// electrical.hxx - a flexible, generic electrical system model.
//
// Written by Curtis Olson, started September 2002.
//
// Copyright (C) 2002  Curtis L. Olson  - http://www.flightgear.org/~curt
//
// 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.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
//
// $Id$


#ifndef _SYSTEMS_ELECTRICAL_HXX
#define _SYSTEMS_ELECTRICAL_HXX 1

#ifndef __cplusplus
# error This library requires C++
#endif

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include STL_STRING
#include <vector>

SG_USING_STD(string);
SG_USING_STD(vector);

#include <simgear/props/props.hxx>
#include <simgear/structure/subsystem_mgr.hxx>


// Forward declaration
class FGElectricalSystem;


// Base class for other electrical components
class FGElectricalComponent {

public:

enum FGElectricalComponentType {
    FG_UNKNOWN,
    FG_SUPPLIER,
    FG_BUS,
    FG_OUTPUT,
    FG_CONNECTOR
};

protected:

    typedef vector<FGElectricalComponent *> comp_list;
    typedef vector<string> string_list;

    int kind;
    string name;
    float volts;
    float load_amps;            // sum of current draw (load) due to
                                // this node and all it's children
    float available_amps;       // available current (after the load
                                // is subtracted)

    comp_list inputs;
    comp_list outputs;
    string_list props;

public:

    FGElectricalComponent();
    virtual ~FGElectricalComponent() {}

    inline const string& get_name() { return name; }

    inline int get_kind() const { return kind; }

    inline float get_volts() const { return volts; }
    inline void set_volts( float val ) { volts = val; }

    inline float get_load_amps() const { return load_amps; }
    inline void set_load_amps( float val ) { load_amps = val; }

    inline float get_available_amps() const { return available_amps; }
    inline void set_available_amps( float val ) { available_amps = val; }

    inline int get_num_inputs() const { return outputs.size(); }
    inline FGElectricalComponent *get_input( const int i ) {
        return inputs[i];
    }
    inline void add_input( FGElectricalComponent *c ) {
        inputs.push_back( c );
    }

    inline int get_num_outputs() const { return outputs.size(); }
    inline FGElectricalComponent *get_output( const int i ) {
        return outputs[i];
    }
    inline void add_output( FGElectricalComponent *c ) {
        outputs.push_back( c );
    }

    inline int get_num_props() const { return props.size(); }
    inline const string& get_prop( const int i ) {
        return props[i];
    }
    inline void add_prop( const string &s ) {
        props.push_back( s );
    }

};


// Electrical supplier
class FGElectricalSupplier : public FGElectricalComponent {

public:

    enum FGSupplierType {
        FG_BATTERY,
        FG_ALTERNATOR,
        FG_EXTERNAL,
        FG_UNKNOWN
    };

private:

    SGPropertyNode_ptr _rpm_node;

    FGSupplierType model;       // store supplier type
    float ideal_volts;          // ideal volts

    // alternator fields
    string rpm_src;             // property name of alternator power source
    float rpm_threshold;        // minimal rpm to generate full power

    // alt & ext supplier fields
    float ideal_amps;           // total amps produced (above rpm threshold).

    // battery fields
    float amp_hours;            // fully charged battery capacity
    float percent_remaining;    // percent of charge remaining
    float charge_amps;          // maximum charge load battery can draw

public:

    FGElectricalSupplier ( SGPropertyNode *node );
    ~FGElectricalSupplier () {}

    inline FGSupplierType get_model() const { return model; }
    float apply_load( float amps, float dt );
    float get_output_volts();
    float get_output_amps();
    float get_charge_amps() const { return charge_amps; }
};


// Electrical bus (can take multiple inputs and provide multiple
// outputs)
class FGElectricalBus : public FGElectricalComponent {

public:

    FGElectricalBus ( SGPropertyNode *node );
    ~FGElectricalBus () {}
};


// A lot like an FGElectricalBus, but here for convenience and future
// flexibility
class FGElectricalOutput : public FGElectricalComponent {

public:

    FGElectricalOutput ( SGPropertyNode *node );
    ~FGElectricalOutput () {}
};


// Model an electrical switch.  If the rating_amps > 0 then this
// becomes a circuit breaker type switch that can trip
class FGElectricalSwitch {

private:

    SGPropertyNode_ptr switch_node;
    float rating_amps;
    bool circuit_breaker;

public:

    FGElectricalSwitch( SGPropertyNode *node );

    ~FGElectricalSwitch() { };

    inline bool get_state() const { return switch_node->getBoolValue(); }
    void set_state( bool val ) { switch_node->setBoolValue( val ); }
};


// Connects multiple sources to multiple destinations with optional
// switches/fuses/circuit breakers inline
class FGElectricalConnector : public FGElectricalComponent {

    comp_list inputs;
    comp_list outputs;
    typedef vector< FGElectricalSwitch> switch_list;
    switch_list switches;

public:

    FGElectricalConnector ( SGPropertyNode *node, FGElectricalSystem *es );
    ~FGElectricalConnector () {}

    void add_switch( FGElectricalSwitch s ) {
        switches.push_back( s );
    }

    // set all switches to the specified state
    void set_switches( bool state );

    bool get_state();
};


/**
 * Model an electrical system.  This is a fairly simplistic system
 * 
 */

class FGElectricalSystem : public SGSubsystem
{

public:

    FGElectricalSystem ( SGPropertyNode *node );
    virtual ~FGElectricalSystem ();

    virtual void init ();
    virtual void bind ();
    virtual void unbind ();
    virtual void update (double dt);

    bool build ();
    float propagate( FGElectricalComponent *node, double dt,
                     float input_volts, float input_amps,
                     string s = "" );
    FGElectricalComponent *find ( const string &name );

protected:

    typedef vector<FGElectricalComponent *> comp_list;

private:

    string name;
    int num;
    string path;
    SGPropertyNode *config_props;

    bool enabled;

    comp_list suppliers;
    comp_list buses;
    comp_list outputs;
    comp_list connectors;

    SGPropertyNode_ptr _volts_out;
    SGPropertyNode_ptr _amps_out;
};


#endif // _SYSTEMS_ELECTRICAL_HXX