package demo.tool;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import demo.constants.Gender;
import demo.exception.InvalidParameterException;
import demo.entity.IDCertNoValidateResult;

public class IDCertNoTool {

    private static final Logger LOGGER = LoggerFactory.getLogger(IDCertNoTool.class);

    public static final String INVALID_FIELD_NAME_CERT_NO = "certNo";
    public static final String INVALID_FIELD_NAME_AREA_CODE = "areaCode";
    public static final String INVALID_FIELD_NAME_BIRTHDAY = "birthday";
    public static final String INVALID_FIELD_NAME_CHECK_CHAR = "checkChar";
    public static final String INVALID_FIELD_NAME_GENDER = "gender";

    private final static char[] PARITYBIT = {'1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2'};
    private final static int[] POWER_LIST = {7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2};
    private final static SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("yyyyMMddHHmmssSSS") {
        private static final long serialVersionUID = 1L;
        {
            this.setLenient(false);
        }
    };
    private final static String BIRTHDAY_PADDING = "000000000";
    private final static Map<String, String> ZONE_NUMBER = new HashMap<String, String>() {
        private static final long serialVersionUID = 1L;
        {
            this.put("11", "北京");
            this.put("12", "天津");
            this.put("13", "河北");
            this.put("14", "山西");
            this.put("15", "内蒙古");
            this.put("21", "辽宁");
            this.put("22", "吉林");
            this.put("23", "黑龙江");
            this.put("31", "上海");
            this.put("32", "江苏");
            this.put("33", "浙江");
            this.put("34", "安徽");
            this.put("35", "福建");
            this.put("36", "江西");
            this.put("37", "山东");
            this.put("41", "河南");
            this.put("42", "湖北");
            this.put("43", "湖南");
            this.put("44", "广东");
            this.put("45", "广西");
            this.put("46", "海南");
            this.put("50", "重庆");
            this.put("51", "四川");
            this.put("52", "贵州");
            this.put("53", "云南");
            this.put("54", "西藏");
            this.put("61", "陕西");
            this.put("62", "甘肃");
            this.put("63", "青海");
            this.put("64", "宁夏");
            this.put("65", "新疆");
            this.put("71", "台湾");
            this.put("81", "香港");
            this.put("82", "澳门");
            this.put("91", "外国");
        }
    };


    public static enum IDCertNoType {
        OLD(15),
        NEW(18);

        private int length;

        private IDCertNoType(int length) {
            this.length = length;
        }

        public int getLength() {
            return length;
        }

        public static IDCertNoType resolve(int length) {
            for (IDCertNoType role : values()) {
                if (role.getLength() == length) {
                    return role;
                }
            }
            throw new IllegalArgumentException("unknown cert number type for length: " + length);
        }

    }

    /**
     * 身份证验证，验证通过，返回性别和出生日期
     *
     * @param certNo 号码内容
     * @return 身份证中包含的性别和生日信息
     */
    public static IDCertNoValidateResult validate(String certNo) throws InvalidParameterException {
        char[] chars = certNo.toCharArray();
        int certNoLength = chars.length;
        IDCertNoType certNoType = null;
        try {
            certNoType = IDCertNoType.resolve(certNoLength);
        } catch (Exception e) {
            String msg = "invalid cert number length: " + certNoLength;
            LOGGER.error(msg);
            Map<String, String> errorDesc = new HashMap<>();
            errorDesc.put(INVALID_FIELD_NAME_CERT_NO, msg);
            throw new InvalidParameterException(errorDesc);
        }

        switch (certNoType) {
            case OLD:
                return validateOldCertNo(chars);

            case NEW:
                return validateNewCertNo(chars);

            default: {
                String msg = "unsupported IDCertNoType: " + certNoType;
                LOGGER.error(msg);
                Map<String, String> errorDesc = new HashMap<>();
                errorDesc.put(INVALID_FIELD_NAME_CERT_NO, msg);
                throw new InvalidParameterException(errorDesc);
            }
        }
    }

    private static IDCertNoValidateResult validateNewCertNo(char[] chars) throws InvalidParameterException {
        checkAreaCode(chars, 0, 6);

        String birthdayStr = new String(chars, 6, 8) + BIRTHDAY_PADDING;
        Date birthday = parseBirthday(birthdayStr);

        Gender gender = parseGender(chars[16]);

        validateCheckChar(chars);

        return new IDCertNoValidateResult(gender, birthday);
    }

    /**
     * 校验旧版身份证号，这里在处理年龄时，会根据年龄位进行判断，若是"0x"则补充为"200x"，否则补充为"19xx"。
     *
     * @param certNo 旧版身份证号
     * @return
     * @throws InvalidParameterException
     */
    private static IDCertNoValidateResult validateOldCertNo(char[] chars) throws InvalidParameterException {
        checkAreaCode(chars, 0, 6);

        StringBuilder birthdayBuilder = new StringBuilder();
        char firstBirthdayChar = chars[6];
        switch (firstBirthdayChar) {
            case '0':
                birthdayBuilder.append("20").append(chars, 6, 6).append(BIRTHDAY_PADDING);
                break;

            default:
                birthdayBuilder.append("19").append(chars, 6, 6).append(BIRTHDAY_PADDING);
                break;
        }
        Date birthday = parseBirthday(birthdayBuilder.toString());

        Gender gender = parseGender(chars[14]);

        return new IDCertNoValidateResult(gender, birthday);
    }

    private static void checkAreaCode(char[] chars, int startIndex, int length)
            throws InvalidParameterException {
        String areaCode = new String(chars, startIndex, 2);
        if (!ZONE_NUMBER.containsKey(areaCode)) {
            String msg = "parse area code failed: " + areaCode;
            LOGGER.error(msg);
            Map<String, String> errorDesc = new HashMap<>();
            errorDesc.put(INVALID_FIELD_NAME_AREA_CODE, msg);
            throw new InvalidParameterException(errorDesc);
        }
    }

    private static Date parseBirthday(String birthdayStr) throws InvalidParameterException {
        Date birthday = null;
        try {
            birthday = DATE_FORMAT.parse(birthdayStr);
        } catch (ParseException e) {
            String msg = "parse birthday failed: " + birthdayStr;
            LOGGER.error(msg);
            Map<String, String> errorDesc = new HashMap<>();
            errorDesc.put(INVALID_FIELD_NAME_BIRTHDAY, msg);
            throw new InvalidParameterException(errorDesc);
        }
        return birthday;
    }

    private static Gender parseGender(char genderChar) throws InvalidParameterException {
        if ((genderChar < '0') || (genderChar > '9')) {
            String msg = "parse gender failed: " + genderChar;
            LOGGER.error(msg);
            Map<String, String> errorDesc = new HashMap<>();
            errorDesc.put(INVALID_FIELD_NAME_GENDER, msg);
            throw new InvalidParameterException(errorDesc);
        }

        if (((genderChar - '0') & 1) == 0) {
            return Gender.F;
        } else {
            return Gender.M;
        }
    }

    private static void validateCheckChar(char[] chars) throws InvalidParameterException {
        char computedCheckChar = computeCheckChar(chars, 0, 17);
        char targetCheckChar = chars[17];
        if (computedCheckChar != targetCheckChar) {
            String msg = "validate check char failed: " + targetCheckChar;
            LOGGER.error(msg);
            Map<String, String> errorDesc = new HashMap<>();
            errorDesc.put(INVALID_FIELD_NAME_CHECK_CHAR, msg);
            throw new InvalidParameterException(errorDesc);
        }
    }

    private static char computeCheckChar(char[] chars, int startIndex, int length) {
        int checkSum = 0;
        for (int i = 0; i < length; i++) {
            char c = chars[startIndex + i];
            checkSum += (c - '0') * POWER_LIST[i];
        }

        int checkCharIndex = checkSum % 11;
        char checkChar = PARITYBIT[checkCharIndex];
        return checkChar;
    }
}