/**
 * @file  server_lds.c
 * @brief Local Discovery Server implementation.
 *
 * This program runs an OPC UA Local Discovery Server (LDS) with a configurable
 * cleanup timeout.  Encryption is optional: when certificate, privateKey, and
 * trustStore are provided, the server offers all security policies; otherwise
 * it runs with SecurityPolicy#None only.  Other OPC UA servers register
 * with this LDS using the RegisterServer2 service. Clients can query this LDS
 * using the FindServers service to discover registered servers.
 */

#include "common.h"
#include "config.h"

#include <open62541/plugin/log_stdout.h>
#include <open62541/server.h>

#include <signal.h>
#include <stdlib.h>

volatile UA_Boolean g_running = true;

static void
_s_stop_handler (int sig)
{
  g_running = false;
}

int
main (int argc, char *argv[])
{
  signal (SIGINT, _s_stop_handler);
  signal (SIGTERM, _s_stop_handler);

  if (argc < 2 || argc > 3)
    {
      UA_LOG_FATAL (UA_Log_Stdout, UA_LOGCATEGORY_USERLAND,
                    "Usage: %s <config-file> [log-level]", argv[0]);
      return EXIT_FAILURE;
    }

  const char *log_level_str = (argc == 3) ? argv[2] : "info";
  int log_level = parse_log_level (log_level_str);
  if (log_level < 0)
    {
      UA_LOG_FATAL (UA_Log_Stdout, UA_LOGCATEGORY_USERLAND,
                    "Unknown log level: %s "
                    "(expected trace, debug, info, warning, error, fatal)",
                    log_level_str);
      return EXIT_FAILURE;
    }

  config cfg;
  if (config_load (argv[1], &cfg) != 0)
    return EXIT_FAILURE;

  int port = config_require_int (&cfg, "port", "ServerLDS");
  const char *application_uri
      = config_require (&cfg, "applicationUri", "ServerLDS");
  int cleanup_timeout
      = config_require_int (&cfg, "cleanupTimeout", "ServerLDS");

  if (!application_uri || port < 0 || cleanup_timeout < 0)
    {
      config_free (&cfg);
      return EXIT_FAILURE;
    }

  /* The OPC UA specification requires the cleanup timeout to exceed the
     register-server interval.  open62541 enforces a floor of 10 seconds. */
  if (cleanup_timeout <= 10)
    {
      UA_LOG_FATAL (UA_Log_Stdout, UA_LOGCATEGORY_USERLAND,
                    "Cleanup timeout must be > 10 seconds (got %d)",
                    cleanup_timeout);
      config_free (&cfg);
      return EXIT_FAILURE;
    }

  security_config sec;
  if (parse_security_config (&cfg, "ServerLDS", false, &sec) != 0)
    {
      config_free (&cfg);
      return EXIT_FAILURE;
    }

  auth_config auth;
  if (parse_auth_config (&cfg, "ServerLDS", &auth) != 0)
    {
      free_trust_store (sec.trust_paths, sec.trust_size);
      config_free (&cfg);
      return EXIT_FAILURE;
    }

  UA_StatusCode retval;
  UA_Server *server
      = create_server ((UA_UInt16)port, application_uri,
                       sec.cert_path ? &sec : NULL, true, &retval);
  if (!server)
    {
      free_trust_store (sec.trust_paths, sec.trust_size);
      config_free (&cfg);
      return EXIT_FAILURE;
    }

  UA_ServerConfig *server_config = UA_Server_getConfig (server);
  server_config->logging->context = (void *)(uintptr_t)log_level;

  /* Some OPC UA stacks omit the timestamp in the request header.  The
     default behaviour rejects these requests with BadInvalidTimestamp.
     Downgrade to a warning so third-party servers can still register. */
  server_config->verifyRequestTimestamp = UA_RULEHANDLING_WARN;

  retval = configure_access_control (server_config, &auth);
  if (retval != UA_STATUSCODE_GOOD)
    {
      UA_Server_delete (server);
      free_trust_store (sec.trust_paths, sec.trust_size);
      config_free (&cfg);
      return EXIT_FAILURE;
    }

  /* Mark this server as a Discovery Server so clients can identify it. */
  server_config->applicationDescription.applicationType
      = UA_APPLICATIONTYPE_DISCOVERYSERVER;

  /* Time (seconds) after which stale registrations are removed.  Must
     exceed the registering server's re-register interval. */
  server_config->discoveryCleanupTimeout = cleanup_timeout;

  retval = UA_Server_run (server, &g_running);

  UA_Server_delete (server);
  free_trust_store (sec.trust_paths, sec.trust_size);
  config_free (&cfg);
  return retval == UA_STATUSCODE_GOOD ? EXIT_SUCCESS : EXIT_FAILURE;
}