text: /**
   *  @file
   *  @copyright defined in pose/LICENSE.txt
   */
  #include <eosio.system/eosio.system.hpp>
  
  #include <eosiolib/eosio.hpp>
  #include <eosiolib/crypto.h>
  #include <eosiolib/datastream.hpp>
  #include <eosiolib/serialize.hpp>
  #include <eosiolib/multi_index.hpp>
  #include <eosiolib/privileged.hpp>
  #include <eosiolib/singleton.hpp>
  #include <eosiolib/transaction.hpp>
  #include <eosio.token/eosio.token.hpp>
  
  #include <algorithm>
  #include <cmath>
  
  namespace eosiosystem {
     using eosio::indexed_by;
     using eosio::const_mem_fun;
     using eosio::singleton;
     using eosio::transaction;
  
     /**
      *  This method will create a producer_config and producer_info object for 'producer'
      *
      *  @pre producer is not already registered
      *  @pre producer to register is an account
      *  @pre authority of producer to register
      *
      */
     void system_contract::regproducer( const name producer, const eosio::public_key& producer_key, const std::string& url, uint16_t location ) {
        check( url.size() < 512, "url too long" );
        check( producer_key != eosio::public_key(), "public key should not be the default value" );
        require_auth( producer );
  
        auto prod = _producers.find( producer.value );
        const auto ct = current_time_point();
  
        if ( prod != _producers.end() ) {
           _producers.modify( prod, producer, [&]( producer_info& info ){
              info.producer_key = producer_key;
              info.is_active    = true;
              info.url          = url;
              info.location     = location;
              if ( info.last_claim_time == time_point() )
                 info.last_claim_time = ct;
           });
  
           auto prod2 = _producers2.find( producer.value );
           if ( prod2 == _producers2.end() ) {
              _producers2.emplace( producer, [&]( producer_info2& info ){
                 info.owner                     = producer;
                 info.last_votepay_share_update = ct;
              });
              update_total_votepay_share( ct, 0.0, prod->total_votes );
              // When introducing the producer2 table row for the first time, the producer's votes must also be accounted for in the global total_producer_votepay_share at the same time.
           }
        } else {
           _producers.emplace( producer, [&]( producer_info& info ){
              info.owner           = producer;
              info.total_votes     = 0;
              info.producer_key    = producer_key;
              info.is_active       = true;
              info.url             = url;
              info.location        = location;
              info.last_claim_time = ct;
           });
           _producers2.emplace( producer, [&]( producer_info2& info ){
              info.owner                     = producer;
              info.last_votepay_share_update = ct;
           });
        }
  
     }
  
     void system_contract::unregprod( const name producer ) {
        require_auth( producer );
  
        const auto& prod = _producers.get( producer.value, "producer not found" );
        _producers.modify( prod, same_payer, [&]( producer_info& info ){
           info.deactivate();
        });
     }
  
     void system_contract::update_elected_producers( block_timestamp block_time ) {
        _gstate.last_producer_schedule_update = block_time;
  
        auto idx = _producers.get_index<"prototalvote"_n>();
  
        std::vector< std::pair<eosio::producer_key,uint16_t> > top_producers;
        top_producers.reserve(25);
  
        for ( auto it = idx.cbegin(); it != idx.cend() && top_producers.size() < 25 && 0 < it->total_votes && it->active(); ++it ) {
           top_producers.emplace_back( std::pair<eosio::producer_key,uint16_t>({{it->owner, it->producer_key}, it->location}) );
        }
  
        if ( top_producers.size() < _gstate.last_producer_schedule_size ) {
           return;
        }
  
        /// sort by producer name
        std::sort( top_producers.begin(), top_producers.end() );
  
        std::vector<eosio::producer_key> producers;
  
        producers.reserve(top_producers.size());
        for( const auto& item : top_producers )
           producers.push_back(item.first);
  
        auto packed_schedule = pack(producers);
  
        if( set_proposed_producers( packed_schedule.data(),  packed_schedule.size() ) >= 0 ) {
           _gstate.last_producer_schedule_size = static_cast<decltype(_gstate.last_producer_schedule_size)>( top_producers.size() );
        }
     }
  
     double stake2vote( int64_t staked ) {
        /// TODO subtract 2080 brings the large numbers closer to this decade
        double weight = int64_t( (now() - (block_timestamp::block_timestamp_epoch / 1000)) / (seconds_per_day * 7) )  / double( 52 );
        return double(staked) * std::pow( 2, weight );
     }
  
     double system_contract::update_total_votepay_share( time_point ct,
                                                         double additional_shares_delta,
                                                         double shares_rate_delta )
     {
        double delta_total_votepay_share = 0.0;
        if( ct > _gstate3.last_vpay_state_update ) {
           delta_total_votepay_share = _gstate3.total_vpay_share_change_rate
                                         * double( (ct - _gstate3.last_vpay_state_update).count() / 1E6 );
        }
  
        delta_total_votepay_share += additional_shares_delta;
        if( delta_total_votepay_share < 0 && _gstate2.total_producer_votepay_share < -delta_total_votepay_share ) {
           _gstate2.total_producer_votepay_share = 0.0;
        } else {
           _gstate2.total_producer_votepay_share += delta_total_votepay_share;
        }
  
        if( shares_rate_delta < 0 && _gstate3.total_vpay_share_change_rate < -shares_rate_delta ) {
           _gstate3.total_vpay_share_change_rate = 0.0;
        } else {
           _gstate3.total_vpay_share_change_rate += shares_rate_delta;
        }
  
        _gstate3.last_vpay_state_update = ct;
  
        return _gstate2.total_producer_votepay_share;
     }
  
     double system_contract::update_producer_votepay_share( const producers_table2::const_iterator& prod_itr,
                                                            time_point ct,
                                                            double shares_rate,
                                                            bool reset_to_zero )
     {
        double delta_votepay_share = 0.0;
        if( shares_rate > 0.0 && ct > prod_itr->last_votepay_share_update ) {
           delta_votepay_share = shares_rate * double( (ct - prod_itr->last_votepay_share_update).count() / 1E6 ); // cannot be negative
        }
  
        double new_votepay_share = prod_itr->votepay_share + delta_votepay_share;
        _producers2.modify( prod_itr, same_payer, [&](auto& p) {
           if( reset_to_zero )
              p.votepay_share = 0.0;
           else
              p.votepay_share = new_votepay_share;
  
           p.last_votepay_share_update = ct;
        } );
  
        return new_votepay_share;
     }
  
     /**
      *  @pre producers must be sorted from lowest to highest and must be registered and active
      *  @pre if proxy is set then no producers can be voted for
      *  @pre if proxy is set then proxy account must exist and be registered as a proxy
      *  @pre every listed producer or proxy must have been previously registered
      *  @pre voter must authorize this action
      *  @pre voter must have previously staked some amount of CORE_SYMBOL for voting
      *  @pre voter->staked must be up to date
      *
      *  @post every producer previously voted for will have vote reduced by previous vote weight
      *  @post every producer newly voted for will have vote increased by new vote amount
      *  @post prior proxy will proxied_vote_weight decremented by previous vote weight
      *  @post new proxy will proxied_vote_weight incremented by new vote weight
      *
      *  If voting for a proxy, the producer votes will not change until the proxy updates their own vote.
      */
     void system_contract::voteproducer( const name voter_name, const name proxy, const std::vector<name>& producers ) {
        check( producers.size() == 1, "cannot vote for more than 1 producer");
        require_auth( voter_name );
        vote_stake_updater( voter_name );
        update_votes( voter_name, proxy, producers, true );
        auto rex_itr = _rexbalance.find( voter_name.value );
        if( rex_itr != _rexbalance.end() && rex_itr->rex_balance.amount > 0 ) {
           check_voting_requirement( voter_name, "voter holding REX tokens must vote for at least 21 producers or for a proxy" );
        }
     }
  
     void system_contract::update_votes( const name voter_name, const name proxy, const std::vector<name>& producers, bool voting ) {
        //validate input
        if ( proxy ) {
           check( producers.size() == 0, "cannot vote for producers and proxy at same time" );
           check( voter_name != proxy, "cannot proxy to self" );
        } else {
           check( producers.size() <= 30, "attempt to vote for too many producers" );
           for( size_t i = 1; i < producers.size(); ++i ) {
              check( producers[i-1] < producers[i], "producer votes must be unique and sorted" );
           }
        }
  
        auto voter = _voters.find( voter_name.value );
        check( voter != _voters.end(), "user must stake before they can vote" ); /// staking creates voter object
        check( !proxy || !voter->is_proxy, "account registered as a proxy is not allowed to use a proxy" );
  
        /**
         * The first time someone votes we calculate and set last_vote_weight, since they cannot unstake until
         * after total_activated_stake hits threshold, we can use last_vote_weight to determine that this is
         * their first vote and should consider their stake activated.
         */
        if( voter->last_vote_weight <= 0.0 ) {
           _gstate.total_activated_stake += voter->staked;
           if( _gstate.total_activated_stake >= min_activated_stake && _gstate.thresh_activated_stake_time == time_point() ) {
              _gstate.thresh_activated_stake_time = current_time_point();
           }
        }
  
        auto new_vote_weight = stake2vote( voter->staked );
        if( voter->is_proxy ) {
           new_vote_weight += voter->proxied_vote_weight;
        }
  
        boost::container::flat_map<name, pair<double, bool /*new*/> > producer_deltas;
        if ( voter->last_vote_weight > 0 ) {
           if( voter->proxy ) {
              auto old_proxy = _voters.find( voter->proxy.value );
              check( old_proxy != _voters.end(), "old proxy not found" ); //data corruption
              _voters.modify( old_proxy, same_payer, [&]( auto& vp ) {
                    vp.proxied_vote_weight -= voter->last_vote_weight;
                 });
              propagate_weight_change( *old_proxy );
           } else {
              for( const auto& p : voter->producers ) {
                 auto& d = producer_deltas[p];
                 d.first -= voter->last_vote_weight;
                 d.second = false;
              }
           }
        }
  
        if( proxy ) {
           auto new_proxy = _voters.find( proxy.value );
           check( new_proxy != _voters.end(), "invalid proxy specified" ); //if ( !voting ) { data corruption } else { wrong vote }
           check( !voting || new_proxy->is_proxy, "proxy not found" );
           if ( new_vote_weight >= 0 ) {
              _voters.modify( new_proxy, same_payer, [&]( auto& vp ) {
                    vp.proxied_vote_weight += new_vote_weight;
                 });
              propagate_weight_change( *new_proxy );
           }
        } else {
           if( new_vote_weight >= 0 ) {
              for( const auto& p : producers ) {
                 auto& d = producer_deltas[p];
                 d.first += new_vote_weight;
                 d.second = true;
              }
           }
        }
  
        const auto ct = current_time_point();
        double delta_change_rate         = 0.0;
        double total_inactive_vpay_share = 0.0;
        for( const auto& pd : producer_deltas ) {
           auto pitr = _producers.find( pd.first.value );
           if( pitr != _producers.end() ) {
              check( !voting || pitr->active() || !pd.second.second /* not from new set */, "producer is not currently registered" );
              double init_total_votes = pitr->total_votes;
              _producers.modify( pitr, same_payer, [&]( auto& p ) {
                 p.total_votes += pd.second.first;
                 if ( p.total_votes < 0 ) { // floating point arithmetics can give small negative numbers
                    p.total_votes = 0;
                 }
                 _gstate.total_producer_vote_weight += pd.second.first;
                 //check( p.total_votes >= 0, "something bad happened" );
              });
              auto prod2 = _producers2.find( pd.first.value );
              if( prod2 != _producers2.end() ) {
                 const auto last_claim_plus_3days = pitr->last_claim_time + microseconds(3 * useconds_per_day);
                 bool crossed_threshold       = (last_claim_plus_3days <= ct);
                 bool updated_after_threshold = (last_claim_plus_3days <= prod2->last_votepay_share_update);
                 // Note: updated_after_threshold implies cross_threshold
  
                 double new_votepay_share = update_producer_votepay_share( prod2,
                                               ct,
                                               updated_after_threshold ? 0.0 : init_total_votes,
                                               crossed_threshold && !updated_after_threshold // only reset votepay_share once after threshold
                                            );
  
                 if( !crossed_threshold ) {
                    delta_change_rate += pd.second.first;
                 } else if( !updated_after_threshold ) {
                    total_inactive_vpay_share += new_votepay_share;
                    delta_change_rate -= init_total_votes;
                 }
              }
           } else {
              check( !pd.second.second /* not from new set */, "producer is not registered" ); //data corruption
           }
        }
  
        update_total_votepay_share( ct, -total_inactive_vpay_share, delta_change_rate );
  
        _voters.modify( voter, same_payer, [&]( auto& av ) {
           av.last_vote_weight = new_vote_weight;
           av.producers = producers;
           av.proxy     = proxy;
        });
     }
  
     /**
      *  An account marked as a proxy can vote with the weight of other accounts which
      *  have selected it as a proxy. Other accounts must refresh their voteproducer to
      *  update the proxy's weight.
      *
      *  @param isproxy - true if proxy wishes to vote on behalf of others, false otherwise
      *  @pre proxy must have something staked (existing row in voters table)
      *  @pre new state must be different than current state
      */
     void system_contract::regproxy( const name proxy, bool isproxy ) {
        require_auth( proxy );
  
        auto pitr = _voters.find( proxy.value );
        if ( pitr != _voters.end() ) {
           check( isproxy != pitr->is_proxy, "action has no effect" );
           check( !isproxy || !pitr->proxy, "account that uses a proxy is not allowed to become a proxy" );
           _voters.modify( pitr, same_payer, [&]( auto& p ) {
                 p.is_proxy = isproxy;
              });
           propagate_weight_change( *pitr );
        } else {
           _voters.emplace( proxy, [&]( auto& p ) {
                 p.owner  = proxy;
                 p.is_proxy = isproxy;
              });
        }
     }
  
     void system_contract::propagate_weight_change( const voter_info& voter ) {
        check( !voter.proxy || !voter.is_proxy, "account registered as a proxy is not allowed to use a proxy" );
        double new_weight = stake2vote( voter.staked );
        if ( voter.is_proxy ) {
           new_weight += voter.proxied_vote_weight;
        }
  
        /// don't propagate small changes (1 ~= epsilon)
        if ( fabs( new_weight - voter.last_vote_weight ) > 1 )  {
           if ( voter.proxy ) {
              auto& proxy = _voters.get( voter.proxy.value, "proxy not found" ); //data corruption
              _voters.modify( proxy, same_payer, [&]( auto& p ) {
                    p.proxied_vote_weight += new_weight - voter.last_vote_weight;
                 }
              );
              propagate_weight_change( proxy );
           } else {
              auto delta = new_weight - voter.last_vote_weight;
              const auto ct = current_time_point();
              double delta_change_rate         = 0;
              double total_inactive_vpay_share = 0;
              for ( auto acnt : voter.producers ) {
                 auto& prod = _producers.get( acnt.value, "producer not found" ); //data corruption
                 const double init_total_votes = prod.total_votes;
                 _producers.modify( prod, same_payer, [&]( auto& p ) {
                    p.total_votes += delta;
                    _gstate.total_producer_vote_weight += delta;
                 });
                 auto prod2 = _producers2.find( acnt.value );
                 if ( prod2 != _producers2.end() ) {
                    const auto last_claim_plus_3days = prod.last_claim_time + microseconds(3 * useconds_per_day);
                    bool crossed_threshold       = (last_claim_plus_3days <= ct);
                    bool updated_after_threshold = (last_claim_plus_3days <= prod2->last_votepay_share_update);
                    // Note: updated_after_threshold implies cross_threshold
  
                    double new_votepay_share = update_producer_votepay_share( prod2,
                                                  ct,
                                                  updated_after_threshold ? 0.0 : init_total_votes,
                                                  crossed_threshold && !updated_after_threshold // only reset votepay_share once after threshold
                                               );
  
                    if( !crossed_threshold ) {
                       delta_change_rate += delta;
                    } else if( !updated_after_threshold ) {
                       total_inactive_vpay_share += new_votepay_share;
                       delta_change_rate -= init_total_votes;
                    }
                 }
              }
  
              update_total_votepay_share( ct, -total_inactive_vpay_share, delta_change_rate );
           }
        }
        _voters.modify( voter, same_payer, [&]( auto& v ) {
              v.last_vote_weight = new_weight;
           }
        );
     }
  
  } /// namespace eosiosystem
  