package net.knarcraft.minecraftserverlauncher.server;

import net.knarcraft.minecraftserverlauncher.Main;
import net.knarcraft.minecraftserverlauncher.profile.Collection;
import net.knarcraft.minecraftserverlauncher.profile.ServerLauncherController;
import net.knarcraft.minecraftserverlauncher.userinterface.ServerLauncherGUI;

import javax.naming.ConfigurationException;
import java.io.BufferedWriter;
import java.io.IOException;
import java.util.concurrent.TimeUnit;

public class ServerHandler {

    /**
     * Available ram sizes. For ServerLauncherGUI combo
     */
    private static final String[] ramList = {"512M", "1G", "2G", "3G", "4G", "5G", "6G", "7G", "8G", "9G", "10G",
            "11G", "12G", "13G", "14G", "15G", "16G"};

    private static boolean stoppingServers = false;
    private static final ServerLauncherGUI gui = Main.getController().getGUI();

    /**
     * Gets the list of available RAM choices allowed
     *
     * @return <p>All available RAM choices</p>
     */
    public static String[] getRamList() {
        return ramList;
    }

    /**
     * Gets whether the servers are currently in the process of stopping
     *
     * @return <p>True if the servers are in the process of stopping.</p>
     */
    public static boolean stoppingServers() {
        return stoppingServers;
    }

    /**
     * Marks the servers as finished stopping when a stop is confirmed
     */
    public static void serversStopped() {
        if (stoppingServers) {
            stoppingServers = false;
        }
    }

    /**
     * Tries to stop all enabled servers
     *
     * @throws IOException <p>If a writer's process is already closed but not null</p>
     */
    public static void stop() throws IOException, InterruptedException {
        if (stoppingServers) {
            killServers();
            return;
        }

        stoppingServers = true;
        int serversRunning = 0;

        for (Collection collection : Main.getController().getCurrentProfile().getCollections()) {
            Server server = collection.getServer();
            BufferedWriter writer = server.getWriter();
            if (writer != null) {
                serversRunning++;
                if (server.isProxy()) {
                    writer.write("end\n");
                } else {
                    writer.write("stop\n");
                }
                writer.flush();
                server.setWriter(null);
                server.setStopped();
            }
        }

        if (serversRunning == 0) {
            stoppingServers = false;
        }
    }

    /**
     * Kills all server processes
     *
     * @throws InterruptedException <p>If interrupted waiting for any of the servers to stop</p>
     */
    private static void killServers() throws InterruptedException {
        for (Collection collection : Main.getController().getCurrentProfile().getCollections()) {
            Server server = collection.getServer();
            killServer(server);
        }
    }

    /**
     * Kills the given server after waiting 30 seconds for it to terminate normally
     *
     * @param server <p>The server to kill</p>
     * @throws InterruptedException <p>If interrupted waiting for the server to stop</p>
     */
    private static void killServer(Server server) throws InterruptedException {
        Process serverProcess = server.getProcess();
        if (serverProcess != null) {
            if (!serverProcess.waitFor(30, TimeUnit.SECONDS)) {
                serverProcess.destroyForcibly();
                serverProcess.waitFor();
            }
        }
    }

    /**
     * Runs all enabled servers with their settings
     */
    public static void startServers() {
        ServerLauncherController controller = Main.getController();
        gui.setStatus("Starting servers");
        Server previouslyStartedServer = null;

        for (Collection collection : controller.getCurrentProfile().getCollections()) {
            Server server = collection.getServer();
            if (!server.runServer(previouslyStartedServer == null || previouslyStartedServer.isProxy())) {
                gui.showError("An error occurred. Start aborted. Please check relevant log files.");
                try {
                    stop();
                } catch (IOException | InterruptedException e) {
                    e.printStackTrace();
                }
                gui.updateGUIElementsWhenServersStartOrStop(false);
                return;
            }
            if (server.isEnabled()) {
                previouslyStartedServer = server;
            }
        }
    }

    /**
     * Gets a server object from a server save string
     *
     * @param saveString <p>The string containing necessary data regarding the server</p>
     * @return <p>A server in the same state it was saved in</p>
     */
    public static Server fromString(String saveString) throws ConfigurationException {
        String[] data = saveString.split(";");
        return new Server(data[0], data[1], Boolean.parseBoolean(data[2]), data[3], data[4], data[5]);
    }

}