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/*
 * Copyright 2018-2021 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.r2dbc.convert;

import io.r2dbc.spi.Row;
import io.r2dbc.spi.RowMetadata;
import org.springframework.core.CollectionFactory;
import org.springframework.core.convert.ConversionService;
import org.springframework.dao.InvalidDataAccessApiUsageException;
import org.springframework.data.convert.CustomConversions;
import org.springframework.data.mapping.MappingException;
import org.springframework.data.mapping.PersistentProperty;
import org.springframework.data.mapping.PersistentPropertyAccessor;
import org.springframework.data.mapping.PreferredConstructor;
import org.springframework.data.mapping.context.MappingContext;
import org.springframework.data.mapping.model.*;
import org.springframework.data.r2dbc.mapping.OutboundRow;
import org.springframework.data.r2dbc.support.ArrayUtils;
import org.springframework.data.r2dbc.support.FastMethodInvoker;
import org.springframework.data.r2dbc.support.SqlField;
import org.springframework.data.relational.core.conversion.BasicRelationalConverter;
import org.springframework.data.relational.core.conversion.RelationalConverter;
import org.springframework.data.relational.core.dialect.ArrayColumns;
import org.springframework.data.relational.core.mapping.RelationalPersistentEntity;
import org.springframework.data.relational.core.mapping.RelationalPersistentProperty;
import org.springframework.data.util.ClassTypeInformation;
import org.springframework.data.util.TypeInformation;
import org.springframework.lang.Nullable;
import org.springframework.r2dbc.core.Parameter;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.CollectionUtils;

import java.util.*;
import java.util.function.BiFunction;

/**
 * Converter for R2DBC.
 *
 * @author Mark Paluch
 * @author Oliver Drotbohm
 */
public class MappingR2dbcConverter extends BasicRelationalConverter implements R2dbcConverter {

	/**
	 * Creates a new {@link MappingR2dbcConverter} given {@link MappingContext}.
	 *
	 * @param context must not be {@literal null}.
	 */
	public MappingR2dbcConverter(
			MappingContext, ? extends RelationalPersistentProperty> context) {
		super(context, new R2dbcCustomConversions(R2dbcCustomConversions.STORE_CONVERSIONS, Collections.emptyList()));
	}

	/**
	 * Creates a new {@link MappingR2dbcConverter} given {@link MappingContext} and {@link CustomConversions}.
	 *
	 * @param context must not be {@literal null}.
	 */
	public MappingR2dbcConverter(
			MappingContext, ? extends RelationalPersistentProperty> context,
			CustomConversions conversions) {
		super(context, conversions);
	}

	// ----------------------------------
	// Entity reading
	// ----------------------------------

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.convert.EntityReader#read(java.lang.Class, S)
	 */
	@Override
	public  R read(Class type, Row row) {
		return read(type, row, null);
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.r2dbc.convert.R2dbcConverter#read(java.lang.Class, io.r2dbc.spi.Row, io.r2dbc.spi.RowMetadata)
	 */
	@Override
	public  R read(Class type, Row row, @Nullable RowMetadata metadata) {

		TypeInformation typeInfo = ClassTypeInformation.from(type);
		Class rawType = typeInfo.getType();

		if (Row.class.isAssignableFrom(rawType)) {
			return type.cast(row);
		}

		if (getConversions().hasCustomReadTarget(Row.class, rawType)
				&& getConversionService().canConvert(Row.class, rawType)) {
			return getConversionService().convert(row, rawType);
		}

		return read(getRequiredPersistentEntity(type), row, metadata);
	}

	private  R read(RelationalPersistentEntity entity, Row row, @Nullable RowMetadata metadata) {

		R result = createInstance(row, metadata, "", entity);

		if (entity.requiresPropertyPopulation()) {
			ConvertingPropertyAccessor propertyAccessor = new ConvertingPropertyAccessor<>(
					entity.getPropertyAccessor(result), getConversionService());

			for (RelationalPersistentProperty property : entity) {

				if (entity.isConstructorArgument(property)) {
					continue;
				}

				Object value = readFrom(row, metadata, property, "");

				if (value != null) {
					propertyAccessor.setProperty(property, value);
				}
			}
		}

		return result;
	}

	/**
	 * Read a single value or a complete Entity from the {@link Row} passed as an argument.
	 *
	 * @param row the {@link Row} to extract the value from. Must not be {@literal null}.
	 * @param metadata the {@link RowMetadata}. Can be {@literal null}.
	 * @param property the {@link RelationalPersistentProperty} for which the value is intended. Must not be
	 *          {@literal null}.
	 * @param prefix to be used for all column names accessed by this method. Must not be {@literal null}.
	 * @return the value read from the {@link Row}. May be {@literal null}.
	 */
	@Nullable
	private Object readFrom(Row row, @Nullable RowMetadata metadata, RelationalPersistentProperty property,
							String prefix) {

		String identifier = prefix + property.getColumnName().getReference();

		try {

			Object value = null;
			if (metadata == null || metadata.getColumnNames().contains(identifier)) {
				value = row.get(identifier);
			}

			if (value == null) {
				return null;
			}

			if (getConversions().hasCustomReadTarget(value.getClass(), property.getType())) {
				return readValue(value, property.getTypeInformation());
			}

			if (property.isEntity()) {
				return readEntityFrom(row, metadata, property);
			}

			return readValue(value, property.getTypeInformation());

		} catch (Exception o_O) {
			throw new MappingException(String.format("Could not read property %s from column %s!", property, identifier),
					o_O);
		}
	}


	public Object readValue(@Nullable Object value, TypeInformation type) {

		if (null == value) {
			return null;
		}

		if (getConversions().hasCustomReadTarget(value.getClass(), type.getType())) {
			return getConversionService().convert(value, type.getType());
		} else if (value instanceof Collection || value.getClass().isArray()) {
			return readCollectionOrArray(asCollection(value), type);
		} else {
			return getPotentiallyConvertedSimpleRead(value, type.getType());
		}
	}

	/**
	 * Reads the given value into a collection of the given {@link TypeInformation}.
	 *
	 * @param source must not be {@literal null}.
	 * @param targetType must not be {@literal null}.
	 * @return the converted {@link Collection} or array, will never be {@literal null}.
	 */
	@SuppressWarnings("unchecked")
	private Object readCollectionOrArray(Collection source, TypeInformation targetType) {

		Assert.notNull(targetType, "Target type must not be null!");

		Class collectionType = targetType.isSubTypeOf(Collection.class) //
				? targetType.getType() //
				: List.class;

		TypeInformation componentType = targetType.getComponentType() != null //
				? targetType.getComponentType() //
				: ClassTypeInformation.OBJECT;
		Class rawComponentType = componentType.getType();

		Collection items = targetType.getType().isArray() //
				? new ArrayList<>(source.size()) //
				: CollectionFactory.createCollection(collectionType, rawComponentType, source.size());

		if (source.isEmpty()) {
			return getPotentiallyConvertedSimpleRead(items, targetType.getType());
		}

		for (Object element : source) {

			if (!Object.class.equals(rawComponentType) && element instanceof Collection) {
				if (!rawComponentType.isArray() && !ClassUtils.isAssignable(Iterable.class, rawComponentType)) {
					throw new MappingException(String.format(
							"Cannot convert %1$s of type %2$s into an instance of %3$s! Implement a custom Converter<%2$s, %3$s> and register it with the CustomConversions",
							element, element.getClass(), rawComponentType));
				}
			}
			if (element instanceof List) {
				items.add(readCollectionOrArray((Collection) element, componentType));
			} else {
				items.add(getPotentiallyConvertedSimpleRead(element, rawComponentType));
			}
		}

		return getPotentiallyConvertedSimpleRead(items, targetType.getType());
	}

	/**
	 * Checks whether we have a custom conversion for the given simple object. Converts the given value if so, applies
	 * {@link Enum} handling or returns the value as is.
	 *
	 * @param value
	 * @param target must not be {@literal null}.
	 * @return
	 */
	@Nullable
	@SuppressWarnings({ "rawtypes", "unchecked" })
	private Object getPotentiallyConvertedSimpleRead(@Nullable Object value, @Nullable Class target) {

		if (value == null || target == null || ClassUtils.isAssignableValue(target, value)) {
			return value;
		}

		if (getConversions().hasCustomReadTarget(value.getClass(), target)) {
			return getConversionService().convert(value, target);
		}

		if (Enum.class.isAssignableFrom(target)) {
			return Enum.valueOf((Class) target, value.toString());
		}

		return getConversionService().convert(value, target);
	}

	@SuppressWarnings("unchecked")
	private  S readEntityFrom(Row row, @Nullable RowMetadata metadata, PersistentProperty property) {

		String prefix = property.getName() + "_";

		RelationalPersistentEntity entity = getMappingContext().getRequiredPersistentEntity(property.getActualType());

		if (entity.hasIdProperty()) {
			if (readFrom(row, metadata, entity.getRequiredIdProperty(), prefix) == null) {
				return null;
			}
		}

		Object instance = createInstance(row, metadata, prefix, entity);

		if (entity.requiresPropertyPopulation()) {
			PersistentPropertyAccessor accessor = entity.getPropertyAccessor(instance);
			ConvertingPropertyAccessor propertyAccessor = new ConvertingPropertyAccessor<>(accessor,
					getConversionService());

			for (RelationalPersistentProperty p : entity) {
				if (!entity.isConstructorArgument(property)) {
					propertyAccessor.setProperty(p, readFrom(row, metadata, p, prefix));
				}
			}
		}

		return (S) instance;
	}

	private  S createInstance(Row row, @Nullable RowMetadata rowMetadata, String prefix,
								 RelationalPersistentEntity entity) {

		PreferredConstructor persistenceConstructor = entity.getPersistenceConstructor();
		ParameterValueProvider provider;

		if (persistenceConstructor != null && persistenceConstructor.hasParameters()) {

			SpELContext spELContext = new SpELContext(new RowPropertyAccessor(rowMetadata));
			SpELExpressionEvaluator expressionEvaluator = new DefaultSpELExpressionEvaluator(row, spELContext);
			provider = new SpELExpressionParameterValueProvider<>(expressionEvaluator, getConversionService(),
					new RowParameterValueProvider(row, rowMetadata, entity, this, prefix));
		} else {
			provider = NoOpParameterValueProvider.INSTANCE;
		}

		return createInstance(entity, provider::getParameterValue);
	}

	// ----------------------------------
	// Entity writing
	// ----------------------------------

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.convert.EntityWriter#write(java.lang.Object, java.lang.Object)
	 */
	@Override
	public void write(Object source, OutboundRow sink) {

		Class userClass = ClassUtils.getUserClass(source);

		Optional> customTarget = getConversions().getCustomWriteTarget(userClass, OutboundRow.class);
		if (customTarget.isPresent()) {

			OutboundRow result = getConversionService().convert(source, OutboundRow.class);
			sink.putAll(result);
			return;
		}

		writeInternal(source, sink, userClass);
	}

	private void writeInternal(Object source, OutboundRow sink, Class userClass) {

		RelationalPersistentEntity entity = getRequiredPersistentEntity(userClass);
		PersistentPropertyAccessor propertyAccessor = entity.getPropertyAccessor(source);

		writeProperties(sink, entity, propertyAccessor, entity.isNew(source));
	}

	private void writeProperties(OutboundRow sink, RelationalPersistentEntity entity,
								 PersistentPropertyAccessor accessor, boolean isNew) {

		for (RelationalPersistentProperty property : entity) {

			if (!property.isWritable()) {
				continue;
			}

			Object value = accessor.getProperty(property);

			if (value == null) {
				writeNullInternal(sink, property);
				continue;
			}

			if (getConversions().isSimpleType(value.getClass())) {
				writeSimpleInternal(sink, value, isNew, property);
			} else {
				writePropertyInternal(sink, value, isNew, property);
			}
		}
	}

	private void writeSimpleInternal(OutboundRow sink, Object value, boolean isNew,
									 RelationalPersistentProperty property) {

		Object result = getPotentiallyConvertedSimpleWrite(value);

		sink.put(property.getColumnName(),
				Parameter.fromOrEmpty(result, getPotentiallyConvertedSimpleNullType(property.getType())));
	}

	private void writePropertyInternal(OutboundRow sink, Object value, boolean isNew,
									   RelationalPersistentProperty property) {

		TypeInformation valueType = ClassTypeInformation.from(value.getClass());

		if (valueType.isCollectionLike()) {

			if (valueType.getActualType() != null && valueType.getRequiredActualType().isCollectionLike()) {

				// pass-thru nested collections
				writeSimpleInternal(sink, value, isNew, property);
				return;
			}

			List collectionInternal = createCollection(asCollection(value), property);
			sink.put(property.getColumnName(), Parameter.from(collectionInternal));
			return;
		}

		throw new InvalidDataAccessApiUsageException("Nested entities are not supported");
	}

	/**
	 * Writes the given {@link Collection} using the given {@link RelationalPersistentProperty} information.
	 *
	 * @param collection must not be {@literal null}.
	 * @param property must not be {@literal null}.
	 * @return
	 */
	protected List createCollection(Collection collection, RelationalPersistentProperty property) {
		return writeCollectionInternal(collection, property.getTypeInformation(), new ArrayList<>());
	}

	/**
	 * Populates the given {@link Collection sink} with converted values from the given {@link Collection source}.
	 *
	 * @param source the collection to create a {@link Collection} for, must not be {@literal null}.
	 * @param type the {@link TypeInformation} to consider or {@literal null} if unknown.
	 * @param sink the {@link Collection} to write to.
	 * @return
	 */
	@SuppressWarnings("unchecked")
	private List writeCollectionInternal(Collection source, @Nullable TypeInformation type,
												 Collection sink) {

		TypeInformation componentType = null;

		List collection = sink instanceof List ? (List) sink : new ArrayList<>(sink);

		if (type != null) {
			componentType = type.getComponentType();
		}

		for (Object element : source) {

			Class elementType = element == null ? null : element.getClass();

			if (elementType == null || getConversions().isSimpleType(elementType)) {
				collection.add(getPotentiallyConvertedSimpleWrite(element,
						componentType != null ? componentType.getType() : Object.class));
			} else if (element instanceof Collection || elementType.isArray()) {
				collection.add(writeCollectionInternal(asCollection(element), componentType, new ArrayList<>()));
			} else {
				throw new InvalidDataAccessApiUsageException("Nested entities are not supported");
			}
		}

		return collection;
	}

	private void writeNullInternal(OutboundRow sink, RelationalPersistentProperty property) {

		sink.put(property.getColumnName(), Parameter.empty(getPotentiallyConvertedSimpleNullType(property.getType())));
	}

	private Class getPotentiallyConvertedSimpleNullType(Class type) {

		Optional> customTarget = getConversions().getCustomWriteTarget(type);

		if (customTarget.isPresent()) {
			return customTarget.get();

		}

		if (type.isEnum()) {
			return String.class;
		}

		return type;
	}

	/**
	 * Checks whether we have a custom conversion registered for the given value into an arbitrary simple type. Returns
	 * the converted value if so. If not, we perform special enum handling or simply return the value as is.
	 *
	 * @param value
	 * @return
	 */
	@Nullable
	private Object getPotentiallyConvertedSimpleWrite(@Nullable Object value) {
		return getPotentiallyConvertedSimpleWrite(value, Object.class);
	}

	/**
	 * Checks whether we have a custom conversion registered for the given value into an arbitrary simple type. Returns
	 * the converted value if so. If not, we perform special enum handling or simply return the value as is.
	 *
	 * @param value
	 * @return
	 */
	@Nullable
	private Object getPotentiallyConvertedSimpleWrite(@Nullable Object value, Class typeHint) {

		if (value == null) {
			return null;
		}

		if (Object.class != typeHint) {

			if (getConversionService().canConvert(value.getClass(), typeHint)) {
				value = getConversionService().convert(value, typeHint);
			}
		}

		Optional> customTarget = getConversions().getCustomWriteTarget(value.getClass());

		if (customTarget.isPresent()) {
			return getConversionService().convert(value, customTarget.get());
		}

		return Enum.class.isAssignableFrom(value.getClass()) ? ((Enum) value).name() : value;
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.r2dbc.convert.R2dbcConverter#getArrayValue(org.springframework.data.r2dbc.dialect.ArrayColumns, org.springframework.data.relational.core.mapping.RelationalPersistentProperty, java.lang.Object)
	 */
	@Override
	public Object getArrayValue(ArrayColumns arrayColumns, RelationalPersistentProperty property, Object value) {

		Class actualType = null;
		if (value instanceof Collection) {
			actualType = CollectionUtils.findCommonElementType((Collection) value);
		} else if (value.getClass().isArray()) {
			actualType = value.getClass().getComponentType();
		}

		if (actualType == null) {
			actualType = property.getActualType();
		}

		Class targetType = arrayColumns.getArrayType(actualType);

		if (!property.isArray() || !targetType.isAssignableFrom(value.getClass())) {

			int depth = value.getClass().isArray() ? ArrayUtils.getDimensionDepth(value.getClass()) : 1;
			Class targetArrayType = ArrayUtils.getArrayClass(targetType, depth);
			return getConversionService().convert(value, targetArrayType);
		}

		return value;
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.r2dbc.convert.R2dbcConverter#getTargetType(Class)
	 */
	@Override
	public Class getTargetType(Class valueType) {

		Optional> writeTarget = getConversions().getCustomWriteTarget(valueType);

		return writeTarget.orElseGet(() -> {
			return Enum.class.isAssignableFrom(valueType) ? String.class : valueType;
		});
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.r2dbc.convert.R2dbcConverter#isSimpleType(Class)
	 */
	@Override
	public boolean isSimpleType(Class type) {
		return getConversions().isSimpleType(type);
	}

	// ----------------------------------
	// Id handling
	// ----------------------------------

	/**
	 * Returns a {@link java.util.function.Function} that populates the id property of the {@code object} from a
	 * {@link Row}.
	 *
	 * @param object must not be {@literal null}.
	 * @return
	 */
	@Override
	@SuppressWarnings("unchecked")
	public  BiFunction populateIdIfNecessary(T object) {

		Assert.notNull(object, "Entity object must not be null!");

		Class userClass = ClassUtils.getUserClass(object);
		RelationalPersistentEntity entity = getMappingContext().getRequiredPersistentEntity(userClass);

		return (row, metadata) -> {
			PersistentPropertyAccessor propertyAccessor = entity.getPropertyAccessor(object);
			RelationalPersistentProperty idProperty = null;
			if (FastMethodInvoker.has(object, SqlField.id)) {
				RelationalPersistentEntity persist = getMappingContext().getPersistentEntity(object.getClass());
				idProperty = persist.getPersistentProperty(SqlField.id);
			} else {
				idProperty = entity.getRequiredIdProperty();
			}

			boolean idPropertyUpdateNeeded = false;

			Object id = propertyAccessor.getProperty(idProperty);
			if (idProperty.getType().isPrimitive()) {
				idPropertyUpdateNeeded = id instanceof Number && ((Number) id).longValue() == 0;
			} else {
				idPropertyUpdateNeeded = id == null;
			}

			if (idPropertyUpdateNeeded) {
				return potentiallySetId(row, metadata, propertyAccessor, idProperty) //
						? (T) propertyAccessor.getBean() //
						: object;
			}

			return object;
		};
	}

	private boolean potentiallySetId(Row row, RowMetadata metadata, PersistentPropertyAccessor propertyAccessor,
									 RelationalPersistentProperty idProperty) {

		Collection columns = metadata.getColumnNames();
		Object generatedIdValue = null;
		String idColumnName = idProperty.getColumnName().getReference();

		if (columns.contains(idColumnName)) {
			generatedIdValue = row.get(idColumnName);
		} else if (columns.size() == 1) {

			String key = columns.iterator().next();
			generatedIdValue = row.get(key);
		}

		if (generatedIdValue == null) {
			return false;
		}

		ConversionService conversionService = getConversionService();
		propertyAccessor.setProperty(idProperty, conversionService.convert(generatedIdValue, idProperty.getType()));

		return true;
	}

	private  RelationalPersistentEntity getRequiredPersistentEntity(Class type) {
		return (RelationalPersistentEntity) getMappingContext().getRequiredPersistentEntity(type);
	}

	/**
	 * Returns given object as {@link Collection}. Will return the {@link Collection} as is if the source is a
	 * {@link Collection} already, will convert an array into a {@link Collection} or simply create a single element
	 * collection for everything else.
	 *
	 * @param source
	 * @return
	 */
	private static Collection asCollection(Object source) {

		if (source instanceof Collection) {
			return (Collection) source;
		}

		return source.getClass().isArray() ? CollectionUtils.arrayToList(source) : Collections.singleton(source);
	}

	enum NoOpParameterValueProvider implements ParameterValueProvider {

		INSTANCE;

		@Override
		public  T getParameterValue(PreferredConstructor.Parameter parameter) {
			return null;
		}
	}

	private class RowParameterValueProvider implements ParameterValueProvider {

		private final Row resultSet;
		private final RowMetadata metadata;
		private final RelationalPersistentEntity entity;
		private final RelationalConverter converter;
		private final String prefix;

		public RowParameterValueProvider(Row resultSet, RowMetadata metadata, RelationalPersistentEntity entity,
										 RelationalConverter converter, String prefix) {
			this.resultSet = resultSet;
			this.metadata = metadata;
			this.entity = entity;
			this.converter = converter;
			this.prefix = prefix;
		}

		/*
		 * (non-Javadoc)
		 * @see org.springframework.data.mapping.model.ParameterValueProvider#getParameterValue(org.springframework.data.mapping.PreferredConstructor.Parameter)
		 */
		@Override
		@Nullable
		public  T getParameterValue(PreferredConstructor.Parameter parameter) {

			RelationalPersistentProperty property = this.entity.getRequiredPersistentProperty(parameter.getName());
			Object value = readFrom(this.resultSet, this.metadata, property, this.prefix);

			if (value == null) {
				return null;
			}

			Class type = parameter.getType().getType();

			if (type.isInstance(value)) {
				return type.cast(value);
			}

			try {
				return this.converter.getConversionService().convert(value, type);
			} catch (Exception o_O) {
				throw new MappingException(String.format("Couldn't read parameter %s.", parameter.getName()), o_O);
			}
		}
	}
}
    

    

    

            

    

            



    
    






    
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