/** @file
 * @brief The updater class implementation. This class implements the updater logic.
 *
 *
 *
 * @copyright Intra2net AG
 * @license GPLv2
*/

#include "updater.hpp"

#include "serviceholder.hpp"


#include <boost/foreach.hpp>
#include <boost/serialization/export.hpp>


using namespace std;


/// Server error threshold: When the host IP is not current, the DNS TTL expired
/// and we already sent an update.
const int ServerErrorTTLExpiredThreshold = 15 * 60;


/**
 * Default constructor which initializes the member Conf.
 */
Updater::Updater()
    : IPAddrHelp(new IPAddrHelper)
{
    // Initialize program wide Logger, at this point we don't know where to log and with which loglevel.
    Log = Logger::Ptr(new Logger);

    // initialize Serviceholder
    ServiceHolder = Serviceholder::Ptr(new Serviceholder(Log));

    // initialize Config
    Conf = Config::Ptr(new Config(Log,ServiceHolder));
}


/**
 * Default destructor.
 */
Updater::~Updater()
{
}



/**
 * Load config and initialize helper classes.
 * @param argc Number of arguments in array
 * @param argv Array with cmd options
 */
int Updater::load_config(int argc, char *argv[])
{
    // load the cmd options
    if ( init_config_from_cmd(argc,argv) != 0 )
        return -1;

    // load the config and service files
    if ( init_config_from_files() != 0 )
        return -1;

    // init all helper classes
    if ( init_helper_classes() != 0 )
        return -1;

    return 0;
}


/**
 * Reloading the config. Delete all Service objects and then init new Service objects from config files.
 */
int Updater::reload_config()
{
    // serialize all service objects
    if ( ServiceHolder->serialize_services() != 0 )
        return -1;

    // delete all service objects
    ServiceHolder->delete_services();

    // delete the actual Variables_map, perhaps with old cmd options which would overwrite new config file options.
    Conf->delete_variables_map();

    // clear the external send messages.
    Log->clear_external_send_messages();

    // load only config files
    if ( init_config_from_files() != 0 )
        return -1;

    // init all helper classes
    if ( init_helper_classes() != 0 )
        return -1;

    return 0;
}


/**
 * Parse the command line arguments and initialize corresponding options.
 * @param argc Number command line arguments.
 * @param argv[] Array with arguments.
 * @return 0 if cmd options successfully parsed, 1 if usage or version.
 */
int Updater::init_config_from_cmd(int argc, char *argv[]) const
{
    // Load the command line parameters
    if( Conf->parse_cmd_line( argc, argv) != 0)
        return -1;

    // If we have loaded the cmd options we need to init the log facility immediately in case debugging is enabled from cmd.
    init_log_facility();

    // successful parsed
    Log->print_cmd_parsed();
    return 0;
}


/**
 * Load the main config and the service definition files in config path.
 * @return 0 if all is fine,
 */
int Updater::init_config_from_files() const
{
    // Load the main and service config files in config path
    if ( Conf->load_config_from_files() != 0 )
        return -1;

    // Re-init log facility, perhaps new config file options for logger are set.
    // These config file options will only overwrite the cmd options if the SIGHUP (reload config) is caught.
    init_log_facility();

    // Here we are. All Service Objects should be initialized, so it is time to deserialize the old service objects and compare them.
    if ( ServiceHolder->deserialize_services() != 0 )
        return -1;

    // successful loaded
    Log->print_conf_files_parsed();
    return 0;
}


/**
 * Init all Helper classes
 * @return
 */
int Updater::init_helper_classes()
{
    // Initialize IPHelper
    if ( init_ip_helper() != 0 )
        return -1;

    return 0;
}


/**
 * Init the IPHelp member with needed values.
 * @return 0 if all is fine, -1 otherwise.
 */
int Updater::init_ip_helper()
{
    // Try to get deserialized IPAddrHelper from ServiceHolder
    IPAddrHelper::Ptr _ip_addr_help = ServiceHolder->get_ip_addr_helper();
    if ( _ip_addr_help.use_count() != 0 )
    {
        // Initialize IPHelper
        IPAddrHelp = IPAddrHelper::Ptr( new IPAddrHelper( Log, Conf->get_webcheck_ip_url(), Conf->get_webcheck_ip_url_alt(), Conf->get_webcheck_interval(), _ip_addr_help->get_last_webcheck(), Conf->get_enable_ipv6(), Conf->get_proxy(), Conf->get_proxy_port() ) );
    }
    else
    {
        // IPAddrHelper from ServiceHolder was not declared, so init oen with LastWebcheck 0
        IPAddrHelp = IPAddrHelper::Ptr( new IPAddrHelper( Log, Conf->get_webcheck_ip_url(), Conf->get_webcheck_ip_url_alt(), Conf->get_webcheck_interval(), (size_t)0, Conf->get_enable_ipv6(), Conf->get_proxy(), Conf->get_proxy_port() ) );
    }

    // Put the IPAddrHelper into ServiceHolder, so the LastWebcheck state will be serialized too.
    ServiceHolder->set_ip_addr_helper(IPAddrHelp);

    return 0;
}


/**
 * Getter for member Config.
 * @return Member Config.
 */
Config::Ptr Updater::get_config() const
{
    return Conf;
}


/**
 * Getter for member Logger.
 * @return Member Logger.
 */
Logger::Ptr Updater::get_logger() const
{
    return Log;
}


/**
 * Initialize the logging facility with loglevel and syslog.
 */
void Updater::init_log_facility() const
{
    Log->set_log_facility(Conf->get_loglevel(),Conf->get_syslog(),Conf->get_external_warning_log(),Conf->get_external_warning_level(),Conf->get_external_log_only_once());
    Log->print_init_log_facility();

    Log->set_log_passwords(Conf->get_log_passwords());
}


/**
 * Update all configured services.
 * @param changed_to_online True if we just changed to online, false if we were already online
 */
void Updater::update_services(bool changed_to_online) const
{
    // Get all services from the ServiceHolder.
    list<Service::Ptr> services = ServiceHolder->get_services();

    // Get the actual IP of this host.
    string ip_host = IPAddrHelp->get_actual_ip(Conf->get_webcheck_enabled(), changed_to_online, Conf->get_wan_ip_override());
    if ( ip_host.empty() )
    {
        Log->print_no_wan_ip(changed_to_online);
        return;
    } else
    {
        Log->print_external_wan_ip(changed_to_online, ip_host);
    }

    BOOST_FOREACH(Service::Ptr &service, services )
    {
        string ip_last_update = service->get_actual_ip();
        string hostname = service->get_hostname();
        time_t current_time = time(NULL);

        // Get the last update time of the service.
        time_t lastupdated = service->get_last_update_time();

        Log->print_check_service_update(hostname, current_time, lastupdated);

        // Do a DNS Query for the dynamic hostname.
        string ip_dns_recheck = IPAddrHelp->dns_query(hostname);

        Log->print_cached_dns_entry(hostname, ip_dns_recheck, ip_last_update, ip_host);

        // Test if the DNS-Record could not be found.
        // If DNS-Record was not found but service was not activated, the hostname could be deactivated, offline or not existent. In this case try a ordinary update.
        if ( ip_dns_recheck.empty() && service->get_activated() )
        {
            Log->print_dns_lookup_failed(changed_to_online, hostname);
            continue;
        }

        // Test if the actual DNS-Record differs from the host's IP.
        if (ip_host == ip_dns_recheck )
        {
            Log->print_no_update_needed(changed_to_online, hostname, ip_dns_recheck, ip_last_update, ip_host, lastupdated);
            // No update needed
            continue;
        }

        // Check if the IP set in last update differs from the actual host's ip.
        if ( ip_last_update != ip_host )
        {
            // Update
            if ( !ip_dns_recheck.empty() )
            {
                Log->print_update_service(hostname, ip_dns_recheck, ip_last_update, ip_host, lastupdated);
            }
            else
            {
                // Service gets updated the first time and no DNS-Record was found. This is either a initial update or the hostname is really not available.
                Log->print_update_service(hostname, "<NO IP SET>", ip_last_update, ip_host, lastupdated);
            }

            service->update(ip_host, current_time, changed_to_online);
        }
        else
        {
            int dns_cache_ttl = service->get_dns_cache_ttl();

            // Add server error threshold so we don't jam the server with updates for the same IP
            // in case the server doesn't hand out the already sent IP via DNS
            // (might indicate a server error).
            dns_cache_ttl += ServerErrorTTLExpiredThreshold;

            // Check if DNS Cache TTL is expired, if so, then update the same IP again.
            if ( (lastupdated + dns_cache_ttl) < current_time )
            {
                // Update
                Log->print_update_service_ttl_expired(hostname, ip_dns_recheck, ip_last_update, ip_host, lastupdated, dns_cache_ttl, current_time);
                service->update(ip_host, current_time, changed_to_online);
            }
            else
            {
                // DNS cache TTL isn't expired
                Log->print_update_service_ttl_not_expired(changed_to_online, hostname, ip_dns_recheck, ip_last_update, ip_host, lastupdated, dns_cache_ttl, current_time);
            }
        }
    }
}


/**
 * Getter for member ServiceHolder.
 * @return ServiceHolder
 */
Serviceholder::Ptr Updater::get_service_holder() const
{
    return ServiceHolder;
}