Clients.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data.SqlClient;
using System.Diagnostics.Eventing.Reader;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Hotel_Management_System
{
    internal class Clients
    {
        private Int64 client_id { get; set; }
        private string name { get; set; }
        private string surname { get; set; }
        private string email { get; set; }
        private string phone { get; set; }
        private string city { get; set; }
        private string address { get; set; }
        private string password { get; set; }
        private DateTime date { get; set; }
        private Int64 hotel_id { get; set; }
        private bool isSaveAllowed { get; set; }
        private bool isUpdateAllowed { get; set; }

        public bool CheckIfExists()
        {
            DatabaseConnection conn = new DatabaseConnection();
            using (SqlCommand cmd = conn.executeCommand("SELECT email FROM clients WHERE email = @em AND hotel_id = :hid"))
            {
                cmd.Parameters.AddWithValue("@email", this.email);
                cmd.Parameters.AddWithValue("@hid", this.hotel_id);
                SqlDataReader reader = cmd.ExecuteReader();
                if (reader.Read())
                {
                    string email = reader.GetString(3);
                    if (string.IsNullOrEmpty(email))
                    {
                        return false;
                    }
                    reader.Close();
                    this.isSaveAllowed = false;
                    this.isUpdateAllowed = true;
                    return true;
                }
            }
            return false;
        }
        public void getDataByClientId(Int64 clientId)
        {
            DatabaseConnection conn = new DatabaseConnection();
            using(SqlCommand cmd = conn.executeCommand("SELECT * FROM clients WHERE client_id = @id"))
            {
                cmd.Parameters.AddWithValue("@id", clientId);
                SqlDataReader reader = cmd.ExecuteReader();
                if (reader.Read())
                {
                    this.client_id = reader.GetInt64(0);
                    this.name = reader.GetString(1);
                    this.surname = reader.GetString(2);
                    this.email = reader.GetString(3);
                    this.phone = reader.GetString(4);
                    this.city = reader.GetString(5);
                    this.address = reader.GetString(6);
                    this.password = reader.GetString(7);
                    this.date = reader.GetDateTime(8);
                    this.hotel_id = reader.GetInt64(9);
                }
                reader.Close();
            }
        }
        public void PreSave() {
            if (string.IsNullOrEmpty(this.name) || string.IsNullOrEmpty(this.surname) || string.IsNullOrEmpty(this.email) ||
                string.IsNullOrEmpty(this.phone) || string.IsNullOrEmpty(this.city) || string.IsNullOrEmpty(this.address) ||
                string.IsNullOrEmpty(this.password) || this.hotel_id < 1)
            {
                this.isSaveAllowed = false;
                this.isUpdateAllowed = false;
            } else
            {
                if(this.client_id > 0)
                {
                    this.isUpdateAllowed = true;
                    this.isSaveAllowed = false;
                } else
                {
                    this.isUpdateAllowed = false;
                    this.isSaveAllowed = true;
                }
            }
        }
        public void Update()
        {
            if (this.isUpdateAllowed)
            {
                DatabaseConnection conn = new DatabaseConnection();
                using (SqlCommand cmd = conn.executeCommand("select client_id from clients where client_id = @cid"))
                {
                    cmd.Parameters.AddWithValue("@cid", this.client_id);
                    int count = cmd.ExecuteNonQuery();
                    if (count > 0)
                    {
                        using (SqlCommand updatecmd = conn.executeCommand("update clients set name = @n, surname=@sur,email=@em,phone=@ph,city=@cit,address=@addr,password=@pass,date=@dat,hotel_id=@hid where client_id = @cid"))
                        {
                            updatecmd.Parameters.AddWithValue("@n", this.name);
                            updatecmd.Parameters.AddWithValue("@sur", this.surname);
                            updatecmd.Parameters.AddWithValue("@em", this.email);
                            updatecmd.Parameters.AddWithValue("@ph", this.phone);
                            updatecmd.Parameters.AddWithValue("@cit", this.city);
                            updatecmd.Parameters.AddWithValue("@addr", this.address);
                            updatecmd.Parameters.AddWithValue("@pass", this.password);
                            updatecmd.Parameters.AddWithValue("@dat", this.date);
                            updatecmd.Parameters.AddWithValue("@hid", this.hotel_id);
                            updatecmd.Parameters.AddWithValue("@cid", this.client_id);
                            updatecmd.ExecuteNonQuery();
                            // since we already updated the data, we will disable updating and saving again until we change something.
                            this.isSaveAllowed = false;
                            this.isUpdateAllowed = false;
                        }
                    }
                }
            }
        }
        public void Save()
        {
            this.PreSave();
            switch (this.isSaveAllowed)
            {
                case true:
                    // let's check first if we already have loaded client and when we call this function we should only update the item;
                    if(this.client_id > 0)
                    {
                        this.Update();
                    } else
                    {
                        DatabaseConnection conn = new DatabaseConnection();
                        using(SqlCommand cmd = conn.executeCommand("insert into clients values(@name,@surname,@email,@phone,@city,@address,@password,@date,@hotel)"))
                        {
                            cmd.Parameters.AddWithValue("@name", this.name);
                            cmd.Parameters.AddWithValue("@surname", this.surname);
                            cmd.Parameters.AddWithValue("@email", this.email);
                            cmd.Parameters.AddWithValue("@phone", this.phone);
                            cmd.Parameters.AddWithValue("@city", this.city);
                            cmd.Parameters.AddWithValue("@address", this.address);
                            cmd.Parameters.AddWithValue("@password", this.password);
                            cmd.Parameters.AddWithValue("@date", this.date);
                            cmd.Parameters.AddWithValue("@hotel", this.hotel_id);
                            cmd.ExecuteScalar();
                            this.isSaveAllowed = false;
                            this.isUpdateAllowed = false;
                        }
                        conn.closeConnection();
                    }
                    break;
            }
        }
    }
}