/*************************************************************************
 *                                                                       *
 *  SignServer: The OpenSource Automated Signing Server                  *
 *                                                                       *
 *  This software is free software; you can redistribute it and/or       *
 *  modify it under the terms of the GNU Lesser General Public           *
 *  License as published by the Free Software Foundation; either         *
 *  version 2.1 of the License, or any later version.                    *
 *                                                                       *
 *  See terms of license at gnu.org.                                     *
 *                                                                       *
 *************************************************************************/
package org.signserver.validationservice.server;

import java.util.Enumeration;
import java.util.HashMap;
import java.util.Properties;

import javax.persistence.EntityManager;

import org.signserver.common.SignServerException;
import org.signserver.common.WorkerConfig;
import org.signserver.server.cryptotokens.ICryptoToken;
import org.signserver.validationservice.common.ValidationServiceConstants;
import org.signserver.validationservice.server.IValidator;

/**
 * Class containing helper methods for the validation service sub framework.
 * 
 * @author Philip Vendil
 * @version $Id: ValidationHelper.java 2345 2012-05-06 09:03:57Z netmackan $
 */
public class ValidationHelper {

    private static final String VALIDATOR_PREFIX1 = "validator";
    private static final String VALIDATOR_PREFIX2 = "val";
    private static final String ISSUER_PREFIX = "issuer";
    private static final int SUPPORTED_NUMBER_OF_VALIDATORS = 255;

    /**
     * Method returning a validation properties from a worker properties.
     * 
     * It will work in the following manner:
     * <ul>
     * <li>All properties starting with 'validator<validatorId>.' or 'val<validatorId>.' will have
     *   the following keys added without the 'val...' prefix.
     * <li>All properties without 'val...' prefix will be added if the key doesn't exist already. I.e
     * all properties with keys starting 'val..' overrides general properties.
     * <li>If no 'validator<validatorId>.' exists for the given id then, null will be returned.
     * </ul>
     * @param config a worker config containing all properties
     * @return a Propertes according to above specification or 'null' if no property with 'val...' exists
     * in configuration.
     */
    public static Properties getValidatorProperties(int validatorId, WorkerConfig config) {
        Properties retval = new Properties();
        Properties workerProps = config.getProperties();

        boolean foundValidatorId = false;
        // find validator properties
        Enumeration<?> en = config.getProperties().propertyNames();
        while (en.hasMoreElements()) {
            String next = (String) en.nextElement();
            String strippedKey = validatorPrefix(validatorId, next);
            if (strippedKey != null) {
                foundValidatorId = true;
                retval.setProperty(strippedKey, workerProps.getProperty(next));
            }
        }
        if (foundValidatorId) {
            // Separate general properties from validator specific and add if they already doesn't exist.
            en = config.getProperties().propertyNames();
            while (en.hasMoreElements()) {
                String next = (String) en.nextElement();
                if (validatorPrefix(0, next) == null) {
                    if (retval.getProperty(next) == null) {
                        retval.setProperty(next, workerProps.getProperty(next));
                    }
                }
            }
        } else {
            retval = null;
        }

        return retval;
    }

    /**
     * Returns the value after the validator_prefix
     * @param next input property key
     * @return the subset of the property key with validator prefix removed, or null if no
     * validator prefix could be found.
     */
    private static String validatorPrefix(int validatorId, String key) {
        String retval = null;

        if (key.length() > VALIDATOR_PREFIX1.length() + 2) {
            String tmp = key.substring(0, VALIDATOR_PREFIX1.length());
            if (tmp.equalsIgnoreCase(VALIDATOR_PREFIX1)) {
                if (key.substring(VALIDATOR_PREFIX1.length()).substring(0, 1).matches("\\d")) {
                    try {
                        int id = Integer.parseInt(key.substring(VALIDATOR_PREFIX1.length(), key.indexOf('.')));
                        if (id == validatorId || validatorId == 0) {
                            retval = key.substring(key.indexOf('.') + 1);
                        }
                    } catch (NumberFormatException e) {
                    }
                }
            }
        }
        if (key.length() > VALIDATOR_PREFIX2.length() + 2) {
            String tmp = key.substring(0, VALIDATOR_PREFIX2.length());
            if (tmp.equalsIgnoreCase(VALIDATOR_PREFIX2)) {
                if (key.substring(VALIDATOR_PREFIX2.length()).substring(0, 1).matches("\\d")) {
                    try {
                        int id = Integer.parseInt(key.substring(VALIDATOR_PREFIX2.length(), key.indexOf('.')));
                        if (id == validatorId || validatorId == 0) {
                            retval = key.substring(key.indexOf('.') + 1);
                        }
                    } catch (NumberFormatException e) {
                    }
                }
            }
        }

        return retval;
    }

    /**
     * Help method instantiating all configured validators and initializes them and
     * returns a HashMap containing all available validators by validatorId as key.
     * 
     * @param workerId current workerId
     * @param config worker config for the ValidationServiceWorker
     * @return available validators, never null
     * @throws SignServerException if validators are missconfigured.
     */
    public static HashMap<Integer, IValidator> genValidators(int workerId, WorkerConfig config, EntityManager em, ICryptoToken ct) throws SignServerException {
        HashMap<Integer, IValidator> retval = new HashMap<Integer, IValidator>();

        for (int i = 1; i <= SUPPORTED_NUMBER_OF_VALIDATORS; i++) {
            Properties valprops = getValidatorProperties(i, config);
            if (valprops != null) {
                String classpath = valprops.getProperty(ValidationServiceConstants.VALIDATOR_SETTING_CLASSPATH);
                if (classpath != null) {
                    try {
                        Class<?> c = ValidationHelper.class.getClassLoader().loadClass(classpath);
                        IValidator v = (IValidator) c.newInstance();
                        v.init(workerId, i, valprops, em, ct);
                        retval.put(i, v);
                    } catch (ClassNotFoundException e) {
                        throw new SignServerException("Error validator with validatorId " + i + " with workerId " + workerId + " have got the required setting " + ValidationServiceConstants.VALIDATOR_SETTING_CLASSPATH + " set correctly.");
                    } catch (InstantiationException e) {
                        throw new SignServerException("Error validator with validatorId " + i + " with workerId " + workerId + " have got the required setting " + ValidationServiceConstants.VALIDATOR_SETTING_CLASSPATH + " set correctly.");
                    } catch (IllegalAccessException e) {
                        throw new SignServerException("Error validator with validatorId " + i + " with workerId " + workerId + " have got the required setting " + ValidationServiceConstants.VALIDATOR_SETTING_CLASSPATH + " set correctly.");
                    }
                } else {
                    throw new SignServerException("Error validator with validatorId " + i + " with workerId " + workerId + " have got the required setting " + ValidationServiceConstants.VALIDATOR_SETTING_CLASSPATH + " set correctly.");
                }
            }
        }

        return retval;
    }

    /**
     * Method returning a validation properties from a validation properties.
     * 
     * It will work in the following manner:
     * <ul>
     * <li>All properties starting with 'issuer<issuerId>.'  will have
     *   the following keys added without the 'issuer...' prefix.
     * <li>All properties without 'issuer...' prefix will be added if the key doesn't exist already. I.e
     * all properties with keys starting 'issuer..' overrides general properties.
     * <li>If no 'issuer<issuerId>.' exists for the given id then, null will be returned.
     * </ul>
     * @param validatorProperties a worker config containing all properties
     * @return a Propertes according to above specification or 'null' if no property with 'issuer...' exists
     * in configuration.
     */
    public static Properties getIssuerProperties(int issuerId, Properties validatorProperties) {
        Properties retval = new Properties();

        boolean foundIssuerId = false;
        // find issuer properties
        Enumeration<?> en = validatorProperties.propertyNames();
        while (en.hasMoreElements()) {
            String next = (String) en.nextElement();
            String strippedKey = issuerPrefix(issuerId, next);
            if (strippedKey != null) {
                foundIssuerId = true;
                retval.setProperty(strippedKey, validatorProperties.getProperty(next));
            }
        }
        if (foundIssuerId) {
            // Separate general properties from issuer specific and add if they already doesn't exist.
            en = validatorProperties.propertyNames();
            while (en.hasMoreElements()) {
                String next = (String) en.nextElement();
                if (issuerPrefix(0, next) == null) {
                    if (retval.getProperty(next) == null) {
                        retval.setProperty(next, validatorProperties.getProperty(next));
                    }
                }
            }
        } else {
            retval = null;
        }

        return retval;
    }

    /**
     * Returns the value after the issuer prefix
     * @param next input property key
     * @return the subset of the property key with issuer prefix removed, or null if no
     * issuer prefix could be found.
     */
    private static String issuerPrefix(int issuerId, String key) {
        String retval = null;

        if (key.length() > ISSUER_PREFIX.length() + 2) {
            String tmp = key.substring(0, ISSUER_PREFIX.length());
            if (tmp.equalsIgnoreCase(ISSUER_PREFIX)) {
                if (key.substring(ISSUER_PREFIX.length()).substring(0, 1).matches("\\d")) {
                    try {
                        int id = Integer.parseInt(key.substring(ISSUER_PREFIX.length(), key.indexOf('.')));
                        if (id == issuerId || issuerId == 0) {
                            retval = key.substring(key.indexOf('.') + 1);
                        }
                    } catch (NumberFormatException e) {
                    }
                }
            }
        }
        return retval;
    }
}