/**
 * mds — A micro-display server
 * Copyright © 2014, 2015, 2016, 2017  Mattias Andrée (maandree@kth.se)
 * 
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */
#include "client.h"

#include "multicast.h"

#include <libmdsserver/macros.h>

#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <errno.h>



/**
 * Initialise a client
 * 
 * The following fields will not be initialised:
 * - message
 * - thread
 * - mutex
 * - modify_mutex
 * - modify_cond
 * 
 * The follow fields will be initialised to `-1`:
 * - list_entry
 * - socket_fd
 * 
 * @param  this  Memory slot in which to store the new client information
 */
void
client_initialise(client_t *restrict this)
{
	this->list_entry = -1;
	this->socket_fd = -1;
	this->open = 0;
	this->id = 0;
	this->mutex_created = 0;
	this->interception_conditions = NULL;
	this->interception_conditions_count = 0;
	this->multicasts = NULL;
	this->multicasts_count = 0;
	this->send_pending = NULL;
	this->send_pending_size = 0;
	this->modify_message = NULL;
	this->modify_mutex_created = 0;
	this->modify_cond_created = 0;
}


/**
 * Initialise fields that have to do with threading
 * 
 * This method initialises the following fields:
 * - thread
 * - mutex
 * - modify_mutex
 * - modify_cond
 * 
 * @param   this  The client information
 * @return        Zero on success, -1 on error
 */
int
client_initialise_threading(client_t *restrict this)
{
	/* Store the thread so that other threads can kill it. */
	this->thread = pthread_self();

	/* Create mutex to make sure two thread to not try to send
	   messages concurrently, and other client local actions. */
	fail_if ((errno = pthread_mutex_init(&(this->mutex), NULL)));
	this->mutex_created = 1;

	/* Create mutex and codition for multicast interception replies. */
	fail_if ((errno = pthread_mutex_init(&(this->modify_mutex), NULL)));
	this->modify_mutex_created = 1;
	fail_if ((errno = pthread_cond_init(&(this->modify_cond), NULL)));
	this->modify_cond_created = 1;

	return 0;
 fail:
	return -1;
}


/**
 * Release all resources assoicated with a client
 * 
 * @param  this  The client information
 */
void
client_destroy(client_t *restrict this)
{
	size_t i;
	if (this->interception_conditions) {
		for (i = 0; i < this->interception_conditions_count; i++)
			free(this->interception_conditions[i].condition);
		free(this->interception_conditions);
	}
	if (this->mutex_created)
		pthread_mutex_destroy(&(this->mutex));
	mds_message_destroy(&(this->message));
	if (this->multicasts) {
		for (i = 0; i < this->multicasts_count; i++)
			multicast_destroy(this->multicasts + i);
		free(this->multicasts);
	}
	free(this->send_pending);
	if (this->modify_message) {
		mds_message_destroy(this->modify_message);
		free(this->modify_message);
	}
	if (this->modify_mutex_created)
		pthread_mutex_destroy(&(this->modify_mutex));
	if (this->modify_cond_created)
		pthread_cond_destroy(&(this->modify_cond));
	free(this);
}


/**
 * Calculate the buffer size need to marshal client information
 * 
 * @param   this  The client information
 * @return        The number of bytes to allocate to the output buffer
 */
size_t
client_marshal_size(const client_t *restrict this)
{
	size_t i, n = sizeof(ssize_t) + 3 * sizeof(int) + sizeof(uint64_t) + 5 * sizeof(size_t);

	n += mds_message_marshal_size(&(this->message));
	for (i = 0; i < this->interception_conditions_count; i++)
		n += interception_condition_marshal_size(this->interception_conditions + i);
	for (i = 0; i < this->multicasts_count; i++)
		n += multicast_marshal_size(this->multicasts + i);
	n += this->send_pending_size * sizeof(char);
	n += !this->modify_message ? 0 : mds_message_marshal_size(this->modify_message);

	return n;
}


/**
 * Marshals client information
 * 
 * @param   this  The client information
 * @param   data  Output buffer for the marshalled data
 * @return        The number of bytes that have been written (everything will be written)
 */
size_t
client_marshal(const client_t *restrict this, char *restrict data)
{
	size_t i, n;
	buf_set_next(data, int, CLIENT_T_VERSION);
	buf_set_next(data, ssize_t, this->list_entry);
	buf_set_next(data, int, this->socket_fd);
	buf_set_next(data, int, this->open);
	buf_set_next(data, uint64_t, this->id);
	n = mds_message_marshal_size(&(this->message));
	buf_set_next(data, size_t, n);
	if (n > 0)
		mds_message_marshal(&(this->message), data);
	data += n / sizeof(char);
	buf_set_next(data, size_t, this->interception_conditions_count);
	for (i = 0; i < this->interception_conditions_count; i++)
		data += n = interception_condition_marshal(this->interception_conditions + i, data) / sizeof(char);
	buf_set_next(data, size_t, this->multicasts_count);
	for (i = 0; i < this->multicasts_count; i++)
		data += multicast_marshal(this->multicasts + i, data) / sizeof(char);
	buf_set_next(data, size_t, this->send_pending_size);
	if (this->send_pending_size > 0)
		memcpy(data, this->send_pending, this->send_pending_size * sizeof(char));
	data += this->send_pending_size;
	n = !this->modify_message ? 0 : mds_message_marshal_size(this->modify_message);
	buf_set_next(data, size_t, n);
	if (this->modify_message)
		mds_message_marshal(this->modify_message, data);
	return client_marshal_size(this);
}


/**
 * Unmarshals client information
 * 
 * @param   this  Memory slot in which to store the new client information
 * @param   data  In buffer with the marshalled data
 * @return        Zero on error, `errno` will be set accordingly, otherwise the number of read bytes
 */
size_t
client_unmarshal(client_t *restrict this, char *restrict data)
{
	size_t i, n, m, rc = sizeof(ssize_t) + 3 * sizeof(int) + sizeof(uint64_t) + 5 * sizeof(size_t);
	int saved_errno, stage = 0;
	this->interception_conditions = NULL;
	this->multicasts = NULL;
	this->send_pending = NULL;
	this->mutex_created = 0;
	this->modify_mutex_created = 0;
	this->modify_cond_created = 0;
	this->multicasts_count = 0;
	/* buf_get_next(data, int, CLIENT_T_VERSION); */
	buf_next(data, int, 1);
	buf_get_next(data, ssize_t, this->list_entry);
	buf_get_next(data, int, this->socket_fd);
	buf_get_next(data, int, this->open);
	buf_get_next(data, uint64_t, this->id);
	buf_get_next(data, size_t, n);
	if (n > 0)
		fail_if (mds_message_unmarshal(&(this->message), data));
	stage++;
	data += n / sizeof(char);
	rc += n;
	buf_get_next(data, size_t, this->interception_conditions_count);
	fail_if (xmalloc(this->interception_conditions, this->interception_conditions_count, interception_condition_t));
	for (i = 0; i < this->interception_conditions_count; i++) {
		n = interception_condition_unmarshal(this->interception_conditions + i, data);
		if (!n) {
			this->interception_conditions_count = i - 1;
			fail_if (1);
		}
		data += n / sizeof(char);
		rc += n;
	}
	buf_get_next(data, size_t, n);
	fail_if (xmalloc(this->multicasts, n, multicast_t));
	for (i = 0; i < n; i++, this->multicasts_count++) {
		m = multicast_unmarshal(this->multicasts + i, data);
		fail_if (!m);
		data += m / sizeof(char);
		rc += m;
	}
	buf_get_next(data, size_t, this->send_pending_size);
	if (this->send_pending_size > 0) {
		fail_if (xmemdup(this->send_pending, data, this->send_pending_size, char));
		data += this->send_pending_size, rc += this->send_pending_size * sizeof(char);
	}
	buf_get_next(data, size_t, n);
	if (n > 0)
		mds_message_unmarshal(this->modify_message, data);
	else
		this->modify_message = NULL;
	rc += n * sizeof(char);
	return rc;

fail:
	saved_errno = errno;
	if (!stage)
		goto done_failing;
	mds_message_destroy(&(this->message));
	for (i = 0; i < this->interception_conditions_count; i++)
		free(this->interception_conditions[i].condition);
	free(this->interception_conditions);
	for (i = 0; i < this->multicasts_count; i++)
		multicast_destroy(this->multicasts + i);
	free(this->multicasts);
	free(this->send_pending);
	if (this->modify_message) {
		mds_message_destroy(this->modify_message);
		free(this->modify_message);
	}
done_failing:
	return errno = saved_errno, (size_t)0;
}


/**
 * Pretend to unmarshal client information
 * 
 * @param   data  In buffer with the marshalled data
 * @return        The number of read bytes
 */
size_t
client_unmarshal_skip(char *restrict data)
{
	size_t n, c, rc = sizeof(ssize_t) + 3 * sizeof(int) + sizeof(uint64_t) + 5 * sizeof(size_t);
	buf_next(data, int, 1);
	buf_next(data, ssize_t, 1);
	buf_next(data, int, 2);
	buf_next(data, uint64_t, 1);
	buf_get_next(data, size_t, n);
	data += n / sizeof(char);
	rc += n;
	buf_get_next(data, size_t, c);
	while (c--) {
		n = interception_condition_unmarshal_skip(data);
		data += n / sizeof(char);
		rc += n;
	}
	buf_get_next(data, size_t, c);
	while (c--) {
		n = multicast_unmarshal_skip(data);
		data += n / sizeof(char);
		rc += n;
	}
	buf_get_next(data, size_t, n);
	data += n;
	rc += n * sizeof(char);
	buf_get_next(data, size_t, n);
	rc += n * sizeof(char);
	return rc;
}