package com.ryanmichela.sshd.jline;

import com.ryanmichela.sshd.*;
import com.ryanmichela.sshd.implementations.commandsenders.SSHDCommandSender;
import jline.console.ConsoleReader;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.core.Logger;
import org.apache.sshd.server.shell.ShellFactory;
import org.apache.sshd.server.command.Command;
import org.apache.sshd.server.channel.ChannelSession;
import org.apache.sshd.server.Environment;
import org.apache.sshd.server.ExitCallback;
import org.bukkit.Bukkit;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Optional;
import java.util.logging.Level;
import java.util.logging.StreamHandler;

public class ConsoleShellFactory implements ShellFactory 
{

	public Command createShell(ChannelSession cs) 
	{
		return new ConsoleShell();
	}

	public class ConsoleShell implements Command, Runnable 
	{

		private InputStream in;
		private OutputStream out;
		private OutputStream err;
		private ExitCallback callback;
		private Environment environment;
		private Thread thread;
		private String Username;

		StreamHandlerAppender streamHandlerAppender;
		public ConsoleReader ConsoleReader;
		public SSHDCommandSender SshdCommandSender;

		public InputStream getIn() 
		{
			return in;
		}

		public OutputStream getOut() 
		{
			return out;
		}

		public OutputStream getErr() 
		{
			return err;
		}

		public Environment getEnvironment() 
		{
			return environment;
		}

		public void setInputStream(InputStream in) 
		{
			this.in = in;
		}

		public void setOutputStream(OutputStream out) 
		{
			this.out = out;
		}

		public void setErrorStream(OutputStream err) 
		{
			this.err = err;
		}

		public void setExitCallback(ExitCallback callback) 
		{
			this.callback = callback;
		}

		@Override
		public void start(ChannelSession cs, Environment env) throws IOException
		{
			try
			{
				String username = env.getEnv().get(Environment.ENV_USER);
				Optional<String> optcred = PermissionUtil.GetCredential(username, "console");
				// They don't have access.
				if (optcred.isPresent() && !optcred.get().contains("R"))
				{
					cs.close(true);
					return;
				}
				else
					SshdPlugin.instance.getLogger().warning("There is no $default pseudo-user under credential, allowing unrestricted access...");

				this.ConsoleReader = new ConsoleReader(in, new FlushyOutputStream(out), new SshTerminal());
				this.ConsoleReader.setExpandEvents(true);
				this.ConsoleReader.addCompleter(new ConsoleCommandCompleter());

				StreamHandler streamHandler = new FlushyStreamHandler(out, new ConsoleLogFormatter(), this.ConsoleReader);
				this.streamHandlerAppender		  = new StreamHandlerAppender(streamHandler);

				((Logger)LogManager.getRootLogger()).addAppender(this.streamHandlerAppender);

				this.environment = env;
				this.Username = username;
				this.SshdCommandSender = new SSHDCommandSender();
				this.SshdCommandSender.console = this;
				thread	    = new Thread(this, "SSHD ConsoleShell " + username);
				thread.start();
			}
			catch (Exception e)
			{
				e.printStackTrace();
				throw new IOException("Error starting shell", e);
			}
		}   

		@Override
		public void destroy(ChannelSession cs) { ((Logger)LogManager.getRootLogger()).removeAppender(this.streamHandlerAppender); }

		public void run()
		{
			try
			{
				if (!SshdPlugin.instance.getConfig().getString("Mode", "DEFAULT").equals("RPC"))
					printPreamble(this.ConsoleReader);
				while (true)
				{
					String command = this.ConsoleReader.readLine("\r>", null);
					// The user sent CTRL+D to close the shell, terminate the session.
					if (command == null)
						break;
					// Skip someone spamming enter
					if (command.trim().isEmpty())
						continue;
					// User wants to exit 
					if (command.equals("exit") || command.equals("quit"))
						break;
					// Clear the text from the screen (on supported terminals)
					if (command.equals("cls"))
					{
						this.ConsoleReader.clearScreen();
						this.ConsoleReader.drawLine();
						this.ConsoleReader.flush();
						continue;
					}
					// Hide the mkpasswd command input from other users.
					Boolean mkpasswd = command.split(" ")[0].equals("mkpasswd");
					Optional<String> optcred = PermissionUtil.GetCredential(this.Username, "console");

					if (optcred.isPresent() && !optcred.get().contains("W"))
						continue;

					Bukkit.getScheduler().runTask(
						SshdPlugin.instance, () ->
						{
							if (SshdPlugin.instance.getConfig().getString("Mode", "DEFAULT").equals("RPC") && command.startsWith("rpc"))
							{
								// NO ECHO NO PREAMBLE AND SHIT
								String cmd = command.substring("rpc".length() + 1, command.length());
								Bukkit.dispatchCommand(this.SshdCommandSender, cmd);
							}
							else
							{
								// Don't send our mkpasswd command output. This will echo passwords back
								// to the console for all to see. This command is strictly between
								// our plugin and the connected client.
								if (!mkpasswd)
								{
									SshdPlugin.instance.getLogger().info("<" + this.Username + "> " + command);
									Bukkit.dispatchCommand(Bukkit.getConsoleSender(), command);
								}
								else
								{
									Bukkit.dispatchCommand(this.SshdCommandSender, command);
								}
							}
						});
				}
			}
			catch (IOException e)
			{
				e.printStackTrace();
				SshdPlugin.instance.getLogger().log(Level.SEVERE, "Error processing command from SSH", e);
			}
			finally
			{
				SshdPlugin.instance.getLogger().log(Level.INFO, this.Username + " disconnected from SSH.");
				callback.onExit(0);
			}
		}

		private String GetHostname()
		{
			try 
			{
				return InetAddress.getLocalHost().getHostName();
			}
			catch (UnknownHostException e)
			{
				e.printStackTrace();
				SshdPlugin.instance.getLogger().log(Level.INFO, "The above stacktrace can be ignored, you likely have a misconfigured system hosts file.");
				return "Unknown";
			}
		}

		private void printPreamble(ConsoleReader cr) throws IOException
		{
			File f = new File(SshdPlugin.instance.getDataFolder(), "motd.txt");
			try 
			{
				BufferedReader br = new BufferedReader(new FileReader(f));

				String st;
				while ((st = br.readLine()) != null)
					cr.println(ConsoleLogFormatter.ColorizeString(st) + "\r");
			}
			catch (FileNotFoundException e)
			{
				e.printStackTrace();
				SshdPlugin.instance.getLogger().log(Level.WARNING, "Could not open " + f + ": File does not exist.");
				// Not showing the SSH motd is not a fatal failure, let the session continue. 
			}

			// Doesn't really guarantee our actual system hostname but
			// it's better than not having one at all.
			cr.println("Connected to: " + this.GetHostname() + " (" + Bukkit.getServer().getName() + ")\r");
			cr.println(ConsoleLogFormatter.ColorizeString(Bukkit.getServer().getMotd()).replaceAll("\n", "\r\n"));
			cr.println("\r");
			cr.println("Type 'exit' to exit the shell." + "\r");
			cr.println("===============================================" + "\r");
		}
	}
}