/* Copyright (c) 2001 - 2007 TOPP - www.openplans.org. All rights reserved.
 * This code is licensed under the GPL 2.0 license, available at the root
 * application directory.
 */
package org.geoserver.security.impl;

import static org.geoserver.security.impl.DataAccessRule.*;

import java.io.File;
import java.io.IOException;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import java.util.TreeSet;

import org.geoserver.catalog.Catalog;
import org.geoserver.config.GeoServerDataDirectory;
import org.geoserver.platform.GeoServerExtensions;
import org.geotools.util.logging.Logging;

/**
 * Allows one to manage the rules used by the service layer security subsystem
 * TODO: consider splitting the persistence of properties into two strategies,
 * and in memory one, and a file system one (this class is so marginal that
 * I did not do so right away, in memory access is mostly handy for testing)
 */
public class ServiceAccessRuleDAO extends AbstractAccessRuleDAO<ServiceAccessRule> { 

    static {
        LOGGER = Logging.getLogger(ServiceAccessRuleDAO.class);
    }

    /**
     * property file name
     */
    static final String SERVICES = "services.properties";
    
    /**
     * the catalog
     */
    Catalog rawCatalog;
    
    /**
     * Returns the instanced contained in the Spring context for the UI to use
     * @return
     */
    public static ServiceAccessRuleDAO get() {
       return GeoServerExtensions.bean(ServiceAccessRuleDAO.class); 
    }
    
    public ServiceAccessRuleDAO(GeoServerDataDirectory dd, Catalog rawCatalog) throws IOException {
        super(dd, SERVICES);
        this.rawCatalog = rawCatalog;
    }

    /**
     * Builds a new dao
     * 
     * @param rawCatalog
     */
    public ServiceAccessRuleDAO() throws IOException {
        super(org.vfny.geoserver.global.GeoserverDataDirectory.accessor(), SERVICES);
    }
    
    /**
     * Builds a new dao with a custom security dir. Used mostly for testing purposes
     * 
     * @param rawCatalog
     */
    ServiceAccessRuleDAO(Catalog rawCatalog, File securityDir) {
        super(securityDir, SERVICES);
    }

    /**
     * Parses the rules contained in the property file
     * 
     * @param props
     * @return
     */
    protected void loadRules(Properties props) {
        TreeSet<ServiceAccessRule> result = new TreeSet<ServiceAccessRule>();
        for (Map.Entry<Object,Object> entry : props.entrySet()) {
            String ruleKey = (String) entry.getKey();
            String ruleValue = (String) entry.getValue();

            ServiceAccessRule rule = parseServiceAccessRule(ruleKey, ruleValue);
            if (rule != null) {
                if (result.contains(rule))
                    LOGGER.warning("Rule " + ruleKey + "." + ruleValue
                            + " overwrites another rule on the same path");
                result.add(rule);
            }
        }
        
        // make sure to add the "all access alloed" rule if the set if empty
        if(result.size() == 0) {
            result.add(new ServiceAccessRule(new ServiceAccessRule()));
        }
        
        rules = result;
    }

    /**
     * Parses a single layer.properties line into a {@link DataAccessRule}, returns false if the
     * rule is not valid
     * 
     * @return
     */
    ServiceAccessRule parseServiceAccessRule(String ruleKey, String ruleValue) {
        final String rule = ruleKey + "=" + ruleValue;

        // parse
        String[] elements = parseElements(ruleKey);
        if(elements.length != 2) {
            LOGGER.warning("Invalid rule " + rule + ", the expected format is service.method=role1,role2,...");
            return null;
        }
        String service = elements[0];
        String method = elements[1];
        Set<String> roles = parseRoles(ruleValue);

        // check ANY usage sanity
        if (ANY.equals(service)) {
            if (!ANY.equals(method)) {
                LOGGER.warning("Invalid rule " + rule + ", when namespace "
                        + "is * then also layer must be *. Skipping rule " + rule);
                return null;
            }
        }

        // build the rule
        return new ServiceAccessRule(service, method, roles);
    }
    
    /**
     * Turns the rules list into a property bag
     * @return
     */
    protected Properties toProperties() {
        Properties props = new Properties();
        for (ServiceAccessRule rule : rules) {
            props.put(rule.getKey(), rule.getValue());
        }
        return props;
    }

    /**
     * Parses workspace.layer.mode into an array of strings
     * 
     * @param path
     * @return
     */
    private String[] parseElements(String path) {
        // regexp: ignore extra spaces, split on dot
        return path.split("\\s*\\.\\s*");
    }

}