/*
 * Copyright 2014-2016 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
 *
 *      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 org.springframework.data.rest.webmvc.json.patch;

import java.util.Arrays;
import java.util.stream.Collectors;

import org.springframework.data.mapping.PropertyPath;

/**
 * Operation to add a new value to the given "path". Will throw a {@link PatchException} if the path is invalid or if
 * the given value is not assignable to the given path.
 * 
 * @author Craig Walls
 * @author Oliver Gierke
 */
class AddOperation extends PatchOperation {

	/**
	 * Constructs the add operation
	 * 
	 * @param path The path where the value will be added. (e.g., '/foo/bar/4')
	 * @param value The value to add.
	 */
	public AddOperation(String path, Object value) {
		super("add", path, value);
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.rest.webmvc.json.patch.PatchOperation#perform(java.lang.Object, java.lang.Class)
	 */
	@Override
	<T> void perform(Object targetObject, Class<T> type) {
		addValue(targetObject, evaluateValueFromTarget(targetObject, type));
	}

	/* 
	 * (non-Javadoc)
	 * @see org.springframework.data.rest.webmvc.json.patch.PatchOperation#evaluateValueFromTarget(java.lang.Object, java.lang.Class)
	 */
	@Override
	protected <T> Object evaluateValueFromTarget(Object targetObject, Class<T> entityType) {

		if (!path.endsWith("-")) {
			return super.evaluateValueFromTarget(targetObject, entityType);
		}

		String pathSource = Arrays.stream(path.split("/"))//
				.filter(it -> !it.matches("\\d")) // no digits
				.filter(it -> !it.equals("-")) // no "last element"s
				.filter(it -> !it.isEmpty()) //
				.collect(Collectors.joining("."));

		PropertyPath propertyPath = PropertyPath.from(pathSource, entityType);

		return value instanceof LateObjectEvaluator ? ((LateObjectEvaluator) value).evaluate(propertyPath.getType())
				: value;
	}
}