#ifndef LLARP_ROUTER_HPP
#define LLARP_ROUTER_HPP
#include <llarp/dht.h>
#include <llarp/nodedb.h>
#include <llarp/router_contact.h>
#include <llarp/path.hpp>

#include <functional>
#include <list>
#include <map>
#include <unordered_map>

#include <llarp/dht.hpp>
#include <llarp/handlers/tun.hpp>
#include <llarp/link_message.hpp>
#include <llarp/routing/handler.hpp>
#include <llarp/service.hpp>
#include "llarp/iwp/establish_job.hpp"

#include "crypto.hpp"
#include "fs.hpp"
#include "mem.hpp"

/** 2^15 bytes */
#define MAX_LINK_MSG_SIZE (32768)

// TODO: unused. remove?
// struct try_connect_ctx
// {
//   llarp_router *router = nullptr;
//   llarp_ai addr;
// };

// // forward declare
// namespace path
// {
//   struct TransitHop;
// }

struct llarp_link;
struct llarp_link_session_iter;

bool
llarp_findOrCreateEncryption(llarp_crypto *crypto, const char *fpath,
                             llarp::SecretKey *encryption);

struct llarp_router
{
  bool ready;
  // transient iwp encryption key
  fs::path transport_keyfile = "transport.key";

  // nodes to connect to on startup
  std::map< std::string, fs::path > connect;

  // long term identity key
  fs::path ident_keyfile = "identity.key";

  fs::path encryption_keyfile = "encryption.key";

  // path to write our self signed rc to
  fs::path our_rc_file = "rc.signed";

  // our router contact
  llarp_rc rc;

  // our ipv4 public setting
  bool publicOverride = false;
  struct sockaddr_in ip4addr;
  llarp_ai addrInfo;

  llarp_ev_loop *netloop;
  llarp_threadpool *tp;
  llarp_logic *logic;
  llarp_crypto crypto;
  llarp::path::PathContext paths;
  llarp::SecretKey identity;
  llarp::SecretKey encryption;
  llarp_threadpool *disk;
  llarp_dht_context *dht = nullptr;

  llarp_nodedb *nodedb;

  // buffer for serializing link messages
  byte_t linkmsg_buffer[MAX_LINK_MSG_SIZE];

  // should we be sending padded messages every interval?
  bool sendPadding = false;

  uint32_t ticker_job_id = 0;

  llarp::InboundMessageParser inbound_link_msg_parser;
  llarp::routing::InboundMessageParser inbound_routing_msg_parser;

  llarp_pathbuilder_select_hop_func selectHopFunc = nullptr;
  llarp_pathbuilder_context *explorePool          = nullptr;

  llarp::service::Context hiddenServiceContext;

  llarp_link *outboundLink = nullptr;
  std::list< llarp_link * > inboundLinks;

  typedef std::queue< const llarp::ILinkMessage * > MessageQueue;

  /// outbound message queue
  std::map< llarp::RouterID, MessageQueue > outboundMesssageQueue;

  /// loki verified routers
  std::map< llarp::RouterID, llarp_rc > validRouters;

  // pending establishing session with routers
  std::map< llarp::PubKey, llarp_link_establish_job > pendingEstablishJobs;

  // sessions to persist -> timestamp to end persist at
  std::map< llarp::RouterID, llarp_time_t > m_PersistingSessions;

  llarp_router();
  virtual ~llarp_router();

  bool
  HandleRecvLinkMessage(struct llarp_link_session *from, llarp_buffer_t msg);

  void
  AddInboundLink(struct llarp_link *link);

  bool
  InitOutboundLink();

  /// initialize us as a service node
  void
  InitServiceNode();

  void
  Close();

  bool
  LoadHiddenServiceConfig(const char *fname);

  bool
  AddHiddenService(const llarp::service::Config::section_t &config);

  bool
  Ready();

  void
  Run();

  void
  PersistSessionUntil(const llarp::RouterID &remote, llarp_time_t until);

  static void
  ConnectAll(void *user, uint64_t orig, uint64_t left);

  bool
  EnsureIdentity();

  bool
  EnsureEncryptionKey();

  bool
  SaveRC();

  const byte_t *
  pubkey() const
  {
    return llarp::seckey_topublic(identity);
  }

  bool
  HasPendingConnectJob(const llarp::RouterID &remote);

  void
  try_connect(fs::path rcfile);

  /// send to remote router or queue for sending
  /// returns false on overflow
  /// returns true on successful queue
  /// NOT threadsafe
  /// MUST be called in the logic thread
  bool
  SendToOrQueue(const llarp::RouterID &remote, const llarp::ILinkMessage *msg);

  /// sendto or drop
  void
  SendTo(llarp::RouterID remote, const llarp::ILinkMessage *msg,
         llarp_link *chosen = nullptr);

  /// manually flush outbound message queue for just 1 router
  void
  FlushOutboundFor(const llarp::RouterID &remote, llarp_link *chosen);

  /// manually discard all pending messages to remote router
  void
  DiscardOutboundFor(const llarp::RouterID &remote);

  /// try establishing a session to a remote router
  void
  TryEstablishTo(const llarp::RouterID &remote);

  /// flush outbound message queue
  void
  FlushOutbound();

  /// called by link when a remote session is expunged
  void
  SessionClosed(const llarp::RouterID &remote);

  /// call internal router ticker
  void
  Tick();

  /// schedule ticker to call i ms from now
  void
  ScheduleTicker(uint64_t i = 1000);

  llarp_link *
  GetLinkWithSessionByPubkey(const llarp::RouterID &remote);

  size_t
  NumberOfConnectedRouters() const;

  bool
  GetRandomConnectedRouter(llarp_rc *result) const;

  void
  async_verify_RC(llarp_rc *rc, bool isExpectingClient,
                  llarp_link_establish_job *job = nullptr);

  static bool
  iter_try_connect(llarp_router_link_iter *i, llarp_router *router,
                   llarp_link *l);

  static void
  on_try_connect_result(llarp_link_establish_job *job);

  static void
  connect_job_retry(void *user, uint64_t orig, uint64_t left);

  static void
  on_verify_client_rc(llarp_async_verify_rc *context);

  static void
  on_verify_server_rc(llarp_async_verify_rc *context);

  static void
  handle_router_ticker(void *user, uint64_t orig, uint64_t left);

  static bool
  send_padded_message(struct llarp_link_session_iter *itr,
                      struct llarp_link_session *peer);

  static void
  HandleAsyncLoadRCForSendTo(llarp_async_load_rc *async);

  static void
  HandleDHTLookupForSendTo(llarp_router_lookup_job *job);

  static void
  HandleExploritoryPathBuildStarted(llarp_pathbuild_job *job);

  static void
  HandleDHTLookupForTryEstablishTo(llarp_router_lookup_job *job);
};

#endif