//  gravGun.js
//
//  Created by Mark Brosche February 10, 2019
//  Copyright 2019 Mark Brosche
//
//  DISCLAIMER - This is a derivative work based off of the functionality of the Gravity Gun 
//  as portrayed in the Half Life 2 series of games by Valve Software.  
//
//  Distributed under the Apache License, Version 2.0.
//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html

(function(){
    // Constant Variables
    var MAX_DISTANCE = 30;
    var MAX_ANGLE_FROM_RAY = 45;
    var DETECT_DISTANCE = 10;
    var MAX_WEIGHT = 60;

    // Mutable Variables
    var _this;
    var injector;
    var canGrabAvatars = false;
    var isEquipped = false;
    var children = [];
    var particles = [];
    var captureZone;
    var detectorInterval = false;

    var GravityGun = function(){
        _this = this;
    };

    GravityGun.prototype = {
        // ***** SUPPORT FUNCTIONS *****
        playSound: function(sound, localOnly){
            if (sound.downloaded) {
                if (injector) {
                    injector.stop();
                }
                injector = Audio.playSound(sound, {
                    position: MyAvatar.position,
                    volume: AUDIO_VOLUME,
                    localOnly: localOnly
                });
            } else {
                console.log("no sound downloaded");
            }
        },

        isEntityInsideZone: function(position, zoneProperties) {
            var localPosition = Vec3.multiplyQbyV(Quat.inverse(zoneProperties.rotation),
                Vec3.subtract(position, zoneProperties.position));
            var halfDimensions = Vec3.multiply(zoneProperties.dimensions, HALF_MULTIPLIER);
            return -halfDimensions.x <= localPosition.x &&
                    halfDimensions.x >= localPosition.x &&
                   -halfDimensions.y <= localPosition.y &&
                    halfDimensions.y >= localPosition.y &&
                   -halfDimensions.z <= localPosition.z &&
                    halfDimensions.z >= localPosition.z;
        },

        getEntityData: function() {
            // get any userData
            // get material entities
            // get animations
            // get sounds
            // get particles
            // get lights
        },

        materialSwap: function(entityID1, entityID2) {
            // exchange the priority levels of entityID1 and entityID2
        },
        // ***** END SUPPORT FUNCTIONS *****

        preload: function() {
            _this.getEntityData();
        },
        
        // ***** GUN METHODS *****
        openClaws: function() {
            // vibrate controller a tiny bit
            // play opening sound
        },

        closeClaws: function() {
            // vibrate controller a tiny bit
            // play closing sound
        },

        detectObject: function() {
            // if no entity is being held
            // don't detect things through walls
            // if grabbable object is within detectable range/angle, open claws, get entity props
            // if grabble object moves out of detectable range/angle, close claws
        },

        tractorBeam: function() {
            // don't detect things through walls
            // if no object in range, 
            //      claws stay closed, 
            //      play non-event sound
            //      start soft glow from barrel end
            // else if
            //      object is outside detect range but inside max range
            //      start soft glow from barrel end
            //      get entity props
            //      edit entity acceleration to point to gun's position
            // else
            //      get entity props
            //      edit entity acceleration to point to gun's position
            //      holdObject();
        },

        holdObject: function() {
            // don't detect things through walls
            // automatic when tractored objects are close enough
            // no need to hold a button to continue holding
            // set entity parent to gun
            // openClaws() if not already open
            // start lightning particles from claws to barrel end
            // play oscillating sound
            // vibrate controller a medium bit
            // recoil the gun
            // jiggle gauge needle and go from green to yellow
            // held object should retain orientation relative to player at moment of capture
            // colliding with other objects and surfaces may alter the object's orientation
            // but it will return to it's capture rotation if collisions stop
        },

        puntObject: function(entity, weight) {
            // don't detect things through walls
            // if object is held
            //      set acceleration to gun direction dependent on object weight
            //      play punt sound
            //      recoil the gun
            //      large flash and lightning particles
            //      jiggle the gauge needle
            //      closeClaws()
            //      pulse the controller heavily
            // else if object close but not held
            //      if not aimed at object centroid, calculate torque
            //      add thrust with gun direction dependent on object weight
            //      play punt sound
            //      recoil the gun
            //      pulse the controller heavily
            //      large particles
            //      jiggle the gauge needle
            // else if object not puntable/nothing to punt
            //      recoil the gun
            //      jiggle the gauge needle
        },

        dropObject: function() {
            // don't detect things through walls
            // set object acceleration to [0,-10,0]
            // play drop sound
            // stop lightning particles
            // stop soft glow particle
        },

        setEnergyLevel: function(energy) {
            switch(energy) {
                case "NORMAL":
                    // materialSwap
                    canGrabAvatars = false;
                    break;
                case "SUPERCHARGED":
                    // materialSwap
                    canGrabAvatars = true;
                    // openClaws() is permanent
                    // lightning particles sporadically appear
                    // more lens flares around the claw arms
                    // gun vibrates and hums with energy
                    // entities punted will emit lightning and twitch for a few seconds
                    break;
            }
        },

        equipGun: function() {
            // set gun entity as child of avatar's right hand
            // set twist-grip as parent of avatar's left hand?
            isEquipped = true;
            // disable far grab
            // disable scaling with grip
            detectorInterval = Script.setInterval(function() {
                _this.detectObject();
            }, interval);
        },

        dropGun: function() {
            // set gun entity as having no parent, set acceleration to [0,-10,0]
            // clear intervals
        },

        // ***** END GUN METHODS *****

        // ***** VR CONTROLS ****
        onLeftBackTwist: function() {
            if (isEquipped && leftTriggerHeld) {
                _this.tractorBeam();
                // ramp pulses increase to amount of twist
                // vibrate a lot if too much twist
            }
        },

        onLeftFrontTwist: function() {
            if (isEquipped &&leftTriggerHeld) {
                _this.dropObject();
            }
        },

        onRightButtonOne: function() {
            if (isEquipped) {
                _this.puntObject();
            }
        },

        onRightButtonGrip: function() {
            if (isEquipped){
                _this.dropGun();
            } else {
                _this.equipGun();
            }
            // pulse the controller
        },
        // ***** END VR CONTROLS ****

        // ***** DESKTOP CONTROLS ****
        // ***** END DESKTOP CONTROLS ****

        unload: function() {
            // clear any intervals
            // remove any parented objects
        }
    }
    return new GravityGun;
})