/***************************************************************************
 *   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.                                   *
 ***************************************************************************/

#ifndef PIN_H
#define PIN_H

#include "wire.h"

#include <qguardedptr.h>
#include <qobject.h>
#include <qvaluelist.h>

class ECNode;
class Element;
class Pin;
class Switch;
class Wire;

typedef QValueList<Element*> ElementList;
typedef QValueList<QGuardedPtr<Pin> > PinList;
typedef QValueList<Switch*> SwitchList;
typedef QValueList<QGuardedPtr<Wire> > WireList;


/**
@author David Saxton
*/
class Pin : public QObject
{
	public:
		/**
		 * Priorities for ground pin. gt_always will (as expected) always assign
		 * the given pin as ground, gt_never will never do. If no gt_always pins
		 * exist, then the pin with the highest priority will be set as ground -
		 * if there is at least one pin that is not of ground type gt_never. These
		 * are only predefined recommended values, so if you choose not to use one
		 * of these, please respect the priorities with respect to the examples, and
		 * always specify a priority between 0 and 20.
		 * @see groundLevel
		 */
		enum GroundType
		{
			gt_always = 0, // ground
			gt_high = 5, // voltage points
			gt_medium = 10, // voltage sources
			gt_low = 15, // current sources
			gt_never = 20 // everything else
		};
		Pin( ECNode * parent );
		~Pin();
		
		ECNode * parentECNode() const { return m_pECNode; }
		/**
		 * This function returns the pins that are directly connected to this pins:
		 * either at the ends of connected wires, or via switches.
		 */
		PinList localConnectedPins() const;
		/**
		 * Adds/removes the given pin to the list of ones that this pin is/isn't
		 * connected to via a switch.
		 */
		void setSwitchConnected( Pin * pin, bool isConnected );
		/**
		 * After calculating the nodal voltages in the circuit, this function should
		 * be called to tell the pin what its voltage is.
		 */
		void setVoltage( double v ) { m_voltage = v; }
		/**
		 * Returns the voltage as set by setVoltage.
		 */
		double voltage() const { return m_voltage; }
		/**
		 * After calculating nodal voltages, each component will be called to tell
		 * its pins what the current flowing *into* the component is. This sets it
		 * to zero in preparation to merging the current.
		 */
		void resetCurrent() { m_current = 0.0; }
		/**
		 * Adds the given current to that already flowing into the pin.
		 * @see setCurrent
		 */
		void mergeCurrent( double i ) { m_current += i; }
		/**
		 * Returns the current as set by mergeCurrent.
		 */
		double current() const { return m_current; }
		/**
		 * In many cases (such as if this pin is a ground pin), the current
		 * flowing into the pin has not been calculated, and so the value
		 * returned by current() cannot be trusted.
		 */
		void setCurrentKnown( bool isKnown ) { m_bCurrentIsKnown = isKnown; }
		/**
		 * Tell thie Pin that none of the currents from the switches have yet
		 * been merged.
		 */
		void setSwitchCurrentsUnknown() { m_switchList.remove( 0l ); m_unknownSwitchCurrents = m_switchList; }
		/**
		 * This returns the value given by setCurrentKnown AND'd with whether
		 * we know the current from each switch attached to this pin.
		 * @see setCurrentKnown
		 */
		bool currentIsKnown() const { return m_bCurrentIsKnown && m_unknownSwitchCurrents.isEmpty(); }
		/**
		 * Tells the Pin that the current from the given switch has been merged.
		 */
		void setSwitchCurrentKnown( Switch * sw ) { m_unknownSwitchCurrents.remove( sw ); }
		/**
		 * Tries to calculate the Pin current from the input / output wires.
		 * @return whether was successful.
		 */
		bool calculateCurrentFromWires();
		/**
		 * Sets the "ground type" - i.e. the priority that this pin has for being
		 * ground over other pins in the circuit. Lower gt = higher priority. It's
		 * recommended to use Pin::GroundType.
		 */
		void setGroundType( int gt ) { m_groundType = gt; }
		/**
		 * Returns the priority for ground.
		 */
		int groundType() const { return m_groundType; }
		/**
		 * Adds a dependent pin - one whose voltages will (or might) affect the
		 * voltage of this pin. This is set by Component.
		 */
		void addCircuitDependentPin( Pin * pin );
		/**
		 * Adds a dependent pin - one whose voltages will (or might) affect the
		 * voltage of this pin. This is set by Component.
		 */
		void addGroundDependentPin( Pin * pin );
		/**
		 * Removes all Circuit and Ground dependent pins.
		 */
		void removeDependentPins();
		/**
		 * Returns the ids of the pins whose voltages will affect this pin.
		 * @see void setDependentPins( QStringList ids )
		 */
		PinList circuitDependentPins() const { return m_circuitDependentPins; }
		/**
		 * Returns the ids of the pins whose voltages will affect this pin.
		 * @see void setDependentPins( QStringList ids )
		 */
		PinList groundDependentPins() const { return m_groundDependentPins; }
		/**
		 * Use this function to set the pin identifier for equations,
		 * which should be done every time new pins are registered.
		 */
		void setEqId( int id ) { m_eqId = id; }
		/**
		 * The equation identifier.
		 * @see setEqId
		 */
		int eqId() const { return m_eqId; }
		/**
		 * Returns a list of elements that will affect this pin (e.g. if this
		 * pin is part of a resistor, then that list will contain a pointer to a
		 * Resistance element)
		 */
		ElementList elements() const { return m_elementList; }
		/**
		 * Adds an element to the list of those that will affect this pin.
		 */
		void addElement( Element *e );
		/**
		 * Removes an element from the list of those that will affect this pin.
		 */
		void removeElement( Element *e );
		/**
		 * Adds an switch to the list of those that will affect this pin.
		 */
		void addSwitch( Switch *e );
		/**
		 * Removes an switch from the list of those that will affect this pin.
		 */
		void removeSwitch( Switch *e );
		
		void addInputWire( Wire * wire );
		void addOutputWire( Wire * wire );
		void removeWire( Wire * wire );
		WireList inputWireList() const { return m_inputWireList; }
		WireList outputWireList() const { return m_outputWireList; }
		int numWires() const { return m_inputWireList.size() + m_outputWireList.size(); }
		
	protected:
		double m_voltage;
		double m_current;
		int m_eqId;
		bool m_bCurrentIsKnown;
		PinList m_circuitDependentPins;
		PinList m_groundDependentPins;
		ElementList m_elementList;
		SwitchList m_switchList;
		int m_groundType;
		PinList m_switchConnectedPins;
		WireList m_inputWireList;
		WireList m_outputWireList;
		ECNode * m_pECNode;
		SwitchList m_unknownSwitchCurrents;
};

#endif
