package de.micromata.borgbutler.server;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.HashSet;
import java.util.Set;
import java.util.prefs.BackingStoreException;
import java.util.prefs.Preferences;

public class ServerConfigurationHandler {
    private Logger log = LoggerFactory.getLogger(ServerConfigurationHandler.class);
    private static final ServerConfigurationHandler instance = new ServerConfigurationHandler();
    private static final String WEBSERVER_PORT_PREF = "webserver-port";
    public static final int WEBSERVER_PORT_DEFAULT = 8042;
    private static final String LANGUAGE_PREF = "language";
    private static final String LANGUAGE_DEFAULT = null;
    private static final String SHOW_TEST_DATA_PREF = "show-test-data";
    private static final boolean SHOW_TEST_DATA_PREF_DEFAULT = true;
    private static final String WEB_DEVELOPMENT_MODE_PREF = "web-development-mode";
    private static final boolean WEB_DEVELOPMENT_MODE_PREF_DEFAULT = false;

    private Preferences preferences;
    private ServerConfiguration configuration = new ServerConfiguration();
    private Set<String> extraPreferences = new HashSet<>();

    /**
     * Only for test case.
     *
     * @param preferences
     */
    ServerConfigurationHandler(Preferences preferences) {
        this.preferences = preferences;
    }

    private ServerConfigurationHandler() {
        preferences = Preferences.userRoot().node("de").node("micromata").node("merlin");
        load();
    }

    public static ServerConfigurationHandler getInstance() {
        return instance;
    }

    public static ServerConfiguration getDefaultConfiguration() {
        return instance.getConfiguration();
    }

    public ServerConfiguration getConfiguration() {
        return configuration;
    }

    public void load() {
        configuration.setPort(preferences.getInt(WEBSERVER_PORT_PREF, WEBSERVER_PORT_DEFAULT));
        configuration.setShowTestData(preferences.getBoolean(SHOW_TEST_DATA_PREF, SHOW_TEST_DATA_PREF_DEFAULT));
        configuration.setWebDevelopmentMode(preferences.getBoolean(WEB_DEVELOPMENT_MODE_PREF, WEB_DEVELOPMENT_MODE_PREF_DEFAULT));
        configuration.resetModifiedFlag();
    }

    public void save() {
        log.info("Saving configuration to user prefs.");
        preferences.putInt(WEBSERVER_PORT_PREF, configuration.getPort());
        preferences.putBoolean(SHOW_TEST_DATA_PREF, configuration.isShowTestData());
        preferences.putBoolean(WEB_DEVELOPMENT_MODE_PREF, configuration.isWebDevelopmentMode());
        try {
            preferences.flush();
        } catch (BackingStoreException ex) {
            log.error("Couldn't flush user preferences: " + ex.getMessage(), ex);
        }
    }

    /**
     * For saving own properties.
     *
     * @param key   The key under which to save the given value.
     * @param value The value to store. If null, any previous stored value under the given key will be removed.
     */
    public void save(String key, String value) {
        if (StringUtils.isEmpty(value)) {
            preferences.remove(key);
        } else {
            preferences.put(key, value);
            extraPreferences.add(key);
        }
        try {
            preferences.flush();
        } catch (BackingStoreException ex) {
            log.error("Couldn't flush user preferences: " + ex.getMessage(), ex);
        }
    }

    /**
     * @param key Gets own property saved with {@link #save()}.
     */
    public String get(String key, String defaultValue) {
        extraPreferences.add(key);
        return preferences.get(key, defaultValue);
    }

    public void removeAllSettings() {
        log.warn("Removes all configuration settings from user prefs.");
        preferences.remove(WEBSERVER_PORT_PREF);
        preferences.remove(LANGUAGE_PREF);
        preferences.remove(SHOW_TEST_DATA_PREF);
        preferences.remove(WEB_DEVELOPMENT_MODE_PREF);
        for(String extraKey : extraPreferences) {
            preferences.remove(extraKey);
        }
        try {
            preferences.flush();
        } catch (BackingStoreException ex) {
            log.error("Couldn't flush user preferences: " + ex.getMessage(), ex);
        }
        load();
    }
}