/*
 * Copyright (C) 2008 Martin Willi
 * Hochschule fuer Technik Rapperswil
 *
 * 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 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * 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.
 *
 * $Id$
 */

#include "attribute_manager.h"

#include <daemon.h>
#include <utils/linked_list.h>
#include <utils/mutex.h>

typedef struct private_attribute_manager_t private_attribute_manager_t;

/**
 * private data of attribute_manager
 */
struct private_attribute_manager_t {

	/**
	 * public functions
	 */
	attribute_manager_t public;
	
	/**
	 * list of registered providers
	 */
	linked_list_t *providers;
	
	/**
	 * list of registered handlers
	 */
	linked_list_t *handlers;
	
	/**
	 * rwlock provider list
	 */
	rwlock_t *lock;
};

/**
 * Implementation of attribute_manager_t.acquire_address.
 */
static host_t* acquire_address(private_attribute_manager_t *this,
							   char *pool, identification_t *id,
							   host_t *requested)
{
	enumerator_t *enumerator;
	attribute_provider_t *current;
	host_t *host = NULL;
	
	this->lock->read_lock(this->lock);
	enumerator = this->providers->create_enumerator(this->providers);
	while (enumerator->enumerate(enumerator, &current))
	{
		host = current->acquire_address(current, pool, id, requested);
		if (host)
		{
			break;
		}
	}
	enumerator->destroy(enumerator);
	this->lock->unlock(this->lock);
	
	if (!host)
	{
		DBG1(DBG_CFG, "acquiring address from pool '%s' failed", pool);
	}
	return host;
}

/**
 * Implementation of attribute_manager_t.release_address.
 */
static void release_address(private_attribute_manager_t *this,
							char *pool, host_t *address, identification_t *id)
{
	enumerator_t *enumerator;
	attribute_provider_t *current;
	bool found = FALSE;
	
	this->lock->read_lock(this->lock);
	enumerator = this->providers->create_enumerator(this->providers);
	while (enumerator->enumerate(enumerator, &current))
	{
		if (current->release_address(current, pool, address, id))
		{
			found = TRUE;
			break;
		}
	}
	enumerator->destroy(enumerator);
	this->lock->unlock(this->lock);
	
	if (!found)
	{
		DBG1(DBG_CFG, "releasing address to pool '%s' failed", pool);
	}
}

/**
 * inner enumerator constructor for attributes
 */
static enumerator_t *attrib_enum_create(attribute_provider_t *provider,
										identification_t *id)
{
	return provider->create_attribute_enumerator(provider, id);
}

/**
 * Implementation of attribute_manager_t.create_attribute_enumerator
 */
static enumerator_t* create_attribute_enumerator(
						private_attribute_manager_t *this, identification_t *id)
{
	this->lock->read_lock(this->lock);
	return enumerator_create_cleaner(
				enumerator_create_nested(
					this->providers->create_enumerator(this->providers),
					(void*)attrib_enum_create, id, NULL),
				(void*)this->lock->unlock, this->lock);
}

/**
 * Implementation of attribute_manager_t.add_provider.
 */
static void add_provider(private_attribute_manager_t *this,
						 attribute_provider_t *provider)
{
	this->lock->write_lock(this->lock);
	this->providers->insert_last(this->providers, provider);
	this->lock->unlock(this->lock);
}

/**
 * Implementation of attribute_manager_t.remove_provider.
 */
static void remove_provider(private_attribute_manager_t *this,
							attribute_provider_t *provider)
{
	this->lock->write_lock(this->lock);
	this->providers->remove(this->providers, provider, NULL);
	this->lock->unlock(this->lock);
}

/**
 * Implementation of attribute_manager_t.handle
 */
static attribute_handler_t* handle(private_attribute_manager_t *this,
						ike_sa_t *ike_sa, configuration_attribute_type_t type,
						chunk_t data)
{
	enumerator_t *enumerator;
	attribute_handler_t *current, *handled = NULL;
	
	this->lock->read_lock(this->lock);
	enumerator = this->handlers->create_enumerator(this->handlers);
	while (enumerator->enumerate(enumerator, &current))
	{
		if (current->handle(current, ike_sa, type, data))
		{
			handled = current;
			break;
		}
	}
	enumerator->destroy(enumerator);
	this->lock->unlock(this->lock);
	
	if (!handled)
	{
		DBG1(DBG_CFG, "handling %N attribute failed",
			 configuration_attribute_type_names, type);
	}
	return handled;
}

/**
 * Implementation of attribute_manager_t.release
 */
static void release(private_attribute_manager_t *this,
						attribute_handler_t *handler, ike_sa_t *ike_sa,
						configuration_attribute_type_t type, chunk_t data)
{
	enumerator_t *enumerator;
	attribute_handler_t *current;
	
	this->lock->read_lock(this->lock);
	enumerator = this->handlers->create_enumerator(this->handlers);
	while (enumerator->enumerate(enumerator, &current))
	{
		if (current == handler)
		{
			current->release(current, ike_sa, type, data);
			break;
		}
	}
	enumerator->destroy(enumerator);
	this->lock->unlock(this->lock);
}

/**
 * Implementation of attribute_manager_t.add_handler
 */
static void add_handler(private_attribute_manager_t *this,
						attribute_handler_t *handler)
{
	this->lock->write_lock(this->lock);
	this->handlers->insert_last(this->handlers, handler);
	this->lock->unlock(this->lock);
}

/**
 * Implementation of attribute_manager_t.remove_handler
 */
static void remove_handler(private_attribute_manager_t *this,
						attribute_handler_t *handler)
{
	this->lock->write_lock(this->lock);
	this->handlers->remove(this->handlers, handler, NULL);
	this->lock->unlock(this->lock);
}

/**
 * Implementation of attribute_manager_t.destroy
 */
static void destroy(private_attribute_manager_t *this)
{
	this->providers->destroy(this->providers);
	this->handlers->destroy(this->handlers);
	this->lock->destroy(this->lock);
	free(this);
}

/*
 * see header file
 */
attribute_manager_t *attribute_manager_create()
{
	private_attribute_manager_t *this = malloc_thing(private_attribute_manager_t);
	
	this->public.acquire_address = (host_t*(*)(attribute_manager_t*, char*, identification_t*,host_t*))acquire_address;
	this->public.release_address = (void(*)(attribute_manager_t*, char *, host_t*, identification_t*))release_address;
	this->public.create_attribute_enumerator = (enumerator_t*(*)(attribute_manager_t*, identification_t *id))create_attribute_enumerator;
	this->public.add_provider = (void(*)(attribute_manager_t*, attribute_provider_t *provider))add_provider;
	this->public.remove_provider = (void(*)(attribute_manager_t*, attribute_provider_t *provider))remove_provider;
	this->public.handle = (attribute_handler_t*(*)(attribute_manager_t*, ike_sa_t *ike_sa, configuration_attribute_type_t type, chunk_t data))handle;
	this->public.release = (void(*)(attribute_manager_t*, attribute_handler_t *handler, ike_sa_t *ike_sa, configuration_attribute_type_t type, chunk_t data))release;
	this->public.add_handler = (void(*)(attribute_manager_t*, attribute_handler_t *handler))add_handler;
	this->public.remove_handler = (void(*)(attribute_manager_t*, attribute_handler_t *handler))remove_handler;
	this->public.destroy = (void(*)(attribute_manager_t*))destroy;
	
	this->providers = linked_list_create();
	this->handlers = linked_list_create();
	this->lock = rwlock_create(RWLOCK_DEFAULT);
	
	return &this->public;
}