Widerhall/src/main/java/de/srsoftware/widerhall/Configuration.java

package de.srsoftware.widerhall;

import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;

import static de.srsoftware.widerhall.Constants.*;
public class Configuration {
    private static final Logger LOG = LoggerFactory.getLogger(Configuration.class);
    private static Configuration singleton = null;
    private JSONObject data;
    private File file;

    public static Configuration instance() {
        if (singleton == null) singleton = new Configuration().setDefaults();
        return singleton;
    }

    /**
     * Merges configuration from file into current configuration.
     * Existing entries will be replaced.
     * @param file
     * @return
     * @throws IOException
     * @throws ParseException
     */
    public Configuration load(File file) {
        this.file = file;
        if (file.exists()) try {
            LOG.info("Loading configuration from {}",file);
            var newVals = (JSONObject) new JSONParser().parse(Files.readString(file.toPath()));
            data.putAll(newVals);
        } catch (ParseException | IOException e){
            LOG.warn("Konnte Konfiguration nicht aus {} laden:",file,e);
        }
        return this;
    }

    public Configuration save(File file) throws IOException {
        this.file = file;
        return save();
    }

    public Configuration save() throws IOException {
        if (file == null) throw new NullPointerException("Konnte Konfiguration nicht speichern: Datei ist null!");
        file.getParentFile().mkdirs();
        Files.writeString(file.toPath(),data.toJSONString());
        return this;
    }

    private Configuration setDefaults() {
        if (data == null) data = new JSONObject();
        configFile();
        dbFile();
        baseUrl();
        serverPort();
        archiveDir();
        return this;
    }

    private JSONObject locations() {
        Object o = data.get(LOCATIONS);
        if (!(o instanceof JSONObject)) data.put(LOCATIONS,o = new JSONObject());
        return (JSONObject) o;
    }

    public String baseDir() {
        var locations = locations();
        if (!locations.containsKey(BASE)) locations.put(BASE,System.getProperty("user.dir"));
        return (String) locations.get(BASE);
    }

    public File configFile() {
        var locations = locations();
        if (!locations.containsKey(CONFIG)) locations.put(CONFIG, String.join(File.separator,baseDir(),"config","config.json"));
        return new File((String) locations.get(CONFIG));
    }

    public File dbFile() {
        var locations = locations();
        if (!locations.containsKey(DB)) locations.put(DB, String.join(File.separator,baseDir(),"db","db.sqlite3"));
        return new File((String) locations.get(DB));
    }

    public Configuration dbFile(File dbFile){
        var locations = locations();
        locations.put(DB,dbFile.toString());
        return this;
    }

    public File archiveDir() {
        var locations = locations();
        if (!locations.containsKey(ARCHIVE)) locations.put(ARCHIVE, String.join(File.separator,baseDir(),"archive"));
        return new File((String) locations.get(ARCHIVE));
    }


    public int serverPort() {
        if (!data.containsKey(PORT)) data.put(PORT,80L);
        var o = data.get(PORT);
        return (int) (long) o;
    }

    public String baseUrl() {
        if (!data.containsKey(BASE_URL)) data.put(BASE_URL,"http://localhost");
        return (String) data.get(BASE_URL);
    }


    public File file() {
        return file;
    }

}