Data-Coupler/Data_Coupler/Services/DataConnectionFactory.cs

using CredentialManager.Models;
using DataConnection.EF;
using DataConnection.Interfaces;
using DataConnection.REST.Interfaces;
using DataConnection.REST.Implementations;
using DataConnection.REST.Configuration;
using DataConnection.CredentialManagement.Interfaces;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using System.Security.Cryptography;
using System.Text;

namespace Data_Coupler.Services
{
    /// <summary>
    /// Classe per tracciare i client REST cached con le loro credenziali
    /// </summary>
    internal class CachedRestClient
    {
        public IRestServiceClient Client { get; set; } = null!;
        public string CredentialsHash { get; set; } = string.Empty;
        public DateTime CachedAt { get; set; }
    }

    /// <summary>
    /// Factory service per creare istanze di DatabaseManager e RestClient
    /// </summary>
    public interface IDataConnectionFactory
    {
        /// <summary>
        /// Crea un DatabaseManager per la credenziale specificata
        /// </summary>
        Task<IDatabaseManager> CreateDatabaseManagerAsync(string credentialName);
        
        /// <summary>
        /// Crea un RestServiceClient per la credenziale specificata
        /// </summary>
        Task<IRestServiceClient> CreateRestServiceClientAsync(string credentialName);
        
        /// <summary>
        /// Crea un RestMetadataDiscovery per la credenziale specificata
        /// </summary>
        Task<IRestMetadataDiscovery> CreateRestMetadataDiscoveryAsync(string credentialName);
        
        /// <summary>
        /// Pulisce la cache del client REST per una credenziale specifica
        /// </summary>
        void ClearRestClientCache(string credentialName);
          /// <summary>
        /// Pulisce tutta la cache dei client REST
        /// </summary>
        void ClearAllRestClientCache();
    }

    public class DataConnectionFactory : IDataConnectionFactory
    {
        private readonly IServiceProvider _serviceProvider;
        private readonly ILogger<DataConnectionFactory> _logger;
        private readonly IDataConnectionCredentialService _credentialService;
        
        // Cache intelligente per client REST che mantiene lo stato di autenticazione ma verifica le credenziali
        private readonly Dictionary<string, CachedRestClient> _restClientCache = new();

        public DataConnectionFactory(IServiceProvider serviceProvider, ILogger<DataConnectionFactory> logger, IDataConnectionCredentialService credentialService)
        {
            _serviceProvider = serviceProvider;
            _logger = logger;
            _credentialService = credentialService;
        }public async Task<IDatabaseManager> CreateDatabaseManagerAsync(string credentialName)
        {
            try
            {
                var credential = await _credentialService.GetDatabaseCredentialAsync(credentialName);
                if (credential == null)
                {
                    throw new ArgumentException($"Credenziale database '{credentialName}' non trovata");
                }

                var dbManagerOptions = await _credentialService.GetDbManagerOptionsAsync(credential.Name);
                return new EFCoreDatabaseManager(dbManagerOptions);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Errore nella creazione del DatabaseManager per {CredentialName}", credentialName);
                throw;
            }
        }        public async Task<IRestServiceClient> CreateRestServiceClientAsync(string credentialName)
        {
            try
            {
                // SEMPRE recupera le credenziali fresh dal database per assicurare che siano aggiornate
                var credential = await _credentialService.GetRestApiCredentialAsync(credentialName);
                if (credential == null)
                {
                    throw new ArgumentException($"Credenziale REST API '{credentialName}' non trovata");
                }

                // Calcola l'hash delle credenziali correnti
                var currentCredentialsHash = CalculateCredentialsHash(credential);

                // Controlla se abbiamo un client cached con le stesse credenziali
                if (_restClientCache.TryGetValue(credentialName, out var cachedClient))
                {
                    if (cachedClient.CredentialsHash == currentCredentialsHash)
                    {
                        _logger.LogInformation("Utilizzando client REST cached con credenziali verificate per {CredentialName}", credentialName);
                        return cachedClient.Client;
                    }
                    else
                    {
                        _logger.LogInformation("Credenziali cambiate, rimuovendo client cached per {CredentialName}", credentialName);
                        _restClientCache.Remove(credentialName);
                    }
                }                var options = new RestServiceOptions
                {
                    BaseUrl = credential.BaseUrl,
                    Username = credential.Username,
                    Password = credential.Password,
                    TimeoutSeconds = credential.TimeoutSeconds,
                    IgnoreSslErrors = credential.IgnoreSslErrors
                };                // Mapping specifico per tipo di servizio
                switch (credential.ServiceType)
                {
                    case RestServiceType.Salesforce:
                        // Per Salesforce usiamo i campi specifici ClientId e ClientSecret
                        options.ApiKey = credential.ClientId;     // ClientId -> ApiKey
                        options.AuthToken = credential.ClientSecret; // ClientSecret -> AuthToken
                        _logger.LogInformation("Salesforce mapping - ClientId: '{ClientId}', ClientSecret: {HasSecret}, Username: '{Username}', Password: {HasPassword}", 
                            credential.ClientId, 
                            !string.IsNullOrEmpty(credential.ClientSecret),
                            credential.Username,
                            !string.IsNullOrEmpty(credential.Password));
                        break;
                    case RestServiceType.SapB1ServiceLayer:
                        // Per SAP B1 usiamo il CompanyDatabase come ApiKey
                        options.ApiKey = credential.CompanyDatabase;
                        options.AuthToken = credential.AuthToken;
                        _logger.LogInformation("SAP B1 mapping - CompanyDB: {CompanyDB}, Username: {Username}", 
                            credential.CompanyDatabase, credential.Username);
                        break;
                    default:
                        // Per servizi generici usiamo ApiKey e AuthToken direttamente
                        options.ApiKey = credential.ApiKey;
                        options.AuthToken = credential.AuthToken;
                        _logger.LogInformation("Generic mapping - ApiKey: {ApiKey}, AuthToken: {HasToken}, Username: {Username}", 
                            credential.ApiKey, !string.IsNullOrEmpty(credential.AuthToken), credential.Username);
                        break;
                }

                var client = credential.ServiceType switch
                {
                    RestServiceType.SapB1ServiceLayer => new SapB1ServiceClient(options),
                    RestServiceType.Salesforce => CreateSalesforceClient(options),
                    RestServiceType.Generic => CreateGenericRestClient(options),
                    _ => throw new NotSupportedException($"Tipo di servizio REST non supportato: {credential.ServiceType}")
                };

                // Salva il client nella cache con l'hash delle credenziali
                _restClientCache[credentialName] = new CachedRestClient
                {
                    Client = client,
                    CredentialsHash = currentCredentialsHash,
                    CachedAt = DateTime.UtcNow
                };

                _logger.LogInformation("Client REST creato e cached con credenziali aggiornate per {CredentialName}", credentialName);

                return client;
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Errore nella creazione del RestServiceClient per {CredentialName}", credentialName);
                throw;
            }
        }        public async Task<IRestMetadataDiscovery> CreateRestMetadataDiscoveryAsync(string credentialName)
        {
            try
            {
                // Crea un nuovo client REST con credenziali aggiornate
                var restClient = await CreateRestServiceClientAsync(credentialName);
                
                // I service client già implementano IRestMetadataDiscovery
                if (restClient is IRestMetadataDiscovery metadataDiscovery)
                {
                    _logger.LogInformation("Utilizzando client REST per metadata discovery con credenziali aggiornate per {CredentialName}", credentialName);
                    return metadataDiscovery;
                }
                
                var credential = await _credentialService.GetRestApiCredentialAsync(credentialName);
                throw new NotSupportedException($"Il servizio REST {credential?.ServiceType} non supporta il metadata discovery");
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Errore nella creazione del RestMetadataDiscovery per {CredentialName}", credentialName);
                throw;
            }
        }

        private IRestServiceClient CreateGenericRestClient(RestServiceOptions options)
        {
            var httpClientFactory = _serviceProvider.GetRequiredService<IHttpClientFactory>();
            var httpClient = httpClientFactory.CreateClient();
            return new BaseRestServiceClient(httpClient, options);
        }

        private IRestServiceClient CreateSalesforceClient(RestServiceOptions options)
        {
            var httpClientFactory = _serviceProvider.GetRequiredService<IHttpClientFactory>();
            var httpClient = httpClientFactory.CreateClient();
            return new SalesforceServiceClient(httpClient, options);
        }

        /// <summary>
        /// Calcola un hash delle credenziali per rilevare cambiamenti
        /// </summary>
        private string CalculateCredentialsHash(RestApiCredential credential)
        {
            var credentialString = $"{credential.BaseUrl}|{credential.Username}|{credential.Password}|{credential.ApiKey}|{credential.AuthToken}|{credential.ClientId}|{credential.ClientSecret}|{credential.CompanyDatabase}";
            var bytes = SHA256.HashData(Encoding.UTF8.GetBytes(credentialString));
            return Convert.ToBase64String(bytes);
        }

        /// <summary>
        /// Pulisce la cache del client REST per una credenziale specifica.
        /// </summary>
        public void ClearRestClientCache(string credentialName)
        {
            if (_restClientCache.Remove(credentialName))
            {
                _logger.LogInformation("Cache del client REST rimossa per {CredentialName}", credentialName);
            }
        }

        /// <summary>
        /// Pulisce tutta la cache dei client REST.
        /// </summary>
        public void ClearAllRestClientCache()
        {
            _restClientCache.Clear();
            _logger.LogInformation("Cache di tutti i client REST pulita");
        }
    }
}