using System;
using System.Collections.Generic;
using System.Data.Common;
using System.Data.SqlClient;
using System.Data.SQLite;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Tango.Core
{
    /// <summary>
    /// Represents an SQL data source.
    /// </summary>
    public class DataSource
    {
        //private static bool _has_provider;

        /// <summary>
        /// Gets or sets the type of source.
        /// </summary>
        public DataSourceType Type { get; set; }

        /// <summary>
        /// Gets or sets the address.
        /// </summary>
        public String Address { get; set; }

        /// <summary>
        /// Gets or sets the catalog name.
        /// </summary>
        public String Catalog { get; set; }

        /// <summary>
        /// Gets or sets a value indicating whether to use integrated security.
        /// </summary>
        public bool IntegratedSecurity { get; set; }

        /// <summary>
        /// Gets or sets the user name to use if <see cref="IntegratedSecurity"/> is false.
        /// </summary>
        public String UserName { get; set; }

        /// <summary>
        /// Gets or sets the password to use if <see cref="IntegratedSecurity"/> is false.
        /// </summary>
        public String Password { get; set; }

        /// <summary>
        /// Gets or sets the access token Token.
        /// </summary>
        public String AccessToken { get; set; }

        /// <summary>
        /// Gets or sets the access token expiration.
        /// </summary>
        public DateTime AccessTokenExpiration { get; set; }

        /// <summary>
        /// Initializes a new instance of the <see cref="DataSource"/> class.
        /// </summary>
        public DataSource()
        {
            Type = DataSourceType.SQLServer;
            Address = "localhost\\SQLEXPRESS";
            Catalog = "Tango";
            IntegratedSecurity = true;
            UserName = String.Empty;
            Password = String.Empty;
        }

        /// <summary>
        /// Creates a DBConnection instance which represents this data source.
        /// </summary>
        /// <returns></returns>
        public DbConnection ToConnection()
        {

            switch (Type)
            {
                case DataSourceType.SQLite:

                    var connection = new SQLiteConnection()
                    {
                        ConnectionString = new SQLiteConnectionStringBuilder() { DataSource = Path.GetFullPath(Address), ForeignKeys = true }.ConnectionString
                    };
                    return connection;

                case DataSourceType.MDF:

                    if (IntegratedSecurity)
                    {
                        return new SqlConnection(String.Format("Data Source=(LocalDB)\\MSSQLLocalDB;AttachDbFileName={0};Initial Catalog={1};Integrated Security=True;MultipleActiveResultSets=True;App=EntityFramework", Path.GetFullPath(Address), Catalog));
                    }
                    else
                    {
                        return new SqlConnection(String.Format("Data Source=(LocalDB)\\MSSQLLocalDB;AttachDbFileName={0};Initial Catalog={1};Integrated Security=False;User Id={2};Password={3};MultipleActiveResultSets=True;App=EntityFramework", Path.GetFullPath(Address), Catalog, UserName, Password));
                    }

                case DataSourceType.SQLServer:

                    if (IntegratedSecurity)
                    {
                        return new SqlConnection(String.Format("Data Source={0};Initial Catalog={1};Integrated Security=True;MultipleActiveResultSets=True;App=EntityFramework", Address, Catalog));
                    }
                    else
                    {
                        return new SqlConnection(String.Format("Data Source={0};Initial Catalog={1};Integrated Security=False;User Id={2};Password={3};MultipleActiveResultSets=True;App=EntityFramework", Address, Catalog, UserName, Password));
                    }

                case DataSourceType.Azure:

                    SqlConnectionStringBuilder builder = new SqlConnectionStringBuilder();
                    builder.DataSource = Address;
                    builder.InitialCatalog = Catalog;
                    builder.UserID = UserName;
                    builder.Password = Password;
                    builder.IntegratedSecurity = false;
                    builder.MultipleActiveResultSets = true;
                    builder.ApplicationName = "EntityFramework";
                    builder.Authentication = SqlAuthenticationMethod.ActiveDirectoryPassword;

                    SqlConnection sqlConnection = new SqlConnection(builder.ConnectionString);

                    return sqlConnection;

                case DataSourceType.AccessToken:

                    SqlConnectionStringBuilder b = new SqlConnectionStringBuilder();
                    b.DataSource = Address;
                    b.InitialCatalog = Catalog;
                    b.IntegratedSecurity = false;
                    b.MultipleActiveResultSets = true;
                    b.ApplicationName = "EntityFramework";
                    SqlConnection sqlCon = new SqlConnection(b.ConnectionString);
                    sqlCon.AccessToken = AccessToken;

                    return sqlCon;

                default:

                    return null;
            }
        }

        /// <summary>
        /// Returns a <see cref="System.String" /> that represents this instance.
        /// </summary>
        /// <returns>
        /// A <see cref="System.String" /> that represents this instance.
        /// </returns>
        public override string ToString()
        {
            return $"{Address}\\{Catalog}";
        }
    }
}