using System.Data.Odbc;
using Microsoft.Data.SqlClient;

namespace SQLInsight.Connectivity;

internal static class ConnectionStrings
{
    public const string ApplicationName = "SQLInsight Pro";

    public static string ForSqlClient(ConnectionTarget target)
    {
        var builder = new SqlConnectionStringBuilder
        {
            DataSource = target.Server,
            InitialCatalog = "master",
            ApplicationName = ApplicationName,
            ConnectTimeout = (int)target.ConnectTimeout.TotalSeconds,
            Encrypt = target.Encryption == EncryptionMode.Mandatory ? SqlConnectionEncryptOption.Mandatory : SqlConnectionEncryptOption.Optional,
            TrustServerCertificate = target.TrustServerCertificate,
            // Monitoring must never hold a pooled session with leftover state on a busy server.
            Pooling = false,
        };

        if (target.Authentication == AuthenticationMode.Windows)
        {
            builder.IntegratedSecurity = true;
        }
        else
        {
            builder.UserID = RequireUserName(target);
            builder.Password = target.Password ?? string.Empty;
        }

        return builder.ConnectionString;
    }

    public static string ForOdbc(ConnectionTarget target)
    {
        var builder = new OdbcConnectionStringBuilder
        {
            Driver = target.OdbcDriver,
        };
        builder["Server"] = target.Server;
        builder["Database"] = "master";
        builder["APP"] = ApplicationName;
        builder["Encrypt"] = target.Encryption == EncryptionMode.Mandatory ? "yes" : "no";
        builder["TrustServerCertificate"] = target.TrustServerCertificate ? "yes" : "no";

        if (target.Authentication == AuthenticationMode.Windows)
        {
            builder["Trusted_Connection"] = "yes";
        }
        else
        {
            builder["UID"] = RequireUserName(target);
            builder["PWD"] = target.Password ?? string.Empty;
        }

        return builder.ConnectionString;
    }

    private static string RequireUserName(ConnectionTarget target) =>
        string.IsNullOrWhiteSpace(target.UserName)
            ? throw new ArgumentException($"A user name is required for SQL login authentication to '{target.Server}'.", nameof(target))
            : target.UserName;
}