moloapp/example/fw/App.hpp

#pragma once

// Application: composition root. Owns routers, middleware chain, sub-app
// mounts, and the typed error mapping. Gap: real molo::app::Application in
// 05-request-routing.md owns lifespan hooks, plugin registry, and the full DI
// container; this skeleton passes a Services struct to route factories.

#include <functional>
#include <memory>
#include <string>
#include <vector>

#include "Http.hpp"
#include "Router.hpp"

namespace molo::example::fw {

enum class MiddlewareSlot {
  Errors = 0,
  Observability = 1,
  Security = 2,
  SessionAuth = 3,
  User = 4,
};

using Next = std::function<Response(Request)>;
using Middleware = std::function<Response(Request, Next)>;

class HttpError {
 public:
  HttpError(int status, std::string code, std::string message);
  int status() const;
  const std::string& code() const;
  const std::string& message() const;

 private:
  int status_;
  std::string code_;
  std::string message_;
};

class Application : public std::enable_shared_from_this<Application> {
 public:
  void use(MiddlewareSlot slot, Middleware middleware);
  void include_router(const std::string& prefix, const Router& router,
                      const std::string& name_prefix = "");
  void mount(const std::string& path, std::shared_ptr<Application> sub);

  Response dispatch(Request req);

  const std::vector<Route>& routes() const;

 private:
  Response dispatch_inner(Request req, int depth);
  Response run_chain(Request req, int depth);

  Router router_;
  std::vector<std::pair<MiddlewareSlot, Middleware>> middlewares_;
  std::vector<std::pair<std::string, std::shared_ptr<Application>>> mounts_;
  MiddlewareSlot last_slot_ = MiddlewareSlot::Errors;
  bool has_middleware_ = false;
};

Middleware errors_middleware();
Middleware request_id_middleware();

}  // namespace molo::example::fw