/*
 * rtables.c
 * This file is part of Network-inador
 *
 * Copyright (C) 2025 - Félix Arreola Rodríguez
 *
 * Network-inador 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.
 *
 * Network-inador 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 Network-inador; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, 
 * Boston, MA  02110-1301  USA
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <stdint.h>
#include <unistd.h>
#include <sys/types.h>
#include <dirent.h>

#include <linux/rtnetlink.h>

#include <netlink/socket.h>
#include <netlink/msg.h>

#include "flist.h"
#include "network-inador-private.h"
#include "rtables.h"
#include "event_notify.h"
#include "file_watcher.h"

static int _routes_table_find_by_number (const void * left, const void * right) {
	RouteTable *a, *b;
	
	a = (RouteTable *) left;
	b = (RouteTable *) right;
	
	return a->table != b->table;
}

static void _routes_table_parse_file (NetworkInadorHandle *handle, FILE *fd) {
	FList *g;
	int ret;
	RouteTable *rtable, temp_table;
	char buffer[2048];
	
	while (fgets (buffer, sizeof (buffer), fd), feof (fd) == 0) {
		if (buffer[0] == '#') continue; /* Ignorar las lineas con comentarios */
		
		ret = sscanf (buffer, "%d %s", &(temp_table.table), temp_table.name);
		
		if (ret < 2) {
			continue;
		}
		
		if (temp_table.table == 0) continue; /* Omitir la tabla número 0 */
		
		g = f_list_find_custom (handle->route_tables_names, &temp_table, _routes_table_find_by_number);
		
		if (g != NULL) {
			/* El número de tabla ya existe, marcar y actualizar el nombre */
			rtable = (RouteTable *) g->data;
			
			printf ("Tabla ya existe en la lista ligada: %d\n", temp_table.table);
			rtable->for_delete = 0;
			rtable->was_new = 0;
		} else {
			printf ("Creando tabla en la lista ligada: %i, %s\n", temp_table.table, temp_table.name);
			/* No existe, crear nueva */
			rtable = (RouteTable *) malloc (sizeof (RouteTable));
			rtable->table = temp_table.table;
			rtable->for_delete = 0;
			rtable->was_new = 1;
			
			handle->route_tables_names = f_list_append (handle->route_tables_names, rtable);
			handle->rtables_counter++;
		}
		/* En cualquier caso actualizar el nombre */
		strncpy (rtable->name, temp_table.name, sizeof (rtable->name));
	}
}

static void routes_tables_read_all (NetworkInadorHandle *handle, int do_notify) {
	FILE *fd;
	FList *g, *h;
	RouteTable *rtable;
	DIR *dir;
	struct dirent *direntry;
	int len;
	char buffer[4096];
	
	g = handle->route_tables_names;
	while (g != NULL) {
		rtable = (RouteTable *) g->data;
		
		rtable->for_delete = 1;
		rtable->was_new = 0;
		g = g->next;
	}
	
	/* Intentar abrir /etc/iproute2/rt_tables */
	fd = fopen ("/etc/iproute2/rt_tables", "r");
	if (fd != NULL) {
		printf ("Parsing main rt_tables file\n");
		_routes_table_parse_file (handle, fd);
			
		fclose (fd);
	}
	
	/* Ahora leer todo el directorio /etc/iproute2/rt_tables.d/ y buscar archivos *.conf */
	dir = opendir ("/etc/iproute2/rt_tables.d");
	if (dir != NULL) {
		
		while (direntry = readdir (dir), direntry != NULL) {
			len = strlen (direntry->d_name);
			
			/* Buscar por archivos que terminen en .conf */
			if (len > 5 && strcmp (&(direntry->d_name[len - 5]), ".conf") == 0) {
				/* Intentar abrir este archivo y parsearlo */
				snprintf (buffer, sizeof (buffer), "/etc/iproute2/rt_tables.d/%s", direntry->d_name);
				printf ("Parsing %s secundary\n", buffer);
				fd = fopen (buffer, "r");
				
				if (fd != NULL) {
					_routes_table_parse_file (handle, fd);
			
					fclose (fd);
				}
			}
		}
		
		closedir (dir);
	}
	
	/* Ahora, todas las tablas que están marcadas para eliminar, eliminarlas */
	g = handle->route_tables_names;
	
	while (g != NULL) {
		h = g->next;
		
		rtable = (RouteTable *) g->data;
		
		if (rtable->for_delete) {
			handle->route_tables_names = f_list_delete_link (handle->route_tables_names, g);
			handle->rtables_counter--;
			
			if (do_notify) {
				network_manager_trigger_route_table_deleted_event (handle, rtable->table);
			}
			
			free (rtable);
		}
		
		g = h;
	}
	
	g = handle->route_tables_names;
	while (g != NULL) {
		rtable = (RouteTable *) g->data;
		
		if (rtable->was_new) {
			if (do_notify) {
				network_manager_trigger_route_table_added_event (handle, rtable->table, rtable->name);
			}
			rtable->was_new = 0;
		}
		
		g = g->next;
	}
}

static void rtables_notify_close_write_cb (NetworkInadorHandle *handle, const char *path, void *data) {
	/* Cuando se nos notifique acerca de un cambio en el /etc/iproute2/rt_tables re-leer el archivo */
	routes_tables_read_all (handle, TRUE);
}

static void rtables_notify_directory_close_write_cb (NetworkInadorHandle *handle, const char *path, void *data) {
	int path_len;
	
	path_len = strlen (path);
	
	if (path_len < 5) {
		/* Si ni siquiera tiene 5 letras ".conf", este archivo no nos interesa */
		return;
	}
	
	if (strcmp (&path[path_len - 5], ".conf") != 0) return;
	
	/* Cuando se nos notifique acerca de un cambio en el resolv.conf re-leer el archivo */
	routes_tables_read_all (handle, TRUE);
}

void rtables_init (NetworkInadorHandle *handle) {
	network_inador_file_watcher_add_file (handle, "/etc/iproute2/rt_tables", rtables_notify_close_write_cb, NULL);
	
	/* TODO: La vigilancia de directorios necesita vigilar eliminar archivos y archivos movidos */
	network_inador_file_watcher_add_file (handle, "/etc/iproute2/rt_tables.d/", rtables_notify_directory_close_write_cb, NULL);
	
	routes_tables_read_all (handle, FALSE);
}

void rtables_clean_up (NetworkInadorHandle *handle) {
	f_list_free_full (handle->route_tables_names, free);
	handle->route_tables_names = NULL;
	handle->rtables_counter = 0;
}