/***************************************************************************
 *   Copyright (C) 2005 by David Saxton                                    *
 *   david@bluehaze.org                                                    *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 ***************************************************************************/

#include "pin.h"
#include "wire.h"
#include <assert.h>

Wire::Wire( Pin * startPin, Pin * endPin )
{
	assert(startPin);
	assert(endPin);
	
	m_pStartPin = startPin;
	m_pEndPin = endPin;
	m_current = 0.;
	m_bCurrentIsKnown = false;
	
	m_pStartPin->addOutputWire(this);
	m_pEndPin->addInputWire(this);
}


Wire::~Wire()
{
}


bool Wire::calculateCurrent()
{
	if ( m_pStartPin->currentIsKnown() && m_pStartPin->numWires() < 2 )
	{
		m_current = m_pStartPin->current();
		m_bCurrentIsKnown = true;
		return true;
	}
	
	if ( m_pEndPin->currentIsKnown() && m_pEndPin->numWires() < 2 )
	{
		m_current = -m_pEndPin->current();
		m_bCurrentIsKnown = true;
		return true;
	}
	
	if ( m_pStartPin->currentIsKnown() )
	{
		double i = m_pStartPin->current();
		bool ok = true;
		const WireList outlist = m_pStartPin->outputWireList();
		WireList::const_iterator end = outlist.end();
		for ( WireList::const_iterator it = outlist.begin(); it != end && ok; ++it )
		{
			if ( *it && (Wire*)*it != this )
			{
				if ( (*it)->currentIsKnown() )
					i -= (*it)->current();
				
				else
					ok = false;
			}
		}
		const WireList inlist = m_pStartPin->inputWireList();
		end = inlist.end();
		for ( WireList::const_iterator it = inlist.begin(); it != end && ok; ++it )
		{
			if ( *it && (Wire*)*it != this )
			{
				if ( (*it)->currentIsKnown() )
					i += (*it)->current();
				
				else
					ok = false;
			}
		}
		
		if (ok)
		{
			m_current = i;
			m_bCurrentIsKnown = true;
			return true;
		}
	}
	
	if ( m_pEndPin->currentIsKnown() )
	{
		double i = -m_pEndPin->current();
		bool ok = true;
		const WireList outlist = m_pEndPin->outputWireList();
		WireList::const_iterator end = outlist.end();
		for ( WireList::const_iterator it = outlist.begin(); it != end && ok; ++it )
		{
			if ( *it && (Wire*)*it != this )
			{
				if ( (*it)->currentIsKnown() )
					i += (*it)->current();
				
				else
					ok = false;
			}	
		}
		const WireList inlist = m_pEndPin->inputWireList();
		end = inlist.end();
		for ( WireList::const_iterator it = inlist.begin(); it != end && ok; ++it )
		{
			if ( *it && (Wire*)*it != this )
			{
				if ( (*it)->currentIsKnown() )
					i -= (*it)->current();
				
				else
					ok = false;
			}	
		}
		
		if (ok)
		{	
			m_current = i;
			m_bCurrentIsKnown = true;
			return true;
		}
	}
	
	m_bCurrentIsKnown = false;
	return false;
}


double Wire::voltage() const
{
	return ( m_pStartPin->voltage() + m_pEndPin->voltage() )/2;
}


void Wire::setCurrentKnown( bool known )
{
	m_bCurrentIsKnown = known;
	if (!known)
		m_current = 0.;
}