/*
 * Copyright (C) 2019 Weber Yann
 * 
 * This file is part of PyFCGI.
 * 
 * PyFCGI is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * any later version.
 * 
 * PyFCGI 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 Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with PyFCGI.  If not, see <http://www.gnu.org/licenses/>.
 */

/**@defgroup libpyfcgi libpyfcgi python module
 * @brief The libpyfcgi python module
 *
 * PyFCGI defines a python module : libpyfcgi for PEP333 implementation.
 * This module contains 2 methods : start_response() and write_body()
 *
 * The first one is given as argument to the application function, and
 * the second one is returned when start_method() is called.
 */

/**@file python_pyfcgi.h
 * @ingroup libpyfcgi
 */
#ifndef _PYTHON_PYFCGI__H__
#define _PYTHON_PYFCGI__H__

#include "config.h"

#include <fcgiapp.h>
#include <fcgi_stdio.h> /* fcgi library; put it first*/

#define PY_SSIZE_T_CLEAN
#include <Python.h>
#include "structmember.h"

#include "logger.h"
#include "python_ioin.h"

#define LIBPYFCGI_TIMEOUT_HEADERS "Content-Type: text/plain\r\nStatus: 504 Gateway Timeout\r\n\r\n"
#define LIBPYFCGI_DEFAULT_HEADERS "Content-Type: text/html\r\nStatus: %s\r\n\r\n"
#define LIBPYFCGI_DEFAULT_STATUS "200 OK"
#define LIBPYFCGI_DEFAULT_CTYPE "Content-Type: text/html\r\n"
#define LIBPYFCGI_STATUS_SZ 128

struct libpyfcgi_context_s
{
	/**@brief PEP333 handling python module reference
	 * @ingroup libpyfcgi */
	PyObject *self;
	/**@brief PEP333 status ref
	 * @ingroup libpyfcgi */
	PyObject *status;
	/**@brief PEP333 headers ref
	 * @ingroup libpyfcgi */
	PyObject *headers;
	/**@brief libpyfcgi.IoIn instance */
	PyIO_t *ioin;
	/**@brief libpyfcgi.IoOut instances for stdout & stderr */
	PyIO_t *stdio[2];
	/**@brief Indicate if headers was sent in a PEP333 application
	 * @ingroup libpyfcgi */
	short headers_sent;
	/**@brief Stores the libFCGI stream for PEP333 application
	 * @ingroup libpyfcgi */
	FCGX_Stream *out;
	/**@brief Stores the libFCGI stream from wich HTTP request can be read
	 * @ingroup libpyfcgi */
	FCGX_Stream *in;
	/**@brief Persistent buffer (avoid malloc) for PEP333 headers */
	char *heads_buf;
	/**@brief Buffer size */
	size_t heads_buf_sz;
	/**@brief Persistent buffer for PEP333 status */
	char status_buf[LIBPYFCGI_STATUS_SZ];
	size_t rep_sz;
};

typedef struct libpyfcgi_context_s libpyfcgi_context_t;

/**@brief Stores python module context */
extern libpyfcgi_context_t libpyfcgi;
/**@brief libpyfcgi methods */
extern PyMethodDef pyfcgimodule_methods[];
/**@brief libpyfcgi module structure */
extern PyModuleDef pyfcgimodule;

/**@brief Clean response_status & response_headers globals */
static inline void libpyfcgi_clean_response()
{
	if(libpyfcgi.status) { Py_DECREF(libpyfcgi.status); }
	libpyfcgi.status = NULL;
	if(libpyfcgi.headers) { Py_DECREF(libpyfcgi.headers); }
	libpyfcgi.headers = NULL;
	libpyfcgi.headers_sent = 0;
	libpyfcgi.rep_sz = 0;
	libpyfcgi.ioin->eof=0;
	libpyfcgi.ioin->closed=Py_False;
}

/**@brief Send headers stored in @ref libpyfcgi context
 * @note Set python error if called from outside a valid context
 */
void libpyfcgi_send_headers();

/**@brief Send body to fcgi
 * @param body_data the body data object (returned by PEP333 app)
 * @return Python None
 */
PyObject* _pyfcgi_write_body(PyObject *body_data);

/**@brief Called by the SIGALRM sighandler @ref worker_sigalrmhandler()
 *
 * If no headers sent send a timeout header.
 *
 * Attempt to generate a python exception and to log exception before
 * exiting.
 */
void libpyfcgi_timeout();

/* Defining Python module */

/**@brief Public module initialisation function
 * @ingroup libpyfcgi
 * @return A python module (PyObject*)
 */
PyMODINIT_FUNC PyInit_libpyfcgi(void);

/**@brief libpyfcgi.start_response() python callable
 * @ingroup libpyfcgi
 * @note This python callable is a fastcall C method of libpyfcgi module.
 * 
 * The python function header is :
 * start_response(status, response_headers, exc_info = None)
 * @param self
 * @param argv
 * @param argc
 * @return A PyObject* referencing a callable allowing to write data without
 * cache : libpyfcgi.write_body()
 */
PyObject* pyfcgi_start_response(PyObject* self, PyObject** argv,
	Py_ssize_t argc);

/**@brief libpyfcgi.write_body() python callable
 * @ingroup libpyfcgi
 * @note This python callable is a fastcall C method of libpyfcgi module.
 *
 * The python function header is : write_body(body_data)
 * @param self
 * @param argv
 * @param argc
 * @return ???
 */
PyObject* pyfcgi_write_body(PyObject* self, PyObject** argv, Py_ssize_t argc);

int _libpyfcgi_stdout_write(const char*, size_t);
int _libpyfcgi_stderr_write(const char*, size_t);

#endif