using System;
using System.Linq;
using System.Text;
using System.Windows.Forms;

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

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

        private void btnParse_Click(object sender, EventArgs e)
        {
            string fullEmail = txtEmail.Text.Trim();

            if (fullEmail.Contains('@'))
            {
                string[] emails = fullEmail.Split('@');
                string userName = emails[0];
                string domain = emails[1];
                MessageBox.Show("User name: " + userName + "\n\n" + "Domain name: " + domain.Trim(), "Parsed String");
            }
            else
            {
                MessageBox.Show("Please enter a valid email address", "Invalid input");
            }
        }

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

        private void btnFormat_Click(object sender, EventArgs e)
        {
            if (IsValidData())

            {
                StringBuilder full_Address = new StringBuilder("City, State, Zip: ");
                string city = txtCity.Text.Trim();
                string state = txtState.Text.Trim().ToUpper();
                string zipCode = txtZipCode.Text.Trim().ToUpper();
                string firstLetter = city.Substring(0, 1).ToUpper();
                string otherLetters = city.Substring(1).ToLower();
                city = firstLetter + otherLetters;
                full_Address.Insert(full_Address.Length, city + " ," + state + " " + zipCode);

                MessageBox.Show(full_Address.ToString(), "Formated Address");
            }
        }

        private bool IsPresent(TextBox tb, string name)
        {
            if (tb.Text == "")
            {
                MessageBox.Show(name + " is a required field");
                return false;
            }

            return true;
        }

        private bool IsValidData()
        {
            return

                IsPresent(txtCity, "City") &&
                IsPresent(txtState, "State") &&
                IsPresent(txtZipCode, "Zip Code");
        }
    }
}