import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.Map;

import org.apache.commons.lang.StringUtils;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.entity.ContentType;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.util.EntityUtils;
import org.json.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;





public class WeiXinAuthService 
{

	private static final Logger logger = LoggerFactory.getLogger(WeiXinAuthService.class);
	
	public static final String WX_AUTH_LOGIN_URL = "https://api.weixin.qq.com/sns/oauth2/access_token";
	public static final String WX_USERINFO_URL = "https://api.weixin.qq.com/sns/userinfo";
	//appid和appSecret 是在公眾平臺上申請的
	//AppId
	public static final String WX_APP_ID = "wxb6411cbea5c*****";
	//AppSecret
	public static final String WX_APP_KEY = "86b91b295d23f34337b76cacd*******";

	

	
	public UserInfoData checkLogin(String code) 
	{
		//獲取授權 access_token
		StringBuffer loginUrl = new StringBuffer();
		loginUrl.append(WX_AUTH_LOGIN_URL).append("?appid=")
				.append(WX_APP_ID).append("&secret=")
				.append(WX_APP_KEY).append("&code=").append(code)
				.append("&grant_type=authorization_code");
		String loginRet = WeiXinAuthService.get(loginUrl.toString());
		JSONObject grantObj = new JSONObject(loginRet);
		String errcode = grantObj.optString("errcode");
		if (!StringUtils.isEmpty(errcode)) 
		{
			logger.error("login weixin error"+loginRet);
			return null;
		}
		String openId = grantObj.optString("openid");
		if (StringUtils.isEmpty(openId)) 
		{
			logger.error("login weixin getOpenId error"+loginRet);
			return null;
		}
		
		String accessToken = grantObj.optString("access_token");
		String expiresIn = grantObj.optString("expires_in");
		String refreshToken = grantObj.optString("refresh_token");
		String scope = grantObj.optString("scope");
		
		//獲取使用者資訊
		StringBuffer userUrl = new StringBuffer();
		userUrl.append(WX_USERINFO_URL).append("?access_token=").append(accessToken).append("&openid=").append(openId);
		String userRet = WeiXinAuthService.get(userUrl.toString());
		JSONObject userObj = new JSONObject(userRet);
		UserInfoData userInfo = new UserInfoData();
		userInfo.setOpenId(openId);
		userInfo.setAuthToken(accessToken);
		userInfo.setAuthRefreshToken(refreshToken);
		userInfo.setScope(scope);
		userInfo.setExpiresIn(Integer.valueOf(expiresIn));
		String nickname = userObj.optString("nickname");
		String sex = userObj.optString("sex");
		String userImg = userObj.optString("headimgurl");
		String unionid = userObj.optString("unionid");
		userInfo.setName(nickname);
		userInfo.setIcon(userImg);
		userInfo.setGender(sex);
		userInfo.setLoginId(unionid);
		return userInfo;
	}
	
	
	public static String get(String url) {
		String body = null;
		try (CloseableHttpClient httpClient = HttpClientBuilder.create().build()) {		
			logger.info("create httppost:" + url);
			HttpGet get = new HttpGet(url);
			get.addHeader("Accept-Charset","utf-8");
			HttpResponse response = sendRequest(httpClient, get);
			body = parseResponse(response);
		} catch (IOException e) {
			logger.error("send post request failed: {}", e.getMessage());
		}

		return body;
	}
	
	private static String paramsToString(Map<String, String> params) {
		StringBuilder sb = new StringBuilder();
		try{
			for (String key : params.keySet()) {
				sb.append(String.format("&%s=%s", key, URLEncoder.encode(params.get(key),StandardCharsets.UTF_8.toString())));
			}
		}catch(UnsupportedEncodingException e){
			logger.warn("{}: encode url parameters failed", e.getMessage());
		}
		return sb.length() > 0 ? "?".concat(sb.substring(1)) : "";
	}
	
	private static HttpResponse sendRequest(CloseableHttpClient httpclient, HttpUriRequest httpost)
			throws ClientProtocolException, IOException {
		HttpResponse response = null;
		response = httpclient.execute(httpost);
		return response;
	}
	
	private static String parseResponse(HttpResponse response) {
		logger.info("get response from http server..");
		HttpEntity entity = response.getEntity();

		logger.info("response status: " + response.getStatusLine());
		Charset charset = ContentType.getOrDefault(entity).getCharset();
		if (charset != null) {
			logger.info(charset.name());
		}

		String body = null;
		try {
			body = EntityUtils.toString(entity, "utf-8");
			logger.info("body " + body);
		} catch (IOException e) {
			logger.warn("{}: cannot parse the entity", e.getMessage());
		}

		return body;
	}


	

}