package org.simantics.logging;

import java.lang.reflect.Field;
import java.net.URL;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;

import org.eclipse.core.runtime.Platform;
import org.osgi.framework.Bundle;
import org.slf4j.LoggerFactory;

public class DBAndMetadataLogProvider implements LogProvider {

    private static final org.slf4j.Logger LOGGER = LoggerFactory.getLogger(DBAndMetadataLogProvider.class);
    
    @Override
    public List<Path> get() {
        List<Path> logs = new ArrayList<>();
        Path dbClientLog = getDBClientLogLocation();
        if (dbClientLog != null)
            logs.add(dbClientLog);
        Path metadataLogLocation = getMetadataLogLocation();
        if (metadataLogLocation != null)
            logs.add(metadataLogLocation);
        return logs;
    }

    private static Path getDBClientLogLocation() {
        Bundle bundle = Platform.getBundle("org.simantics.db.common");
        try {
            Class<?> forName = bundle.loadClass("org.simantics.db.common.internal.config.InternalClientConfig");
            Field field = forName.getField("DB_CLIENT_LOG_FILE");
            String value = (String) field.get(null);
            return Paths.get(value);
        } catch (ClassNotFoundException | NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException e) {
            LOGGER.error("Could not read db-client.log location", e);
        }
        return null;
    }

    private static Path getMetadataLogLocation() {
        String prop = System.getProperty("osgi.instance.area", null);
        if (prop != null) {
            try {
                URL url = new URL(prop);
                if ("file".equals(url .getProtocol())) {
                    Path path = Paths.get(url.toURI());
                    return path.resolve(".metadata").resolve(".log");
                } else {
                    LOGGER.warn("Unsupported protocol {}", url);
                }
            } catch (Throwable t) {
                LOGGER.error("Could not get .metadata/.log", t);
            }
        }
        return null;
    }
}