/*
 * Copyright 1999-2018 Alibaba Group Holding Ltd.
 *
 * 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 com.alibaba.nacos.filter;

import com.alibaba.nacos.api.common.Constants;
import com.alibaba.nacos.security.nacos.JwtTokenManager;
import com.alibaba.nacos.security.nacos.NacosAuthConfig;
import org.apache.commons.lang3.StringUtils;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.web.filter.OncePerRequestFilter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * jwt auth token filter.
 *
 * @author wfnuser
 */
public class JwtAuthenticationTokenFilter extends OncePerRequestFilter {

	private static final String TOKEN_PREFIX = "Bearer ";

	private final JwtTokenManager tokenManager;

	public JwtAuthenticationTokenFilter(JwtTokenManager tokenManager) {
		this.tokenManager = tokenManager;
	}

	@Override
	protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
			throws IOException, ServletException {

		String jwt = resolveToken(request);

		if (StringUtils.isNotBlank(jwt) && SecurityContextHolder.getContext().getAuthentication() == null) {
			this.tokenManager.validateToken(jwt);
			Authentication authentication = this.tokenManager.getAuthentication(jwt);
			SecurityContextHolder.getContext().setAuthentication(authentication);
		}
		chain.doFilter(request, response);
	}

	/**
	 * Get token from header.
	 */
	private String resolveToken(HttpServletRequest request) {
		String bearerToken = request.getHeader(NacosAuthConfig.AUTHORIZATION_HEADER);
		if (StringUtils.isNotBlank(bearerToken) && bearerToken.startsWith(TOKEN_PREFIX)) {
			return bearerToken.substring(7);
		}
		String jwt = request.getParameter(Constants.ACCESS_TOKEN);
		if (StringUtils.isNotBlank(jwt)) {
			return jwt;
		}
		return null;
	}

}
