c# assembly reference error , namespace can't be found

I am very new to C#. I got C# source code from a friend but I have to compile by my self. I don't have visual studio, so I use mono compiler to compile it but got an error and I cant fix it:

The type or namespace name `KageForm' could not be found (are you missing a using directive or an assembly reference?)

namespace JustNull {

internal static class Program
{
    public static List<KageForm> dittos = new List<KageForm>();
    public static bool uses_date = false;
    public static bool uses_license = false;
    public static DateTime myDate = DateTime.ParseExact("2018-06-01 00:00:00,000", "yyyy-MM-dd HH:mm:ss,fff",
                                   System.Globalization.CultureInfo.InvariantCulture);
    public static string licensed_to = "2652626616161613161041212-45191120151619109184101118-45191120151619109184101118-16185692413";

    public static string Magnemite()
    {
        string str = string.Empty;
        using (ManagementObjectCollection.ManagementObjectEnumerator enumerator = new ManagementClass("win32_processor").GetInstances().GetEnumerator())
        {
            if (enumerator.MoveNext())
            {
                str = enumerator.Current.Properties["processorID"].Value.ToString();
            }
        }
        string str2 = string.Concat(new object[] { str, Environment.ProcessorCount, "/", Environment.MachineName, "/", Environment.UserDomainName, "/", Environment.UserName, Environment.GetLogicalDrives().Length });
        str2.ToCharArray();
        string str3 = "";
        foreach (char ch in str2)
        {
            str3 = (ch != '/') ? (str3 + ((int)(char.ToUpper(ch) - '@')).ToString()) : (str3 + "/");
        }
        return str3.Replace("-", "").Replace("/", "-");
    }

    [STAThread]
    private static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        if (!licensed_to.Equals(Magnemite()) && uses_license)
        {
            MessageBox.Show("Program doesn't belong to you! If u think this is error contact the seller!");
            Application.Exit();
            return;
        }
        DateTime ctime = GetNetworkTime();
        DateTime temp;
        // Try to check if got time from NTP
        if(uses_date) { 
            if (DateTime.TryParse(ctime.ToString(), out temp))
            {
                // compare dates
                int result = DateTime.Compare(myDate, ctime);
                if (result > 0)
                {
                    MessageBox.Show(string.Format("Your copy is valid until: {0}", (string)myDate.ToString()));
                }
                else {
                    MessageBox.Show(string.Format("Your copy has expired! It was valid until {0}", (string)myDate.ToString()));
                    Application.Exit();
                    return;
                }
            }
            else
            {
                // If time failed
                MessageBox.Show(string.Format("It was failure with date checkup! Program won't start!"));
                Application.Exit();
                return;
            }
        }

        KageControl mainForm = new KageControl();
        mainForm.Show();
        Application.Run(mainForm);

    }

    public static DateTime GetNetworkTime()
    {
        //default Windows time server
        const string ntpServer = "time.windows.com";

        // NTP message size - 16 bytes of the digest (RFC 2030)
        var ntpData = new byte[48];

        //Setting the Leap Indicator, Version Number and Mode values
        ntpData[0] = 0x1B; //LI = 0 (no warning), VN = 3 (IPv4 only), Mode = 3 (Client Mode)

        var addresses = Dns.GetHostEntry(ntpServer).AddressList;

        //The UDP port number assigned to NTP is 123
        var ipEndPoint = new IPEndPoint(addresses[0], 123);
        //NTP uses UDP

        using (var socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp))
        {
            socket.Connect(ipEndPoint);

            //Stops code hang if NTP is blocked
            socket.ReceiveTimeout = 3000;

            socket.Send(ntpData);
            socket.Receive(ntpData);
            socket.Close();
        }

        //Offset to get to the "Transmit Timestamp" field (time at which the reply 
        //departed the server for the client, in 64-bit timestamp format."
        const byte serverReplyTime = 40;

        //Get the seconds part
        ulong intPart = BitConverter.ToUInt32(ntpData, serverReplyTime);

        //Get the seconds fraction
        ulong fractPart = BitConverter.ToUInt32(ntpData, serverReplyTime + 4);

        //Convert From big-endian to little-endian
        intPart = SwapEndianness(intPart);
        fractPart = SwapEndianness(fractPart);

        var milliseconds = (intPart * 1000) + ((fractPart * 1000) / 0x100000000L);

        //**UTC** time
        var networkDateTime = (new DateTime(1900, 1, 1, 0, 0, 0, DateTimeKind.Utc)).AddMilliseconds((long)milliseconds);

        return networkDateTime.ToLocalTime();
    }

    // stackoverflow.com/a/3294698/162671
    static uint SwapEndianness(ulong x)
    {
        return (uint)(((x & 0x000000ff) << 24) +
                       ((x & 0x0000ff00) << 8) +
                       ((x & 0x00ff0000) >> 8) +
                       ((x & 0xff000000) >> 24));
    }

    public static KageForm newDitto()
    {
        KageForm item = new KageForm();
        dittos.Add(item);
        item.Show();
        return item;
    }

    private static void newThread()
    {
        KageForm item = new KageForm();
        dittos.Add(item);
        Application.Run(item);
    }
}

}

here , kageform.cs

    namespace JustNull

{

public class KageForm : Form
{
    private IContainer components = null;
    private Button f8button;
    private Gastly gastly = new Gastly();
    private TextBox handlerBox;
    private int index;
    private string instructions = "";
    private RichTextBox instructionsDisplay;
    private TextBox instructionsField;
    private Jigglypuff jigglypuff = new Jigglypuff();
    private Point point = new Point();
    private bool running = false;
    private Button startButton;
    private Thread worker;
    private bool choosing_key = false;
    private Button button1;
    private Label label1;
    private Label label2;
    private Label label3;
    private Label label4;
    private bool chosen_key = false;

    public KageForm()
    {
        this.InitializeComponent();
        this.worker = new Thread(new ThreadStart(this.PerformMacro));
        this.worker.IsBackground = true;
        this.worker.Start();
        this.index = Program.dittos.Count;
        this.Text = "JustNull - " + this.index;
        this.instructionsDisplay.Hide();
        this.instructionsDisplay.Enabled = false;
        JustNull.InterceptKeys.OnKeyDown += new KeyEventHandler(onGlobalKeypress);
        JustNull.InterceptKeys.Start();
    }

    void onGlobalKeypress(object sender, KeyEventArgs e)
    {
        if (!chosen_key && !choosing_key)
            return;
        if (chosen_key && !choosing_key)
        {
            if (e.KeyCode.ToString().Equals(this.button1.Text))
            {
                PlayPause();
            }
        }
        else if (!chosen_key && choosing_key)
        {
            this.button1.Text = e.KeyCode.ToString();
            choosing_key = false;
            chosen_key = true;
        }
        else if (chosen_key && choosing_key)
        {
            if (e.KeyCode.ToString().Equals(this.button1.Text))
                return;

            this.button1.Text = e.KeyCode.ToString();
            choosing_key = false;
            chosen_key = true;
        }
    }

    void myKeyDown(object sender, KeyEventArgs e)
    {
        choosing_key = true;
    }


    private void Debug(string text)
    {
        this.startButton.Invoke((Action)(() => this.startButton.Text = text));
    }

    protected override void Dispose(bool disposing)
    {
        if (disposing && (this.components != null))
        {
            this.components.Dispose();
        }
        base.Dispose(disposing);
    }

    private void f8button_Click(object sender, EventArgs e)
    {
        RegisterHotKey(base.Handle, 1, 0, 0x77);
        this.f8button.Enabled = false;
    }

    [DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
    private static extern IntPtr FindWindowByCaption(IntPtr ZeroOnly, string lpWindowName);
    private IntPtr GetActiveWindow() =>
        GetForegroundWindow();

    [DllImport("user32.dll")]
    private static extern IntPtr GetForegroundWindow();
    private void getHwnd()
    {
        string str = "false";
        IntPtr activeWindow = this.GetActiveWindow();
        this.point = Cursor.Position;
        UnregisterHotKey(base.Handle, 1);
        try
        {
            this.handlerBox.Text = "Loading Handler...";
            str = "o_O cracked :)";
        }
        catch (Exception)
        {
            str = "false";
        }
        finally
        {
            if (str != "false")
            {
                this.handlerBox.Text = "h: " + activeWindow.ToString() + " x:" + this.point.X.ToString() + " y:" + this.point.Y.ToString();
                this.gastly.setWindow(activeWindow);
                this.jigglypuff.setWindow(activeWindow);
            }
            else
            {
                this.handlerBox.Text = "You don't have enough badges";
            }
            this.f8button.Enabled = true;
        }
    }

    public string GetInstructions() =>
        this.instructionsField.Text;

    private void InitializeComponent()
    {
        System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(KageForm));
        this.startButton = new System.Windows.Forms.Button();
        this.instructionsField = new System.Windows.Forms.TextBox();
        this.handlerBox = new System.Windows.Forms.TextBox();
        this.f8button = new System.Windows.Forms.Button();
        this.instructionsDisplay = new System.Windows.Forms.RichTextBox();
        this.button1 = new System.Windows.Forms.Button();
        this.label1 = new System.Windows.Forms.Label();
        this.label2 = new System.Windows.Forms.Label();
        this.label3 = new System.Windows.Forms.Label();
        this.label4 = new System.Windows.Forms.Label();
        this.SuspendLayout();
        // 
        // startButton
        // 
        this.startButton.Enabled = false;
        this.startButton.Location = new System.Drawing.Point(12, 12);
        this.startButton.Name = "startButton";
        this.startButton.Size = new System.Drawing.Size(215, 75);
        this.startButton.TabIndex = 0;
        this.startButton.Text = "Start";
        this.startButton.UseVisualStyleBackColor = true;
        this.startButton.Click += new System.EventHandler(this.startButton_Click);
        // 
        // instructionsField
        // 
        this.instructionsField.Location = new System.Drawing.Point(14, 120);
        this.instructionsField.Multiline = true;
        this.instructionsField.Name = "instructionsField";
        this.instructionsField.Size = new System.Drawing.Size(214, 95);
        this.instructionsField.TabIndex = 1;
        this.instructionsField.TextChanged += new System.EventHandler(this.instructionsField_TextChanged);
        // 
        // handlerBox
        // 
        this.handlerBox.Enabled = false;
        this.handlerBox.Location = new System.Drawing.Point(13, 234);
        this.handlerBox.Name = "handlerBox";
        this.handlerBox.Size = new System.Drawing.Size(169, 20);
        this.handlerBox.TabIndex = 2;
        this.handlerBox.TextChanged += new System.EventHandler(this.handlerBox_TextChanged);
        // 
        // f8button
        // 
        this.f8button.Location = new System.Drawing.Point(187, 234);
        this.f8button.Name = "f8button";
        this.f8button.Size = new System.Drawing.Size(40, 23);
        this.f8button.TabIndex = 3;
        this.f8button.Text = "F8";
        this.f8button.UseVisualStyleBackColor = true;
        this.f8button.Click += new System.EventHandler(this.f8button_Click);
        // 
        // instructionsDisplay
        // 
        this.instructionsDisplay.Location = new System.Drawing.Point(13, 120);
        this.instructionsDisplay.Name = "instructionsDisplay";
        this.instructionsDisplay.Size = new System.Drawing.Size(214, 95);
        this.instructionsDisplay.TabIndex = 4;
        this.instructionsDisplay.Text = "";
        this.instructionsDisplay.TextChanged += new System.EventHandler(this.instructionsDisplay_TextChanged);
        // 
        // button1
        // 
        this.button1.Location = new System.Drawing.Point(136, 270);
        this.button1.Name = "button1";
        this.button1.Size = new System.Drawing.Size(75, 23);
        this.button1.TabIndex = 5;
        this.button1.UseVisualStyleBackColor = true;
        this.button1.KeyDown += new System.Windows.Forms.KeyEventHandler(this.myKeyDown);
        // 
        // label1
        // 
        this.label1.AutoSize = true;
        this.label1.Location = new System.Drawing.Point(13, 275);
        this.label1.Name = "label1";
        this.label1.Size = new System.Drawing.Size(117, 13);
        this.label1.TabIndex = 6;
        this.label1.Text = "Button to start program:";
        // 
        // label2
        // 
        this.label2.AutoSize = true;
        this.label2.Location = new System.Drawing.Point(93, 257);
        this.label2.Name = "label2";
        this.label2.Size = new System.Drawing.Size(46, 13);
        this.label2.TabIndex = 7;
        this.label2.Text = "Optional";
        this.label2.TextAlign = System.Drawing.ContentAlignment.TopCenter;
        // 
        // label3
        // 
        this.label3.AutoSize = true;
        this.label3.Location = new System.Drawing.Point(12, 218);
        this.label3.Name = "label3";
        this.label3.Size = new System.Drawing.Size(225, 13);
        this.label3.TabIndex = 8;
        this.label3.Text = "Smash that F8 button go to game and click F8";
        this.label3.TextAlign = System.Drawing.ContentAlignment.TopCenter;
        // 
        // label4
        // 
        this.label4.AutoSize = true;
        this.label4.Location = new System.Drawing.Point(37, 97);
        this.label4.Name = "label4";
        this.label4.Size = new System.Drawing.Size(169, 13);
        this.label4.TabIndex = 9;
        this.label4.Text = "Charge your rage to this macro tab";
        this.label4.TextAlign = System.Drawing.ContentAlignment.TopCenter;
        // 
        // KageForm
        // 
        this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.ClientSize = new System.Drawing.Size(239, 302);
        this.Controls.Add(this.label4);
        this.Controls.Add(this.label3);
        this.Controls.Add(this.label2);
        this.Controls.Add(this.label1);
        this.Controls.Add(this.button1);
        this.Controls.Add(this.instructionsDisplay);
        this.Controls.Add(this.f8button);
        this.Controls.Add(this.handlerBox);
        this.Controls.Add(this.instructionsField);
        this.Controls.Add(this.startButton);
        this.Icon = ((System.Drawing.Icon)(resources.GetObject("$this.Icon")));
        this.Name = "KageForm";
        this.Text = "JustNull";
        this.Load += new System.EventHandler(this.KageForm_Load);
        this.ResumeLayout(false);
        this.PerformLayout();

    }

    private void KageForm_Load(object sender, EventArgs e)
    {

    }

    private void instructionsDisplay_TextChanged(object sender, EventArgs e)
    {
    }

    private void instructionsField_TextChanged(object sender, EventArgs e)
    {
        this.instructions = this.instructionsField.Text.ToString();
    }

    private void Mock()
    {
        this.Debug("LOOOL");
    }

    private void newBtn_Click(object sender, EventArgs e)
    {
        Program.newDitto();
    }

    private void Pause()
    {
        this.startButton.Text = "Start";
        this.running = false;
        this.instructionsField.Show();
        this.instructionsDisplay.Hide();
    }

    private void PerformMacro()
    {
        while (true)
        {
            if (this.running)
            {
                Action method = null;
                this.instructions = this.GetInstructions();
                string[] lines = this.instructions.Trim().Split(new char[] { '\n' });
                int linecount = 0;
                foreach (string str in lines)
                {
                    linecount++;
                    if (method == null)
                    {
                        method = delegate {
                            this.instructionsDisplay.Clear();
                            int num = 0;
                            foreach (string tekstas in lines)
                            {
                                num++;
                                if (num == linecount)
                                {
                                    int start = this.instructionsDisplay.TextLength;
                                    this.instructionsDisplay.AppendText(tekstas);
                                    int textLength = this.instructionsDisplay.TextLength;
                                    this.instructionsDisplay.Select(start, textLength);
                                    this.instructionsDisplay.SelectionColor = Color.Blue;
                                    this.instructionsDisplay.ScrollToCaret();
                                    this.instructionsDisplay.Select(0, 0);
                                }
                                else
                                {
                                    this.instructionsDisplay.AppendText(tekstas);
                                }
                            }
                        };
                    }
                    this.instructionsDisplay.BeginInvoke(method);
                    if (this.running)
                    {
                        string[] strArray = str.Trim().Split(new char[] { ' ' });
                        if (strArray[0] == "keypress")
                        {
                            this.gastly.KeyPress(strArray[1]);
                        }
                        if (strArray[0] == "rightclick")
                        {
                            if (strArray.Length == 1)
                            {
                                this.gastly.RightClick(this.point);
                            }
                            else
                            {
                                this.gastly.RightClick(new Point(int.Parse(strArray[1]), int.Parse(strArray[2])));
                            }
                        }
                        if (strArray[0] == "leftclick")
                        {
                            if (strArray.Length == 1)
                            {
                                this.gastly.LeftClick(this.point);
                            }
                            else
                            {
                                this.gastly.LeftClick(new Point(int.Parse(strArray[1]), int.Parse(strArray[2])));
                            }
                        }
                        if (strArray[0] == "startditto")
                        {
                            KageForm ditto = Program.dittos[int.Parse(strArray[1])];
                            ditto.BeginInvoke((Action)(() => ditto.Play()));
                        }
                        if (strArray[0] == "stopditto")
                        {
                            KageForm ditto = Program.dittos[int.Parse(strArray[1])];
                            ditto.BeginInvoke((Action)(() => ditto.Pause()));
                        }
                        if (strArray[0] == "wait")
                        {
                            int num = 0;
                            if (strArray.Length > 2)
                            {
                                int x = int.Parse(strArray[1]);
                                int y = int.Parse(strArray[2]);
                                if (strArray.Length == 5)
                                {
                                    num = this.timeString(strArray[4]);
                                }
                                bool flag = true;
                                while (flag)
                                {
                                    flag = this.jigglypuff.ExpectColor(new Point(x, y), strArray[3]);
                                    Thread.Sleep(100);
                                    if (strArray.Length == 5)
                                    {
                                        num -= 100;
                                        if (num <= 0)
                                        {
                                            flag = false;
                                        }
                                    }
                                }
                            }
                            else
                            {
                                int num4 = this.timeString(strArray[1]) / 100;
                                for (int i = 0; (i < num4) && this.running; i++)
                                {
                                    this.gastly.Wait(100);
                                }
                            }
                        }
                        if (strArray[0] == "closeclient")
                        {
                            this.gastly.Kill();
                        }
                        Thread.Sleep(100);
                    }
                }
            }
            else
            {
                this.gastly.Wait(100);
            }
        }
    }

    private void Play()
    {
        string[] strArray = this.instructionsField.Text.Trim().Split(new char[] { '\n' });
        List<string> list = new List<string>();
        foreach (string str in strArray)
        {
            if (str.Contains("#"))
            {
                this.Text = this.Text.Replace("JustNull", str.Replace("#", ""));
            }
            else
            {
                list.Add(str);
            }
        }
        this.instructionsField.Text = string.Join('\n'.ToString(), list.ToArray());
        this.startButton.Text = "Stop";
        this.running = true;
        this.instructionsField.Hide();
        this.instructionsDisplay.Show();
    }

    private void PlayPause()
    {
        if (this.running)
        {
            this.Pause();
        }
        else
        {
            this.Play();
        }
    }

    [DllImport("user32.dll")]
    public static extern bool RegisterHotKey(IntPtr hWnd, int id, int fsModifiers, int vlc);
    [DllImport("user32.dll")]
    private static extern bool SetForegroundWindow(IntPtr hWnd);
    private void setGastly()
    {
    }

    public void SetInstructions(string instruction)
    {
        this.instructionsField.Text = instruction;
    }

    private void startButton_Click(object sender, EventArgs e)
    {
        this.PlayPause();
    }

    private int timeString(string masked)
    {
        if (masked.Contains("y"))
        {
            masked = masked.Replace("y", "");
            return (int.Parse(masked));
        }
        if (masked.Contains("s"))
        {
            masked = masked.Replace("s", "");
            return (int.Parse(masked) * 0x3e8);
        }
        if (masked.Contains("m"))
        {
            masked = masked.Replace("m", "");
            return (int.Parse(masked) * 0xea60);
        }
        return int.Parse(masked);
    }

    [DllImport("user32.dll")]
    public static extern bool UnregisterHotKey(IntPtr hWnd, int id);
    protected override void WndProc(ref Message m)
    {
        if ((m.Msg == 0x312) && (m.WParam.ToInt32() == 1))
        {
            this.getHwnd();
        }
        base.WndProc(ref m);
    }

    private void label1_Click(object sender, EventArgs e)
    {

    }

    public delegate void Action();

    private void handlerBox_TextChanged(object sender, EventArgs e)
    {
        if (!this.startButton.Enabled)
            this.startButton.Enabled = true;
    }
}

}