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package org.talend.dataquality.datamasking.functions;

import java.util.regex.Pattern;

import org.apache.commons.lang.StringUtils;

/**
 * DOC qzhao class global comment. Detailled comment<br>
 * 
 * This MaskEmailDomain class extends {@link Function} class. It offers the methods to verify the validation of a given
 * email address and other auxiliary methods.<br>
 * 
 */
public abstract class MaskEmail extends Function<String> {

    private static final long serialVersionUID = 3837984827035744721L;

    protected static final Pattern EMAIL_REGEX = Pattern.compile("^[\\w-_\\.+]*[\\w-_\\.]\\@([\\w-]+\\.)+[\\w-]+[\\w-]$");

    /**
     * DOC qzhao Comment method "isValidEmailAddress".<br>
     * Verifies whether it is a valid email address
     * 
     * @param email email address
     * @return true when the input is valid
     */
    protected boolean isValidEmailAddress(String email) {
        return EMAIL_REGEX.matcher(email).matches();
    }

    /**
     * Conditions in masking full email domain randomly:<br>
     * <ul>
     * <li>When user gives a space, masks the full domain with X</li>
     * <li>When user gives a list of parameters, chooses from the list randomly</li>
     * <li>When user gives a list of parameters with one or more space in the list, removes the spaces directly</li>
     * <li>when user gives a local file, gets the choices from the file</li>
     * </ul>
     */
    @Override
    protected String doGenerateMaskedField(String str) {
        if (StringUtils.isEmpty(str)) {
            return EMPTY_STRING;
        }
        if (!isValidEmailAddress(str)) {
            return maskInvalidEmail(str);
        }
        return maskEmail(str);
    }

    protected abstract String maskInvalidEmail(String address);

    protected abstract String maskEmail(String address);
}