/*
 * This file is part of the Distributed Network Block Device 3
 *
 * Copyright(c) 2011-2012 Johann Latocha <johann@latocha.de>
 *
 * This file may be licensed under the terms of of the
 * GNU General Public License Version 2 (the ``GPL'').
 *
 * Software distributed under the License is distributed
 * on an ``AS IS'' basis, WITHOUT WARRANTY OF ANY KIND, either
 * express or implied. See the GPL for the specific language
 * governing rights and limitations.
 *
 * You should have received a copy of the GPL along with this
 * program. If not, go to http://www.gnu.org/licenses/gpl.html
 * or write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */

#include <stdlib.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <pthread.h>
#include <string.h>

#include "server.h"
#include "utils.h"

void dnbd3_load_config(char *file)
{
    int fd;
    gint i;
    GKeyFile* gkf;

    gkf = g_key_file_new();
    if (!g_key_file_load_from_file(gkf, file, G_KEY_FILE_NONE, NULL))
    {
        printf("ERROR: Config file not found: %s\n", file);
        exit(EXIT_FAILURE);
    }

    gchar **groups = NULL;
    groups = g_key_file_get_groups(gkf, &_num_images);
    _images = calloc(_num_images, sizeof(dnbd3_image_t));

    for (i = 0; i < _num_images; i++)
    {
    	_images[i].group = malloc(strlen(groups[i]));
    	strcpy(_images[i].group, groups[i]);
        _images[i].file = g_key_file_get_string(gkf, groups[i], "file", NULL);
        _images[i].servers = g_key_file_get_string_list(gkf, groups[i], "servers", &_images[i].num_servers, NULL);
        _images[i].serverss = g_key_file_get_string(gkf, groups[i], "servers", NULL);
        _images[i].vid = g_key_file_get_integer(gkf, groups[i], "vid", NULL);
        _images[i].rid = g_key_file_get_integer(gkf, groups[i], "rid", NULL);
        _images[i].cache_file = g_key_file_get_string(gkf, groups[i], "cache", NULL);
        _images[i].atime = 0;

        if (_images[i].num_servers > NUMBER_SERVERS)
            printf("WARN: Max allowed servers %i\n", NUMBER_SERVERS);

        fd = open(_images[i].file, O_RDONLY);
        if (fd > 0)
            _images[i].filesize = lseek(fd, 0, SEEK_END);
        else
            printf("ERROR: Image file not found: %s\n", _images[i].file);

        close(fd);

        if (_images[i].cache_file)
        {
            // read cache map from file
            _images[i].cache_map  = calloc(_images[i].filesize >> 15, sizeof(char));
            memset(_images[i].cache_map, 0, (_images[i].filesize >> 15) * sizeof(char));
            char tmp[strlen(_images[i].cache_file)+4];
            strcpy(tmp, _images[i].cache_file);
            strcat(tmp, ".map");
            fd = open(tmp, O_RDONLY);
            if (fd > 0)
                read(fd, _images[i].cache_map, (_images[i].filesize >> 15) * sizeof(char));
            close(fd);

            // open cache file
            fd = open(_images[i].cache_file, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
            if (fd < 1)
                printf("ERROR: Could't create cache file\n");

            if (_images[i].filesize != lseek(fd, 0, SEEK_END))
                fallocate(fd, 0, 0, _images[i].filesize);

            close(fd);
        }
    }

    g_strfreev(groups);
    g_key_file_free(gkf);
}

void dnbd3_reload_config(char* config_file_name)
{
    int i, fd;
    pthread_spin_lock(&_spinlock);
    GSList *iterator = NULL;
    for (iterator = _dnbd3_clients; iterator; iterator = iterator->next)
    {
        dnbd3_client_t *client = iterator->data;
        pthread_spin_lock(&client->spinlock);
        client->image = NULL;
    }

    for (i = 0; i < _num_images; i++)
    {
    	// save cache maps
        if (_images[i].cache_file)
        {
            char tmp[strlen(_images[i].cache_file)+4];
            strcpy(tmp, _images[i].cache_file);
            strcat(tmp, ".map");
            fd = open(tmp, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);

            if (fd > 0)
                write(fd, _images[i].cache_map,  (_images[i].filesize >> 15) * sizeof(char));

            close(fd);
        }

        free(_images[i].group);
        free(_images[i].file);
        free(_images[i].servers);
        free(_images[i].serverss);
        free(_images[i].cache_file);
        free(_images[i].cache_map);
    }

    _num_images = 0;
    free(_images);
    dnbd3_load_config(config_file_name);
    for (iterator = _dnbd3_clients; iterator; iterator = iterator->next)
    {
        dnbd3_client_t *client = iterator->data;
        pthread_spin_unlock(&client->spinlock);
    }
    pthread_spin_unlock(&_spinlock);
}

int dnbd3_add_image(dnbd3_image_t *image, char *file)
{
	FILE* f = fopen(image->file,"r");
	if (f == NULL)
	{
		printf("ERROR: Image file not found: %s\n", image->file);
		return ERROR_FILE_NOT_FOUND;
	}
	fclose (f);

	dnbd3_image_t* tmp = dnbd3_get_image(image->vid, image->rid);
	if (image->rid == 0)
	{
		if(tmp)
			image->rid = tmp->rid +1;
		else
			image->rid = 1;
	} else if (tmp)
	{
		printf("ERROR: Image already exists (%d,%d)\n", image->vid, image->rid);
		return ERROR_IMAGE_ALREADY_EXISTS;
	}

    GKeyFile* gkf;
    gkf = g_key_file_new();
    if (!g_key_file_load_from_file(gkf, file, G_KEY_FILE_NONE, NULL))
    {
        printf("ERROR: Config file not found: %s\n", file);
        exit(EXIT_FAILURE);
    }

    g_key_file_set_integer(gkf, image->group, "vid", image->vid);
    g_key_file_set_integer(gkf, image->group, "rid", image->rid);
    g_key_file_set_string(gkf, image->group, "file", image->file);
    g_key_file_set_string(gkf, image->group, "servers", image->serverss);
    g_key_file_set_string(gkf, image->group, "cache", image->cache_file);

    gchar* data = g_key_file_to_data(gkf, NULL, NULL);

    f = fopen(file,"w");
    if (f)
    {
    	fputs((char*) data, f);
    	fclose(f);
        g_free(data);
        g_key_file_free(gkf);
        return 0;
    }
    else
    {
    	g_free(data);
    	g_key_file_free(gkf);
    	printf("ERROR: Config file is not writable: %s\n", file);
    	return ERROR_CONFIG_FILE_PERMISSIONS;
    }
}

int dnbd3_del_image(dnbd3_image_t *image, char *file)
{
	if (image->rid == 0)
	{
        printf("ERROR: Delete with rid=0 is not allowed\n");
        return ERROR_RID;
	}

	dnbd3_image_t* tmp = dnbd3_get_image(image->vid, image->rid);
	if (!tmp)
	{
        printf("ERROR: Image not found: (%d,%d)\n", image->vid, image->rid);
        return ERROR_IMAGE_NOT_FOUND;
	}

	GSList *iterator = NULL;
    for (iterator = _dnbd3_clients; iterator; iterator = iterator->next)
    {
        dnbd3_client_t *client = iterator->data;
        if (tmp == client->image)
        {
        	printf("ERROR: Delete is not allowed, image is in use (%d,%d)\n", tmp->vid, tmp->rid);
        	return ERROR_IMAGE_IN_USE;
        }
    }

    GKeyFile* gkf;
    gkf = g_key_file_new();
    if (!g_key_file_load_from_file(gkf, file, G_KEY_FILE_NONE, NULL))
    {
        printf("ERROR: Config file not found: %s\n", file);
        exit(EXIT_FAILURE);
    }

    g_key_file_remove_group(gkf, tmp->group, NULL);
    gchar* data = g_key_file_to_data(gkf, NULL, NULL);

    FILE* f = fopen(file,"w");
    if (f)
    {
    	fputs((char*) data, f);
    	fclose(f);
        g_free(data);
        g_key_file_free(gkf);
        // TODO: unlink image file
        return 0;
    }
    else
    {
    	g_free(data);
    	g_key_file_free(gkf);
    	printf("ERROR: Config file is not writable: %s\n", file);
    	return ERROR_CONFIG_FILE_PERMISSIONS;
    }
}

dnbd3_image_t* dnbd3_get_image(int vid, int rid)
{
    int i, max = 0;
    dnbd3_image_t *result = NULL;
    for (i = 0; i < _num_images; ++i)
    {
        if (rid != 0) // rid was specified
        {
            if (_images[i].vid == vid && _images[i].rid == rid)
                result = &_images[i];
        }
        else // search max. rid available
        {
            if (_images[i].vid == vid && _images[i].rid > max)
            {
                result = &_images[i];
                max = _images[i].rid;
            }
        }
    }
    return result;
}

void dnbd3_handle_sigpipe(int signum)
{
    printf("ERROR: SIGPIPE received!\n");
}

void dnbd3_handle_sigterm(int signum)
{
    printf("INFO: SIGTERM or SIGINT received!\n");
    dnbd3_cleanup();
}