/**
 * @file  server_lds.c
 * @brief Local Discovery Server implementation.
 *
 * This program runs an OPC UA Local Discovery Server (LDS) configured with
 * encryption and a configurable cleanup timeout. 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 <open62541/plugin/accesscontrol_default.h>
#include <open62541/plugin/log_stdout.h>
#include <open62541/server.h>
#include <open62541/server_config_default.h>

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

UA_Boolean running = true;

static void
stopHandler (int sig)
{
  UA_LOG_INFO (UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "received ctrl-c");
  running = false;
}

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

  if (argc < 7)
    {
      UA_LOG_FATAL (UA_Log_Stdout, UA_LOGCATEGORY_USERLAND,
                    "Usage: %s\n"
                    "  <port> <applicationUri>\n"
                    "  <server-certificate.der> <private-key.der>\n"
                    "  <cleanup-timeout-seconds>\n"
                    "  <auth-mode> [<username> <password>]\n"
                    "  [<trustlist1.der>, ...]\n"
                    "\n"
                    "Auth modes: anonymous, user",
                    argv[0]);
      return EXIT_FAILURE;
    }

  UA_UInt16 port = (UA_UInt16)atoi (argv[1]);
  int cleanupTimeout = atoi (argv[5]);

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

  int idx = 6;
  const char *authMode = argv[idx++];
  UA_Boolean allowAnonymous;
  char *username = NULL, *password = NULL;

  if (strcmp (authMode, "anonymous") == 0)
    {
      allowAnonymous = true;
    }
  else if (strcmp (authMode, "user") == 0)
    {
      if (idx + 2 > argc)
        {
          UA_LOG_FATAL (UA_Log_Stdout, UA_LOGCATEGORY_USERLAND,
                        "Auth mode 'user' requires <username> <password>");
          return EXIT_FAILURE;
        }
      allowAnonymous = false;
      username = argv[idx++];
      password = argv[idx++];
    }
  else
    {
      UA_LOG_FATAL (UA_Log_Stdout, UA_LOGCATEGORY_USERLAND,
                    "Unknown auth mode: %s "
                    "(expected 'anonymous' or 'user')",
                    authMode);
      return EXIT_FAILURE;
    }

  size_t trustSize = (idx < argc) ? (size_t)(argc - idx) : 0;

  UA_StatusCode retval;
  UA_Server *server = createSecureServer (port, argv[2], argv[3], argv[4],
                                          argv + idx, trustSize, &retval);
  if (!server)
    return EXIT_FAILURE;

  UA_ServerConfig *serverConfig = UA_Server_getConfig (server);

  /* Configure access control after server creation because
     UA_ServerConfig_setDefaultWithSecurityPolicies (called by
     createSecureServer) resets the access control plugin.  The credential
     list is deep-copied by UA_AccessControl_default. */
  if (!allowAnonymous)
    {
      UA_UsernamePasswordLogin logins[1];
      logins[0].username = UA_STRING (username);
      logins[0].password = UA_STRING (password);
      retval = UA_AccessControl_default (serverConfig, false, NULL, 1, logins);
      if (retval != UA_STATUSCODE_GOOD)
        {
          UA_Server_delete (server);
          return EXIT_FAILURE;
        }
    }

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

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

  retval = UA_Server_run (server, &running);

  UA_Server_delete (server);
  return retval == UA_STATUSCODE_GOOD ? EXIT_SUCCESS : EXIT_FAILURE;
}