package com.github.binarywang.wxpay.util;

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.SortedMap;
import java.util.TreeMap;

import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;

import com.github.binarywang.wxpay.bean.request.BaseWxPayRequest;
import com.github.binarywang.wxpay.bean.result.BaseWxPayResult;
import com.github.binarywang.wxpay.constant.WxPayConstants.SignType;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.thoughtworks.xstream.annotations.XStreamAlias;
import lombok.extern.slf4j.Slf4j;

/**
 * <pre>
 * 签名相关工具类.
 * Created by Binary Wang on 2017-3-23.
 * </pre>
 *
 * @author <a href="https://github.com/binarywang">binarywang(Binary Wang)</a>
 */
@Slf4j
public class SignUtils {
  /**
   * 请参考并使用 {@link #createSign(Object, String, String, String[])}.
   *
   * @param xmlBean the xml bean
   * @param signKey the sign key
   * @return the string
   */
  @Deprecated
  public static String createSign(Object xmlBean, String signKey) {
    return createSign(xmlBean2Map(xmlBean), signKey);
  }

  /**
   * 请参考并使用 {@link #createSign(Map, String, String, String[])} .
   *
   * @param params  the params
   * @param signKey the sign key
   * @return the string
   */
  @Deprecated
  public static String createSign(Map<String, String> params, String signKey) {
    return createSign(params, SignType.MD5, signKey, new String[0]);
  }

  /**
   * 微信支付签名算法(详见:https://pay.weixin.qq.com/wiki/doc/api/tools/cash_coupon.php?chapter=4_3).
   *
   * @param xmlBean       Bean里的属性如果存在XML注解，则使用其作为key，否则使用变量名
   * @param signType      签名类型，如果为空，则默认为MD5
   * @param signKey       签名Key
   * @param ignoredParams 签名时需要忽略的特殊参数
   * @return 签名字符串 string
   */
  public static String createSign(Object xmlBean, String signType, String signKey, String[] ignoredParams) {
    return createSign(xmlBean2Map(xmlBean), signType, signKey, ignoredParams);
  }

  /**
   * 微信支付签名算法(详见:https://pay.weixin.qq.com/wiki/doc/api/tools/cash_coupon.php?chapter=4_3).
   *
   * @param params        参数信息
   * @param signType      签名类型，如果为空，则默认为MD5
   * @param signKey       签名Key
   * @param ignoredParams 签名时需要忽略的特殊参数
   * @return 签名字符串 string
   */
  public static String createSign(Map<String, String> params, String signType, String signKey, String[] ignoredParams) {
    SortedMap<String, String> sortedMap = new TreeMap<>(params);

    StringBuilder toSign = new StringBuilder();
    for (String key : sortedMap.keySet()) {
      String value = params.get(key);
      boolean shouldSign = false;
      if (StringUtils.isNotEmpty(value) && !ArrayUtils.contains(ignoredParams, key)
        && !Lists.newArrayList("sign", "key", "xmlString", "xmlDoc", "couponList").contains(key)) {
        shouldSign = true;
      }

      if (shouldSign) {
        toSign.append(key).append("=").append(value).append("&");
      }
    }

    toSign.append("key=").append(signKey);
    if (SignType.HMAC_SHA256.equals(signType)) {
      return me.chanjar.weixin.common.util.SignUtils.createHmacSha256Sign(toSign.toString(), signKey);
    } else {
      return DigestUtils.md5Hex(toSign.toString()).toUpperCase();
    }
  }

  /**
   * 校验签名是否正确.
   *
   * @param xmlBean  Bean需要标记有XML注解
   * @param signType 签名类型，如果为空，则默认为MD5
   * @param signKey  校验的签名Key
   * @return true - 签名校验成功，false - 签名校验失败
   */
  public static boolean checkSign(Object xmlBean, String signType, String signKey) {
    return checkSign(xmlBean2Map(xmlBean), signType, signKey);
  }

  /**
   * 校验签名是否正确.
   *
   * @param params   需要校验的参数Map
   * @param signType 签名类型，如果为空，则默认为MD5
   * @param signKey  校验的签名Key
   * @return true - 签名校验成功，false - 签名校验失败
   */
  public static boolean checkSign(Map<String, String> params, String signType, String signKey) {
    String sign = createSign(params, signType, signKey, new String[0]);
    return sign.equals(params.get("sign"));
  }

  /**
   * 将bean按照@XStreamAlias标识的字符串内容生成以之为key的map对象.
   *
   * @param bean 包含@XStreamAlias的xml bean对象
   * @return map对象 map
   */
  public static Map<String, String> xmlBean2Map(Object bean) {
    Map<String, String> result = Maps.newHashMap();
    List<Field> fields = new ArrayList<>(Arrays.asList(bean.getClass().getDeclaredFields()));
    fields.addAll(Arrays.asList(bean.getClass().getSuperclass().getDeclaredFields()));
    if (bean.getClass().getSuperclass().getSuperclass() == BaseWxPayRequest.class) {
      fields.addAll(Arrays.asList(BaseWxPayRequest.class.getDeclaredFields()));
    }

    if (bean.getClass().getSuperclass().getSuperclass() == BaseWxPayResult.class) {
      fields.addAll(Arrays.asList(BaseWxPayResult.class.getDeclaredFields()));
    }

    for (Field field : fields) {
      try {
        boolean isAccessible = field.isAccessible();
        field.setAccessible(true);
        if (field.get(bean) == null) {
          field.setAccessible(isAccessible);
          continue;
        }

        if (field.isAnnotationPresent(XStreamAlias.class)) {
          result.put(field.getAnnotation(XStreamAlias.class).value(), field.get(bean).toString());
        } else if (!Modifier.isStatic(field.getModifiers())) {
          //忽略掉静态成员变量
          result.put(field.getName(), field.get(bean).toString());
        }

        field.setAccessible(isAccessible);
      } catch (SecurityException | IllegalArgumentException | IllegalAccessException e) {
        log.error(e.getMessage(), e);
      }

    }

    return result;
  }
}
