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

namespace WindowsFormsApp5
{
    public partial class Form1 : Form
    {
        bool searchFor;

        public Form1()
        {
            InitializeComponent();
            textBox2.MaxLength = 1;
            splitterBox.MaxLength = 1;
        }

        private void button1_Click(object sender, EventArgs e)
        {

            string input = textBox1.Text;
            if (!searchFor)
            {
                char ill = Convert.ToChar(textBox2.Text);
                MessageBox.Show("An folgender Stelle kommt der illegale Charakter vor: " + input.IndexOf(ill));
            }
            else
            {
                string ill = textBox2.Text;
                MessageBox.Show("An folgender Stelle kommt der illegale Charakter vor: " + input.IndexOf(ill));
            }


        }

        private void checkChange(object sender, EventArgs e)
        {
            if (searchFor)
            {
                illegal.Text = "illegal char";
                textBox2.MaxLength = 1;
                textBox2.Text = "";
                searchFor = false;
            }
            else
            {
                illegal.Text = "illegal string";
                textBox2.MaxLength = 0;
                textBox2.Text = "";
                searchFor = true;
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            string splitterString = splitBox.Text;
            char splitter = Convert.ToChar(splitterBox.Text);
            string[] splittedStrings = splitterString.Split(splitter);
            for(int i = 0; i < splittedStrings.Length; i++)
            {
                richTextBox1.AppendText(splittedStrings[i]);
                richTextBox1.AppendText("\n");
            }
        }

        private void button3_Click(object sender, EventArgs e)
        {
            string trimmerString = stringTrim.Text;
            char[] remove = new char[] { 'a', 'e', 'i', 'u' };
            trimmerString = trimmerString.Trim(remove);
            richTextBox2.AppendText(trimmerString.Trim(remove));

        }

        private void button4_Click(object sender, EventArgs e)
        {
            string p = precodeString.Text;
            int s = Convert.ToInt32(cipherShiftBox.Text);
            encodeStringBox.Text = encodeString(p, s);
        }

        private string encodeString(string s, int shift)
        {
            s = s.ToLower();
            string res = null;
            char[] code = s.ToCharArray();
            for(int i = 0; i < code.Length; i++)
            {
                int a = code[i];
                if(code[i] >= 'a' && code[i] <= 'z')
                {
                    a += shift;
                    if(a > 'z')
                    {
                        a -= 26;

                    }
                    if(a < 'a')
                    {
                        a += 26;
                    }
                }
                code[i] = (char)a;
                res += code[i];
            }
            return res;
        }

        private string decodeString(string s, int shift)
        {
            s = s.ToLower();
            string res = null;
            char[] code = s.ToCharArray();
            for (int i = 0; i < code.Length; i++)
            {
                int a = code[i];
                if (code[i] >= 'a' && code[i] <= 'z')
                {
                    a -= shift;
                    if (a > 'z')
                    {
                        a -= 26;

                    }
                    if (a < 'a')
                    {
                        a += 26;
                    }
                }
                code[i] = (char)a;
                res += code[i];
            }
            return res;
        }

        private void decodeButton_Click(object sender, EventArgs e)
        {
            string p = ripcodeString.Text;
            int s = Convert.ToInt32(decipherShiftBox.Text);
            decodedString.Text = decodeString(p, s);
        }
    }
}