// -*-c++-*- osgWidget - Code by: Jeremy Moles (cubicool) 2007-2008
// $Id: Python.cpp 59 2008-05-15 20:55:31Z cubicool $

// Python.h needs to be included before anything else.
#ifdef OSGWIDGET_USEPYTHON
#include <Python.h>
#endif

#include <osgDB/FileUtils>
#include <osgWidget/Python>
#include <osgWidget/Box>
#include <osgWidget/WindowManager>

namespace osgWidget {

// Our Python library.
namespace py {
#ifdef OSGWIDGET_USEPYTHON

// TODO: Until I can find a way to move data around inside of the context, this will
// have to do. I don't really like it, but I've got no choice.
static PyObject* G_ERR = 0;

PyObject* newWindow(PyObject* self, PyObject* args) {
	PyObject*   buffer = 0;
	const char* name   = 0;
	int         width  = 0;
	int         height = 0;

	/*
	if(PyArg_ParseTuple(args, "sO!ii", &name, &PyBuffer_Type, &buffer, &width, &height)) {
		const void* buf = 0;
		int         len = 0;

		if(!PyObject_AsReadBuffer(buffer, &buf, &len)) {
			// if(Database::instance().add(name, buf, width, height))
			return Py_BuildValue("i", len);

			// else PyErr_SetString(G_ERR, "Couldn't add image to database.");
		}

		else PyErr_SetString(G_ERR, "Couldn't read buffer data.");

		return 0;
	}
	*/

	PyErr_SetString(G_ERR, "still testing...");

	return 0;
}

static PyMethodDef methods[] = {
	{
		"newWindow", newWindow, METH_VARARGS,
		"docstring"
	},
	{ 0, 0, 0, 0 }
};

#endif
}

// A helper function for all those cases where we need to inform the user that there isn't
// a LUA engine available.
bool noPythonFail(const std::string& err) {
	warn() << err << "; Python not compiled in library." << std::endl;

	return false;
}

// Our "private", internal data.
struct PythonEngineData {
#ifdef OSGWIDGET_USEPYTHON
	PythonEngineData():
	mod  (0),
	err  (0),
	main (0) {
	}

	bool valid() const {
		return mod && err && main;
	}

	PyObject* mod;
	PyObject* err;
	PyObject* main;
#endif
};

PythonEngine::PythonEngine(WindowManager* wm):
_wm(wm) {
#ifdef OSGWIDGET_USEPYTHON
	_data = new PythonEngineData();

#else
	_data = 0;
#endif
}

bool PythonEngine::initialize() {
#ifdef OSGWIDGET_USEPYTHON
	Py_InitializeEx(0);

	if(!_data->valid()) {
		_data->mod  = Py_InitModule3("osgwidget", py::methods, "main docstring");
		_data->err  = PyErr_NewException((char*)("osgwidget.error"), 0, 0);
		_data->main = PyModule_GetDict(PyImport_AddModule("__main__"));

		Py_INCREF(_data->err);

		// TODO: ...sigh...
		py::G_ERR = _data->err;

		PyModule_AddObject(_data->mod, "error", _data->err);
	}

	return true;

#else
	return noPythonFail("Can't initialize the PythonEngine");
#endif
}

bool PythonEngine::close() {
#ifdef OSGWIDGET_USEPYTHON
	if(_data->valid()) {
		Py_DECREF(_data->err);

		Py_Finalize();
	}

	delete _data;

	return true;

#else
	return noPythonFail("Can't close the PythonEngine");
#endif
}

bool PythonEngine::eval(const std::string& code) {
#ifdef OSGWIDGET_USEPYTHON
	PyObject* r = PyRun_String(code.c_str(), Py_file_input, _data->main, _data->main);

	if(!r) {
		r = PyErr_Occurred();

		if(r) {
			PyErr_Print();
			PyErr_Clear();
		}

		return false;
	}

	return true;

#else
	return noPythonFail("Can't evaluate code in PythonEngine");
#endif
}

bool PythonEngine::runFile(const std::string& filePath) {
#ifdef OSGWIDGET_USEPYTHON
	if(!osgDB::fileExists(filePath)) {
		warn()
			<< "Couldn't find file \"" << filePath << "\" for PythonEngine."
			<< std::endl
		;

		return false;
	}

	FILE*     f = fopen(filePath.c_str(), "r");
	PyObject* r = PyRun_File(f, filePath.c_str(), Py_file_input, _data->main, _data->main);

	fclose(f);

	if(!r) {
		r = PyErr_Occurred();

		if(r) {
			// The following snippet lets us get the return code. That is: if the
			// script is stopped with sys.exit() or similar. We could use this
			// return code to do something sensible... later.
			if(PyErr_ExceptionMatches(PyExc_SystemExit)) {
				PyObject* ty = 0;
				PyObject* er = 0;
				PyObject* tr = 0;

				PyErr_Fetch(&ty, &er, &tr);

				Py_DECREF(ty);
				Py_DECREF(er);
				Py_DECREF(er);
			}

			else {
				PyErr_Print();
				PyErr_Clear();
			}
		}

		return false;
	}

	return true;

#else
	return noPythonFail("Can't evaluate code in PythonEngine");
#endif
}

}