/**********************************************************************

  Audacity: A Digital Audio Editor

  ModuleManager.cpp

  Dominic Mazzoni
  James Crook


*******************************************************************//*!

\file ModuleManager.cpp
\brief Based on LoadLadspa, this code loads pluggable Audacity 
extension modules.  It also has the code to (a) invoke a script
server and (b) invoke a function returning a replacement window,
i.e. an alternative to the usual interface, for Audacity.

*//*******************************************************************/

#include "Audacity.h"
#include "ModuleManager.h"
#include "audacity/ModuleInterface.h"



#include <wx/dynlib.h>
#include <wx/log.h>
#include <wx/string.h>
#include <wx/filename.h>

#include "FileNames.h"
#include "PluginManager.h"

#include "commands/ScriptCommandRelay.h"

#include "audacity/PluginInterface.h"

#ifdef EXPERIMENTAL_MODULE_PREFS
#include "Prefs.h"
#include "./prefs/ModulePrefs.h"
#endif

#include "widgets/MultiDialog.h"

#include "widgets/AudacityMessageBox.h"

#define initFnName      "ExtensionModuleInit"
#define versionFnName   "GetVersionString"
#define scriptFnName    "RegScriptServerFunc"
#define mainPanelFnName "MainPanelFunc"

typedef wxWindow * pwxWindow;
typedef int (*tModuleInit)(int);
//typedef wxString (*tVersionFn)();
typedef wxChar * (*tVersionFn)();
typedef pwxWindow (*tPanelFn)(int);

// This variable will hold the address of a subroutine in 
// a DLL that can hijack the normal panel.
static tPanelFn pPanelHijack=NULL;

// Next two commented out lines are handy when investigating
// strange DLL behaviour.  Instead of dynamic linking,
// link the library which has the replacement panel statically.
// Give the address of the routine here.
// This is a great help in identifying missing 
// symbols which otherwise cause a dll to unload after loading
// without an explanation as to why!
//extern wxWindow * MainPanelFunc( int i );
//tPanelFn pPanelHijack=&MainPanelFunc;

/// IF pPanelHijack has been found in a module DLL
/// THEN when this function is called we'll go and
/// create that window instead of the normal one.
wxWindow * MakeHijackPanel()
{
   if( pPanelHijack == NULL )
      return NULL;
   return pPanelHijack(0);
}

// This variable will hold the address of a subroutine in a DLL that
// starts a thread and reads script commands.
static tpRegScriptServerFunc scriptFn;

Module::Module(const FilePath & name)
{
   mName = name;
   mLib = std::make_unique<wxDynamicLibrary>();
   mDispatch = NULL;
}

Module::~Module()
{
}

bool Module::Load()
{
   // Will this ever happen???
   if (mLib->IsLoaded()) {
      if (mDispatch) {
         return true;
      }

      // Any messages should have already been generated the first time it was loaded.
      return false;
   }

   auto ShortName = wxFileName(mName).GetName();

   if (!mLib->Load(mName, wxDL_LAZY | wxDL_QUIET)) {
      auto Error = wxString(wxSysErrorMsg());
      AudacityMessageBox(XO("Unable to load the \"%s\" module.\n\nError: %s").Format(ShortName, Error),
                         XO("Module Unsuitable"));
      wxLogMessage(wxT("Unable to load the module \"%s\". Error: %s"), mName, Error);
      return false;
   }

   // Check version string matches.  (For now, they must match exactly)
   tVersionFn versionFn = (tVersionFn)(mLib->GetSymbol(wxT(versionFnName)));
   if (versionFn == NULL){
      AudacityMessageBox(
         XO("The module \"%s\" does not provide a version string.\n\nIt will not be loaded.")
            .Format( ShortName),
         XO("Module Unsuitable"));
      wxLogMessage(wxT("The module \"%s\" does not provide a version string. It will not be loaded."), mName);
      mLib->Unload();
      return false;
   }

   wxString moduleVersion = versionFn();
   if( moduleVersion != AUDACITY_VERSION_STRING) {
      AudacityMessageBox(
         XO("The module \"%s\" is matched with Audacity version \"%s\".\n\nIt will not be loaded.")
            .Format(ShortName, moduleVersion),
         XO("Module Unsuitable"));
      wxLogMessage(wxT("The module \"%s\" is matched with Audacity version \"%s\". It will not be loaded."), mName, moduleVersion);
      mLib->Unload();
      return false;
   }

   mDispatch = (fnModuleDispatch) mLib->GetSymbol(wxT(ModuleDispatchName));
   if (!mDispatch) {
      // Module does not provide a dispatch function. Special case modules like this could be:
      // (a) for scripting (RegScriptServerFunc entry point)
      // (b) for hijacking the entire Audacity panel (MainPanelFunc entry point)
      return true;
   }

   // However if we do have it and it does not work, 
   // then the module is bad.
   bool res = ((mDispatch(ModuleInitialize))!=0);
   if (res) {
      return true;
   }

   mDispatch = NULL;

   AudacityMessageBox(
      XO("The module \"%s\" failed to initialize.\n\nIt will not be loaded.").Format(ShortName),
      XO("Module Unsuitable"));
   wxLogMessage(wxT("The module \"%s\" failed to initialize.\nIt will not be loaded."), mName);
   mLib->Unload();

   return false;
}

// This isn't yet used?
void Module::Unload()
{
   if (mLib->IsLoaded()) {
      if (mDispatch)
         mDispatch(ModuleTerminate);
   }

   mLib->Unload();
}

int Module::Dispatch(ModuleDispatchTypes type)
{
   if (mLib->IsLoaded())
      if( mDispatch != NULL )
         return mDispatch(type);

   return 0;
}

void * Module::GetSymbol(const wxString &name)
{
   return mLib->GetSymbol(name);
}

// ============================================================================
//
// ModuleManager
//
// ============================================================================

// The one and only ModuleManager
std::unique_ptr<ModuleManager> ModuleManager::mInstance{};

// Provide builtin modules a means to identify themselves
using BuiltinModuleList = std::vector<ModuleMain>;
namespace {
   BuiltinModuleList &builtinModuleList()
   {
      static BuiltinModuleList theList;
      return theList;
   }
}

void RegisterBuiltinModule(ModuleMain moduleMain)
{
   builtinModuleList().push_back(moduleMain);

   return;
}

// ----------------------------------------------------------------------------
// Creation/Destruction
// ----------------------------------------------------------------------------

ModuleManager::ModuleManager()
{
}

ModuleManager::~ModuleManager()
{
   mDynModules.clear();
   builtinModuleList().clear();
}

// static 
void ModuleManager::Initialize(CommandHandler &cmdHandler)
{
   const auto &audacityPathList = FileNames::AudacityPathList();
   FilePaths pathList;
   FilePaths files;
   wxString pathVar;
   size_t i;

   // Code from LoadLadspa that might be useful in load modules.
   pathVar = wxGetenv(wxT("AUDACITY_MODULES_PATH"));
   if (!pathVar.empty())
      FileNames::AddMultiPathsToPathList(pathVar, pathList);

   for (i = 0; i < audacityPathList.size(); i++) {
      wxString prefix = audacityPathList[i] + wxFILE_SEP_PATH;
      FileNames::AddUniquePathToPathList(prefix + wxT("modules"),
                                         pathList);
      if (files.size()) {
         break;
      }
   }

   #if defined(__WXMSW__)
   FileNames::FindFilesInPathList(wxT("*.dll"), pathList, files);
   #else
   FileNames::FindFilesInPathList(wxT("*.so"), pathList, files);
   #endif

   FilePaths checked;
   wxString saveOldCWD = ::wxGetCwd();
   for (i = 0; i < files.size(); i++) {
      // As a courtesy to some modules that might be bridges to
      // open other modules, we set the current working
      // directory to be the module's directory.
      auto prefix = ::wxPathOnly(files[i]);
      ::wxSetWorkingDirectory(prefix);

      // Only process the first module encountered in the
      // defined search sequence.
      wxString ShortName = wxFileName( files[i] ).GetName();
      if( checked.Index( ShortName, false ) != wxNOT_FOUND )
         continue;
      checked.Add( ShortName );

#ifdef EXPERIMENTAL_MODULE_PREFS
      int iModuleStatus = ModulePrefs::GetModuleStatus( files[i] );
      if( iModuleStatus == kModuleDisabled )
         continue;
      if( iModuleStatus == kModuleFailed )
         continue;
      // New module?  You have to go and explicitly enable it.
      if( iModuleStatus == kModuleNew ){
         // To ensure it is noted in config file and so
         // appears on modules page.
         ModulePrefs::SetModuleStatus( files[i], kModuleNew);
         continue;
      }

      if( iModuleStatus == kModuleAsk )
#endif
      // JKC: I don't like prompting for the plug-ins individually
      // I think it would be better to show the module prefs page,
      // and let the user decide for each one.
      {
         auto msg = XO("Module \"%s\" found.").Format( ShortName );
         msg += XO("\n\nOnly use modules from trusted sources");
         const TranslatableStrings buttons{
            XO("Yes"), XO("No"),
         };  // could add a button here for 'yes and remember that', and put it into the cfg file.  Needs more thought.
         int action;
         action = ShowMultiDialog(msg, XO("Audacity Module Loader"),
            buttons,
            "",
            XO("Try and load this module?"), 
            false);
#ifdef EXPERIMENTAL_MODULE_PREFS
         // If we're not prompting always, accept the answer permanently
         if( iModuleStatus == kModuleNew ){
            iModuleStatus = (action==1)?kModuleDisabled : kModuleEnabled;
            ModulePrefs::SetModuleStatus( files[i], iModuleStatus );
         }
#endif
         if(action == 1){   // "No"
            continue;
         }
      }
#ifdef EXPERIMENTAL_MODULE_PREFS
      // Before attempting to load, we set the state to bad.
      // That way, if we crash, we won't try again.
      ModulePrefs::SetModuleStatus( files[i], kModuleFailed );
#endif

      auto umodule = std::make_unique<Module>(files[i]);
         if (umodule->Load())   // it will get rejected if there  are version problems
      {
         auto module = umodule.get();

         {
            // We've loaded and initialised OK.
            // So look for special case functions:
            wxLogNull logNo; // Don't show wxWidgets errors if we can't do these. (Was: Fix bug 544.)

            // (a) for scripting.
            if (scriptFn == NULL)
            {
               scriptFn = (tpRegScriptServerFunc)(module->GetSymbol(wxT(scriptFnName)));
            }

            // (b) for hijacking the entire Audacity panel.
            if (pPanelHijack == NULL)
            {
               pPanelHijack = (tPanelFn)(module->GetSymbol(wxT(mainPanelFnName)));
            }
         }

         if (!module->HasDispatch() && !scriptFn && !pPanelHijack)
         {
            auto ShortName = wxFileName(files[i]).GetName();
            AudacityMessageBox(
               XO("The module \"%s\" does not provide any of the required functions.\n\nIt will not be loaded.").Format(ShortName),
               XO("Module Unsuitable"));
            wxLogMessage(wxT("The module \"%s\" does not provide any of the required functions. It will not be loaded."), files[i]);
            module->Unload();
         }
         else
         {
            Get().mModules.push_back(std::move(umodule));

#ifdef EXPERIMENTAL_MODULE_PREFS
            // Loaded successfully, restore the status.
            ModulePrefs::SetModuleStatus(files[i], iModuleStatus);
#endif
         }
      }
   }
   ::wxSetWorkingDirectory(saveOldCWD);

   // After loading all the modules, we may have a registered scripting function.
   if(scriptFn)
   {
      ScriptCommandRelay::StartScriptServer(scriptFn);
   }
}

// static
int ModuleManager::Dispatch(ModuleDispatchTypes type)
{
   for (const auto &module: mModules) {
      module->Dispatch(type);
   }
   return 0;
}

// ============================================================================
//
// Return reference to singleton
//
// (Thread-safe...no active threading during construction or after destruction)
// ============================================================================
ModuleManager & ModuleManager::Get()
{
   if (!mInstance)
   {
      mInstance.reset(safenew ModuleManager);
   }

   return *mInstance;
}

bool ModuleManager::DiscoverProviders()
{
   InitializeBuiltins();

// The commented out code loads modules whether or not they are enabled.
// none of our modules is a 'provider' of effects, so this code commented out. 
#if 0
   FilePaths provList;
   FilePaths pathList;

   // Code from LoadLadspa that might be useful in load modules.
   wxString pathVar = wxString::FromUTF8(getenv("AUDACITY_MODULES_PATH"));

   if (!pathVar.empty())
   {
      FileNames::AddMultiPathsToPathList(pathVar, pathList);
   }
   else
   {
      FileNames::AddUniquePathToPathList(FileNames::ModulesDir(), pathList);
   }

#if defined(__WXMSW__)
   FileNames::FindFilesInPathList(wxT("*.dll"), pathList, provList);
#elif defined(__WXMAC__)
   FileNames::FindFilesInPathList(wxT("*.dylib"), pathList, provList);
#else
   FileNames::FindFilesInPathList(wxT("*.so"), pathList, provList);
#endif

   PluginManager & pm = PluginManager::Get();

   for (int i = 0, cnt = provList.size(); i < cnt; i++)
   {
      ModuleInterface *module = LoadModule(provList[i]);
      if (module)
      {
         // Register the provider
         pm.RegisterPlugin(module);

         // Now, allow the module to auto-register children
         module->AutoRegisterPlugins(pm);
      }
   }
#endif

   return true;
}

void ModuleManager::InitializeBuiltins()
{
   PluginManager & pm = PluginManager::Get();

   for (auto moduleMain : builtinModuleList())
   {
      ModuleInterfaceHandle module {
         moduleMain(nullptr), ModuleInterfaceDeleter{}
      };

      if (module->Initialize())
      {
         // Register the provider
         ModuleInterface *pInterface = module.get();
         const PluginID & id = pm.RegisterPlugin(pInterface);

         // Need to remember it 
         mDynModules[id] = std::move(module);

         // Allow the module to auto-register children
         pInterface->AutoRegisterPlugins(pm);
      }
      else
      {
         // Don't leak!  Destructor of module does that.
      }
   }
}

ModuleInterface *ModuleManager::LoadModule(const PluginPath & path)
{
   auto lib = std::make_unique<wxDynamicLibrary>();

   if (lib->Load(path, wxDL_NOW))
   {
      bool success = false;
      ModuleMain audacityMain = (ModuleMain) lib->GetSymbol(wxSTRINGIZE_T(MODULE_ENTRY),
                                                            &success);
      if (success && audacityMain)
      {
         ModuleInterfaceHandle handle {
            audacityMain(&path), ModuleInterfaceDeleter{}
         };
         if (handle)
         {
            if (handle->Initialize())
            {

               auto module = handle.get();
               mDynModules[PluginManager::GetID(module)] = std::move(handle);
               mLibs[module] = std::move(lib);

               return module;
            }
         }
      }

      lib->Unload();
   }

   return NULL;
}

void ModuleInterfaceDeleter::operator() (ModuleInterface *pInterface) const
{
   if (pInterface)
   {
      pInterface->Terminate();

      auto &libs = ModuleManager::Get().mLibs;

      auto iter = libs.find(pInterface);
      if (iter != libs.end())
         libs.erase(iter); // This causes unloading in ~wxDynamicLibrary

      std::unique_ptr < ModuleInterface > { pInterface }; // DELETE it
   }
}

PluginPaths ModuleManager::FindPluginsForProvider(const PluginID & providerID,
                                                    const PluginPath & path)
{
   // Instantiate if it hasn't already been done
   if (mDynModules.find(providerID) == mDynModules.end())
   {
      // If it couldn't be created, just give up and return an empty list
      if (!CreateProviderInstance(providerID, path))
      {
         return {};
      }
   }

   return mDynModules[providerID]->FindPluginPaths(PluginManager::Get());
}

bool ModuleManager::RegisterEffectPlugin(const PluginID & providerID, const PluginPath & path, TranslatableString &errMsg)
{
   errMsg = {};
   if (mDynModules.find(providerID) == mDynModules.end())
   {
      return false;
   }

   auto nFound = mDynModules[providerID]->DiscoverPluginsAtPath(path, errMsg, PluginManagerInterface::DefaultRegistrationCallback);

   return nFound > 0;
}

ModuleInterface *ModuleManager::CreateProviderInstance(const PluginID & providerID,
                                                      const PluginPath & path)
{
   if (path.empty() && mDynModules.find(providerID) != mDynModules.end())
   {
      return mDynModules[providerID].get();
   }

   return LoadModule(path);
}

ComponentInterface *ModuleManager::CreateInstance(const PluginID & providerID,
                                              const PluginPath & path)
{
   if (mDynModules.find(providerID) == mDynModules.end())
   {
      return NULL;
   }

   return mDynModules[providerID]->CreateInstance(path);
}

void ModuleManager::DeleteInstance(const PluginID & providerID,
                                   ComponentInterface *instance)
{
   if (mDynModules.find(providerID) == mDynModules.end())
   {
      return;
   }

   mDynModules[providerID]->DeleteInstance(instance);
}

bool ModuleManager::IsProviderValid(const PluginID & WXUNUSED(providerID),
                                    const PluginPath & path)
{
   // Builtin modules do not have a path
   if (path.empty())
   {
      return true;  
   }

   wxFileName lib(path);
   if (lib.FileExists() || lib.DirExists())
   {
      return true;
   }

   return false;
}

bool ModuleManager::IsPluginValid(const PluginID & providerID,
                                  const PluginPath & path,
                                  bool bFast)
{
   if (mDynModules.find(providerID) == mDynModules.end())
   {
      return false;
   }

   return mDynModules[providerID]->IsPluginValid(path, bFast);
}