/*
 * Copyright (c) 2015, Cryptonomex, Inc.
 * All rights reserved.
 *
 * This source code is provided for evaluation in private test networks only, until September 8, 2015. After this date, this license expires and
 * the code may not be used, modified or distributed for any purpose. Redistribution and use in source and binary forms, with or without modification,
 * are permitted until September 8, 2015, provided that the following conditions are met:
 *
 * 1. The code and/or derivative works are used only for private test networks consisting of no more than 10 P2P nodes.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include <graphene/chain/block_database.hpp>

namespace graphene { namespace chain {

struct index_entry
{
   uint64_t      block_pos = 0;
   uint32_t      block_size = 0;
   block_id_type block_id;
};
 }}
FC_REFLECT( graphene::chain::index_entry, (block_pos)(block_size)(block_id) );

namespace graphene { namespace chain {

void block_database::open( const fc::path& dbdir )
{ try {
   fc::create_directories(dbdir);
   _block_num_to_pos.exceptions(std::ios_base::failbit | std::ios_base::badbit);
   _blocks.exceptions(std::ios_base::failbit | std::ios_base::badbit);

   if( !fc::exists( dbdir/"index" ) )
   {
     _block_num_to_pos.open( (dbdir/"index").generic_string().c_str(), std::fstream::binary | std::fstream::in | std::fstream::out | std::fstream::trunc);
     _blocks.open( (dbdir/"blocks").generic_string().c_str(), std::fstream::binary | std::fstream::in | std::fstream::out | std::fstream::trunc);
   }
   else
   {
     _block_num_to_pos.open( (dbdir/"index").generic_string().c_str(), std::fstream::binary | std::fstream::in | std::fstream::out );
     _blocks.open( (dbdir/"blocks").generic_string().c_str(), std::fstream::binary | std::fstream::in | std::fstream::out );
   }
} FC_CAPTURE_AND_RETHROW( (dbdir) ) }


bool block_database::is_open()const
{
  return _blocks.is_open();
}


void block_database::close()
{
  _blocks.close();
  _block_num_to_pos.close();
}

void block_database::flush()
{
  _blocks.flush();
  _block_num_to_pos.flush();
}


void block_database::store( const block_id_type& id, const signed_block& b )
{
   auto num = block_header::num_from_id(id);
   _block_num_to_pos.seekp( sizeof( index_entry ) * num );
   index_entry e;
   _blocks.seekp( 0, _blocks.end );
   auto vec = fc::raw::pack( b );
   e.block_pos  = _blocks.tellp();
   e.block_size = vec.size();
   e.block_id   = id;
   _blocks.write( vec.data(), vec.size() );
   _block_num_to_pos.write( (char*)&e, sizeof(e) );
}


void block_database::remove( const block_id_type& id )
{ try {
   index_entry e;
   auto index_pos = sizeof(e)*block_header::num_from_id(id);
   _block_num_to_pos.seekg( 0, _block_num_to_pos.end );
   FC_ASSERT( _block_num_to_pos.tellg() > index_pos );

   _block_num_to_pos.seekg( index_pos );
   _block_num_to_pos.read( (char*)&e, sizeof(e) );

   if( e.block_id == id )
   {
      e.block_size = 0;
      _block_num_to_pos.seekp( sizeof(e)*block_header::num_from_id(id) );
      _block_num_to_pos.write( (char*)&e, sizeof(e) );
   }
} FC_CAPTURE_AND_RETHROW( (id) ) }





bool  block_database::contains( const block_id_type& id )const
{
   index_entry e;
   auto index_pos = sizeof(e)*block_header::num_from_id(id);
   _block_num_to_pos.seekg( 0, _block_num_to_pos.end );
   FC_ASSERT( _block_num_to_pos.tellg() > index_pos );

   _block_num_to_pos.seekg( index_pos );
   _block_num_to_pos.read( (char*)&e, sizeof(e) );

   return e.block_id == id;
}


block_id_type          block_database::fetch_block_id( uint32_t block_num )const
{
   index_entry e;
   auto index_pos = sizeof(e)*block_num;
   _block_num_to_pos.seekg( 0, _block_num_to_pos.end );
   FC_ASSERT( _block_num_to_pos.tellg() > index_pos );

   _block_num_to_pos.seekg( index_pos );
   _block_num_to_pos.read( (char*)&e, sizeof(e) );

   return e.block_id;
}


optional<signed_block> block_database::fetch_optional( const block_id_type& id )const
{
   try 
   {
      index_entry e;
      auto index_pos = sizeof(e)*block_header::num_from_id(id);
      _block_num_to_pos.seekg( 0, _block_num_to_pos.end );
      FC_ASSERT( _block_num_to_pos.tellg() > index_pos );
   
      _block_num_to_pos.seekg( index_pos );
      _block_num_to_pos.read( (char*)&e, sizeof(e) );
   
      if( e.block_id != id ) return optional<signed_block>();
   
      vector<char> data( e.block_size );
      _blocks.seekg( e.block_pos );
      _blocks.read( data.data(), e.block_size );
      auto result = fc::raw::unpack<signed_block>(data);
      FC_ASSERT( result.id() == e.block_id );
      return result;
   }
   catch (const fc::exception&)
   {
   }
   catch (const std::exception&)
   {
   }
   return optional<signed_block>();
}

optional<signed_block> block_database::fetch_by_number( uint32_t block_num )const
{
   try 
   {
      index_entry e;
      auto index_pos = sizeof(e)*block_num;
      _block_num_to_pos.seekg( 0, _block_num_to_pos.end );
      FC_ASSERT( _block_num_to_pos.tellg() > index_pos );

      _block_num_to_pos.seekg( index_pos, _block_num_to_pos.beg );
      _block_num_to_pos.read( (char*)&e, sizeof(e) );

      vector<char> data( e.block_size );
      _blocks.seekg( e.block_pos );
      _blocks.read( data.data(), e.block_size );
      auto result = fc::raw::unpack<signed_block>(data);
      FC_ASSERT( result.id() == e.block_id );
      return result;
   }
   catch (const fc::exception&)
   {
   }
   catch (const std::exception&)
   {
   }
   return optional<signed_block>();
}


optional<signed_block> block_database::last()const
{
   try 
   {
      index_entry e;
      _block_num_to_pos.seekg( 0, _block_num_to_pos.end );

      if( _block_num_to_pos.tellp() < sizeof(index_entry) )
         return optional<signed_block>();

      _block_num_to_pos.seekg( -sizeof(index_entry), _block_num_to_pos.end );
      _block_num_to_pos.read( (char*)&e, sizeof(e) );
      while( e.block_size == 0 && _blocks.tellg() > 0 )
      {
         _block_num_to_pos.seekg( -sizeof(index_entry), _block_num_to_pos.cur );
         _block_num_to_pos.read( (char*)&e, sizeof(e) );
      }

      if( e.block_size == 0 )
         return optional<signed_block>();

      vector<char> data( e.block_size );
      _blocks.seekg( e.block_pos );
      _blocks.read( data.data(), e.block_size );
      auto result = fc::raw::unpack<signed_block>(data);
      return result;
   }
   catch (const fc::exception&)
   {
   }
   catch (const std::exception&)
   {
   }
   return optional<signed_block>();
}

} }