#include "externals.hh"
#include "undo.hh"


/*= A_UndoAction ===============================================================*/

A_UndoAction::~A_UndoAction( )
{}


/*= T_UndoManager ==============================================================*/

void T_UndoManager::undo( ) noexcept
{
	if ( pos_ > 0 ) {
		pos_ --;
		actions_[ ( start_ + pos_ ) % MaxUndo ]->undo( );
	}
}

void T_UndoManager::redo( ) noexcept
{
	if ( pos_ < count_ ) {
		pos_ ++;
		actions_[ ( start_ + pos_ ) % MaxUndo ]->redo( );
	}
}

A_UndoAction& T_UndoManager::addAction(
		P_UndoAction action ) noexcept
{
	assert( action );
	while ( pos_ < count_ ) {
		count_ --;
		actions_[ ( start_ + count_ ) % MaxUndo ].clear( );
	}

	const auto ai{ count_ == MaxUndo ? start_ : ( ( start_ + pos_ ) % MaxUndo ) };
	if ( count_ == MaxUndo ) {
		start_ = ( start_ + 1 ) % MaxUndo;
	} else {
		count_ ++;
		pos_ ++;
	}
	actions_[ ai ] = std::move( action );
	return *actions_[ ai ];
}