/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying

   file LICENSE.rst or https://cmake.org/licensing for details.  */

#include "cmVariableWatchCommand.h"

#include <limits>

#include <memory>

#include <utility>

#include "cmExecutionStatus.h"

#include "cmListFileCache.h"

#include "cmMakefile.h"

#include "cmMessageType.h"

#include "cmStringAlgorithms.h"

#include "cmSystemTools.h"

#include "cmValue.h"

#include "cmVariableWatch.h"

#include "cmake.h"

class cmLocalGenerator;

namespace {

struct cmVariableWatchCallbackData

{

  bool InCallback;

  std::string Command;

};

void cmVariableWatchCommandVariableAccessed(std::string const& variable,

                                            int access_type, void* client_data,

                                            char const* newValue,

                                            cmMakefile const* mf)

{

  cmVariableWatchCallbackData* data =

    static_cast<cmVariableWatchCallbackData*>(client_data);

  if (data->InCallback) {

    return;

  }

  data->InCallback = true;

  auto accessString = cmVariableWatch::GetAccessAsString(access_type);

  /// Ultra bad!!

  cmMakefile* makefile = const_cast<cmMakefile*>(mf);

  std::string stack = *mf->GetProperty("LISTFILE_STACK");

  if (!data->Command.empty()) {

    cmValue const currentListFile =

      mf->GetDefinition("CMAKE_CURRENT_LIST_FILE");

    auto const fakeLineNo =

      std::numeric_limits<decltype(cmListFileArgument::Line)>::max();

    std::vector<cmListFileArgument> newLFFArgs{

      { variable, cmListFileArgument::Quoted, fakeLineNo },

      { accessString, cmListFileArgument::Quoted, fakeLineNo },

      { newValue ? newValue : "", cmListFileArgument::Quoted, fakeLineNo },

      { *currentListFile, cmListFileArgument::Quoted, fakeLineNo },

      { stack, cmListFileArgument::Quoted, fakeLineNo }

    };

    cmListFileFunction newLFF{ data->Command, fakeLineNo, fakeLineNo,

                               std::move(newLFFArgs) };

    cmExecutionStatus status(*makefile);

    if (!makefile->ExecuteCommand(newLFF, status)) {

      cmSystemTools::Error(

        cmStrCat("Error in cmake code at\nUnknown:0:\nA command failed "

                 "during the invocation of callback \"",

                 data->Command, "\"."));

    }

  } else {

    makefile->IssueMessage(

      MessageType::LOG,

      cmStrCat("Variable \"", variable, "\" was accessed using ", accessString,

               " with value \"", (newValue ? newValue : ""), "\"."));

  }

  data->InCallback = false;

}

void deleteVariableWatchCallbackData(void* client_data)

{

  cmVariableWatchCallbackData* data =

    static_cast<cmVariableWatchCallbackData*>(client_data);

  delete data;

}

/** This command does not really have a final pass but it needs to

    stay alive since it owns variable watch callback information. */

class FinalAction

{

public:

  /* NOLINTNEXTLINE(performance-unnecessary-value-param) */

  FinalAction(cmMakefile* makefile, std::string variable)

    : Action{ std::make_shared<Impl>(makefile, std::move(variable)) }

  {

  }

  void operator()(cmLocalGenerator&, cmListFileBacktrace const&) const {}

private:

  struct Impl

  {

    Impl(cmMakefile* makefile, std::string variable)

      : Makefile{ makefile }

      , Variable{ std::move(variable) }

    {

    }

    ~Impl()

    {

      this->Makefile->GetCMakeInstance()->GetVariableWatch()->RemoveWatch(

        this->Variable, cmVariableWatchCommandVariableAccessed);

    }

    cmMakefile* const Makefile;

    std::string const Variable;

  };

  std::shared_ptr<Impl const> Action;

};

} // anonymous namespace

bool cmVariableWatchCommand(std::vector<std::string> const& args,

                            cmExecutionStatus& status)

{

  if (args.empty()) {

    status.SetError("must be called with at least one argument.");

    return false;

  }

  std::string const& variable = args[0];

  std::string command;

  if (args.size() > 1) {

    command = args[1];

  }

  if (variable == "CMAKE_CURRENT_LIST_FILE") {

    status.SetError(cmStrCat("cannot be set on the variable: ", variable));

    return false;

  }

  auto* const data = new cmVariableWatchCallbackData;

  data->InCallback = false;

  data->Command = std::move(command);

  if (!status.GetMakefile().GetCMakeInstance()->GetVariableWatch()->AddWatch(

        variable, cmVariableWatchCommandVariableAccessed, data,

        deleteVariableWatchCallbackData)) {

    deleteVariableWatchCallbackData(data);

    return false;

  }

  status.GetMakefile().AddGeneratorAction(

    FinalAction{ &status.GetMakefile(), variable });

  return true;

}