HelpC# (Bot Programming) - Send Mouse Input to an inactive Application with given coords?

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace _0xD3F_1
{
    public partial class Main : Form
    {
        #region Imports
        [DllImport("user32.dll", SetLastError = true)]
        static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

        [DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
        static extern IntPtr FindWindowByCaption(IntPtr ZeroOnly, string lpWindowName);
        // Alternativ:
        // FindWindow(default(string), lpWindowName)
        // FindWindow((string)null, lpWindowName)

        [DllImport("user32.dll")]
        static extern bool ClientToScreen(IntPtr hWnd, ref Point lpPoint);

        [DllImport("user32.dll")]
        internal static extern uint SendInput(uint nInputs, [MarshalAs(UnmanagedType.LPArray), In] INPUT[] pInputs, int cbSize);
        #endregion

        #region Structs
        #pragma warning disable 649
        internal struct INPUT
        {
            public UInt32 Type;
            public MOUSEKEYBDHARDWAREINPUT Data;
        }

        [StructLayout(LayoutKind.Explicit)]
        internal struct MOUSEKEYBDHARDWAREINPUT
        {
            [FieldOffset(0)]
            public MOUSEINPUT Mouse;
        }

        internal struct MOUSEINPUT
        {
            public Int32 X;
            public Int32 Y;
            public UInt32 MouseData;
            public UInt32 Flags;
            public UInt32 Time;
            public IntPtr ExtraInfo;
        }

        #pragma warning restore 649
        #endregion

        #region Coords
        // Removed since I wanted to do a full rework.
        #endregion

        public Main()
        {
            InitializeComponent();
        }

        private void Main_Load(object sender, EventArgs e)
        {
            // Removed since I wanted to do a full rework.
        }

        private void Start_Click(object sender, EventArgs e)
        {
            IntPtr windowHandle = FindWindow(default(string), "Snipping Tool");
            ClickOnPoint(windowHandle, new Point(5, 5));
        }

        // Removed since I wanted to do a full rework.

        public static void ClickOnPoint(IntPtr wndHandle, Point clientPoint)
        {
            var oldPos = Cursor.Position;

            /// get screen coordinates
            ClientToScreen(wndHandle, ref clientPoint);

            /// set cursor on coords, and press mouse
            Cursor.Position = new Point(clientPoint.X, clientPoint.Y);

            var inputMouseDown = new INPUT();
            inputMouseDown.Type = 0; /// input type mouse
            inputMouseDown.Data.Mouse.Flags = 0x0002; /// left button down

            var inputMouseUp = new INPUT();
            inputMouseUp.Type = 0; /// input type mouse
            inputMouseUp.Data.Mouse.Flags = 0x0004; /// left button up

            var inputs = new INPUT[] { inputMouseDown, inputMouseUp };
            SendInput((uint)inputs.Length, inputs, Marshal.SizeOf(typeof(INPUT)));

            /// return mouse 
            Cursor.Position = oldPos;
        }

    }
}