text: /*
   * Copyright (c) 2015 Cryptonomex, Inc., and contributors.
   *
   * The MIT License
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  #pragma once
  
  #include <graphene/net/node.hpp>
  #include <graphene/net/peer_database.hpp>
  #include <graphene/net/message_oriented_connection.hpp>
  #include <graphene/net/stcp_socket.hpp>
  #include <graphene/net/config.hpp>
  
  #include <boost/tuple/tuple.hpp>
  
  #include <boost/multi_index_container.hpp>
  #include <boost/multi_index/ordered_index.hpp>
  #include <boost/multi_index/mem_fun.hpp>
  #include <boost/multi_index/member.hpp>
  #include <boost/multi_index/random_access_index.hpp>
  #include <boost/multi_index/tag.hpp>
  #include <boost/multi_index/sequenced_index.hpp>
  #include <boost/multi_index/hashed_index.hpp>
  
  #include <queue>
  #include <boost/container/deque.hpp>
  #include <fc/thread/future.hpp>
  
  namespace graphene { namespace net
    {
      struct firewall_check_state_data
      {
        node_id_t        expected_node_id;
        fc::ip::endpoint endpoint_to_test;
  
        // if we're coordinating a firewall check for another node, these are the helper
        // nodes we've already had do the test (if this structure is still relevant, that
        // that means they have all had indeterminate results
        std::set<node_id_t> nodes_already_tested;
  
        // If we're a just a helper node, this is the node we report back to
        // when we have a result
        node_id_t        requesting_peer;
      };
  
      class peer_connection;
      class peer_connection_delegate
      {
      public:
        virtual void on_message(peer_connection* originating_peer,
                                const message& received_message) = 0;
        virtual void on_connection_closed(peer_connection* originating_peer) = 0;
        virtual message get_message_for_item(const item_id& item) = 0;
      };
  
      class peer_connection;
      typedef std::shared_ptr<peer_connection> peer_connection_ptr;
      class peer_connection : public message_oriented_connection_delegate,
                              public std::enable_shared_from_this<peer_connection>
      {
      public:
        enum class our_connection_state
        {
          disconnected,
          just_connected, // if in this state, we have sent a hello_message
          connection_accepted, // remote side has sent us a connection_accepted, we're operating normally with them
          connection_rejected // remote side has sent us a connection_rejected, we may be exchanging address with them or may just be waiting for them to close
        };
        enum class their_connection_state
        {
          disconnected,
          just_connected, // we have not yet received a hello_message
          connection_accepted, // we have sent them a connection_accepted
          connection_rejected // we have sent them a connection_rejected
        };
        enum class connection_negotiation_status
        {
          disconnected,
          connecting,
          connected,
          accepting,
          accepted,
          hello_sent,
          peer_connection_accepted,
          peer_connection_rejected,
          negotiation_complete,
          closing,
          closed
        };
      private:
        peer_connection_delegate*      _node;
        fc::optional<fc::ip::endpoint> _remote_endpoint;
        message_oriented_connection    _message_connection;
  
        /* a base class for messages on the queue, to hide the fact that some
         * messages are complete messages and some are only hashes of messages.
         */
        struct queued_message
        {
          fc::time_point enqueue_time;
          fc::time_point transmission_start_time;
          fc::time_point transmission_finish_time;
  
          queued_message(fc::time_point enqueue_time = fc::time_point::now()) :
            enqueue_time(enqueue_time)
          {}
  
          virtual message get_message(peer_connection_delegate* node) = 0;
          /** returns roughly the number of bytes of memory the message is consuming while
           * it is sitting on the queue
           */
          virtual size_t get_size_in_queue() = 0;
          virtual ~queued_message() {}
        };
  
        /* when you queue up a 'real_queued_message', a full copy of the message is
         * stored on the heap until it is sent
         */
        struct real_queued_message : queued_message
        {
          message        message_to_send;
          size_t         message_send_time_field_offset;
  
          real_queued_message(message message_to_send,
                              size_t message_send_time_field_offset = (size_t)-1) :
            message_to_send(std::move(message_to_send)),
            message_send_time_field_offset(message_send_time_field_offset)
          {}
  
          message get_message(peer_connection_delegate* node) override;
          size_t get_size_in_queue() override;
        };
  
        /* when you queue up a 'virtual_queued_message', we just queue up the hash of the
         * item we want to send.  When it reaches the top of the queue, we make a callback
         * to the node to generate the message.
         */
        struct virtual_queued_message : queued_message
        {
          item_id item_to_send;
  
          virtual_queued_message(item_id item_to_send) :
            item_to_send(std::move(item_to_send))
          {}
  
          message get_message(peer_connection_delegate* node) override;
          size_t get_size_in_queue() override;
        };
  
  
        size_t _total_queued_messages_size = 0;
        std::queue<std::unique_ptr<queued_message>, std::list<std::unique_ptr<queued_message> > > _queued_messages;
        fc::future<void> _send_queued_messages_done;
      public:
        fc::time_point connection_initiation_time;
        fc::time_point connection_closed_time;
        fc::time_point connection_terminated_time;
        peer_connection_direction direction = peer_connection_direction::unknown;
        //connection_state state;
        firewalled_state is_firewalled = firewalled_state::unknown;
        fc::microseconds clock_offset;
        fc::microseconds round_trip_delay;
  
        our_connection_state our_state = our_connection_state::disconnected;
        bool they_have_requested_close = false;
        their_connection_state their_state = their_connection_state::disconnected;
        bool we_have_requested_close = false;
  
        connection_negotiation_status negotiation_status = connection_negotiation_status::disconnected;
        fc::oexception connection_closed_error;
  
        fc::time_point get_connection_time()const { return _message_connection.get_connection_time(); }
        fc::time_point get_connection_terminated_time()const { return connection_terminated_time; }
  
        /// data about the peer node
        /// @{
        /** node_public_key from the hello message, zero-initialized before we get the hello */
        node_id_t        node_public_key;
        /** the unique identifier we'll use to refer to the node with.  zero-initialized before
         * we receive the hello message, at which time it will be filled with either the "node_id"
         * from the user_data field of the hello, or if none is present it will be filled with a
         * copy of node_public_key */
        node_id_t        node_id;
        uint32_t         core_protocol_version = 0;
        std::string      user_agent;
        fc::optional<std::string> graphene_git_revision_sha;
        fc::optional<fc::time_point_sec> graphene_git_revision_unix_timestamp;
        fc::optional<std::string> fc_git_revision_sha;
        fc::optional<fc::time_point_sec> fc_git_revision_unix_timestamp;
        fc::optional<std::string> platform;
        fc::optional<uint32_t> bitness;
        fc::optional<hive::protocol::chain_id_type> chain_id;
  
        // for inbound connections, these fields record what the peer sent us in
        // its hello message.  For outbound, they record what we sent the peer
        // in our hello message
        fc::ip::address inbound_address;
        uint16_t inbound_port = 0;
        uint16_t outbound_port = 0;
        /// @}
  
        typedef std::unordered_map<item_id, fc::time_point> item_to_time_map_type;
  
        /// blockchain synchronization state data
        /// @{
        boost::container::deque<item_hash_t> ids_of_items_to_get; /// id of items in the blockchain that this peer has told us about
        std::set<item_hash_t> ids_of_items_being_processed; /// list of all items this peer has offered use that we've already handed to the client but the client hasn't finished processing
        uint32_t number_of_unfetched_item_ids = 0; /// number of items in the blockchain that follow ids_of_items_to_get but the peer hasn't yet told us their ids
        bool peer_needs_sync_items_from_us = false;
        bool we_need_sync_items_from_peer = false;
        fc::optional<boost::tuple<std::vector<item_hash_t>, fc::time_point> > item_ids_requested_from_peer; /// we check this to detect a timed-out request and in busy()
        fc::time_point last_sync_item_received_time; /// the time we received the last sync item or the time we sent the last batch of sync item requests to this peer
        std::set<item_hash_t> sync_items_requested_from_peer; /// ids of blocks we've requested from this peer during sync.  fetch from another peer if this peer disconnects
        item_hash_t last_block_delegate_has_seen; /// the hash of the last block  this peer has told us about that the peer knows
        fc::time_point_sec last_block_time_delegate_has_seen;
        bool inhibit_fetching_sync_blocks = false;
        /// @}
  
        /// latency timing data
        std::unordered_map< item_hash_t, fc::time_point > pending_item_request_times;
        /// @}
  
        /// non-synchronization state data
        /// @{
        struct timestamped_item_id
        {
          item_id            item;
          fc::time_point_sec timestamp;
          timestamped_item_id(const item_id& item, const fc::time_point_sec timestamp) :
            item(item),
            timestamp(timestamp)
          {}
        };
        struct timestamp_index{};
        typedef boost::multi_index_container<timestamped_item_id,
                                             boost::multi_index::indexed_by<boost::multi_index::hashed_unique<boost::multi_index::member<timestamped_item_id, item_id, &timestamped_item_id::item>,
                                                                                                              std::hash<item_id> >,
                                                                            boost::multi_index::ordered_non_unique<boost::multi_index::tag<timestamp_index>,
                                                                                                                   boost::multi_index::member<timestamped_item_id, fc::time_point_sec, &timestamped_item_id::timestamp> > > > timestamped_items_set_type;
        timestamped_items_set_type inventory_peer_advertised_to_us;
        timestamped_items_set_type inventory_advertised_to_peer;
  
        item_to_time_map_type items_requested_from_peer;  /// items we've requested from this peer during normal operation.  fetch from another peer if this peer disconnects
        /// @}
  
        // if they're flooding us with transactions, we set this to avoid fetching for a few seconds to let the
        // blockchain catch up
        fc::time_point transaction_fetching_inhibited_until;
  
        uint32_t last_known_fork_block_number = 0;
  
        fc::future<void> accept_or_connect_task_done;
  
        firewall_check_state_data *firewall_check_state = nullptr;
  #ifndef NDEBUG
      private:
        fc::thread* _thread = nullptr;
        unsigned _send_message_queue_tasks_running = 0; // temporary debugging
  #endif
        bool _currently_handling_message = false; // true while we're in the middle of handling a message from the remote system
      private:
        peer_connection(peer_connection_delegate* delegate);
        void destroy(const char* caller);
      public:
        static peer_connection_ptr make_shared(peer_connection_delegate* delegate); // use this instead of the constructor
        virtual ~peer_connection();
  
        fc::tcp_socket& get_socket();
        void accept_connection();
        void connect_to(const fc::ip::endpoint& remote_endpoint, fc::optional<fc::ip::endpoint> local_endpoint = fc::optional<fc::ip::endpoint>());
  
        void on_message(message_oriented_connection* originating_connection, const message& received_message) override;
        void on_connection_closed(message_oriented_connection* originating_connection) override;
  
        void send_queueable_message(std::unique_ptr<queued_message>&& message_to_send);
        void send_message(const message& message_to_send, size_t message_send_time_field_offset = (size_t)-1);
        void send_item(const item_id& item_to_send);
        void close_connection();
        void destroy_connection(const char* caller);
  
        uint64_t get_total_bytes_sent() const;
        uint64_t get_total_bytes_received() const;
  
        fc::time_point get_last_message_sent_time() const;
        fc::time_point get_last_message_received_time() const;
  
        fc::optional<fc::ip::endpoint> get_remote_endpoint();
        fc::ip::endpoint get_local_endpoint();
        void set_remote_endpoint(fc::optional<fc::ip::endpoint> new_remote_endpoint);
  
        bool busy() const;
        bool idle() const;
        bool is_currently_handling_message() const;
  
        bool is_transaction_fetching_inhibited() const;
        fc::sha512 get_shared_secret() const;
        void clear_old_inventory();
        bool is_inventory_advertised_to_us_list_full_for_transactions() const;
        bool is_inventory_advertised_to_us_list_full() const;
        bool performing_firewall_check() const;
        fc::optional<fc::ip::endpoint> get_endpoint_for_connecting() const;
      private:
        void send_queued_messages_task();
        void accept_connection_task();
        void connect_to_task(const fc::ip::endpoint& remote_endpoint);
      };
      typedef std::shared_ptr<peer_connection> peer_connection_ptr;
  
   } } // end namespace graphene::net
  
  // not sent over the wire, just reflected for logging
  FC_REFLECT_ENUM(graphene::net::peer_connection::our_connection_state, (disconnected)
                                                                   (just_connected)
                                                                   (connection_accepted)
                                                                   (connection_rejected))
  FC_REFLECT_ENUM(graphene::net::peer_connection::their_connection_state, (disconnected)
                                                                     (just_connected)
                                                                     (connection_accepted)
                                                                     (connection_rejected))
  FC_REFLECT_ENUM(graphene::net::peer_connection::connection_negotiation_status, (disconnected)
                                                                            (connecting)
                                                                            (connected)
                                                                            (accepting)
                                                                            (accepted)
                                                                            (hello_sent)
                                                                            (peer_connection_accepted)
                                                                            (peer_connection_rejected)
                                                                            (negotiation_complete)
                                                                            (closing)
                                                                            (closed) )
  
  FC_REFLECT( graphene::net::peer_connection::timestamped_item_id, (item)(timestamp));
  