#include "StockMarket.h"
#include "Stock.h"
#include "Order.h"
#include <iostream>
#include <iomanip>
#include <algorithm>

class HigherPrice
{
public:
  bool operator() ( const Order* o1, const Order* o2 ) const
  { return ( o1->price() > o2->price() ); }
};

class LowerPrice
{
public:
  bool operator() ( const Order* o1, const Order* o2 ) const
  { return ( o1->price() < o2->price() ); }
};

void StockMarket::add( Stock* stock )
{
  stocks_.push_back( stock );
}

void StockMarket::addSell( Order* order )
{
  orders_[ order->stock() ].sell.push_back( order );
}

void StockMarket::addBuy( Order* order )
{
  orders_[ order->stock() ].buy.push_back( order );
}

void StockMarket::doTask()
{
  vector< Stock* >::iterator i;
  for( i = stocks_.begin(); i != stocks_.end(); i++ )
    execute( * i );
}

list<Order*>::iterator StockMarket::topSell( Stock* stock )
{
  list<Order*> & l = orders_[ stock ].sell;
  HigherPrice c;
  return max_element( l.begin(), l.end(), c );
}

list<Order *>::iterator StockMarket::topBuy( Stock* stock )
{
  list<Order*> & l = orders_[ stock ].buy;
  LowerPrice c;
  return max_element( l.begin(), l.end(), c );
}

void StockMarket::execute( Stock* stock )
{
  //  cout << "*** Executing transactions ***" << endl;

  list<Order*>::iterator i;
  // cancel expired orders
  vector<list<Order*>::iterator> expiredBuy, expiredSell;
  list<Order*> & buyList = orders_[ stock ].buy;
  list<Order*> & sellList = orders_[ stock ].sell;
  for ( i = buyList.begin();  i != buyList.end();  i++ ) if ( (*i)->expired() ) expiredBuy.push_back( i );
  for ( i = sellList.begin(); i != sellList.end(); i++ ) if ( (*i)->expired() ) expiredSell.push_back( i );
  vector<list<Order*>::iterator>::iterator j;
  for( j = expiredBuy.begin(); j != expiredBuy.end(); j++ )
  {
    buyList.erase( *j );
    delete **j;
  }
  for( j = expiredSell.begin(); j != expiredSell.end(); j++ )
  {
    sellList.erase( *j );
    delete **j;
  }
  // execute active orders
  double sum = 0;
  long volume = 0;
  while ( ! sellList.empty() && ! buyList.empty() )
  {
    list<Order*>::iterator isell = topSell( stock );
    list<Order*>::iterator ibuy  = topBuy( stock );
    Order * sell = * isell;
    Order * buy  = * ibuy;
    if ( buy->price() < sell->price() ) break;
    long amount = min( buy->amount(), sell->amount() );
    double price = sell->price();
    if ( buy->execute( price, amount ) )
    {
      sell->execute( price, amount );
      sum += price * amount;
      volume += amount;
      //      cout << "executed transaction: " << amount << " " << stock->symbol() 
      //	   << " at $" << price << " ($" << buy->price() << ")" << endl;
      if ( buy->amount() == 0 ) 
       {
	 buyList.erase( ibuy );
	 delete buy;
       }
      if ( sell->amount() == 0 ) 
      {
	sellList.erase( isell );
	delete sell;
      }
    }
  }
  
  // update stock price history
  double price = stock->price();
  if ( volume > 0 )
  {
    price = sum / volume;
  }
  double gain = ( ( price - stock->price()) / stock->price() ) * 100;
  cout << stock->symbol() << ": $" << setprecision(7) << setw(8) << price 
       << " (" << setprecision(7) << setw(8) << gain << "%)"
       << " volume: $" << setprecision(7) << setw(8) << volume*price << endl;
  stock->setPrice( price );

  // notify active orders
  for ( i = buyList.begin(); i != buyList.end(); i++ )   (*i)->notify();
  for ( i = sellList.begin(); i != sellList.end(); i++ ) (*i)->notify();

  //  cout << "*** End of transactions ***" << endl;
}