package com.xeiam.xchange.bitvc.service;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import javax.ws.rs.FormParam;
import si.mazi.rescu.Params;
import si.mazi.rescu.ParamsDigest;
import si.mazi.rescu.RestInvocation;
public class BitVcDigest implements ParamsDigest {
private static final char[] DIGITS_LOWER = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
private final String secretKey;
private final MessageDigest md;
private final Comparator<Entry<String, String>> comparator = new Comparator<Map.Entry<String, String>>() {
@Override
public int compare(Entry<String, String> o1, Entry<String, String> o2) {
return o1.getKey().compareTo(o2.getKey());
}
};
public BitVcDigest(final String secretKey) {
this.secretKey = secretKey;
try {
md = MessageDigest.getInstance("MD5");
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("Problem instantiating message digest.");
}
}
private static char[] encodeHex(byte[] data, char[] toDigits) {
int l = data.length;
char[] out = new char[l << 1];
// two characters form the hex value.
for (int i = 0, j = 0; i < l; i++) {
out[j++] = toDigits[(0xF0 & data[i]) >>> 4];
out[j++] = toDigits[0x0F & data[i]];
}
return out;
}
@Override
public String digestParams(RestInvocation restInvocation) {
final Params params = restInvocation.getParamsMap().get(FormParam.class);
final Map<String, String> nameValueMap = params.asHttpHeaders();
nameValueMap.remove("sign");
nameValueMap.put("secret_key", secretKey);
final List<Map.Entry<String, String>> nameValueList = new ArrayList<Map.Entry<String, String>>(nameValueMap.entrySet());
Collections.sort(nameValueList, comparator);
final Params newParams = Params.of();
for (int i = 0; i < nameValueList.size(); i++) {
Map.Entry<String, String> param = nameValueList.get(i);
newParams.add(param.getKey(), param.getValue());
}
final String message = newParams.asQueryString();
try {
md.reset();
byte[] digest = md.digest(message.getBytes("UTF-8"));
return String.valueOf(encodeHex(digest, DIGITS_LOWER));
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("Codec error", e);
}
}
}