package cn.cnnic.ops.udf;

public class GetChineseFromPunycode {

    static int TMIN = 1;

    static int TMAX = 26;

    static int BASE = 36;

    static int INITIAL_N = 128;

    static int INITIAL_BIAS = 72;

    static int DAMP = 700;

    static int SKEW = 38;

    static char DELIMITER = '-';

    static String PUNY_PREFIX = "xn--";

    static char DOT = '.';

    static String SPLIT_DOT = "\\.";

    public static void main(String[] args) {

        String str = "xn--fiq7iz9az60bsyah94knxag3d.xn--fiqs8s";

        GetChineseFromPunycode gpfc = new GetChineseFromPunycode();

        System.out.println(gpfc.evaluate(str));

    }

    public String evaluate(String txt) {

        String strResult = txt.toString().trim();

        try {

            strResult = fromPunycodeToChinese(txt.toString().trim());

        } catch (Exception e) {

            e.printStackTrace();

        }

        return strResult;

    }

    /**

     *

     * @param input

     * @return

     * @throws Exception

     */

    public static String fromPunycodeToChineseUnit(String input) throws Exception {

        int n = INITIAL_N;

        int i = 0;

        int bias = INITIAL_BIAS;

        StringBuilder output = new StringBuilder();

        int d = input.lastIndexOf(DELIMITER);

        if (d > 0) {

            for (int j = 0; j < d; j++) {

                char c = input.charAt(j);

                if (!isBasic(c)) {

                    throw new Exception("BAD_INPUT");

                }

                output.append(c);

            }

            d++;

        } else {

            d = 0;

        }

        while (d < input.length()) {

            int oldi = i;

            int w = 1;

            for (int k = BASE;; k += BASE) {

                if (d == input.length()) {

                    throw new Exception("BAD_INPUT");

                }

                int c = input.charAt(d++);

                int digit = codepoint2digit(c);

                if (digit > (Integer.MAX_VALUE - i) / w) {

                    throw new Exception("OVERFLOW");

                }

                i = i + digit * w;

                int t;

                if (k <= bias) {

                    t = TMIN;

                } else if (k >= bias + TMAX) {

                    t = TMAX;

                } else {

                    t = k - bias;

                }

                if (digit < t) {

                    break;

                }

                w = w * (BASE - t);

            }

            bias = adapt(i - oldi, output.length() + 1, oldi == 0);

            if (i / (output.length() + 1) > Integer.MAX_VALUE - n) {

                throw new Exception("OVERFLOW");

            }

            n = n + i / (output.length() + 1);

            i = i % (output.length() + 1);

            output.insert(i, (char) n);

            i++;

        }

        return output.toString();

    }

    /**

     *

     * @param delta

     * @param numpoints

     * @param first

     * @return

     */

    public static int adapt(int delta, int numpoints, boolean first) {

        if (first) {

            delta = delta / DAMP;

        } else {

            delta = delta / 2;

        }

        delta = delta + (delta / numpoints);

        int k = 0;

        while (delta > ((BASE - TMIN) * TMAX) / 2) {

            delta = delta / (BASE - TMIN);

            k = k + BASE;

        }

        return k + ((BASE - TMIN + 1) * delta) / (delta + SKEW);

    }

    /**

     *

     * @param c

     * @return

     */

    public static boolean isBasic(char c) {

        return c < 0x80;

    }

    /**

     *

     * @param d

     * @return

     * @throws Exception

     */

    public static int digit2codepoint(int d) throws Exception {

        if (d < 26) {

            // 0..25 : 'a'..'z'

            return d + 'a';

        } else if (d < 36) {

            // 26..35 : '0'..'9';

            return d - 26 + '0';

        } else {

            throw new Exception("BAD_INPUT");

        }

    }

    /**

     *

     * @param c

     * @return

     * @throws Exception

     */

    public static int codepoint2digit(int c) throws Exception {

        if (c - '0' < 10) {

            // '0'..'9' : 26..35

            return c - '0' + 26;

        } else if (c - 'a' < 26) {

            // 'a'..'z' : 0..25

            return c - 'a';

        } else {

            throw new Exception("BAD_INPUT");

        }

    }

    /**

     *

     * @param input

     * @return

     * @throws Exception

     */

    public static String fromPunycodeToChinese(String input) throws Exception {

        if (input == null || input.equalsIgnoreCase("")) {

            return "";

        } else if (input.indexOf(DOT) < 0) {

            if (input.startsWith(PUNY_PREFIX)) {

                return fromPunycodeToChineseUnit(input.substring(PUNY_PREFIX.length()));

            } else {

                return input;

            }

        } else if (input.indexOf(DOT) > 0) {

            String[] arr = input.split(SPLIT_DOT);

            String result = "";

            for (int index = 0; index < arr.length; index++) {

                if (arr[index].startsWith(PUNY_PREFIX)) {

                    result += fromPunycodeToChineseUnit(arr[index].substring(PUNY_PREFIX.length())) + ".";

                } else {

                    result += arr[index] + ".";

                }

            }

            return result.substring(0, result.length() - 1);

        }

        return input;

    }

}