/*
 * 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.
 */

#include <graphene/chain/database.hpp>

#include <graphene/chain/asset_object.hpp>
#include <graphene/chain/chain_property_object.hpp>
#include <graphene/chain/global_property_object.hpp>
#include <graphene/chain/son_object.hpp>
#include <graphene/chain/son_proposal_object.hpp>
#include <fc/smart_ref_impl.hpp>

#include <ctime>
#include <algorithm>

namespace graphene { namespace chain {

const asset_object& database::get_core_asset() const
{
   return get(asset_id_type());
}

const global_property_object& database::get_global_properties()const
{
   return get( global_property_id_type() );
}

const chain_property_object& database::get_chain_properties()const
{
   return get( chain_property_id_type() );
}

const dynamic_global_property_object& database::get_dynamic_global_properties() const
{
   return get( dynamic_global_property_id_type() );
}

const fee_schedule&  database::current_fee_schedule()const
{
   return get_global_properties().parameters.current_fees;
}

time_point_sec database::head_block_time()const
{
   return get( dynamic_global_property_id_type() ).time;
}

uint32_t database::head_block_num()const
{
   return get( dynamic_global_property_id_type() ).head_block_number;
}

block_id_type database::head_block_id()const
{
   return get( dynamic_global_property_id_type() ).head_block_id;
}

decltype( chain_parameters::block_interval ) database::block_interval( )const
{
   return get_global_properties().parameters.block_interval;
}

const chain_id_type& database::get_chain_id( )const
{
   return get_chain_properties().chain_id;
}

const node_property_object& database::get_node_properties()const
{
   return _node_property_object;
}

node_property_object& database::node_properties()
{
   return _node_property_object;
}

uint32_t database::last_non_undoable_block_num() const
{
   return head_block_num() - _undo_db.size();
}

std::vector<uint32_t> database::get_seeds(asset_id_type for_asset, uint8_t count_winners) const
{
   FC_ASSERT( count_winners <= 64 );
   std::string salted_string = std::string(_random_number_generator._seed) + std::to_string(for_asset.instance.value);
   uint32_t* seeds = (uint32_t*)(fc::sha256::hash(salted_string)._hash);

   std::vector<uint32_t> result;
   result.reserve(64);

   for( int s = 0; s < 8; ++s ) {
      uint32_t* sub_seeds = ( uint32_t* ) fc::sha256::hash( std::to_string( seeds[s] ) + std::to_string( for_asset.instance.value ) )._hash;
      for( int ss = 0; ss < 8; ++ss ) {
         result.push_back(sub_seeds[ss]);
      }
   }
   return result;
}

const std::vector<uint32_t> database::get_winner_numbers( asset_id_type for_asset, uint32_t count_members, uint8_t count_winners ) const
{
   std::vector<uint32_t> result;
   if( count_members < count_winners ) count_winners = count_members;
   if( count_winners == 0 ) return result;
   result.reserve(count_winners);

   auto seeds = get_seeds(for_asset, count_winners);

   for (auto current_seed = seeds.begin(); current_seed != seeds.end(); ++current_seed) {
      uint8_t winner_num = *current_seed % count_members;
      while( std::find(result.begin(), result.end(), winner_num) != result.end() ) {
         *current_seed = (*current_seed * 1103515245 + 12345) / 65536; //using gcc's consts for pseudorandom
         winner_num = *current_seed % count_members;
      }
      result.push_back(winner_num);
      if (result.size() >= count_winners) break;
   }
   
   FC_ASSERT(result.size() == count_winners);
   return result;
}

std::set<son_id_type> database::get_sons_being_deregistered()
{
   std::set<son_id_type> ret;
   const auto& son_proposal_idx = get_index_type<son_proposal_index>().indices().get< by_id >();

   for( auto& son_proposal : son_proposal_idx )
   {
      if(son_proposal.proposal_type == son_proposal_type::son_deregister_proposal)
      {
         ret.insert(son_proposal.son_id);
      }
   }
   return ret;
}

std::set<son_id_type> database::get_sons_to_be_deregistered()
{
   std::set<son_id_type> ret;
   const auto& son_idx = get_index_type<son_index>().indices().get< by_id >();

   for( auto& son : son_idx )
   {
      if(son.status == son_status::in_maintenance)
      {
         auto stats = son.statistics(*this);
         // TODO : We need to add a function that returns if we can deregister SON 
         // i.e. with introduction of PW code, we have to make a decision if the SON 
         // is needed for release of funds from the PW
         if(head_block_time() - stats.last_down_timestamp >= fc::hours(SON_DEREGISTER_TIME))
         {
            ret.insert(son.id);
         }
      }
   }
   return ret;
}

fc::optional<operation> database::create_son_deregister_proposal(const son_id_type& son_id, const witness_object& current_witness )
{
   son_delete_operation son_dereg_op;
   son_dereg_op.payer = current_witness.witness_account;
   son_dereg_op.son_id = son_id;

   proposal_create_operation proposal_op;
   proposal_op.fee_paying_account = current_witness.witness_account;
   proposal_op.proposed_ops.push_back( op_wrapper( son_dereg_op ) );
   uint32_t lifetime = ( get_global_properties().parameters.block_interval * get_global_properties().active_witnesses.size() ) * 3;
   proposal_op.expiration_time = time_point_sec( head_block_time().sec_since_epoch() + lifetime );
   return proposal_op;
}

signed_transaction database::create_signed_transaction( const fc::ecc::private_key& signing_private_key, const operation& op )
{
   signed_transaction processed_trx;
   auto dyn_props = get_dynamic_global_properties();
   processed_trx.set_reference_block( dyn_props.head_block_id );
   processed_trx.set_expiration( head_block_time() + get_global_properties().parameters.maximum_time_until_expiration );
   processed_trx.operations.push_back( op );
   current_fee_schedule().set_fee( processed_trx.operations.back() );

   processed_trx.sign( signing_private_key, get_chain_id() );

   return processed_trx;
}

void database::process_son_proposals( const witness_object& current_witness, const fc::ecc::private_key& private_key )
{
   const auto& son_proposal_idx = get_index_type<son_proposal_index>().indices().get< by_id >();
   const auto& proposal_idx = get_index_type<proposal_index>().indices().get< by_id >();

   auto approve_proposal = [ & ]( const proposal_id_type& id )
   {
      proposal_update_operation puo;
      puo.fee_paying_account = current_witness.witness_account;
      puo.proposal = id;
      puo.active_approvals_to_add = { current_witness.witness_account };
      _pending_tx.insert( _pending_tx.begin(), create_signed_transaction( private_key, puo ) );
   };

   for( auto& son_proposal : son_proposal_idx )
   {
      const auto& proposal = proposal_idx.find( son_proposal.proposal_id );
      FC_ASSERT( proposal != proposal_idx.end() );
      if( proposal->proposer == current_witness.witness_account)
      {
         approve_proposal( proposal->id );
      }
   }
}

void database::remove_son_proposal( const proposal_object& proposal )
{ try {
   if( proposal.proposed_transaction.operations.size() == 1 &&
     ( proposal.proposed_transaction.operations.back().which() == operation::tag<son_delete_operation>::value) )
   {
      const auto& son_proposal_idx = get_index_type<son_proposal_index>().indices().get<by_proposal>();
      auto son_proposal_itr = son_proposal_idx.find( proposal.id );
      if( son_proposal_itr == son_proposal_idx.end() ) {
         return;
      }
      remove( *son_proposal_itr );
   }
} FC_CAPTURE_AND_RETHROW( (proposal) ) }

bool database::is_son_dereg_valid( const son_id_type& son_id )
{
   const auto& son_idx = get_index_type<son_index>().indices().get< by_id >();
   auto son = son_idx.find( son_id );
   FC_ASSERT( son != son_idx.end() );
   bool ret = ( son->status == son_status::in_maintenance &&
                (head_block_time() - son->statistics(*this).last_down_timestamp >= fc::hours(SON_DEREGISTER_TIME)));
   return ret;
}

} }