/* 
 * $Id$
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program 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.
 *
 * This program 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 this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * This is a new part of Blender.
 *
 * Contributor(s): Willian P. Germano
 *
 * ***** END GPL LICENSE BLOCK *****
*/

/** \file blender/python/generic/bpy_internal_import.c
 *  \ingroup pygen
 */


#include <Python.h>
#include <stddef.h>

#include "compile.h"	/* for the PyCodeObject */
#include "eval.h"		/* for PyEval_EvalCode */

#include "bpy_internal_import.h"

#include "MEM_guardedalloc.h"

#include "DNA_text_types.h"

#include "BLI_listbase.h"
#include "BLI_path_util.h"
#include "BLI_string.h"
#include "BLI_utildefines.h"

 /* UNUSED */	
#include "BKE_text.h" /* txt_to_buf */	
#include "BKE_main.h"
#include "BKE_global.h" /* grr, only for G.main->name */

static Main *bpy_import_main= NULL;

/* 'builtins' is most likely PyEval_GetBuiltins() */
void bpy_import_init(PyObject *builtins)
{
	PyObject *item;
	PyObject *mod;

	PyDict_SetItemString(builtins, "__import__",	item=PyCFunction_New(&bpy_import_meth, NULL));	Py_DECREF(item);

	/* move reload here
	 * XXX, use import hooks */
	mod= PyImport_ImportModuleLevel((char *)"imp", NULL, NULL, NULL, 0);
	if(mod) {
		PyDict_SetItemString(PyModule_GetDict(mod), "reload", item=PyCFunction_New(&bpy_reload_meth, NULL)); Py_DECREF(item);
		Py_DECREF(mod);
	}
	else {
		BLI_assert(!"unable to load 'imp' module.");
	}
}


static void free_compiled_text(Text *text)
{
	if(text->compiled) {
		Py_DECREF((PyObject *)text->compiled);
	}
	text->compiled= NULL;
}

struct Main *bpy_import_main_get(void)
{
	return bpy_import_main;
}

void bpy_import_main_set(struct Main *maggie)
{
	bpy_import_main= maggie;
}

/* returns a dummy filename for a textblock so we can tell what file a text block comes from */
void bpy_text_filename_get(char *fn, size_t fn_len, Text *text)
{
	BLI_snprintf(fn, fn_len, "%s%c%s", text->id.lib ? text->id.lib->filepath : G.main->name, SEP, text->id.name+2);
}

PyObject *bpy_text_import(Text *text)
{
	char *buf= NULL;
	char modulename[24];
	int len;

	if(!text->compiled) {
		char fn_dummy[256];
		bpy_text_filename_get(fn_dummy, sizeof(fn_dummy), text);

		buf= txt_to_buf(text);
		text->compiled= Py_CompileString(buf, fn_dummy, Py_file_input);
		MEM_freeN(buf);

		if(PyErr_Occurred()) {
			PyErr_Print();
			PyErr_Clear();
			PySys_SetObject("last_traceback", NULL);
			free_compiled_text(text);
			return NULL;
		}
	}

	len= strlen(text->id.name+2);
	strncpy(modulename, text->id.name+2, len);
	modulename[len - 3]= '\0'; /* remove .py */
	return PyImport_ExecCodeModule(modulename, text->compiled);
}

PyObject *bpy_text_import_name(char *name, int *found)
{
	Text *text;
	char txtname[MAX_ID_NAME-2];
	int namelen= strlen(name);
//XXX	Main *maggie= bpy_import_main ? bpy_import_main:G.main;
	Main *maggie= bpy_import_main;
	
	*found= 0;

	if(!maggie) {
		printf("ERROR: bpy_import_main_set() was not called before running python. this is a bug.\n");
		return NULL;
	}
	
	if (namelen >= (MAX_ID_NAME-2) - 3) return NULL; /* we know this cant be importable, the name is too long for blender! */
	
	memcpy(txtname, name, namelen);
	memcpy(&txtname[namelen], ".py", 4);

	text= BLI_findstring(&maggie->text, txtname, offsetof(ID, name) + 2);

	if(!text)
		return NULL;
	else
		*found= 1;
	
	return bpy_text_import(text);
}


/*
 * find in-memory module and recompile
 */

PyObject *bpy_text_reimport(PyObject *module, int *found)
{
	Text *text;
	const char *name;
	char *filepath;
	char *buf= NULL;
//XXX	Main *maggie= bpy_import_main ? bpy_import_main:G.main;
	Main *maggie= bpy_import_main;
	
	if(!maggie) {
		printf("ERROR: bpy_import_main_set() was not called before running python. this is a bug.\n");
		return NULL;
	}
	
	*found= 0;
	
	/* get name, filename from the module itself */
	if((name= PyModule_GetName(module)) == NULL)
		return NULL;

	if((filepath= (char *)PyModule_GetFilename(module)) == NULL)
		return NULL;

	/* look up the text object */
	text= BLI_findstring(&maggie->text, BLI_path_basename(filepath), offsetof(ID, name) + 2);

	/* uh-oh.... didn't find it */
	if(!text)
		return NULL;
	else
		*found= 1;

	/* if previously compiled, free the object */
	/* (can't see how could be NULL, but check just in case) */ 
	if(text->compiled){
		Py_DECREF((PyObject *)text->compiled);
	}

	/* compile the buffer */
	buf= txt_to_buf(text);
	text->compiled= Py_CompileString(buf, text->id.name+2, Py_file_input);
	MEM_freeN(buf);

	/* if compile failed.... return this error */
	if(PyErr_Occurred()) {
		PyErr_Print();
		PyErr_Clear();
		PySys_SetObject("last_traceback", NULL);
		free_compiled_text(text);
		return NULL;
	}

	/* make into a module */
	return PyImport_ExecCodeModule((char *)name, text->compiled);
}


static PyObject *blender_import(PyObject *UNUSED(self), PyObject *args, PyObject * kw)
{
	PyObject *exception, *err, *tb;
	char *name;
	int found= 0;
	PyObject *globals= NULL, *locals= NULL, *fromlist= NULL;
	int level= -1; /* relative imports */
	
	PyObject *newmodule;
	//PyObject_Print(args, stderr, 0);
	static const char *kwlist[]= {"name", "globals", "locals", "fromlist", "level", NULL};
	
	if(!PyArg_ParseTupleAndKeywords(args, kw, "s|OOOi:bpy_import_meth", (char **)kwlist,
				   &name, &globals, &locals, &fromlist, &level))
		return NULL;

	/* import existing builtin modules or modules that have been imported already */
	newmodule= PyImport_ImportModuleLevel(name, globals, locals, fromlist, level);
	
	if(newmodule)
		return newmodule;
	
	PyErr_Fetch(&exception, &err, &tb);	/* get the python error incase we cant import as blender text either */
	
	/* importing from existing modules failed, see if we have this module as blender text */
	newmodule= bpy_text_import_name(name, &found);
	
	if(newmodule) {/* found module as blender text, ignore above exception */
		PyErr_Clear();
		Py_XDECREF(exception);
		Py_XDECREF(err);
		Py_XDECREF(tb);
		/* printf("imported from text buffer...\n"); */
	}
	else if (found==1) { /* blender text module failed to execute but was found, use its error message */
		Py_XDECREF(exception);
		Py_XDECREF(err);
		Py_XDECREF(tb);
		return NULL;
	}
	else {
		/* no blender text was found that could import the module
		 * rause the original error from PyImport_ImportModuleEx */
		PyErr_Restore(exception, err, tb);
	}
	return newmodule;
}


/*
 * our reload() module, to handle reloading in-memory scripts
 */

static PyObject *blender_reload(PyObject *UNUSED(self), PyObject * module)
{
	PyObject *exception, *err, *tb;
	PyObject *newmodule= NULL;
	int found= 0;

	/* try reimporting from file */
	newmodule= PyImport_ReloadModule(module);
	if(newmodule)
		return newmodule;

	/* no file, try importing from memory */
	PyErr_Fetch(&exception, &err, &tb);	/*restore for probable later use */

	newmodule= bpy_text_reimport(module, &found);
	if(newmodule) {/* found module as blender text, ignore above exception */
		PyErr_Clear();
		Py_XDECREF(exception);
		Py_XDECREF(err);
		Py_XDECREF(tb);
		/* printf("imported from text buffer...\n"); */
	}
	else if (found==1) { /* blender text module failed to execute but was found, use its error message */
		Py_XDECREF(exception);
		Py_XDECREF(err);
		Py_XDECREF(tb);
		return NULL;
	}
	else {
		/* no blender text was found that could import the module
		 * rause the original error from PyImport_ImportModuleEx */
		PyErr_Restore(exception, err, tb);
	}

	return newmodule;
}

PyMethodDef bpy_import_meth= {"bpy_import_meth", (PyCFunction)blender_import, METH_VARARGS | METH_KEYWORDS, "blenders import"};
PyMethodDef bpy_reload_meth= {"bpy_reload_meth", (PyCFunction)blender_reload, METH_O, "blenders reload"};


/* Clear user modules.
 * This is to clear any modules that could be defined from running scripts in blender.
 * 
 * Its also needed for the BGE Python api so imported scripts are not used between levels
 * 
 * This clears every modules that has a __file__ attribute (is not a builtin)
 *
 * Note that clearing external python modules is important for the BGE otherwise
 * it wont reload scripts between loading different blend files or while making the game.
 * - use 'clear_all' arg in this case.
 *
 * Since pythons bultins include a full path even for win32.
 * even if we remove a python module a reimport will bring it back again.
 */

#if 0 // not used anymore but may still come in handy later

#if defined(WIN32) || defined(WIN64)
#define SEPSTR "\\"
#else
#define SEPSTR "/"
#endif


void bpy_text_clear_modules(int clear_all)
{
	PyObject *modules= PyImport_GetModuleDict();
	
	char *fname;
	char *file_extension;
	
	/* looping over the dict */
	PyObject *key, *value;
	int pos= 0;
	
	/* new list */
	PyObject *list;

	if (modules==NULL)
		return; /* should never happen but just incase */

	list= PyList_New(0);

	/* go over sys.modules and remove anything with a 
	 * sys.modukes[x].__file__ thats ends with a .py and has no path
	 */
	while (PyDict_Next(modules, &pos, &key, &value)) {
		fname= PyModule_GetFilename(value);
		if(fname) {
			if (clear_all || ((strstr(fname, SEPSTR))==0)) { /* no path ? */
				file_extension= strstr(fname, ".py");
				if(file_extension && (*(file_extension + 3) == '\0' || *(file_extension + 4) == '\0')) { /* .py or pyc extension? */
					/* now we can be fairly sure its a python import from the blendfile */
					PyList_Append(list, key); /* free'd with the list */
				}
			}
		}
		else {
			PyErr_Clear();
		}
	}
	
	/* remove all our modules */
	for(pos=0; pos < PyList_Size(list); pos++) {
		/* PyObject_Print(key, stderr, 0); */
		key= PyList_GET_ITEM(list, pos);
		PyDict_DelItem(modules, key);
	}
	
	Py_DECREF(list); /* removes all references from append */
}
#endif