//========= Copyright Valve Corporation, All rights reserved. ============//
//
// The copyright to the contents herein is the property of Valve, L.L.C.
// The contents may be used and/or copied only with the written permission of
// Valve, L.L.C., or in accordance with the terms and conditions stipulated in
// the agreement/contract under which the contents have been supplied.
//
// Purpose: Defines a group of app systems that all have the same lifetime
// that need to be connected/initialized, etc. in a well-defined order
//
// $Revision: $
// $NoKeywords: $
//=============================================================================

#ifndef IAPPSYSTEMGROUP_H
#define IAPPSYSTEMGROUP_H

#ifdef _WIN32
#pragma once
#endif

#include "IAppSystem.h"
#include "tier1/interface.h"
#include "tier1/utldict.h"
#include "tier1/utlvector.h"

//-----------------------------------------------------------------------------
// forward declarations
//-----------------------------------------------------------------------------
class IAppSystem;
class CSysModule;
class IBaseInterface;
class IFileSystem;

//-----------------------------------------------------------------------------
// Handle to a DLL
//-----------------------------------------------------------------------------
typedef int AppModule_t;

enum { APP_MODULE_INVALID = (AppModule_t)~0 };

//-----------------------------------------------------------------------------
// NOTE: The following methods must be implemented in your application
// although they can be empty implementations if you like...
//-----------------------------------------------------------------------------
abstract_class IAppSystemGroup {
   public:
    // An installed application creation function, you should tell the group
    // the DLLs and the singleton interfaces you want to instantiate.
    // Return false if there's any problems and the app will abort
    virtual bool Create() = 0;

    // Allow the application to do some work after AppSystems are connected but
    // they are all Initialized.
    // Return false if there's any problems and the app will abort
    virtual bool PreInit() = 0;

    // Main loop implemented by the application
    virtual int Main() = 0;

    // Allow the application to do some work after all AppSystems are shut down
    virtual void PostShutdown() = 0;

    // Call an installed application destroy function, occurring after all
    // modules are unloaded
    virtual void Destroy() = 0;
};

//-----------------------------------------------------------------------------
// Specifies a module + interface name for initialization
//-----------------------------------------------------------------------------
struct AppSystemInfo_t {
    const char *m_pModuleName;
    const char *m_pInterfaceName;
};

//-----------------------------------------------------------------------------
// This class represents a group of app systems that all have the same lifetime
// that need to be connected/initialized, etc. in a well-defined order
//-----------------------------------------------------------------------------
class CAppSystemGroup : public IAppSystemGroup {
   public:
    // Used to determine where we exited out from the system
    enum AppSystemGroupStage_t {
        CREATION = 0,
        CONNECTION,
        PREINITIALIZATION,
        INITIALIZATION,
        SHUTDOWN,
        POSTSHUTDOWN,
        DISCONNECTION,
        DESTRUCTION,

        NONE,  // This means no error
    };

   public:
    // constructor
    CAppSystemGroup(CAppSystemGroup *pParentAppSystem = NULL);

    // Runs the app system group.
    // First, modules are loaded, next they are connected, followed by
    // initialization Then Main() is run Then modules are shut down,
    // disconnected, and unloaded
    int Run();

    // Use this version in cases where you can't control the main loop and
    // expect to be ticked
    virtual int Startup();
    virtual void Shutdown();

    // Returns the stage at which the app system group ran into an error
    AppSystemGroupStage_t GetErrorStage() const;

   protected:
    // These methods are meant to be called by derived classes of
    // CAppSystemGroup

    // Methods to load + unload DLLs
    AppModule_t LoadModule(const char *pDLLName);
    AppModule_t LoadModule(CreateInterfaceFn factory);

    // Method to add various global singleton systems
    IAppSystem *AddSystem(AppModule_t module, const char *pInterfaceName);
    void AddSystem(IAppSystem *pAppSystem, const char *pInterfaceName);

    // Simpler method of doing the LoadModule/AddSystem thing.
    // Make sure the last AppSystemInfo has a NULL module name
    bool AddSystems(AppSystemInfo_t *pSystems);

    // Method to look up a particular named system...
    void *FindSystem(const char *pInterfaceName);

    // Gets at a class factory for the topmost appsystem group in an appsystem
    // stack
    static CreateInterfaceFn GetFactory();

   private:
    int OnStartup();
    void OnShutdown();

    void UnloadAllModules();
    void RemoveAllSystems();

    // Method to connect/disconnect all systems
    bool ConnectSystems();
    void DisconnectSystems();

    // Method to initialize/shutdown all systems
    InitReturnVal_t InitSystems();
    void ShutdownSystems();

    // Gets at the parent appsystem group
    CAppSystemGroup *GetParent();

    // Loads a module the standard way
    virtual CSysModule *LoadModuleDLL(const char *pDLLName);

    void ReportStartupFailure(int nErrorStage, int nSysIndex);

    struct Module_t {
        CSysModule *m_pModule;
        CreateInterfaceFn m_Factory;
        char *m_pModuleName;
    };

    CUtlVector<Module_t> m_Modules;
    CUtlVector<IAppSystem *> m_Systems;
    CUtlDict<int, unsigned short> m_SystemDict;
    CAppSystemGroup *m_pParentAppSystem;
    AppSystemGroupStage_t m_nErrorStage;

    friend void *AppSystemCreateInterfaceFn(const char *pName,
                                            int *pReturnCode);
    friend class CSteamAppSystemGroup;
};

//-----------------------------------------------------------------------------
// This class represents a group of app systems that are loaded through steam
//-----------------------------------------------------------------------------
class CSteamAppSystemGroup : public CAppSystemGroup {
   public:
    CSteamAppSystemGroup(IFileSystem *pFileSystem = NULL,
                         CAppSystemGroup *pParentAppSystem = NULL);

    // Used by CSteamApplication to set up necessary pointers if we can't do it
    // in the constructor
    void Setup(IFileSystem *pFileSystem, CAppSystemGroup *pParentAppSystem);

   protected:
    // Sets up the search paths
    bool SetupSearchPaths(const char *pStartingDir, bool bOnlyUseStartingDir,
                          bool bIsTool);

    // Returns the game info path. Only works if you've called SetupSearchPaths
    // first
    const char *GetGameInfoPath() const;

   private:
    virtual CSysModule *LoadModuleDLL(const char *pDLLName);

    IFileSystem *m_pFileSystem;
    char m_pGameInfoPath[MAX_PATH];
};

//-----------------------------------------------------------------------------
// Helper empty decorator implementation of an IAppSystemGroup
//-----------------------------------------------------------------------------
template <class CBaseClass>
class CDefaultAppSystemGroup : public CBaseClass {
   public:
    virtual bool Create() { return true; }
    virtual bool PreInit() { return true; }
    virtual void PostShutdown() {}
    virtual void Destroy() {}
};

//-----------------------------------------------------------------------------
// Special helper for game info directory suggestion
//-----------------------------------------------------------------------------

class CFSSteamSetupInfo;  // Forward declaration

//
// SuggestGameInfoDirFn_t
//		Game info suggestion function.
//		Provided by the application to possibly detect the suggested game
//info 		directory and initialize all the game-info-related systems appropriately.
// Parameters:
//		pFsSteamSetupInfo		steam file system setup information
//if available. 		pchPathBuffer			buffer to hold game info
//directory path on return.
//		nBufferLength			length of the provided buffer to
//hold game info directory path. 		pbBubbleDirectories		should contain
//"true" on return to bubble the directories up searching for game info file.
// Return values:
//		Returns "true" if the game info directory path suggestion is
//available and 		was successfully copied into the provided buffer. 		Returns
//"false" otherwise, interpreted that no suggestion will be used.
//
typedef bool (*SuggestGameInfoDirFn_t)(
    CFSSteamSetupInfo const *pFsSteamSetupInfo, char *pchPathBuffer,
    int nBufferLength, bool *pbBubbleDirectories);

//
// SetSuggestGameInfoDirFn
//		Installs the supplied game info directory suggestion function.
// Parameters:
//		pfnNewFn				the new game info directory
//suggestion function.
// Returns:
//		The previously installed suggestion function or NULL if none was
//installed before. 		This function never fails.
//
SuggestGameInfoDirFn_t SetSuggestGameInfoDirFn(SuggestGameInfoDirFn_t pfnNewFn);

#endif  // APPSYSTEMGROUP_H