// Copyright Epic Games, Inc. All Rights Reserved.

#pragma once

#include <zencore/basicfile.h>
#include <zenhttp/httpserver.h>
#include <zenhttp/httpstats.h>
#include <zenhttp/httpstatus.h>
#include <zenutil/zenserverprocess.h>

#include <memory>
#include <string_view>
#include "config/config.h"

ZEN_THIRD_PARTY_INCLUDES_START
#include <asio.hpp>
ZEN_THIRD_PARTY_INCLUDES_END

#include "diag/diagsvcs.h"
#include "stats/statsreporter.h"

#ifndef ZEN_APP_NAME
#	define ZEN_APP_NAME "Unreal Zen Storage Server"
#endif

namespace zen {

struct FLLMTag;
extern const FLLMTag& GetZenserverTag();

struct ZenStorageServerConfig;

class ZenServerBase : public IHttpStatusProvider
{
	ZenServerBase& operator=(ZenServerBase&&) = delete;
	ZenServerBase(ZenServerBase&&)			  = delete;

public:
	ZenServerBase();
	~ZenServerBase();

	void RequestExit(int ExitCode);

	void SetIsReadyFunc(std::function<void()>&& IsReadyFunc) { m_IsReadyFunc = std::move(IsReadyFunc); }

protected:
	int	 Initialize(const ZenServerConfig& ServerOptions, ZenServerState::ZenServerEntry* ServerEntry);
	void Finalize();
	void GetBuildOptions(StringBuilderBase& OutOptions, char Separator = ',') const;
	void LogSettingsSummary(const ZenServerConfig& ServerConfig);

protected:
	NamedMutex						m_ServerMutex;
	ZenServerState::ZenServerEntry* m_ServerEntry  = nullptr;
	bool							m_UseSentry	   = false;
	bool							m_IsPowerCycle = false;

	std::thread		 m_IoRunner;
	asio::io_context m_IoContext;
	void			 EnsureIoRunner();

	enum ServerState
	{
		kInitializing,
		kRunning,
		kShuttingDown
	} m_CurrentState = kInitializing;

	inline void				SetNewState(ServerState NewState) { m_CurrentState = NewState; }
	static std::string_view ToString(ServerState Value);

	std::function<void()> m_IsReadyFunc;
	void				  OnReady();

	Ref<HttpServer>	  m_Http;
	HttpHealthService m_HealthService;
	HttpStatusService m_StatusService;

	// Stats reporting

	StatsReporter	   m_StatsReporter;
	asio::steady_timer m_StatsReportingTimer{m_IoContext};
	void			   EnqueueStatsReportingTimer();

	// Process Monitoring

	void CheckOwnerPid();
	bool UpdateProcessMonitor();
	void EnqueueProcessMonitorTimer();

	ProcessMonitor	   m_ProcessMonitor;
	asio::steady_timer m_PidCheckTimer{m_IoContext};
	bool			   m_FoundNoActiveSponsors = false;

	// Server state exit signaling

	asio::steady_timer m_StateExitFlagTimer{m_IoContext};

	void EnqueueStateExitFlagTimer();
	void CheckStateExitFlag();

	// SIGINT handling

	void			   EnqueueSigIntTimer();
	void			   CheckSigInt();
	asio::steady_timer m_SigIntTimer{m_IoContext};

	// IHttpStatusProvider
	virtual void HandleStatusRequest(HttpServerRequest& Request) override;
};

class ZenServerMain
{
public:
	ZenServerMain(ZenServerConfig& ServerOptions);
	~ZenServerMain();

	int Run();

	ZenServerMain(const ZenServerMain&) = delete;
	ZenServerMain& operator=(const ZenServerMain&) = delete;

protected:
	ZenServerConfig& m_ServerOptions;
	LockFile		 m_LockFile;

	virtual void InitializeLogging();
	virtual void DoRun(ZenServerState::ZenServerEntry* Entry) = 0;

	void	 NotifyReady();
	CbObject MakeLockData(bool IsReady);
};

}  // namespace zen