using System;
using System.Security.Cryptography;
using System.Text;
using BWP.ABCClient.Common;

namespace BWP.ABCClient
{
	public static class RSAService
	{
		public static void Sign(MessageBase msgObj, string merchantID, Encoding msgEncoding, bool isMarket)
		{
			string xml = MsgUtil.MsgToBareXml(msgObj);
			var message = MsgUtil.GetInnerXml(xml, "Message");
			message = isMarket ? string.Format("<Message>{0}</Message>", message) : message;
			msgObj.Signature = Sign(message, merchantID, msgEncoding);
		}

		public static string Sign(string msg, string merchantID)
		{
			return Sign(msg, merchantID, Encoding.Default);
		}

		public static string Sign(string msg, string merchantID, Encoding msgEncoding)
		{
			var cert = new CertManager().Fetch(merchantID);
			var privateKey = (RSACryptoServiceProvider)cert.PrivateKey;
            if (privateKey == null)
            {
                throw new Exception("商户的证书中没有私钥，请上传有效的证书");
            }
			byte[] rgbHash = new SHA1Managed().ComputeHash(msgEncoding.GetBytes(msg));
			byte[] data = privateKey.SignHash(rgbHash, cert.SignatureAlgorithm.Value);
			return Convert.ToBase64String(data);
		}

		public static bool Verify(string returnMsg, string abcSign)
		{
			return Verify(returnMsg, abcSign, Encoding.Default, false);
		}

		public static bool Verify(string returnMsg, string abcSign, Encoding msgEncoding, bool isTest)
		{
			var certMgr = new CertManager();
			var cert = isTest ? certMgr.GetABCTestPubKey() : certMgr.GetABCPubKey();
			var publicKey = (RSACryptoServiceProvider)cert.PublicKey.Key;
			var singature = Convert.FromBase64String(abcSign);
			var msgHash = new SHA1Managed().ComputeHash(msgEncoding.GetBytes(returnMsg));
			return publicKey.VerifyHash(msgHash, cert.SignatureAlgorithm.Value, singature);
		}
 
		public static bool Verify(string receivedXml, Encoding msgEncoding, bool isMarket, bool isTest)
		{
			string message = MsgUtil.GetInnerXml(receivedXml, "Message");
			message = isMarket ? string.Format("<Message>{0}</Message>", message) : message;
			string signature = MsgUtil.GetInnerXml(receivedXml, "Signature"); 
 
			return Verify(message, signature, msgEncoding, isTest);
		}
 
		public static bool TestVerify(string returnMsg, string abcSign)
		{
			return TestVerify(returnMsg, abcSign, Encoding.Default);
		}

		public static bool TestVerify(string returnMsg, string abcSign, Encoding msgEncoding)
		{
			var cert = new CertManager().GetABCTestPubKey();
			var publicKey = (RSACryptoServiceProvider)cert.PublicKey.Key;
			var singature = Convert.FromBase64String(abcSign);
			var msgHash = new SHA1Managed().ComputeHash(msgEncoding.GetBytes(returnMsg));
			return publicKey.VerifyHash(msgHash, cert.SignatureAlgorithm.Value, singature);
		}
	}
}