMetadata annotationMetadata) {
        return (MemberElement) Element.super.withAnnotationMetadata(annotationMetadata);
    }

    /**
     * Checks if this member element hides another.
     *
     * @param hidden The possibly hidden element
     * @return true if this member element hides passed field element
     * @since 4.0.0
     */
    default boolean hides(@NonNull MemberElement hidden) {
        return false;
    }
}
