package cn.living.sharecenter.utils;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;

public class EncodeUtil {
    private static final char[] legalChars = "ghijk67stuJKLM89rvwxyzAlmnOUV+/abcdefPQRSTopqCDEFG012345BHINWXYZ"
            .toCharArray();// 瀛楀吀鍐呴『搴忎换鎰忔洿鏀癸紝鍙鍐呭淇濊瘉涓嶇己灏辫
    private static HashMap<Character, Integer> hashDecode = new HashMap<Character, Integer>();
    private static byte[] iv = { 1, 2, 3, 4, 5, 6, 7, 8 };

    /**
     * data[]杩涜缂栫爜
     *
     * @param data
     * @return
     */
    public static String encode(byte[] data) {
        int start = 0;
        int len = data.length;
        StringBuffer buf = new StringBuffer(data.length * 3 / 2);

        int end = len - 3;
        int i = start;
        int n = 0;

        while (i <= end) {
            int d = ((((int) data[i]) & 0x0ff) << 16)
                    | ((((int) data[i + 1]) & 0x0ff) << 8)
                    | (((int) data[i + 2]) & 0x0ff);

            buf.append(legalChars[(d >> 18) & 63]);
            buf.append(legalChars[(d >> 12) & 63]);
            buf.append(legalChars[(d >> 6) & 63]);
            buf.append(legalChars[d & 63]);

            i += 3;

            if (n++ >= 14) {
                n = 0;
                buf.append(" ");
            }
        }

        if (i == start + len - 2) {
            int d = ((((int) data[i]) & 0x0ff) << 16)
                    | ((((int) data[i + 1]) & 255) << 8);

            buf.append(legalChars[(d >> 18) & 63]);
            buf.append(legalChars[(d >> 12) & 63]);
            buf.append(legalChars[(d >> 6) & 63]);
            buf.append("=");
        } else if (i == start + len - 1) {
            int d = (((int) data[i]) & 0x0ff) << 16;

            buf.append(legalChars[(d >> 18) & 63]);
            buf.append(legalChars[(d >> 12) & 63]);
            buf.append("==");
        }

        return buf.toString();
    }

    public static byte[] decode(String s) {

        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        try {
            decode(s, bos);
        } catch (IOException e) {
            throw new RuntimeException();
        }
        byte[] decodedBytes = bos.toByteArray();
        try {
            bos.close();
            bos = null;
        } catch (IOException ex) {
            System.err.println("Error while decoding BASE64: " + ex.toString());
        }
        return decodedBytes;
    }

    private static void decode(String s, OutputStream os) throws IOException {
        int i = 0;

        int len = s.length();

        while (true) {
            while (i < len && s.charAt(i) <= ' ')
                i++;

            if (i == len)
                break;

            int tri = (decode(s.charAt(i)) << 18)
                    + (decode(s.charAt(i + 1)) << 12)
                    + (decode(s.charAt(i + 2)) << 6)
                    + (decode(s.charAt(i + 3)));

            os.write((tri >> 16) & 255);
            if (s.charAt(i + 2) == '=')
                break;
            os.write((tri >> 8) & 255);
            if (s.charAt(i + 3) == '=')
                break;
            os.write(tri & 255);

            i += 4;
        }
    }

    private static int decode(char c) {

        if (hashDecode.size() == 0) {
            for (int i = 0; i < 64; i++) {
                char ch = legalChars[i];
                hashDecode.put(ch, i);
            }
        }
        if (hashDecode.containsKey(c)) {
            return hashDecode.get(c);
        } else if (c == '=')
            return 0;
        else
            throw new RuntimeException("unexpected code: " + c);
    }

    public static String encryptDES(String encryptString, String keyCode)
            throws Exception {
        IvParameterSpec zeroIv = new IvParameterSpec(iv);
        SecretKeySpec key = new SecretKeySpec(keyCode.getBytes(), "DES");
        Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, key, zeroIv);
        byte[] encryptedData = cipher.doFinal(encryptString.getBytes("utf-8"));
        return encode(encryptedData);
    }

    public static String decryptDES(String decryptString, String keyCode)
            throws Exception {
        byte[] byteMi = decode(decryptString);
        IvParameterSpec zeroIv = new IvParameterSpec(iv);
        SecretKeySpec key = new SecretKeySpec(keyCode.getBytes(), "DES");
        Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, key, zeroIv);
        byte decryptedData[] = cipher.doFinal(byteMi);

        return new String(decryptedData, "utf-8");
    }

    /**
     * 灏嗕簩杩涘埗杞崲鎴�16杩涘埗
     *
     * @param buf
     * @return String
     */
    public static String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }
}