/**
 * Copyright (c) 2018-2028, Chill Zhuang 庄骞 (smallchill@163.com).
 * <p>
 * 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
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * 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.springblade.gateway.config;

import lombok.AllArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springblade.gateway.props.AuthProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.web.cors.reactive.CorsUtils;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebFilter;
import org.springframework.web.server.WebFilterChain;
import reactor.core.publisher.Mono;

/**
 * 路由配置信息
 *
 * @author Chill
 */
@Slf4j
@Configuration
@AllArgsConstructor
@EnableConfigurationProperties({AuthProperties.class})
public class RouterFunctionConfiguration {

	/**
	 * 这里为支持的请求头，如果有自定义的header字段请自己添加
	 */
	private static final String ALLOWED_HEADERS = "X-Requested-With, Tenant-Id, Blade-Auth, Content-Type, Authorization, credential, X-XSRF-TOKEN, token, username, client, knfie4j-gateway-request, request-origion";
	private static final String ALLOWED_METHODS = "GET,POST,PUT,DELETE,OPTIONS,HEAD";
	private static final String ALLOWED_ORIGIN = "*";
	private static final String ALLOWED_EXPOSE = "*";
	private static final String MAX_AGE = "18000L";

	/**
	 * 跨域配置
	 */
	@Bean
	public WebFilter corsFilter() {
		return (ServerWebExchange ctx, WebFilterChain chain) -> {
			ServerHttpRequest request = ctx.getRequest();
			if (CorsUtils.isCorsRequest(request)) {
				ServerHttpResponse response = ctx.getResponse();
				HttpHeaders headers = response.getHeaders();
				headers.add("Access-Control-Allow-Headers", ALLOWED_HEADERS);
				headers.add("Access-Control-Allow-Methods", ALLOWED_METHODS);
				headers.add("Access-Control-Allow-Origin", ALLOWED_ORIGIN);
				headers.add("Access-Control-Expose-Headers", ALLOWED_EXPOSE);
				headers.add("Access-Control-Max-Age", MAX_AGE);
				headers.add("Access-Control-Allow-Credentials", "true");
				if (request.getMethod() == HttpMethod.OPTIONS) {
					response.setStatusCode(HttpStatus.OK);
					return Mono.empty();
				}
			}
			return chain.filter(ctx);
		};
	}

}
