/**
 * 
 */
package com.imooc.security.app.authentication;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.collections.MapUtils;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.authentication.BadCredentialsException;
import org.springframework.security.core.Authentication;
import org.springframework.security.crypto.codec.Base64;
import org.springframework.security.oauth2.common.OAuth2AccessToken;
import org.springframework.security.oauth2.common.exceptions.UnapprovedClientAuthenticationException;
import org.springframework.security.oauth2.provider.ClientDetails;
import org.springframework.security.oauth2.provider.ClientDetailsService;
import org.springframework.security.oauth2.provider.OAuth2Authentication;
import org.springframework.security.oauth2.provider.OAuth2Request;
import org.springframework.security.oauth2.provider.TokenRequest;
import org.springframework.security.oauth2.provider.token.AuthorizationServerTokenServices;
import org.springframework.security.web.authentication.SavedRequestAwareAuthenticationSuccessHandler;
import org.springframework.stereotype.Component;

import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * APP环境下认证成功处理器
 * 
 * @author zhailiang
 *
 */
@Component("imoocAuthenticationSuccessHandler")
public class ImoocAuthenticationSuccessHandler extends SavedRequestAwareAuthenticationSuccessHandler {

	private Logger logger = LoggerFactory.getLogger(getClass());

	@Autowired
	private ObjectMapper objectMapper;

	@Autowired
	private ClientDetailsService clientDetailsService;
	
	@Autowired
	private AuthorizationServerTokenServices authorizationServerTokenServices;

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.springframework.security.web.authentication.
	 * AuthenticationSuccessHandler#onAuthenticationSuccess(javax.servlet.http.
	 * HttpServletRequest, javax.servlet.http.HttpServletResponse,
	 * org.springframework.security.core.Authentication)
	 */
	@SuppressWarnings("unchecked")
	@Override
	public void onAuthenticationSuccess(HttpServletRequest request, HttpServletResponse response,
			Authentication authentication) throws IOException, ServletException {

		logger.info("登录成功");

		String header = request.getHeader("Authorization");

		if (header == null || !header.startsWith("Basic ")) {
			throw new UnapprovedClientAuthenticationException("请求头中无client信息");
		}

		String[] tokens = extractAndDecodeHeader(header, request);
		assert tokens.length == 2;

		String clientId = tokens[0];
		String clientSecret = tokens[1];

		ClientDetails clientDetails = clientDetailsService.loadClientByClientId(clientId);

		if (clientDetails == null) {
			throw new UnapprovedClientAuthenticationException("clientId对应的配置信息不存在:" + clientId);
		} else if (!StringUtils.equals(clientDetails.getClientSecret(), clientSecret)) {
			throw new UnapprovedClientAuthenticationException("clientSecret不匹配:" + clientId);
		}
		
		TokenRequest tokenRequest = new TokenRequest(MapUtils.EMPTY_MAP, clientId, clientDetails.getScope(), "custom");
		
		OAuth2Request oAuth2Request = tokenRequest.createOAuth2Request(clientDetails);
		
		OAuth2Authentication oAuth2Authentication = new OAuth2Authentication(oAuth2Request, authentication);
		
		OAuth2AccessToken token = authorizationServerTokenServices.createAccessToken(oAuth2Authentication);

		response.setContentType("application/json;charset=UTF-8");
		response.getWriter().write(objectMapper.writeValueAsString(token));

	}

	private String[] extractAndDecodeHeader(String header, HttpServletRequest request) throws IOException {

		byte[] base64Token = header.substring(6).getBytes("UTF-8");
		byte[] decoded;
		try {
			decoded = Base64.decode(base64Token);
		} catch (IllegalArgumentException e) {
			throw new BadCredentialsException("Failed to decode basic authentication token");
		}

		String token = new String(decoded, "UTF-8");

		int delim = token.indexOf(":");

		if (delim == -1) {
			throw new BadCredentialsException("Invalid basic authentication token");
		}
		return new String[] { token.substring(0, delim), token.substring(delim + 1) };
	}

}
