using System;
using System.Text;
using System.Data.SqlClient;
using Microsoft.Azure.KeyVault;
using Microsoft.Azure.KeyVault.Models;
using Microsoft.Azure.Services.AppAuthentication;
using System.Threading.Tasks;

namespace AzureSQLSample
{
    class Program
    {
        static void Main(string[] args)
        {
            Task task = Program.DoWork(args);
            // Becuase this program takes user input, have a long wait.		
            var result = task.Wait(TimeSpan.FromMinutes(30));
        }

        static async Task DoWork(string[] args)
        {
            string sql;

            // Build connection string
            SqlConnectionStringBuilder builder = new SqlConnectionStringBuilder();
            builder.DataSource = "your_server_name.database.windows.net";   // update me
            builder.UserID = "your_user_id";              // update me
            builder.Password = await GetPasswordFromKeyVault();      // taken from Key Vault
            builder.InitialCatalog = "your_database"; // Update me

            using (SqlConnection connection = new SqlConnection(builder.ConnectionString))
            {
                try
                {
                    Console.WriteLine("Connect to Azure SQL and demo Create, Read, Update and Delete operations.");

                    // Connect to Azure SQL
                    Console.Write("Connecting to Azure SQL ... ");
                    connection.Open();
                    Console.WriteLine("Done.");

                    string dropTableIfExists = @"DROP TABLE IF EXISTS Employees";
                    using (SqlCommand command = new SqlCommand(dropTableIfExists, connection))
                    {
                        command.ExecuteNonQuery();
                        Console.WriteLine("Done.");
                    }


                    // Create a Table and insert some sample data
                    Console.Write("Creating sample table with data, press any key to continue...");
                    Console.ReadKey(true);
                    StringBuilder sb = new StringBuilder();
                    sb.Append("CREATE TABLE Employees ( ");
                    sb.Append(" Id INT IDENTITY(1,1) NOT NULL PRIMARY KEY, ");
                    sb.Append(" Name NVARCHAR(50), ");
                    sb.Append(" Location NVARCHAR(50) ");
                    sb.Append("); ");
                    sb.Append("INSERT INTO Employees (Name, Location) VALUES ");
                    sb.Append("(N'Jared', N'Australia'), ");
                    sb.Append("(N'Nikita', N'India'), ");
                    sb.Append("(N'Tom', N'Germany'); ");
                    sql = sb.ToString();
                    using (SqlCommand command = new SqlCommand(sql, connection))
                    {
                        command.ExecuteNonQuery();
                        Console.WriteLine("Done.");
                    }

                    // INSERT demo
                    Console.Write("Inserting a new row into table, press any key to continue...");
                    Console.ReadKey(true);
                    sb.Clear();
                    sb.Append("INSERT Employees (Name, Location) ");
                    sb.Append("VALUES (@name, @location);");
                    sql = sb.ToString();
                    using (SqlCommand command = new SqlCommand(sql, connection))
                    {
                        command.Parameters.AddWithValue("@name", "Jake");
                        command.Parameters.AddWithValue("@location", "United States");
                        int rowsAffected = command.ExecuteNonQuery();
                        Console.WriteLine(rowsAffected + " row(s) inserted");
                    }

                    // UPDATE demo
                    String userToUpdate = "Nikita";
                    Console.Write("Updating 'Location' for user '" + userToUpdate + "', press any key to continue...");
                    Console.ReadKey(true);
                    sb.Clear();
                    sb.Append("UPDATE Employees SET Location = N'United States' WHERE Name = @name");
                    sql = sb.ToString();
                    using (SqlCommand command = new SqlCommand(sql, connection))
                    {
                        command.Parameters.AddWithValue("@name", userToUpdate);
                        int rowsAffected = command.ExecuteNonQuery();
                        Console.WriteLine(rowsAffected + " row(s) updated");
                    }

                    // DELETE demo
                    String userToDelete = "Jared";
                    Console.Write("Deleting user '" + userToDelete + "', press any key to continue...");
                    Console.ReadKey(true);
                    sb.Clear();
                    sb.Append("DELETE FROM Employees WHERE Name = @name;");
                    sql = sb.ToString();
                    using (SqlCommand command = new SqlCommand(sql, connection))
                    {
                        command.Parameters.AddWithValue("@name", userToDelete);
                        int rowsAffected = command.ExecuteNonQuery();
                        Console.WriteLine(rowsAffected + " row(s) deleted");
                    }

                    // READ demo
                    Console.WriteLine("Reading data from table, press any key to continue...");
                    Console.ReadKey(true);
                    sql = "SELECT Id, Name, Location FROM Employees;";
                    using (SqlCommand command = new SqlCommand(sql, connection))
                    {

                        using (SqlDataReader reader = command.ExecuteReader())
                        {
                            while (reader.Read())
                            {
                                Console.WriteLine("{0} {1} {2}", reader.GetInt32(0), reader.GetString(1), reader.GetString(2));
                            }
                        }
                    }
                }
                catch (SqlException e)
                {
                    Console.WriteLine(e.ToString());
                }
                finally
                {
                    Console.WriteLine("Cleaning up table.");
                    string dropTableIfExists = @"DROP TABLE IF EXISTS Employees";
                    using (SqlCommand command = new SqlCommand(dropTableIfExists, connection))
                    {
                        command.ExecuteNonQuery();
                        Console.WriteLine("Done.");
                    }
                }
            }

            Console.WriteLine("All done. Press any key to finish...");
            Console.ReadKey(true);
        }

        private static async Task<string> GetPasswordFromKeyVault()
        {
            Console.WriteLine("Trying to get Password from Key Vault.  Press a key to continue...");
            Console.ReadKey(true);
            /* The next four lines of code show you how to use AppAuthentication library to fetch secrets from your key vault */
            AzureServiceTokenProvider azureServiceTokenProvider = new AzureServiceTokenProvider();
            KeyVaultClient keyVaultClient = new KeyVaultClient(new KeyVaultClient.AuthenticationCallback(azureServiceTokenProvider.KeyVaultTokenCallback));
            SecretBundle secret = await keyVaultClient.GetSecretAsync("https://your_key_vault_name.vault.azure.net/secrets/AppSecret");  // update me
            return secret.Value;
        }
    }
}