package org.oxerr.spring.security.wechat.samples.helloworld.service.impl;
   
   import java.io.IOException;
   import java.net.URI;
   import java.net.URISyntaxException;
   
   import javax.servlet.ServletException;
   import javax.servlet.http.HttpServletRequest;
   import javax.servlet.http.HttpServletResponse;
  
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  import org.oxerr.spring.security.wechat.samples.helloworld.WeChatProperties;
  import org.oxerr.spring.security.wechat.web.authentication.AbstractJavaScriptRedirectWeChatService;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.stereotype.Service;
  
  import com.foxinmy.weixin4j.mp.api.OauthApi;
  
  @Service
  public class WeChatServiceImpl extends AbstractJavaScriptRedirectWeChatService {
  
  	private final Logger log = LogManager.getLogger();
  
  	private WeChatProperties weChatProperties;
  
  	private OauthApi oauthApi;
  
  	@Autowired
  	public WeChatServiceImpl(WeChatProperties weChatProperties, OauthApi oauthApi) {
  		this.weChatProperties = weChatProperties;
  		this.oauthApi = oauthApi;
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	@Override
  	public String getAuthorizationURL(HttpServletRequest request,
  			HttpServletResponse response) throws ServletException, IOException {
  		String redirectUri = this.getRedirectUri(request);
  		String state = null;
  		String scope = "snsapi_userinfo";
  		String url = oauthApi.getUserAuthorizationURL(redirectUri, state, scope);
  		return url;
  	}
  
  	private String getRedirectUri(HttpServletRequest request) {
  		final StringBuffer urlStringBuffer = request.getRequestURL();
  		final String queryString = request.getQueryString();
  		if (queryString != null) {
  			urlStringBuffer.append("?").append(queryString);
  		}
  		final URI uri = URI.create(urlStringBuffer.toString());
  		final String scheme = uri.getScheme();
  
  		// WeChat requires default port.
  		final int port = -1;
  
  		URI redirectUri;
  		try {
  			redirectUri = new URI(
  				scheme, uri.getUserInfo(),
  				this.weChatProperties.getRedirectDomain(), port,
  				uri.getPath(), uri.getQuery(), uri.getFragment()
  			);
  		} catch (URISyntaxException e) {
  			throw new RuntimeException(e);
  		}
  
  		final String redirectUriString = redirectUri.toString();
  		log.debug("redirectUriString: {}", redirectUriString);
  		return redirectUriString;
  	}
  
  }