// This software is released into the Public Domain.  See copying.txt for details.
package org.openstreetmap.osmosis.core.database;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;

import org.openstreetmap.osmosis.core.OsmosisRuntimeException;

/**
 * Loads database authentication details from a properties file.
 * <p>
 * The recognised properties are:
 * <ul>
 * <li>host</li>
 * <li>database</li>
 * <li>user</li>
 * <li>password</li>
 * <li>db</li>
 * </ul>
 * 
 * @author Brett Henderson
 */
public class AuthenticationPropertiesLoader {

    private static final String KEY_HOST = "host";
    private static final String KEY_DATABASE = "database";
    private static final String KEY_USER = "user";
    private static final String KEY_PASSWORD = "password";
    private static final String KEY_DBTYPE = "dbType";

    private final File propertiesFile;
    private Properties properties;

    /**
     * Creates a new instance.
     * 
     * @param propertiesFile The location of the properties file containing authentication
     *        information.
     */
    public AuthenticationPropertiesLoader(File propertiesFile) {
        this.propertiesFile = propertiesFile;
    }

    private Properties loadProperties(File configFile) {
        Properties loadedProperties = new Properties();

        try (FileInputStream fileInputStream = new FileInputStream(configFile)) {
            loadedProperties.load(fileInputStream);
        } catch (IOException e) {
            throw new OsmosisRuntimeException("Unable to load properties from config file " + configFile + ".", e);
        }

        return loadedProperties;
    }

    /**
     * Updates the login credentials with values from the properties file. Only values contained in
     * the properties file will be added.
     * 
     * @param loginCredentials The login credentials to be updated.
     */
    public void updateLoginCredentials(DatabaseLoginCredentials loginCredentials) {
        if (properties == null) {
            properties = loadProperties(propertiesFile);
        }

        if (properties.containsKey(KEY_HOST)) {
            loginCredentials.setHost(properties.getProperty(KEY_HOST));
        }
        if (properties.containsKey(KEY_DATABASE)) {
            loginCredentials.setDatabase(properties.getProperty(KEY_DATABASE));
        }
        if (properties.containsKey(KEY_USER)) {
            loginCredentials.setUser(properties.getProperty(KEY_USER));
        }
        if (properties.containsKey(KEY_PASSWORD)) {
            loginCredentials.setPassword(properties.getProperty(KEY_PASSWORD));
        }

        if (properties.containsKey(KEY_DBTYPE)) {
            loginCredentials.setDbType(properties.getProperty(KEY_DBTYPE));
        }

    }
}