package cz.crcs.ectester.reader;

import cz.crcs.ectester.applet.ECTesterApplet;
import cz.crcs.ectester.applet.EC_Consts;
import javacard.framework.ISO7816;
import javacard.security.CryptoException;

/**
 * Utility class, some byte/hex manipulation, convenient byte[] methods.
 *
 * @author Petr Svenda petr@svenda.com
 * @author Jan Jancar johny@neuromancer.sk
 */
public class Util {

    public static short getShort(byte[] array, int offset) {
        return (short) (((array[offset] & 0xFF) << 8) | (array[offset + 1] & 0xFF));
    }

    public static void setShort(byte[] array, int offset, short value) {
        array[offset + 1] = (byte) (value & 0xFF);
        array[offset] = (byte) ((value >> 8) & 0xFF);
    }

    public static byte[] hexToBytes(String hex) {
        return hexToBytes(hex, true);
    }

    public static byte[] hexToBytes(String hex, boolean bigEndian) {
        hex = hex.replace(" ", "");
        int len = hex.length();
        StringBuilder sb = new StringBuilder();

        if (len % 2 == 1) {
            sb.append("0");
            ++len;
        }

        if (bigEndian) {
            sb.append(hex);
        } else {
            for (int i = 0; i < len / 2; ++i) {
                if (sb.length() >= 2) {
                    sb.insert(sb.length() - 2, hex.substring(2 * i, 2 * i + 2));
                } else {
                    sb.append(hex.substring(2 * i, 2 * i + 2));
                }

            }
        }

        String data = sb.toString();
        byte[] result = new byte[len / 2];
        for (int i = 0; i < len; i += 2) {
            result[i / 2] = (byte) ((Character.digit(data.charAt(i), 16) << 4)
                    + (Character.digit(data.charAt(i + 1), 16)));
        }
        return result;
    }

    public static String byteToHex(byte data) {
        return String.format("%02x", data);
    }

    public static String bytesToHex(byte[] data) {
        return bytesToHex(data, true);
    }

    public static String bytesToHex(byte[] data, boolean addSpace) {
        return bytesToHex(data, 0, data.length, addSpace);
    }

    public static String bytesToHex(byte[] data, int offset, int len) {
        return bytesToHex(data, offset, len, true);
    }

    public static String bytesToHex(byte[] data, int offset, int len, boolean addSpace) {
        StringBuilder buf = new StringBuilder();
        for (int i = offset; i < (offset + len); i++) {
            buf.append(byteToHex(data[i]));
            if (addSpace && i != (offset + len - 1)) {
                buf.append(" ");
            }
        }
        return (buf.toString());
    }

    public static byte[] concatenate(byte[]... arrays) {
        int len = 0;
        for (byte[] array : arrays) {
            if (array == null)
                continue;
            len += array.length;
        }
        byte[] out = new byte[len];
        int offset = 0;
        for (byte[] array : arrays) {
            if (array == null || array.length == 0)
                continue;
            System.arraycopy(array, 0, out, offset, array.length);
            offset += array.length;
        }
        return out;
    }

    public static String getPrintError(short code) {
        if (code == ISO7816.SW_NO_ERROR) {
            return "OK\t(0x9000)";
        } else {
            String codeStr = "unknown";
            switch (code) {
                case CryptoException.ILLEGAL_VALUE:
                    codeStr = "ILLEGAL_VALUE";
                    break;
                case CryptoException.UNINITIALIZED_KEY:
                    codeStr = "UNINITIALIZED_KEY";
                    break;
                case CryptoException.NO_SUCH_ALGORITHM:
                    codeStr = "NO_SUCH_ALG";
                    break;
                case CryptoException.INVALID_INIT:
                    codeStr = "INVALID_INIT";
                    break;
                case CryptoException.ILLEGAL_USE:
                    codeStr = "ILLEGAL_USE";
                    break;
                case ECTesterApplet.SW_SIG_VERIFY_FAIL:
                    codeStr = "SIG_VERIFY_FAIL";
                    break;
            }
            return String.format("fail\t(%s,\t0x%04x)", codeStr, code);
        }
    }

    public static String getCorruption(byte corruptionType) {
        String corrupt;
        switch (corruptionType) {
            case EC_Consts.CORRUPTION_NONE:
                corrupt = "NONE";
                break;
            case EC_Consts.CORRUPTION_FIXED:
                corrupt = "FIXED";
                break;
            case EC_Consts.CORRUPTION_ONE:
                corrupt = "ONE";
                break;
            case EC_Consts.CORRUPTION_ZERO:
                corrupt = "ZERO";
                break;
            case EC_Consts.CORRUPTION_ONEBYTERANDOM:
                corrupt = "ONE_BYTE_RANDOM";
                break;
            case EC_Consts.CORRUPTION_FULLRANDOM:
                corrupt = "FULL_RANDOM";
                break;
            case EC_Consts.CORRUPTION_INCREMENT:
                corrupt = "INCREMENT";
                break;
            default:
                corrupt = "UNKNOWN";
                break;
        }
        return corrupt;
    }
}