/*
 * Copyright 2012-2017 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.boot.context.properties.bind.validation;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.boot.context.properties.source.ConfigurationProperty;
import org.springframework.boot.context.properties.source.ConfigurationPropertyName;
import org.springframework.boot.context.properties.source.ConfigurationPropertyName.Form;
import org.springframework.boot.origin.Origin;
import org.springframework.util.Assert;
import org.springframework.validation.FieldError;
import org.springframework.validation.ObjectError;

/**
 * A collection of {@link ObjectError ObjectErrors} caused by bind validation failures.
 * Where possible, included {@link FieldError FieldErrors} will be OriginProvider.
 *
 * @author Phillip Webb
 * @author Madhura Bhave
 * @since 2.0.0
 */
public class ValidationErrors implements Iterable<ObjectError> {

	private final ConfigurationPropertyName name;

	private final Set<ConfigurationProperty> boundProperties;

	private final List<ObjectError> errors;

	ValidationErrors(ConfigurationPropertyName name,
			Set<ConfigurationProperty> boundProperties, List<ObjectError> errors) {
		Assert.notNull(name, "Name must not be null");
		Assert.notNull(boundProperties, "BoundProperties must not be null");
		Assert.notNull(errors, "Errors must not be null");
		this.name = name;
		this.boundProperties = Collections.unmodifiableSet(boundProperties);
		this.errors = convertErrors(name, boundProperties, errors);
	}

	private List<ObjectError> convertErrors(ConfigurationPropertyName name,
			Set<ConfigurationProperty> boundProperties, List<ObjectError> errors) {
		List<ObjectError> converted = new ArrayList<>(errors.size());
		for (ObjectError error : errors) {
			converted.add(convertError(name, boundProperties, error));
		}
		return Collections.unmodifiableList(converted);
	}

	private ObjectError convertError(ConfigurationPropertyName name,
			Set<ConfigurationProperty> boundProperties, ObjectError error) {
		if (error instanceof FieldError) {
			return convertFieldError(name, boundProperties, (FieldError) error);
		}
		return error;
	}

	private FieldError convertFieldError(ConfigurationPropertyName name,
			Set<ConfigurationProperty> boundProperties, FieldError error) {
		if (error instanceof ObjectProvider<?>) {
			return error;
		}
		return OriginTrackedFieldError.of(error,
				findFieldErrorOrigin(name, boundProperties, error));
	}

	private Origin findFieldErrorOrigin(ConfigurationPropertyName name,
			Set<ConfigurationProperty> boundProperties, FieldError error) {
		for (ConfigurationProperty boundProperty : boundProperties) {
			if (isForError(name, boundProperty.getName(), error)) {
				return Origin.from(boundProperty);
			}
		}
		return null;
	}

	private boolean isForError(ConfigurationPropertyName name,
			ConfigurationPropertyName boundPropertyName, FieldError error) {
		return name.isParentOf(boundPropertyName)
				&& boundPropertyName.getLastElement(Form.UNIFORM).toString()
						.equalsIgnoreCase(error.getField());
	}

	/**
	 * Return the name of the item that was being validated.
	 * @return the name of the item
	 */
	public ConfigurationPropertyName getName() {
		return this.name;
	}

	/**
	 * Return the properties that were bound before validation failed.
	 * @return the boundProperties
	 */
	public Set<ConfigurationProperty> getBoundProperties() {
		return this.boundProperties;
	}

	public boolean hasErrors() {
		return !this.errors.isEmpty();
	}

	/**
	 * Return the list of all validation errors.
	 * @return the errors
	 */
	public List<ObjectError> getAllErrors() {
		return this.errors;
	}

	@Override
	public Iterator<ObjectError> iterator() {
		return this.errors.iterator();
	}

}
