##########################################
# Autostart
##########################################

var autostart = func (msg=1) {
    if (getprop("/engines/active-engine/running")) {
        if (msg)
            gui.popupTip("Engine already running", 5);
        return;
    }

    setprop("/controls/switches/magnetos", 3);
    setprop("/controls/engines/current-engine/throttle", 0.2);
    setprop("/controls/engines/current-engine/mixture", 1.0);
    setprop("/controls/flight/elevator-trim", 0.0);
    setprop("/controls/switches/master-bat", 1);
    setprop("/controls/switches/master-alt", 1);
    setprop("/controls/switches/master-avionics", 1);

    setprop("/controls/lighting/nav-lights", 1);
    setprop("/controls/lighting/strobe", 1);
    setprop("/controls/lighting/beacon", 1);

    setprop("/consumables/fuel/tank[0]/selected", 1);
    setprop("/consumables/fuel/tank[1]/selected", 1);

    # Set the altimeter
    var pressure_sea_level = getprop("/environment/pressure-sea-level-inhg");
    setprop("/instrumentation/altimeter/setting-inhg", pressure_sea_level);

    # Set heading offset
    var magnetic_variation = getprop("/environment/magnetic-variation-deg");
    setprop("/instrumentation/heading-indicator/offset-deg", -magnetic_variation);

    # Pre-flight inspection
    setprop("/sim/model/c172p/brake-parking", 0);
    setprop("/sim/model/c172p/securing/chock", 0);
    setprop("/sim/model/c172p/securing/pitot-cover-visible", 0);
    setprop("/sim/model/c172p/securing/tiedownL-visible", 0);
    setprop("/sim/model/c172p/securing/tiedownR-visible", 0);
    setprop("/sim/model/c172p/securing/tiedownT-visible", 0);

    setprop("/consumables/fuel/tank[0]/water-contamination", 0.0);
    setprop("/consumables/fuel/tank[1]/water-contamination", 0.0);

    # Oil level warning for lazy pro's
    var oil_enabled = getprop("/engines/active-engine/oil_consumption_allowed");
    var oil_level   = getprop("/engines/active-engine/oil-level");

    if (oil_enabled and oil_level < 6.0)
        logger.screen.red("Warning: low oil level! Check level via oil cap on top of engine!");

    # Fuel level warnings
    var fuel_level_left  = getprop("/consumables/fuel/tank[0]/level-norm");
    var fuel_level_right = getprop("/consumables/fuel/tank[1]/level-norm");

    if (fuel_level_left < 0.25)
        logger.screen.red("Warning: fuel level of the left tank lower than 25%!");
    if (fuel_level_right < 0.25)
        logger.screen.red("Warning: fuel level of the right tank lower than 25%!");

    setprop("/controls/engines/engine[0]/primer-lever", 0);
    setprop("/controls/engines/engine/primer", 3);

    if (msg)
        gui.popupTip("Hold down \"s\" to start the engine", 5);
};

##########################################
# Brakes
##########################################

controls.applyBrakes = func (v, which = 0) {
    if (which <= 0 and !getprop("/fdm/jsbsim/gear/unit[1]/broken")) {
        interpolate("/controls/gear/brake-left", v, controls.fullBrakeTime);
    }
    if (which >= 0 and !getprop("/fdm/jsbsim/gear/unit[2]/broken")) {
        interpolate("/controls/gear/brake-right", v, controls.fullBrakeTime);
    }
};

controls.applyParkingBrake = func (v) {
    if (!v) {
        return;
    }

    var p = "/sim/model/c172p/brake-parking";
    setprop(p, var i = !getprop(p));
    return i;
};

##########################################
# Fuel Save State
##########################################
var fuel_save_state = func {
    if (!getprop("/consumables/fuel/save-fuel-state")) {    
        setprop("/consumables/fuel/tank[0]/level-gal_us", 20);
        setprop("/consumables/fuel/tank[1]/level-gal_us", 20);
    };    
};

##########################################
# Fuel Contamination
##########################################
var fuel_contamination = func {
    var chance = rand();

    # Chance of contamination is 1 %
    if (getprop("/consumables/fuel/contamination_allowed") and chance < 0.01) {
        # Quantity of water is much more likely to be small than large, since
        # it's given by x^6 (76 % of the time it will be lower than 0.2)
        var water = math.pow(rand(), 6);

        setprop("/consumables/fuel/tank[0]/water-contamination", water);

        # level of water in the right tank will be the same as in the left tank +- 0.1
        water = water + 0.2 * (rand() - 0.5);
        water = std.max(0.0, std.min(water, 1.0));
        setprop("/consumables/fuel/tank[1]/water-contamination", water);
    }
    else {
        setprop("/consumables/fuel/tank[0]/water-contamination", 0.0);
        setprop("/consumables/fuel/tank[1]/water-contamination", 0.0);
    };
};

##########################################
# Take Fuel Sample
##########################################
var take_fuel_sample = func(index) {
    var fuel = getprop("/consumables/fuel/tank", index, "level-gal_us");
    var water = getprop("/consumables/fuel/tank", index, "water-contamination");

    # Remove 50 ml of fuel
    setprop("/consumables/fuel/tank", index, "level-gal_us", fuel - 0.0132086);

    # Remove a bit of water if contaminated
    if (water > 0.0) {
        water = std.max(0.0, water - 0.2);
        setprop("/consumables/fuel/tank", index, "water-contamination", water);
    };
};

##########################################
# Return Fuel Sample
##########################################
var return_fuel_sample = func(index) {
    var fuel = getprop("/consumables/fuel/tank", index, "level-gal_us");
    var water = getprop("/consumables/fuel/tank", index, "water-contamination");

    # Add back the 50 ml of fuel
    setprop("/consumables/fuel/tank", index, "level-gal_us", fuel + 0.0132086);

    # Add back the (contaminated) water
    if (water > 0.0) {
        water = std.min(water + 0.2, 1.0);
        setprop("/consumables/fuel/tank", index, "water-contamination", water);
    };
};

##########################################
# Switches Save State
##########################################
var switches_save_state = func {
    if (!getprop("/instrumentation/save-switches-state")) {
        setprop("/controls/engines/engine[0]/primer", 0);
        setprop("/controls/engines/engine[0]/primer-lever", 0);
        setprop("/controls/engines/engine[0]/use-primer", 0);
        setprop("/controls/engines/engine[1]/primer", 0);
        setprop("/controls/engines/engine[1]/primer-lever", 0);
        setprop("/controls/engines/engine[1]/use-primer", 0);
        setprop("/controls/engines/current-engine/throttle", 0.0);
        setprop("/controls/engines/current-engine/mixture", 0.0);
        setprop("/controls/circuit-breakers/aircond", 1);
        setprop("/controls/circuit-breakers/autopilot", 1);
        setprop("/controls/circuit-breakers/bcnlt", 1);
        setprop("/controls/circuit-breakers/flaps", 1);
        setprop("/controls/circuit-breakers/instr", 1);
        setprop("/controls/circuit-breakers/intlt", 1);
        setprop("/controls/circuit-breakers/landing", 1);
        setprop("/controls/circuit-breakers/master", 1);
        setprop("/controls/circuit-breakers/navlt", 1);
        setprop("/controls/circuit-breakers/pitot-heat", 1);
        setprop("/controls/circuit-breakers/radio1", 1);
        setprop("/controls/circuit-breakers/radio2", 1);
        setprop("/controls/circuit-breakers/radio3", 1);
        setprop("/controls/circuit-breakers/radio4", 1);
        setprop("/controls/circuit-breakers/radio5", 1);
        setprop("/controls/circuit-breakers/strobe", 1);
        setprop("/controls/circuit-breakers/turn-coordinator", 1);
        setprop("/controls/switches/master-avionics", 0);
        setprop("/controls/switches/starter", 0);
        setprop("/controls/switches/master-alt", 0);
        setprop("/controls/switches/master-bat", 0);
        setprop("/controls/switches/magnetos", 0);
        setprop("/controls/lighting/nav-lights", 0);
        setprop("/controls/lighting/beacon", 0);
        setprop("/controls/lighting/strobe", 0);
        setprop("/controls/lighting/taxi-light", 0);
        setprop("/controls/lighting/landing-lights", 0);
        setprop("/controls/lighting/instruments-norm", 0.0);
        setprop("/controls/gear/water-rudder", 0);
        setprop("/controls/gear/water-rudder-down", 0);
        setprop("/sim/model/c172p/brake-parking", 1);
        setprop("/controls/flight/flaps", 0.0);
        setprop("/surface-positions/flap-pos-norm", 0.0);
        setprop("/controls/flight/elevator-trim", 0.0);
        setprop("/controls/anti-ice/engine[0]/carb-heat", 0);
        setprop("/controls/anti-ice/engine[1]/carb-heat", 0);
        setprop("/controls/anti-ice/pitot-heat", 0);
        setprop("/environment/aircraft-effects/cabin-heat-set", 0.0);
        setprop("/environment/aircraft-effects/cabin-air-set", 0.0);
        setprop("/consumables/fuel/tank[0]/selected", 1);
        setprop("/consumables/fuel/tank[1]/selected", 1);
    };    
};

##########################################
# Click Sounds
##########################################

var click = func (name, timeout=0.1, delay=0) {
    var sound_prop = "/sim/model/c172p/sound/click-" ~ name;

    settimer(func {
        # Play the sound
        setprop(sound_prop, 1);

        # Reset the property after 0.2 seconds so that the sound can be
        # played again.
        settimer(func {
            setprop(sound_prop, 0);
        }, timeout);
    }, delay);
};

##########################################
# Thunder Sound
##########################################

var speed_of_sound = func (t, re) {
    # Compute speed of sound in m/s
    #
    # t = temperature in Celsius
    # re = amount of water vapor in the air

    # Compute virtual temperature using mixing ratio (amount of water vapor)
    # Ratio of gas constants of dry air and water vapor: 287.058 / 461.5 = 0.622
    var T = 273.15 + t;
    var v_T = T * (1 + re/0.622)/(1 + re);

    # Compute speed of sound using adiabatic index, gas constant of air,
    # and virtual temperature in Kelvin.
    return math.sqrt(1.4 * 287.058 * v_T);
};

var thunder = func (name) {
    var thunderCalls = 0;

    var lightning_pos_x = getprop("/environment/lightning/lightning-pos-x");
    var lightning_pos_y = getprop("/environment/lightning/lightning-pos-y");
    var lightning_distance = math.sqrt(math.pow(lightning_pos_x, 2) + math.pow(lightning_pos_y, 2));

    # On the ground, thunder can be heard up to 16 km. Increase this value
    # a bit because the aircraft is usually in the air.
    if (lightning_distance > 20000)
        return;

    var t = getprop("/environment/temperature-degc");
    var re = getprop("/environment/relative-humidity") / 100;
    var delay_seconds = lightning_distance / speed_of_sound(t, re);

    # Maximum volume at 5000 meter
    var lightning_distance_norm = std.min(1.0, 1 / math.pow(lightning_distance / 5000.0, 2));

    settimer(func {
        var thunder1 = getprop("/sim/model/c172p/sound/click-thunder1");
        var thunder2 = getprop("/sim/model/c172p/sound/click-thunder2");
        var thunder3 = getprop("/sim/model/c172p/sound/click-thunder3");

        if (!thunder1) {
            thunderCalls = 1;
            setprop("/sim/model/c172p/sound/lightning/dist1", lightning_distance_norm);
        }
        else if (!thunder2) {
            thunderCalls = 2;
            setprop("/sim/model/c172p/sound/lightning/dist2", lightning_distance_norm);
        }
        else if (!thunder3) {
            thunderCalls = 3;
            setprop("/sim/model/c172p/sound/lightning/dist3", lightning_distance_norm);
        }
        else
            return;

        # Play the sound (sound files are about 9 seconds)
        click("thunder" ~ thunderCalls, 9.0, 0);
    }, delay_seconds);
};

var reset_system = func {
    if (getprop("/fdm/jsbsim/running")) {
        c172p.autostart(0);
        setprop("/controls/switches/starter", 1);
        var engineRunning = setlistener("/engines/active-engine/running", func {
            if (getprop("/engines/active-engine/running")) {
                setprop("/controls/switches/starter", 0);
                removelistener(engineRunning);
            }
        });
    }

    # These properties are aliased to MP properties in /sim/multiplay/generic/.
    # This aliasing seems to work in both ways, because the two properties below
    # appear to receive the random values from the MP properties during initialization.
    # Therefore, override these random values with the proper values we want.
    props.globals.getNode("/fdm/jsbsim/crash", 0).setBoolValue(0);
    props.globals.getNode("/fdm/jsbsim/gear/unit[0]/broken", 0).setBoolValue(0);
    props.globals.getNode("/fdm/jsbsim/gear/unit[1]/broken", 0).setBoolValue(0);
    props.globals.getNode("/fdm/jsbsim/gear/unit[2]/broken", 0).setBoolValue(0);
    props.globals.getNode("/fdm/jsbsim/pontoon-damage/left-pontoon", 0).setIntValue(0);
    props.globals.getNode("/fdm/jsbsim/pontoon-damage/right-pontoon", 0).setIntValue(0);

    setprop("/engines/active-engine/kill-engine", 0);
}

############################################
# Engine coughing sound
############################################

setlistener("/engines/active-engine/killed", func (node) {
    if (node.getValue() and getprop("/engines/active-engine/running")) {
        click("coughing-engine-sound", 0.7, 0);
    };
});

############################################
# Global loop function
# If you need to run nasal as loop, add it in this function
############################################
var global_system_loop = func {
    c172p.physics_loop();
}

##########################################
# SetListerner must be at the end of this file
##########################################
var set_limits = func (node) {
    if (node.getValue() == 1) {
        var limits = props.globals.getNode("/limits/mass-and-balance-180hp");
    }
    else {
        var limits = props.globals.getNode("/limits/mass-and-balance-160hp");
    }
    var ac_limits = props.globals.getNode("/limits/mass-and-balance");

    # Get the mass limits of the current engine
    var ramp_mass = limits.getNode("maximum-ramp-mass-lbs");
    var takeoff_mass = limits.getNode("maximum-takeoff-mass-lbs");
    var landing_mass = limits.getNode("maximum-landing-mass-lbs");

    # Get the actual mass limit nodes of the aircraft
    var ac_ramp_mass = ac_limits.getNode("maximum-ramp-mass-lbs");
    var ac_takeoff_mass = ac_limits.getNode("maximum-takeoff-mass-lbs");
    var ac_landing_mass = ac_limits.getNode("maximum-landing-mass-lbs");

    # Set the mass limits of the aircraft
    ac_ramp_mass.unalias();
    ac_takeoff_mass.unalias();
    ac_landing_mass.unalias();

    ac_ramp_mass.alias(ramp_mass);
    ac_takeoff_mass.alias(takeoff_mass);
    ac_landing_mass.alias(landing_mass);
};

setlistener("/controls/engines/active-engine", func (node) {
    # Set new mass limits for Fuel and Payload Settings dialog
    set_limits(node);

    # Emit a sound because the engine has been replaced
    click("engine-repair", 6.0);
}, 0, 0);

var update_pax = func {
    var state = 0;
    state = bits.switch(state, 0, getprop("pax/co-pilot/present"));
    state = bits.switch(state, 1, getprop("pax/left-passenger/present"));
    state = bits.switch(state, 2, getprop("pax/right-passenger/present"));
    state = bits.switch(state, 3, getprop("pax/pilot/present"));
    setprop("/payload/pax-state", state);
};

setlistener("/pax/co-pilot/present", update_pax, 0, 0);
setlistener("/pax/left-passenger/present", update_pax, 0, 0);
setlistener("/pax/right-passenger/present", update_pax, 0, 0);
setlistener("/pax/pilot/present", update_pax, 0, 0);
update_pax();

var update_securing = func {
    var state = 0;
    state = bits.switch(state, 0, getprop("/sim/model/c172p/securing/pitot-cover-visible"));
    state = bits.switch(state, 1, getprop("/sim/model/c172p/securing/chock-visible"));
    state = bits.switch(state, 2, getprop("/sim/model/c172p/securing/tiedownL-visible"));
    state = bits.switch(state, 3, getprop("/sim/model/c172p/securing/tiedownR-visible"));
    state = bits.switch(state, 4, getprop("/sim/model/c172p/securing/tiedownT-visible"));
    setprop("/payload/securing-state", state);
};

setlistener("/sim/model/c172p/securing/pitot-cover-visible", update_securing, 0, 0);
setlistener("/sim/model/c172p/securing/chock-visible", update_securing, 0, 0);
setlistener("/sim/model/c172p/securing/tiedownL-visible", update_securing, 0, 0);
setlistener("/sim/model/c172p/securing/tiedownR-visible", update_securing, 0, 0);
setlistener("/sim/model/c172p/securing/tiedownT-visible", update_securing, 0, 0);
update_securing();

var log_cabin_temp = func {
    if (getprop("/sim/model/c172p/enable-fog-frost")) {
        var temp_degc = getprop("/fdm/jsbsim/heat/cabin-air-temp-degc");
        if (temp_degc >= 32)
            logger.screen.red("Cabin temperature exceeding 90F/32C!");
        elsif (temp_degc <= 0)
            logger.screen.red("Cabin temperature falling below 32F/0C!");
    }
};
var cabin_temp_timer = maketimer(30.0, log_cabin_temp);

var log_fog_frost = func {
    if (getprop("/sim/model/c172p/enable-fog-frost")) {
        logger.screen.white("Wait until fog/frost clears up or decrease cabin air temperature");
    }
};
var fog_frost_timer = maketimer(30.0, log_fog_frost);

setlistener("/sim/signals/fdm-initialized", func {
    # Use Nasal to make some properties persistent. <aircraft-data> does
    # not work reliably.
    aircraft.data.add("/sim/model/c172p/immat-on-panel");
    aircraft.data.load();

    # Initialize mass limits
    set_limits(props.globals.getNode("/controls/engines/active-engine"));

    # Set alt alert of KAP 140 autopilot to 20_000 ft to get rid of annoying beep
    setlistener("/autopilot/KAP140/settings/target-alt-ft", func (n) {
        if (n.getValue() == 0) {
            kap140.altPreselect = 20000;
            setprop("/autopilot/KAP140/settings/target-alt-ft", kap140.altPreselect);
        }
    });
    
    setlistener("/sim/model/c172p/cabin-air-temp-in-range", func (node) {
        if (node.getValue()) {
            cabin_temp_timer.stop();
            logger.screen.green("Cabin temperature between 32F/0C and 90F/32C");
        }
        else {
            log_cabin_temp();
            cabin_temp_timer.start();
        }
    }, 1, 0);

    setlistener("/sim/model/c172p/fog-or-frost-increasing", func (node) {
        if (node.getValue()) {
            log_fog_frost();
            fog_frost_timer.start();
        }
        else {
            fog_frost_timer.stop();
        }
    }, 1, 0);

    # Checking if fuel tanks should be refilled (in case save state is off)
    fuel_save_state();
    
    # Checking if switches should be moved back to default position (in case save state is off)
    switches_save_state();
    
    # Checking if fuel contamination is allowed, and if so generating a random situation
    fuel_contamination();
    
    # Listening for lightning strikes
    setlistener("/environment/lightning/lightning-pos-y", thunder);

    reset_system();
    var c172_timer = maketimer(0.25, func{global_system_loop()});
    c172_timer.start();
});