// src/backend/python_policy_manager.cc - Copyright 2005, 2006, University
//               of Padova, dept. of Pure and Applied
//               Mathematics
//
// This file is part of SGPEMv2.
//
// This is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// SGPEMv2 is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with SGPEMv2; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

#include "python_policy_manager.hh"

#include <string>
#include <cassert>
#include <cstdio>
using namespace sgpem;

//static object
PythonPolicyManager* PythonPolicyManager::_instance = NULL;

PythonPolicyManager::PythonPolicyManager()
  : _initialized(false)
{
}

PythonPolicyManager&
PythonPolicyManager::get_instance()
{
	if(!_instance)
	  _instance = new PythonPolicyManager();
	return *_instance;
}

Policy&
PythonPolicyManager::get_policy()
{
	// FIXME : assumes that _python_policy is always != NULL!
	return *_python_policy;
}

void
PythonPolicyManager::init()
{
  if(_initialized)
    Py_Finalize();
  
  Py_Initialize();
  _initialized = true;
  
  // The following line is ugly, but necessary if we use 
  // non-standard installation directories. Theoretically,
  // it should be up to the user to set correct 
  // environment variables. 
  // FIXME: find better way to achieve this.
  
  PyRun_SimpleString("import sys\n"
		     "sys.path[:0] = [ '" MODDIR "', '" PYCDIR "' ]\n");

  // Okay, here we go.
  // Black magic at work. 

  // FIXME : Hardcoded policy
  char* policy_name = "fcfs_policy";
  PyObject* pLoadmeStr = PyString_FromString(policy_name);
  PyObject *pModule = PyImport_Import(pLoadmeStr);
  Py_DECREF(pLoadmeStr);
  
  if( !pModule ) 
  {
    PyErr_Print(); // Error in import
    // FIXME : don't exit abruptly, but fall back gracefully
    exit(-1);
  }

  // Dictionary with defined ``symbols'' for .pyc file
  PyObject* pDict = PyModule_GetDict(pModule);
  assert(pDict);

  // Build up UserPythonScriptAdapter
  {
    std::string py_adapter = std::string("class UserPythonScriptAdapter(") + 
                             policy_name + "):\n"
      "   def __init__(self):\n"
      "      pass;\n"
      "   def async_configure():\n"
      "      pass;\n"
      "   def async_sort_queue():\n"
      "      pass;\n"
      "   def async_is_preemptible():\n"
      "      pass;\n"
      "   def async_is_timesliced():\n"
      "      pass;\n"
      "\n";
    PyRun_SimpleString(py_adapter.c_str());
  }

  //build SWIG proxy object inside the interpreter
  PyRun_SimpleString("py_ad = UserPythonScriptAdapter");
  /*  const char *buildPyProcess = 
	  "import proto_process\n"
	  "p = proto_process.Process(19, 'param')\n"
	  "#set ownership to C++ code\n"
	  "p.thisown = 0\n";

  PyRun_SimpleString(buildPyProcess);
  */

  Py_DECREF(pModule);
  
  pModule = PyImport_AddModule("__main__");
  pDict = PyModule_GetDict(pModule);
  
  //  PyObject *pPyProcess = PyMapping_GetItemString(pDict, "p"); 
  // assert(pPyProcess);

  // Matteo: PyTuple_SetItem steals the reference, so
  // we don't DECREF pPyProcess. 
  // See http://www.python.org/doc/2.4.2/api/refcountDetails.html#l2h-13
  //  PyTuple_SetItem(pArgs, 0, pPyProcess);

  // assert(pFunc);

  /*  if(PyCallable_Check(pFunc)) 
    {
      PyObject* ret = PyObject_CallObject(pFunc, pArgs);
      Py_DECREF(pArgs);
      if(!ret) PyErr_Print();
      else Py_DECREF(ret);
    }
  */

  
}