package com.wechat.sdk.kit;

import com.jfinal.kit.HashKit;
import com.jfinal.kit.StrKit;
import com.wechat.sdk.utils.Charsets;
import com.wechat.sdk.utils.XmlHelper;

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.Map;
import java.util.Map.Entry;
import java.util.TreeMap;

/**
 * 微信支付的统一下单工具类
 * @author L.cm
 */
public class PaymentKit {
	
	/**
	 * 组装签名的字段
	 * @param params 参数
	 * @param urlEncoder 是否urlEncoder
	 * @return String
	 */
	public static String packageSign(Map<String, String> params, boolean urlEncoder) {
		// 先将参数以其参数名的字典序升序进行排序
		TreeMap<String, String> sortedParams = new TreeMap<String, String>(params);
		// 遍历排序后的字典，将所有参数按"key=value"格式拼接在一起
		StringBuilder sb = new StringBuilder();
		boolean first = true;
		for (Entry<String, String> param : sortedParams.entrySet()) {
			String value = param.getValue();
			if (StrKit.isBlank(value)) {
				continue;
			}
			if (first) {
				first = false;
			} else {
				sb.append("&");
			}
			sb.append(param.getKey()).append("=");
			if (urlEncoder) {
				try { value = urlEncode(value); } catch (UnsupportedEncodingException e) {}
			}
			sb.append(value);
		}
		return sb.toString();
	}
	
	/**
	 * urlEncode
	 * @param src 微信参数
	 * @return String
	 * @throws UnsupportedEncodingException 编码错误
	 */
	public static String urlEncode(String src) throws UnsupportedEncodingException {
		return URLEncoder.encode(src, Charsets.UTF_8.name()).replace("+", "%20");
	}
	
	/**
	 * 生成签名
	 * @param params 参数
	 * @param paternerKey 支付密钥
	 * @return sign
	 */
	public static String createSign(Map<String, String> params, String paternerKey) {
		// 生成签名前先去除sign
		params.remove("sign");
		String stringA = packageSign(params, false);
		String stringSignTemp = stringA + "&key=" + paternerKey;
		return HashKit.md5(stringSignTemp).toUpperCase();
	}
	
	/**
	 * 支付异步通知时校验sign
	 * @param params 参数
	 * @param paternerKey 支付密钥
	 * @return {boolean}
	 */
	public static boolean verifyNotify(Map<String, String> params, String paternerKey){
		String sign = params.get("sign");
		String localSign = PaymentKit.createSign(params, paternerKey);
		return sign.equals(localSign);
	}
	
	/**
	 * 微信下单，map to xml
	 * @param params 参数
	 * @return String
	 */
	public static String toXml(Map<String, String> params) {
		StringBuilder xml = new StringBuilder();
		xml.append("<xml>");
		for (Entry<String, String> entry : params.entrySet()) {
			String key   = entry.getKey();
			String value = entry.getValue();
			// 略过空值
			if (StrKit.isBlank(value)) continue;
			xml.append("<").append(key).append(">");
				xml.append(entry.getValue());
			xml.append("</").append(key).append(">");
		}
		xml.append("</xml>");
		return xml.toString();
	}
	
	/**
	 * 针对支付的xml，没有嵌套节点的简单处理
	 * @param xmlStr xml字符串
	 * @return map集合
	 */
	public static Map<String, String> xmlToMap(String xmlStr) {
		XmlHelper xmlHelper = XmlHelper.of(xmlStr);
		return xmlHelper.toMap();
	}

}