import org.apache.commons.io.FileUtils;
import org.apache.commons.io.filefilter.DirectoryFileFilter;
import org.apache.commons.io.filefilter.RegexFileFilter;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Comparator;

class CommandClass
{
    //Add your commands here
    public void Initialize()
    {
        AddCommand(new ExitCommand());
        AddCommand(new PlatformCommand());
        AddCommand(new find_files());
        AddCommand(new HelloCommand());
        AddCommand(new addcommand());
        AddCommand(new subcommand());
        AddCommand(new multcommand());
        //AddCommand(new user_recon());

        AddCommand(new user_recon_template());
    }

    //region Add your classes here

    private class ExitCommand extends CommandBase
    {

        public ExitCommand()
        {
            super("exit", "Exit environment");
        }

        public void Windows(String[] args)
        {
            System.exit(0);
        }

        public void Linux(String[] args)
        {
            Windows(args);
        }
    }

    private class PlatformCommand extends CommandBase
    {

        public PlatformCommand()
        {
            super("platform", "args W or L");
        }

        public void Windows(String[] args)
        {
            String arg = args[0].trim().toLowerCase();
            if (args.length != 1 || (!arg.equals("w") && !arg.equals("l")))
            {
                System.out.println("Invalid Arguments provided! Expected W or L but got '" + arg.toUpperCase() + "'");
                return;
            }
            CommandClass.IsWindows = args[0].trim().toLowerCase().equals("w");
        }

        public void Linux(String[] args)
        {
            Windows(args);
        }
    }

    private class HelloCommand extends CommandBase
    {

        public HelloCommand()
        {
            super("Hello", "Prints Hello World");
        }

        public void Windows(String[] args)
        {
            System.out.println("Hello World");
        }

        public void Linux(String[] args)
        {
            Windows(args);
        }
    }

    private class addcommand extends CommandBase
    {

        public addcommand()
        {
            super("add", "adds numbers");
        }

        public void Windows(String[] args)
        {
            int a, b;
            if (args.length != 2)
            {
                System.out.println("wrong amount of args");
                return;
            }
            try
            {
                a = Integer.valueOf(args[0]);
                b = Integer.valueOf(args[1]);
            } catch (Exception e)
            {
                System.out.println("invalid argument");
                return;
            }
            System.out.println(a + " + " + b + " = " + (a + b));
        }

        public void Linux(String[] args)
        {
            Windows(args);
        }
    }

    private class subcommand extends CommandBase
    {

        public subcommand()
        {
            super("subtract", "subtracts numbers");
        }

        public void Windows(String[] args)
        {
            int a, b;
            if (args.length != 2)
            {
                System.out.println("wrong amount of args");
                return;
            }
            try
            {
                a = Integer.valueOf(args[0]);
                b = Integer.valueOf(args[1]);
            } catch (Exception e)
            {
                System.out.println("invalid argument");
                return;
            }
            System.out.println(a + " - " + b + " = " + (a - b));
        }

        public void Linux(String[] args)
        {
            Windows(args);
        }
    }

    private class multcommand extends CommandBase
    {

        public multcommand()
        {
            super("multiply", "multiplies numbers");
        }

        public void Windows(String[] args)
        {
            int a, b;
            if (args.length != 2)
            {
                System.out.println("wrong amount of args");
                return;
            }
            try
            {
                a = Integer.valueOf(args[0]);
                b = Integer.valueOf(args[1]);
            } catch (Exception e)
            {
                System.out.println("invalid argument");
                return;
            }
            System.out.println(a + " * " + b + " = " + (a * b));
        }

        public void Linux(String[] args)
        {
            Windows(args);
        }
    }

    private class find_files extends CommandBase
    {

        public find_files()
        {
            super("find-files", "<dir> <ext,...> <outpath?>");
        }

        public void Windows(String[] args)
        {
            if (args.length < 2 || args.length > 3)
            {
                System.out.println("Bad arguments. Please enter <dir> <regex>");
                return;
            }

            File f = new File(args[0]);

            if (!f.exists())
            {
                System.out.println("Directory: " + args[0] + " doesn't exist!");
                return;
            }

            String regex = ".*\\.(";
            String[] split = (args[1] == null ? "" : args[1]).split(",");
            for (int i = 0; i < split.length; i++)
            {
                regex += split[i] + (i + 1 == split.length ? ")" : "|");
            }


            Collection<File> files = null;
            try
            {
                files = FileUtils.listFiles(
                        new File(args[0]),
                        new RegexFileFilter(regex),
                        DirectoryFileFilter.DIRECTORY
                );
            } catch (java.util.regex.PatternSyntaxException e)
            {
                System.out.println("Bad regex!");
                return;
            }

            String result = "";

            for (File file : files)
            {
                result += file.getAbsolutePath() + "\n";
            }

            if (args.length == 3)
            {
                try
                {
                    FileUtils.writeStringToFile(new File(args[2]), result, Charset.defaultCharset());
                } catch (Exception e)
                {
                    System.out.println("Failed to save file...");
                    return;
                }
                System.out.println("File saved.");
            } else
            {
                System.out.println(result);
            }
        }

        public void Linux(String[] args)
        {
            Windows(args);
        }
    }

    private class user_recon extends CommandBase
    {

        public user_recon()
        {
            super("user-recon", "<input>");
        }

        private boolean IsWin = true;

        public void Windows(String[] args)
        {
            if (args.length != 1)
            {
                System.out.println("Bad arguments");
                return;
            }
            if (!new File(args[0]).exists())
            {
                System.out.println("Input file doesn't exist!!!");
                return;
            }

            ArrayList<UserInfo> Actions = new ArrayList<>();
            UserInfo[] u_info = IsWin ? GetWindowsUsers() : GetLinuxUsers();
            UserInfo[] cp_info = GetCyberPatriotUsers(args[0]);

            for (UserInfo u : u_info)
            {
                UserInfo match = null;
                for (UserInfo c : cp_info)
                {
                    if (c.Name.toLowerCase().equals(u.Name.toLowerCase()))
                    {
                        match = c;
                        break;
                    }
                }
                if (match == null)
                {
                    u.ActionTaken = "delete user";
                    Actions.add(u);
                } else
                {
                    if (match.IsAdmin != u.IsAdmin)
                    {
                        u.ActionTaken = (match.IsAdmin && !u.IsAdmin) ?
                                "Elevate to administrator" :
                                "Change to normal user";
                        Actions.add(u);
                    }
                }
            }
            for (UserInfo c : cp_info)
            {
                UserInfo match = null;
                for (UserInfo u : u_info)
                {
                    if (c.Name.toLowerCase().equals(u.Name.toLowerCase()))
                    {
                        match = c;
                        break;
                    }
                }
                if (match == null)
                {
                    c.ActionTaken = "Add user as " + (c.IsAdmin ? "an administrator" : "a normal user");
                    Actions.add(c);
                }
            }


            for (UserInfo u : Actions)
            {
                if (u.ActionTaken == null)
                {
                    u.ActionTaken = "unknown action";
                }
                System.out.println("User <" + u.Name + "> : Action <" + u.ActionTaken + ">");
            }
        }

        public void Linux(String[] args)
        {
            IsWin = false;
            Windows(args);
        }

        private UserInfo[] GetWindowsUsers()
        {
            String[] users_raw = Env_GetCommandOutput("net", "user");
            ArrayList<UserInfo> users = new ArrayList<>();

            byte ReadMode = 0;

            for (int i = 0; i < users_raw.length; i++)
            {
                if (ReadMode == 0) //searching
                {
                    if (users_raw[i].contains("---"))
                        ReadMode = 1;
                } else if (ReadMode == 1)
                {
                    if (users_raw[i].toLowerCase().contains("the command completed"))
                        ReadMode = 2;
                    else
                    {
                        String[] UserList = users_raw[i].split("\\s+");
                        for (String user : UserList)
                        {
                            String[] userout = Env_GetCommandOutput("net", "user " + user);

                            if (userout.length < 1 || userout[0].contains("could not be"))
                                continue;
                            UserInfo NewUser = new UserInfo();
                            NewUser.Name = user.toLowerCase();

                            for (String s : userout)
                            {
                                if (s.toLowerCase().contains("administrator"))
                                    NewUser.IsAdmin = true;
                            }

                            users.add(NewUser);
                        }
                    }
                } else
                {
                    break;
                }
            }

            return users.toArray(new UserInfo[users.size()]);
        }

        private String[] Env_GetCommandOutput(String command, String args)
        {
            ProcessBuilder processBuilder = null;
            if(args.isEmpty())
                processBuilder = new ProcessBuilder(command);
            else
                processBuilder = new ProcessBuilder(command, args);

            processBuilder.redirectErrorStream(true);

            Process p = null;

            try
            {
                p = processBuilder.start();
            } catch (Exception e)
            {
                return new String[0];
            }

            java.io.BufferedReader reader =
                    new java.io.BufferedReader(new java.io.InputStreamReader(p.getInputStream()));

            ArrayList<String> lines = new ArrayList<>();

            String line = null;

            try
            {
                while ((line = reader.readLine()) != null)
                {
                    lines.add(line);
                }
            } catch (Exception e)
            {
                return new String[0];
            }

            return lines.toArray(new String[lines.size()]);
        }

        private UserInfo[] GetLinuxUsers()
        {
            String[] users_raw = Env_GetCommandOutput("awk -F\'[/:]\' \'{if ($3 >= 1000 && $3 != 65534) print $1}\' /etc/passwd", "");

            ArrayList<UserInfo> users = new ArrayList<>();

            for (String u : users_raw)
            {
                UserInfo userInfo = new UserInfo();
                userInfo.Name = u;

                String[] Info = Env_GetCommandOutput("groups", u);

                for(String sub_info : Info)
                {
                    if(sub_info.contains("sudo"))
                        userInfo.IsAdmin = true;
                }

                users.add(userInfo);
            }

            return users.toArray(new UserInfo[users.size()]);
        }

        private UserInfo[] GetCyberPatriotUsers(String fname)
        {
            ArrayList<UserInfo> users = new ArrayList<>();

            try
            {
                java.util.Scanner lines = new java.util.Scanner(new File(fname));

                byte ReadMode = 0;

                while (true)
                {
                    String line = lines.nextLine();
                    if (line.isEmpty())
                        continue;
                    if (line.trim().toLowerCase().contains("authorized administrators"))
                    {
                        ReadMode = 1;
                        continue;
                    } else if (line.trim().toLowerCase().contains("authorized users"))
                    {
                        ReadMode = 2;
                        continue;
                    }
                    if (ReadMode == 1)
                    {
                        if (Character.isDigit(line.charAt(0)) || Character.isLetter(line.charAt(0)))
                        {
                            UserInfo u = new UserInfo();
                            u.Name = "";
                            for (int i = 0; i < line.length(); i++)
                            {
                                if (Character.isDigit(line.charAt(i)) || Character.isLetter(line.charAt(i)))
                                    u.Name += line.charAt(i);
                                else
                                    break;
                            }
                            u.IsAdmin = true;
                            users.add(u);
                        }
                    } else if (ReadMode == 2)
                    {
                        if (Character.isDigit(line.charAt(0)) || Character.isLetter(line.charAt(0)))
                        {
                            UserInfo u = new UserInfo();
                            u.Name = "";
                            for (int i = 0; i < line.length(); i++)
                            {
                                if (Character.isDigit(line.charAt(i)) || Character.isLetter(line.charAt(i)))
                                    u.Name += line.charAt(i);
                                else
                                    break;
                            }
                            u.IsAdmin = false;
                            users.add(u);
                        }
                    }
                }

            } catch (java.util.NoSuchElementException e)
            {
                UserInfo[] ui = new UserInfo[users.size()];
                return users.toArray(ui);
            } catch (FileNotFoundException e)
            {
                return new UserInfo[0];
            }
        }

        private class UserInfo
        {
            public String Name;
            public boolean IsAdmin;
            public String ActionTaken;
        }
    }


    private class user_recon_template extends CommandBase
    {

        public user_recon_template()
        {
            super("user-recon","<input>");
        }

        public void Windows(String[] args) //TODO:
        {
            //1. Must have 1 argument

            //2. Must have a valid argument (file exists)

            //3. Create a list to hold UserInfo objects that need to change

            //4. Get all users on current platform

            //5. Get all users in the list of users

            //6. Compare users in lists to achieve the following goals (hint: use ActionTaken to track what is wrong)
                //6.1. Users that shouldnt exist are added to your list
                //6.2. Users that don't have proper privileges should be added to your list
                //6.3. Users that need to be created should be added to your list

            //7. Print all the users and actions required to the screen

        }

        public void Linux(String[] args) //TODO:
        {
            //hint: make a variable to determine if the platform is windows and call the windows function
        }

         private UserInfo[] GetWindowsUsers()
        {
            String[] users_raw = Env_GetCommandOutput("net", "user");
            ArrayList<UserInfo> users = new ArrayList<>();

            byte ReadMode = 0;

            for (int i = 0; i < users_raw.length; i++)
            {
                if (ReadMode == 0) //searching
                {
                    if (users_raw[i].contains("---"))
                        ReadMode = 1;
                } else if (ReadMode == 1)
                {
                    if (users_raw[i].toLowerCase().contains("the command completed"))
                        ReadMode = 2;
                    else
                    {
                        String[] UserList = users_raw[i].split("\\s+");
                        for (String user : UserList)
                        {
                            String[] userout = Env_GetCommandOutput("net", "user " + user);

                            if (userout.length < 1 || userout[0].contains("could not be"))
                                continue;
                            UserInfo NewUser = new UserInfo();
                            NewUser.Name = user.toLowerCase();

                            for (String s : userout)
                            {
                                if (s.toLowerCase().contains("administrator"))
                                    NewUser.IsAdmin = true;
                            }

                            users.add(NewUser);
                        }
                    }
                } else
                {
                    break;
                }
            }

            return users.toArray(new UserInfo[users.size()]);
        }

        private String[] Env_GetCommandOutput(String command, String args)
        {
            ProcessBuilder processBuilder = null;
            if(args.isEmpty())
                processBuilder = new ProcessBuilder(command);
            else
                processBuilder = new ProcessBuilder(command, args);

            processBuilder.redirectErrorStream(true);

            Process p = null;

            try
            {
                p = processBuilder.start();
            } catch (Exception e)
            {
                return new String[0];
            }

            java.io.BufferedReader reader =
                    new java.io.BufferedReader(new java.io.InputStreamReader(p.getInputStream()));

            ArrayList<String> lines = new ArrayList<>();

            String line = null;

            try
            {
                while ((line = reader.readLine()) != null)
                {
                    lines.add(line);
                }
            } catch (Exception e)
            {
                return new String[0];
            }

            return lines.toArray(new String[lines.size()]);
        }

        private UserInfo[] GetLinuxUsers()
        {
            String[] users_raw = Env_GetCommandOutput("awk -F\'[/:]\' \'{if ($3 >= 1000 && $3 != 65534) print $1}\' /etc/passwd", "");

            ArrayList<UserInfo> users = new ArrayList<>();

            for (String u : users_raw)
            {
                UserInfo userInfo = new UserInfo();
                userInfo.Name = u;

                String[] Info = Env_GetCommandOutput("groups", u);

                for(String sub_info : Info)
                {
                    if(sub_info.contains("sudo"))
                        userInfo.IsAdmin = true;
                }

                users.add(userInfo);
            }

            return users.toArray(new UserInfo[users.size()]);
        }

        private UserInfo[] GetCyberPatriotUsers(String fname) //TODO:
        {
            ArrayList<UserInfo> users = new ArrayList<>(); //List to return

            try
            {
                java.util.Scanner lines = new java.util.Scanner(new File(fname));

                while(true)
                {
                    String line = lines.nextLine();
                    if(line.isEmpty())
                        continue;
                    //Steps:
                    //1. Determine if you are reading an admin or a normal user
                    //2. Read only the user name from the line
                    //3. Add a userinfo object to the list provided
                }

            }
            catch(java.util.NoSuchElementException e)
            {
                //4. return the users collected
            }
            catch(FileNotFoundException e)
            {
                return new UserInfo[0]; //file wasnt found, returning empty list
            }
            return new UserInfo[0];
        }

        private class UserInfo
        {
            public String Name;
            public boolean IsAdmin;
            public String ActionTaken;
        }
    }

    //endregion


    //region CORE
    public static boolean IsWindows = true;

    public ArrayList<CommandBase> Commands;

    public abstract class CommandBase
    {
        public String Command = "none";
        public String Description = "invalid command";

        public abstract void Windows(String[] args);

        public abstract void Linux(String[] args);

        public void ExecuteCommand(String[] args)
        {
            if (CommandClass.IsWindows)
                Windows(args);
            else
                Linux(args);
        }

        public CommandBase(String cmd, String desc)
        {
            Command = cmd;
            Description = desc;
        }

        @Override
        public String toString()
        {
            return Command;
        }

    }

    public void AddCommand(CommandBase command)
    {
        if (Commands == null)
            Commands = new ArrayList<>();
        Commands.add(command);
        Commands.sort(new CommandComparator());
    }

    private class CommandComparator implements Comparator<CommandBase>
    {

        @Override
        public int compare(CommandBase o1, CommandBase o2)
        {
            return o1.toString().toLowerCase().compareTo(o2.toString().toLowerCase());
        }
    }
    //endregion
}