AMO_Housing/Services/LoginAccountRepository.cs

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

namespace Housing.Services;

public sealed class LoginAccountRepository
{
    private readonly DatabaseSettings _databaseSettings;
    private readonly LoginSettings _loginSettings;

    public LoginAccountRepository(DatabaseSettings databaseSettings, LoginSettings loginSettings)
    {
        _databaseSettings = databaseSettings;
        _loginSettings = loginSettings;
    }

    public async Task<bool> ExistsAsync(string loginId, string password)
    {
        using var connection = new SqlConnection(CreateConnectionString());
        using var command = connection.CreateCommand();

        command.CommandText = $@"
SELECT TOP (1) 1
FROM {_loginSettings.GetQuotedTableName()}
WHERE {_loginSettings.GetQuotedIdColumn()} = @LoginId
  AND {_loginSettings.GetQuotedPasswordColumn()} = @Password;";

        command.Parameters.Add(new SqlParameter("@LoginId", SqlDbType.NVarChar, 50) { Value = loginId });
        command.Parameters.Add(new SqlParameter("@Password", SqlDbType.NVarChar, 50) { Value = password });

        await connection.OpenAsync();
        var result = await command.ExecuteScalarAsync();
        return result is not null;
    }

    private string CreateConnectionString()
    {
        if (string.IsNullOrWhiteSpace(_databaseSettings.Ip) ||
            string.IsNullOrWhiteSpace(_databaseSettings.Database) ||
            string.IsNullOrWhiteSpace(_databaseSettings.DbId))
        {
            throw new InvalidOperationException("Database.ini의 IP, Database, DbId 값을 확인하세요.");
        }

        var builder = new SqlConnectionStringBuilder
        {
            DataSource = _databaseSettings.Ip,
            InitialCatalog = _databaseSettings.Database,
            UserID = _databaseSettings.DbId,
            Password = _databaseSettings.DbPw,
            Encrypt = _databaseSettings.Encrypt,
            TrustServerCertificate = _databaseSettings.TrustServerCertificate,
            ConnectTimeout = _databaseSettings.Timeout
        };

        return builder.ConnectionString;
    }
}