using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace NSD
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            textBox1.Text = "";
            textBox2.Text = "";
            textBox1.Focus();
            listBox1.Items.Clear();
        }

        private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
        {
            if(!((e.KeyChar >= 48 && e.KeyChar <= 57) || (e.KeyChar == 8)))
            {
                e.KeyChar = Convert.ToChar(0); 
            }
        }

        private void textBox2_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (!((e.KeyChar >= 48 && e.KeyChar <= 57) || (e.KeyChar == 8)))
            {
                e.KeyChar = Convert.ToChar(0);
            }
        }

        private void button_vymaz_Click(object sender, EventArgs e)
        {
            textBox1.Text = "";
            textBox2.Text = "";
            textBox1.Focus();
        }

        private void button_close_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void pictureBox1_Click(object sender, EventArgs e)
        {
            System.Diagnostics.Process.Start("https://cs.wikipedia.org/wiki/Eukleid%C5%AFv_algoritmus");
        }

        private void button_vypocet_Click(object sender, EventArgs e)
        {
            uint c1, c2, zb, nsd;
            string nsd_vystup;

            if (textBox1.Text == "" || textBox2.Text == "")
            {
                MessageBox.Show("Musíte zadat číslo!", "Varování", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                return;
            }
            else
            {
               try
                {
                   c1 = Convert.ToUInt32(textBox1.Text);
                   c2 = Convert.ToUInt32(textBox2.Text); 
                }
               catch(OverflowException)
                 {
                   MessageBox.Show("Zadejte menší číslo!", "Chyba", MessageBoxButtons.OK, MessageBoxIcon.Error);
                   textBox1.Text = "";
                   textBox2.Text = "";
                   textBox1.Focus();
                   return;
                 }

               if (c1 == 0 || c2 == 0)
               {
                   MessageBox.Show("Pro nulu nemá smysl!", "Informace", MessageBoxButtons.OK, MessageBoxIcon.Information);
                   return; 
               }
               else
               {
                   zb = 1;
                   while (zb != 0)
                   {
                       zb = c1 % c2;
                       c1 = c2;
                       c2 = zb;
                   }

                   nsd = c1;
                   nsd_vystup = Convert.ToString(nsd);
                   listBox1.Items.Add("  NSD (" + textBox1.Text + " , " + textBox2.Text + ") = " + nsd_vystup);
                   listBox1.Items.Add(""); 
               }
            }
        }
    }
}