using D365MetadataService.Models;
using Serilog;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
namespace D365MetadataService.Handlers
{
/// <summary>
/// Factory for creating and managing request handlers
/// Follows the Factory Pattern + Registry Pattern
/// </summary>
public class RequestHandlerFactory
{
private readonly Dictionary<string, IRequestHandler> _handlers;
private readonly ILogger _logger;
public RequestHandlerFactory(IEnumerable<IRequestHandler> handlers, ILogger logger)
{
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
// Register all handlers by their supported action
_handlers = handlers.ToDictionary(h => h.SupportedAction.ToLower(), h => h);
_logger.Information("Registered {HandlerCount} request handlers: {Actions}",
_handlers.Count,
string.Join(", ", _handlers.Keys));
}
/// <summary>
/// Get a handler for the specified action
/// </summary>
public IRequestHandler GetHandler(string action)
{
if (string.IsNullOrEmpty(action))
{
throw new ArgumentException("Action cannot be null or empty", nameof(action));
}
var actionKey = action.ToLower();
if (_handlers.TryGetValue(actionKey, out var handler))
{
return handler;
}
throw new NotSupportedException($"No handler registered for action: {action}");
}
/// <summary>
/// Check if a handler exists for the specified action
/// </summary>
public bool HasHandler(string action)
{
return !string.IsNullOrEmpty(action) && _handlers.ContainsKey(action.ToLower());
}
/// <summary>
/// Get all supported actions
/// </summary>
public IEnumerable<string> GetSupportedActions()
{
return _handlers.Keys;
}
}
}
