/*
 * Copyright (c) 2012 Vojtech Horky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup remcons
 * @{
 */
/** @file
 */
#include <async.h>
#include <stdio.h>
#include <adt/prodcons.h>
#include <ipc/input.h>
#include <ipc/console.h>
#include <ipc/vfs.h>
#include <errno.h>
#include <str_error.h>
#include <loc.h>
#include <event.h>
#include <io/keycode.h>
#include <align.h>
#include <malloc.h>
#include <as.h>
#include <fibril_synch.h>
#include <task.h>
#include <net/in.h>
#include <net/inet.h>
#include <net/socket.h>
#include <io/console.h>
#include <inttypes.h>
#include <assert.h>
#include "user.h"

static FIBRIL_MUTEX_INITIALIZE(users_guard);
static LIST_INITIALIZE(users);

/** Create new telnet user.
 *
 * @param socket Socket the user communicates through.
 * @return New telnet user or NULL when out of memory.
 */
telnet_user_t *telnet_user_create(int socket)
{
	static int telnet_user_id_counter = 0;

	telnet_user_t *user = malloc(sizeof(telnet_user_t));
	if (user == NULL) {
		return NULL;
	}

	user->id = ++telnet_user_id_counter;

	int rc = asprintf(&user->service_name, "%s/telnet%d", NAMESPACE, user->id);
	if (rc < 0) {
		free(user);
		return NULL;
	}

	user->socket = socket;
	user->service_id = (service_id_t) -1;
	prodcons_initialize(&user->in_events);
	link_initialize(&user->link);
	user->socket_buffer_len = 0;
	user->socket_buffer_pos = 0;

	fibril_condvar_initialize(&user->refcount_cv);
	fibril_mutex_initialize(&user->guard);
	user->task_finished = false;
	user->socket_closed = false;
	user->locsrv_connection_count = 0;


	fibril_mutex_lock(&users_guard);
	list_append(&user->link, &users);
	fibril_mutex_unlock(&users_guard);

	return user;
}

/** Destroy telnet user structure.
 *
 * @param user User to be destroyed.
 */
void telnet_user_destroy(telnet_user_t *user)
{
	assert(user);

	fibril_mutex_lock(&users_guard);
	list_remove(&user->link);
	fibril_mutex_unlock(&users_guard);

	free(user);
}

/** Find user by service id and increments reference counter.
 *
 * @param id Location service id of the telnet user's terminal.
 */
telnet_user_t *telnet_user_get_for_client_connection(service_id_t id)
{
	telnet_user_t *user = NULL;

	fibril_mutex_lock(&users_guard);
	list_foreach(users, link) {
		telnet_user_t *tmp = list_get_instance(link, telnet_user_t, link);
		if (tmp->service_id == id) {
			user = tmp;
			break;
		}
	}
	if (user == NULL) {
		fibril_mutex_unlock(&users_guard);
		return NULL;
	}

	telnet_user_t *tmp = user;
	fibril_mutex_lock(&tmp->guard);
	user->locsrv_connection_count++;

	/*
	 * Refuse to return user whose task already finished or when
	 * the socket is already closed().
	 */
	if (user->task_finished || user->socket_closed) {
		user = NULL;
		user->locsrv_connection_count--;
	}

	fibril_mutex_unlock(&tmp->guard);


	fibril_mutex_unlock(&users_guard);

	return user;
}

/** Notify that client disconnected from the remote terminal.
 *
 * @param user To which user the client was connected.
 */
void telnet_user_notify_client_disconnected(telnet_user_t *user)
{
	fibril_mutex_lock(&user->guard);
	assert(user->locsrv_connection_count > 0);
	user->locsrv_connection_count--;
	fibril_condvar_signal(&user->refcount_cv);
	fibril_mutex_unlock(&user->guard);
}

/** Tell whether the launched task already exited and socket is already closed.
 *
 * @param user Telnet user in question.
 */
bool telnet_user_is_zombie(telnet_user_t *user)
{
	fibril_mutex_lock(&user->guard);
	bool zombie = user->socket_closed || user->task_finished;
	fibril_mutex_unlock(&user->guard);

	return zombie;
}

/** Receive next byte from a socket (use buffering.
 * We need to return the value via extra argument because the read byte
 * might be negative.
 */
static int telnet_user_recv_next_byte_no_lock(telnet_user_t *user, char *byte)
{
	/* No more buffered data? */
	if (user->socket_buffer_len <= user->socket_buffer_pos) {
		int recv_length = recv(user->socket, user->socket_buffer, BUFFER_SIZE, 0);
		if ((recv_length == 0) || (recv_length == ENOTCONN)) {
			user->socket_closed = true;
			return ENOENT;
		}
		if (recv_length < 0) {
			return recv_length;
		}
		user->socket_buffer_len = recv_length;
		user->socket_buffer_pos = 0;
	}

	*byte = user->socket_buffer[user->socket_buffer_pos++];

	return EOK;
}

/** Creates new keyboard event from given char.
 *
 * @param type Event type (press / release).
 * @param c Pressed character.
 */
static kbd_event_t* new_kbd_event(kbd_event_type_t type, wchar_t c) {
	kbd_event_t *event = malloc(sizeof(kbd_event_t));
	assert(event);

	link_initialize(&event->link);
	event->type = type;
	event->c = c;
	event->mods = 0;
	event->key = (c == '\n' ? KC_ENTER : KC_A);

	return event;
}

int telnet_user_get_next_keyboard_event(telnet_user_t *user, kbd_event_t *event)
{
	fibril_mutex_lock(&user->guard);
	if (list_empty(&user->in_events.list)) {
		char next_byte = 0;
		/* Skip zeros, bail-out on error. */
		while (next_byte == 0) {
			int rc = telnet_user_recv_next_byte_no_lock(user, &next_byte);
			DEBUG("Got %d.\n", next_byte);
			if (rc != EOK) {
				fibril_mutex_unlock(&user->guard);
				return rc;
			}
		}

		/* CR-LF conversions. */
		if (next_byte == 13) {
			next_byte = 10;
		}

		kbd_event_t *down = new_kbd_event(KEY_PRESS, next_byte);
		kbd_event_t *up = new_kbd_event(KEY_RELEASE, next_byte);
		assert(down);
		assert(up);
		prodcons_produce(&user->in_events, &down->link);
		prodcons_produce(&user->in_events, &up->link);
	}

	link_t *link = prodcons_consume(&user->in_events);
	kbd_event_t *tmp = list_get_instance(link, kbd_event_t, link);

	fibril_mutex_unlock(&user->guard);

	*event = *tmp;

	free(tmp);

	return EOK;
}

/**
 * @}
 */