MainForm.cs

using Customer_Registry.ContactFiles;
using System;
using System.Windows.Forms;


namespace Customer_Registry
{
    /// <summary>
    /// MainForm is the main user interface for the Customer Registry application.
    /// It handles interactions such as adding, editing, and deleting customer information.
    /// </summary>
    public partial class MainForm : Form
    {
        // Manages the collection of customers.
        private CustomerManager customerManager = new CustomerManager();

        /// <summary>
        /// Constructor for MainForm. Initializes components and sets up event handlers.
        /// </summary>
        public MainForm()
        {
            InitializeComponent();

            // Event handlers for button clicks.
            btnAdd.Click += BtnAdd_Click;
            btnEdit.Click += BtnEdit_Click;
            btnDelete.Click += BtnDelete_Click;

            // Populate the customer list view on form load.
            PopulateCustomerList();
            listView1.SelectedIndexChanged += ListView1_SelectedIndexChanged;
            listView1.MultiSelect = false;

        }

        /// <summary>
        /// Handles the event when a customer is selected from the list.
        /// Displays the selected customer's details.
        /// </summary>
        private void ListView1_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (listView1.SelectedItems.Count > 0)
            {
                // Extracts and displays the details of the selected customer.
                ListViewItem item = listView1.SelectedItems[0];
                Customer selectedCustomer = (Customer)item.Tag;

                var contact = selectedCustomer.CustomerContact;
                var phoneDetails = contact.PhoneDetails;
                var emailDetails = contact.EmailDetails;
                var addressDetails = contact.AddressDetails;

                // Convert the Country enum to a string
                string countryString = addressDetails.Country.ToString().Replace("_", " ");

                // Formatting and displaying the contact details in the text box.
                textBox1.Text = $"{contact.FirstName} {contact.LastName}\r\n" +
                                $" {addressDetails.Street}\r\n " +
                                $"{addressDetails.ZipCode} {addressDetails.City}\r\n" +
                                $" {countryString}\r\n" + // Use the formatted country string here
                                // Empty line for separation.
                                $" \r\n" +
                                $"Emails\r\n" +
                                $"   Private    {emailDetails.PersonalMail}\r\n" +
                                $"   Office      {emailDetails.OfficeMail}\r\n\n" +
                                // Empty line for separation.
                                $" \r\n" +
                                $"Phone numbers\r\n" +
                                $"   Private    {phoneDetails.PrivatePhone}\r\n" +
                                $"   Office      {phoneDetails.OfficePhone}";
            }
            else
            {
                // Clearing the details display if no customer is selected.
                textBox1.Clear();
            }
        }


        /// <summary>
        /// Event handler for the Add button. Opens the ContactForm to add a new customer.
        /// </summary>
        private void BtnAdd_Click(object sender, EventArgs e)
        {
            ContactForm contactForm = new ContactForm();
            contactForm.Text = "Add New Customer";
            if (contactForm.ShowDialog() == DialogResult.OK)
            {
                Contact newContact = contactForm.ContactData;
                Customer newCustomer = new Customer(newContact);
                customerManager.Add(newCustomer);
                PopulateCustomerList();

                // Select the newly added customer in the ListView
                SelectCustomerInListView(newCustomer.CustomerId);
            }
        }
        /// <summary>
        /// A helper method to select a customer in the ListView.
        /// </summary>
        /// <param name="customerId"></param>
        private void SelectCustomerInListView(int customerId)
        {
            foreach (ListViewItem item in listView1.Items)
            {
                if (item.Tag is Customer customer && customer.CustomerId == customerId)
                {
                    item.Selected = true;
                    listView1.EnsureVisible(item.Index);
                    break;
                }
            }
        }

        /// <summary>
        /// Event handler for the Edit button. Opens the ContactForm to edit the selected customer's details.
        /// </summary>
        private void BtnEdit_Click(object sender, EventArgs e)
        {
            if (listView1.SelectedItems.Count > 0)
            {
                // Store the index of the selected item
                int selectedIndex = listView1.SelectedIndices[0];

                ListViewItem selectedItem = listView1.SelectedItems[0];
                Customer selectedCustomer = (Customer)selectedItem.Tag;

                ContactForm contactForm = new ContactForm();
                contactForm.Text = "Edit Customer";
                if (selectedCustomer.CustomerContact != null)
                {
                    contactForm.LoadContactData(selectedCustomer.CustomerContact);

                    if (contactForm.ShowDialog() == DialogResult.OK)
                    {
                        Contact updatedContact = contactForm.GetUpdatedContactData();
                        customerManager.Update(
                            selectedCustomer.CustomerId,
                            updatedContact.FirstName, updatedContact.LastName,
                            updatedContact.PhoneDetails.PrivatePhone, updatedContact.PhoneDetails.OfficePhone,
                            updatedContact.EmailDetails.PersonalMail, updatedContact.EmailDetails.OfficeMail,
                            updatedContact.AddressDetails.Street, updatedContact.AddressDetails.City,
                            updatedContact.AddressDetails.ZipCode, updatedContact.AddressDetails.Country);

                        PopulateCustomerList();

                        // Restore the selected index
                        if (selectedIndex >= 0 && selectedIndex < listView1.Items.Count)
                        {
                            listView1.Items[selectedIndex].Selected = true;
                            listView1.Items[selectedIndex].Focused = true;
                            listView1.EnsureVisible(selectedIndex); // To ensure the item is visible in the ListView
                        }
                    }
                }
                else
                {
                    MessageBox.Show("Contact data is not provided for the selected customer.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                }
            }
            else
            {
                MessageBox.Show("Please select a customer to edit.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        /// <summary>
        /// Event handler for the Delete button. Removes the selected customer from the registry.
        /// </summary>
        private void BtnDelete_Click(object sender, EventArgs e)
        {
            if (listView1.SelectedItems.Count > 0)
            {
                ListViewItem selectedItem = listView1.SelectedItems[0];
                Customer selectedCustomer = (Customer)selectedItem.Tag;

                customerManager.Remove(selectedCustomer.CustomerId);
                PopulateCustomerList();
            }
            else
            {
                MessageBox.Show("Please select a customer to delete.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        /// <summary>
        /// Populates the ListView with customer data.
        /// </summary>
        private void PopulateCustomerList()
        {
            if (customerManager == null)
            {
                MessageBox.Show("Customer manager is not initialized.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            listView1.Items.Clear();
            var customers = customerManager.GetAllCustomers();
            if (customers != null)
            {
                foreach (var customer in customers)
                {
                    // Ensure the customer and its details are not null before accessing them
                    if (customer != null && customer.CustomerContact != null)
                    {
                        var item = new ListViewItem(new[]
                        {
                    customer.CustomerId.ToString(),
                    customer.CustomerContact.LastName + ", " + customer.CustomerContact.FirstName,
                    customer.CustomerContact.PhoneDetails?.OfficePhone,
                    customer.CustomerContact.EmailDetails?.OfficeMail
                })
                        {
                            Tag = customer
                        };

                        listView1.Items.Add(item);
                    }
                }
            }
        }

    }
}