/*
    This file is part of actube.

    actube 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.

    libcapwap 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 Foobar.  If not, see <http://www.gnu.org/licenses/>.

*/

/**
 * @file 
 * @brief Functions for modules (mods) management.
 */

#include <string.h>
#include <errno.h>
#include <dlfcn.h>


#include "mavl.h"
#include "dbg.h"
#include "log.h"
#include "file.h"
#include "cw.h"
#include "msgset.h"

/*
static void (*actions_registered_cb) (struct cw_Mod * capwap, struct cw_Mod * bindings,
				      struct cw_actiondef * actions) = NULL;
*/



/*
void mod_set_actions_registered_cb(void (*fun)
				    (struct cw_Mod *, struct cw_Mod *,
				     struct cw_actiondef *))
{
	actions_registered_cb = fun;
}
*/

struct cache_item {
	const char *capwap;
	const char *bindings;
	struct cw_MsgSet *msgset;
};
static struct mavl *msgset_cache = NULL;

/*
static int mod_null_register_actions(struct cw_actiondef *def, int mode)
{
	return 0;
}
*/

/**
 * mod_null is a dummy mod 
 */
struct cw_Mod mod_null = {
	"none",			/* name */
	NULL,			/* init */
	NULL,			/* init_config */
	NULL,			/* detect */
	NULL			/* data */
};




static int cmp(const void *p1, const void *p2)
{
	struct cache_item *c1 = ((struct cache_item **) p1)[0];
	struct cache_item *c2 = ((struct cache_item **) p2)[0];

	int r;
	r = strcmp(c1->capwap, c2->capwap);
	if (r != 0)
		return r;

	return strcmp(c1->bindings, c2->bindings);
}

struct cw_actiondef *mod_cache_get(const char *capwap, const char *bindings)
{
	return NULL;
}


struct cw_MsgSet *cw_mod_get_msg_set(struct conn *conn,
				     struct cw_Mod *capwap_mod,
				     struct cw_Mod *bindings_mod)
{
	struct cache_item search;
	struct cache_item *cached_set;
	struct cw_MsgSet *set;

	if (!msgset_cache) {
		msgset_cache = mavl_create(cmp, NULL, 1312);
		if (!msgset_cache) {
			cw_log(LOG_ERR, "Can't initialize msgset cache: %s",
			       strerror(errno));
			return NULL;
		}
	}


	search.capwap = capwap_mod->name;
	search.bindings = bindings_mod->name;

	cached_set = mavl_get_ptr(msgset_cache, &search);
	if (cached_set) {
		cw_dbg(DBG_INFO, "Using cached message set for %s,%s", capwap_mod->name,
		       bindings_mod->name);
		return cached_set->msgset;
	}


	cached_set = malloc(sizeof(struct cache_item));
	if (!cached_set) {
		cw_log(LOG_ERR, "Can't allocate memory for mod cache item %s",
		       strerror(errno));
		return NULL;
	}
	memset(cached_set, 0, sizeof(struct cache_item));

	set = cw_msgset_create();
	if (!set) {
		free(cached_set);
		cw_log(LOG_ERR, "Can't allocate memory for mod cache item %s",
		       strerror(errno));
		return NULL;
	}
	cached_set->msgset = set;



	cw_dbg(DBG_INFO, "Loading message set for %s,%s", capwap_mod->name,
	       bindings_mod->name);


	cached_set->capwap = capwap_mod->name;
	cached_set->bindings = bindings_mod->name;
	
	if (capwap_mod != MOD_NULL) {

		capwap_mod->register_messages(cached_set->msgset, CW_MOD_MODE_CAPWAP);
	}
	if (bindings_mod != MOD_NULL) {

		bindings_mod->register_messages(cached_set->msgset, CW_MOD_MODE_BINDINGS);
	}
/*
//	if (actions_registered_cb)
//		actions_registered_cb(capwap_mod, bindings_mod, &(cached_set->actions));
*/
	mavl_add_ptr(msgset_cache, cached_set);
	return cached_set->msgset;
}



/* static mavl to store modules */
static struct mavl *mods_loaded = NULL;
static int mod_cmp_mavl(const void *e1, const void *e2)
{
	const struct cw_Mod *m1 = *((const struct cw_Mod **) e1);
	const struct cw_Mod *m2 = *((const struct cw_Mod **) e2);
	return strcmp(m1->name, m2->name);
}

static int mod_cmp_mlist(const void *e1, const void *e2)
{
	const struct cw_Mod *m1 = e1;
	const struct cw_Mod *m2 = e2;
	return strcmp(m1->name, m2->name);
}



static const char *mod_path = "";

/**
 * @brief Set module path, where to search for modules
 * @param path Path to search
 */
void cw_mod_set_path(const char *path)
{
	mod_path = path;
}

/**
 * @brief Load a module 
 * @param mod_name Name of the module
 * @return a pointer to the module interface
 */
struct cw_Mod *cw_mod_load(const char *mod_name, mavl_t global_cfg, int role)
{
	struct cw_Mod search;
	struct cw_Mod *mod;
	char mod_filename[CW_MOD_MAX_MOD_NAME_LEN + 5];
	char *filename;
	void *handle;

	/* if modlist is not initialized, initialize ... */
	if (mods_loaded == NULL) {
		mods_loaded = mavl_create(mod_cmp_mavl, NULL, 1312);
		if (mods_loaded == NULL) {
			cw_log(LOG_ERROR, "Can't init modlist, no memory");
			return NULL;
		}
	}

	/* Search for the module in mods_loaded, to see if it is
	 * already loaded or was statically linked */

	cw_dbg(DBG_MOD, "MOD: Load module '%s'", mod_name);

	memset(&search, 0, sizeof(search));
	search.name = mod_name;

	mod = mavl_find_ptr(mods_loaded, &search);
	if (mod) {
		cw_dbg(DBG_MOD, "MOD: Module already loaded '%s'", mod_name);
		return mod;
	}

	if (strlen(mod_name) > CW_MOD_MAX_MOD_NAME_LEN) {
		cw_log(LOG_ERROR, "Mod name too long: %s (max allowed = %d)",
		       mod_name, CW_MOD_MAX_MOD_NAME_LEN);
		return NULL;
	}


	sprintf(mod_filename, "mod_%s", mod_name);

	/* we have to load the module dynamically */

	filename = cw_filename(mod_path, mod_filename, ".so");
	if (filename == NULL)
		return NULL;

	cw_dbg(DBG_MOD, "MOD: loading module from file: %s", filename);

	/* Open the DLL */
	handle = dlopen(filename, RTLD_NOW);

	if (!handle) {
		cw_log(LOG_ERROR, "Failed to load module: %s", dlerror());
		goto errX;
	}

	mod = dlsym(handle, mod_filename);
	if (mod == NULL) {
		cw_log(LOG_ERROR, "Failed to load module: %s", dlerror());
		goto errX;
	}

	mod->dll_handle = handle;

	if (!mavl_add_ptr(mods_loaded, mod)) {
		dlclose(handle);
		cw_log(LOG_ERR, "Can' add module %s", mod_name);
		goto errX;
	}
	cw_dbg(DBG_MOD, "MOD: %s sucessfull loaded, calling init now.", filename);
	mod->init(mod, global_cfg, role);
      errX:
	free(filename);
	return mod;
}


static struct mlist *mods_list = NULL;

struct cw_Mod *cw_mod_add_to_list(struct cw_Mod *mod)
{
	mlistelem_t *elem;
	if (!mods_list) {
		mods_list = mlist_create(mod_cmp_mlist, NULL, sizeof(struct cw_Mod *));
		if (!mods_list) {
			cw_log(LOG_ERROR, "Can't init mods_list");
			return 0;
		}
	}

	elem = mlist_append(mods_list, &mod);
	if (elem == NULL)
		return NULL;
	return mlistelem_dataptr(elem);
}

struct cw_Mod *cw_mod_detect(struct conn *conn,
			     uint8_t * rawmsg, int len,
			     int elems_len, struct sockaddr *from, int mode)
{

	struct mlistelem *e;

	if (mods_list == NULL)
		return MOD_NULL;


	mlist_foreach(e, mods_list) {

		struct cw_Mod *mod = *(struct cw_Mod **) (mlistelem_dataptr(e));	/* = e->data; */
		cw_dbg(DBG_MOD, "Checking mod: %s", mod->name);

		/* if there is no detect method, skip */
		if (!mod->detect)
			continue;

		if (mod->detect(conn, rawmsg, len, elems_len, from, mode)) {
			return mod;
		}
	}
	return MOD_NULL;
}