/*
 * Copyright 2011-2020 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.data.mapping.model;

import lombok.AccessLevel;
import lombok.Getter;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Collections;
import java.util.Map;
import java.util.Optional;

import org.springframework.data.annotation.Reference;
import org.springframework.data.mapping.Association;
import org.springframework.data.mapping.PersistentEntity;
import org.springframework.data.mapping.PersistentProperty;
import org.springframework.data.util.Lazy;
import org.springframework.data.util.ReflectionUtils;
import org.springframework.data.util.TypeInformation;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

Simple implementation of PersistentProperty. 
Author:
Jon Brisbin, Oliver Gierke, Christoph Strobl, Mark Paluch/**
 * Simple implementation of {@link PersistentProperty}.
 *
 * @author Jon Brisbin
 * @author Oliver Gierke
 * @author Christoph Strobl
 * @author Mark Paluch
 */
public abstract class AbstractPersistentProperty<P extends PersistentProperty<P>> implements PersistentProperty<P> {

	private static final Field CAUSE_FIELD;

	static {
		CAUSE_FIELD = ReflectionUtils.findRequiredField(Throwable.class, "cause");
	}

	private final String name;
	private final TypeInformation<?> information;
	private final Class<?> rawType;
	private final Lazy<Association<P>> association;
	private final @Getter PersistentEntity<?, P> owner;

	@SuppressWarnings("null") //
	private final @Getter(value = AccessLevel.PROTECTED, onMethod = @__(@SuppressWarnings("null"))) Property property;
	private final Lazy<Integer> hashCode;
	private final Lazy<Boolean> usePropertyAccess;
	private final Lazy<Optional<? extends TypeInformation<?>>> entityTypeInformation;

	private final @Getter(onMethod = @__(@Nullable)) Method getter;
	private final @Getter(onMethod = @__(@Nullable)) Method setter;
	private final @Getter(onMethod = @__(@Nullable)) Field field;
	private final @Getter(onMethod = @__(@Nullable)) Method wither;
	private final boolean immutable;

	public AbstractPersistentProperty(Property property, PersistentEntity<?, P> owner,
			SimpleTypeHolder simpleTypeHolder) {

		Assert.notNull(simpleTypeHolder, "SimpleTypeHolder must not be null!");
		Assert.notNull(owner, "Owner entity must not be null!");

		this.name = property.getName();
		this.information = owner.getTypeInformation().getRequiredProperty(getName());
		this.rawType = this.information.getType();
		this.property = property;
		this.association = Lazy.of(() -> isAssociation() ? createAssociation() : null);
		this.owner = owner;

		this.hashCode = Lazy.of(property::hashCode);
		this.usePropertyAccess = Lazy.of(() -> owner.getType().isInterface() || CAUSE_FIELD.equals(getField()));

		this.entityTypeInformation = Lazy.of(() -> Optional.ofNullable(information.getActualType())//
				.filter(it -> !simpleTypeHolder.isSimpleType(it.getType()))//
				.filter(it -> !it.isCollectionLike())//
				.filter(it -> !it.isMap()));

		this.getter = property.getGetter().orElse(null);
		this.setter = property.getSetter().orElse(null);
		this.field = property.getField().orElse(null);
		this.wither = property.getWither().orElse(null);

		if (setter == null && (field == null || Modifier.isFinal(field.getModifiers()))) {
			this.immutable = true;
		} else {
			this.immutable = false;
		}
	}

	protected abstract Association<P> createAssociation();

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#getName()
	 */
	@Override
	public String getName() {
		return name;
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#getType()
	 */
	@Override
	public Class<?> getType() {
		return information.getType();
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#getRawType()
	 */
	@Override
	public Class<?> getRawType() {
		return this.rawType;
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#getTypeInformation()
	 */
	@Override
	public TypeInformation<?> getTypeInformation() {
		return information;
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#getPersistentEntityTypes()
	 */
	@Override
	public Iterable<? extends TypeInformation<?>> getPersistentEntityTypes() {

		if (!isEntity()) {
			return Collections.emptySet();
		}

		return entityTypeInformation.get()//
				.map(Collections::singleton)//
				.orElseGet(Collections::emptySet);
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#getSpelExpression()
	 */
	@Override
	@Nullable
	public String getSpelExpression() {
		return null;
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#isTransient()
	 */
	@Override
	public boolean isTransient() {
		return false;
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#isWritable()
	 */
	@Override
	public boolean isWritable() {
		return !isTransient();
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#isImmutable()
	 */
	@Override
	public boolean isImmutable() {
		return immutable;
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#isAssociation()
	 */
	@Override
	public boolean isAssociation() {
		return isAnnotationPresent(Reference.class);
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#getAssociation()
	 */
	@Nullable
	@Override
	public Association<P> getAssociation() {
		return association.orElse(null);
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#isCollectionLike()
	 */
	@Override
	public boolean isCollectionLike() {
		return information.isCollectionLike();
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#isMap()
	 */
	@Override
	public boolean isMap() {
		return Map.class.isAssignableFrom(getType());
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#isArray()
	 */
	@Override
	public boolean isArray() {
		return getType().isArray();
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#isEntity()
	 */
	@Override
	public boolean isEntity() {
		return !isTransient() && entityTypeInformation.get().isPresent();
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#getComponentType()
	 */
	@Nullable
	@Override
	public Class<?> getComponentType() {
		return isMap() || isCollectionLike() ? information.getRequiredComponentType().getType() : null;
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#getMapValueType()
	 */
	@Nullable
	@Override
	public Class<?> getMapValueType() {

		if (isMap()) {

			TypeInformation<?> mapValueType = information.getMapValueType();
			if (mapValueType != null) {
				return mapValueType.getType();
			}
		}

		return null;
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.PersistentProperty#getActualType()
	 */
	@Override
	public Class<?> getActualType() {
		return information.getRequiredActualType().getType();
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mongodb.core.mapping.MongoPersistentProperty#usePropertyAccess()
	 */
	public boolean usePropertyAccess() {
		return usePropertyAccess.get();
	}

	/*
	 * (non-Javadoc)
	 * @see java.lang.Object#equals(java.lang.Object)
	 */
	@Override
	public boolean equals(@Nullable Object obj) {

		if (this == obj) {
			return true;
		}

		if (!(obj instanceof AbstractPersistentProperty)) {
			return false;
		}

		AbstractPersistentProperty<?> that = (AbstractPersistentProperty<?>) obj;

		return this.property.equals(that.property);
	}

	/*
	 * (non-Javadoc)
	 * @see java.lang.Object#hashCode()
	 */
	@Override
	public int hashCode() {
		return this.hashCode.get();
	}

	/*
	 * (non-Javadoc)
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {
		return property.toString();
	}
}