/*
 * Copyright 2002-2017 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
 *
 *      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.web.bind;

import java.util.ArrayList;
import java.util.List;

import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.validation.Errors;
import org.springframework.validation.FieldError;
import org.springframework.validation.ObjectError;
import org.springframework.web.util.HtmlUtils;

/**
 * Errors wrapper that adds automatic HTML escaping to the wrapped instance,
 * for convenient usage in HTML views. Can be retrieved easily via
 * RequestContext's {@code getErrors} method.
 *
 * <p>Note that BindTag does <i>not</i> use this class to avoid unnecessary
 * creation of ObjectError instances. It just escapes the messages and values
 * that get copied into the respective BindStatus instance.
 *
 * @author Juergen Hoeller
 * @since 01.03.2003
 * @see org.springframework.web.servlet.support.RequestContext#getErrors
 * @see org.springframework.web.servlet.tags.BindTag
 */
public class EscapedErrors implements Errors {

        private final Errors source;


        /**
         * Create a new EscapedErrors instance for the given source instance.
         */
        public EscapedErrors(Errors source) {
                Assert.notNull(source, "Errors source must not be null");
                this.source = source;
        }

        public Errors getSource() {
                return this.source;
        }


        @Override
        public String getObjectName() {
                return this.source.getObjectName();
        }

        @Override
        public void setNestedPath(String nestedPath) {
                this.source.setNestedPath(nestedPath);
        }

        @Override
        public String getNestedPath() {
                return this.source.getNestedPath();
        }

        @Override
        public void pushNestedPath(String subPath) {
                this.source.pushNestedPath(subPath);
        }

        @Override
        public void popNestedPath() throws IllegalStateException {
                this.source.popNestedPath();
        }


        @Override
        public void reject(String errorCode) {
                this.source.reject(errorCode);
        }

        @Override
        public void reject(String errorCode, String defaultMessage) {
                this.source.reject(errorCode, defaultMessage);
        }

        @Override
        public void reject(String errorCode, @Nullable Object[] errorArgs, @Nullable String defaultMessage) {
                this.source.reject(errorCode, errorArgs, defaultMessage);
        }

        @Override
        public void rejectValue(@Nullable String field, String errorCode) {
                this.source.rejectValue(field, errorCode);
        }

        @Override
        public void rejectValue(@Nullable String field, String errorCode, String defaultMessage) {
                this.source.rejectValue(field, errorCode, defaultMessage);
        }

        @Override
        public void rejectValue(@Nullable String field, String errorCode, @Nullable Object[] errorArgs,
                        @Nullable String defaultMessage) {

                this.source.rejectValue(field, errorCode, errorArgs, defaultMessage);
        }

        @Override
        public void addAllErrors(Errors errors) {
                this.source.addAllErrors(errors);
        }


        @Override
        public boolean hasErrors() {
                return this.source.hasErrors();
        }

        @Override
        public int getErrorCount() {
                return this.source.getErrorCount();
        }

        @Override
        public List<ObjectError> getAllErrors() {
                return escapeObjectErrors(this.source.getAllErrors());
        }

        @Override
        public boolean hasGlobalErrors() {
                return this.source.hasGlobalErrors();
        }

        @Override
        public int getGlobalErrorCount() {
                return this.source.getGlobalErrorCount();
        }

        @Override
        public List<ObjectError> getGlobalErrors() {
                return escapeObjectErrors(this.source.getGlobalErrors());
        }

        @Override
        @Nullable
        public ObjectError getGlobalError() {
                return escapeObjectError(this.source.getGlobalError());
        }

        @Override
        public boolean hasFieldErrors() {
                return this.source.hasFieldErrors();
        }

        @Override
        public int getFieldErrorCount() {
                return this.source.getFieldErrorCount();
        }

        @Override
        public List<FieldError> getFieldErrors() {
                return this.source.getFieldErrors();
        }

        @Override
        @Nullable
        public FieldError getFieldError() {
                return this.source.getFieldError();
        }

        @Override
        public boolean hasFieldErrors(String field) {
                return this.source.hasFieldErrors(field);
        }

        @Override
        public int getFieldErrorCount(String field) {
                return this.source.getFieldErrorCount(field);
        }

        @Override
        public List<FieldError> getFieldErrors(String field) {
                return escapeObjectErrors(this.source.getFieldErrors(field));
        }

        @Override
        @Nullable
        public FieldError getFieldError(String field) {
                return escapeObjectError(this.source.getFieldError(field));
        }

        @Override
        @Nullable
        public Object getFieldValue(String field) {
                Object value = this.source.getFieldValue(field);
                return (value instanceof String ? HtmlUtils.htmlEscape((String) value) : value);
        }

        @Override
        @Nullable
        public Class<?> getFieldType(String field) {
                return this.source.getFieldType(field);
        }

        @SuppressWarnings("unchecked")
        @Nullable
        private <T extends ObjectError> T escapeObjectError(@Nullable T source) {
                if (source == null) {
                        return null;
                }
                String defaultMessage = source.getDefaultMessage();
                if (defaultMessage != null) {
                        defaultMessage = HtmlUtils.htmlEscape(defaultMessage);
                }
                if (source instanceof FieldError) {
                        FieldError fieldError = (FieldError) source;
                        Object value = fieldError.getRejectedValue();
                        if (value instanceof String) {
                                value = HtmlUtils.htmlEscape((String) value);
                        }
                        return (T) new FieldError(
                                        fieldError.getObjectName(), fieldError.getField(), value, fieldError.isBindingFailure(),
                                        fieldError.getCodes(), fieldError.getArguments(), defaultMessage);
                }
                else {
                        return (T) new ObjectError(
                                        source.getObjectName(), source.getCodes(), source.getArguments(), defaultMessage);
                }
        }

        private <T extends ObjectError> List<T> escapeObjectErrors(List<T> source) {
                List<T> escaped = new ArrayList<>(source.size());
                for (T objectError : source) {
                        escaped.add(escapeObjectError(objectError));
                }
                return escaped;
        }

}