// Handles moving pod around during steer mode
// Based on move.js

// These parameters control the motor's speed and strength.
var MAX_MOTOR_TIMESCALE = 0.5;
var PUSHING_MOTOR_TIMESCALE = 0.25;
var BRAKING_MOTOR_TIMESCALE = 0.125;
var VERY_LONG_TIME = 1000000.0;

var AVATAR_SPEED = 4.0;
var MIN_BRAKING_SPEED = 0.2;

var motorAccumulator = {x:0.0, y:0.0, z:0.0};
var isBraking = false;

var MAX_AUTO_REPEAT_DELAY = 3;
var KEY_RELEASE_EXPIRY_MSEC = 100;

PodMover = function() 
{
	print("================  PodMover Constructor");
	// NOTE: the avatar's default orientation is such that "forward" is along the -zAxis, and "left" is along -xAxis.
	this.controlKeys = { 
	    "UP"   : new KeyInfo({x: 0.0, y: 0.0, z:-1.0}),
	    "DOWN" : new KeyInfo({x: 0.0, y: 0.0, z: 1.0}),
	    "SHIFT+LEFT" : new KeyInfo({x:-1.0, y: 0.0, z: 0.0}),
	    "SHIFT+RIGHT": new KeyInfo({x: 1.0, y: 0.0, z: 0.0}),
	    "w" : new KeyInfo({x: 0.0, y: 0.0, z:-1.0}),
	    "s" : new KeyInfo({x: 0.0, y: 0.0, z: 1.0}),
	    "a" : new KeyInfo({x: 0.0, y: 1.0, z: 0.0}),
	    "d" : new KeyInfo({x: 0.0, y:-1.0, z: 0.0})
	};
	this.pressTimestamps = {};
}

// KeyInfo class contructor:
function KeyInfo(contribution) {
    this.motorContribution = contribution; // Vec3 contribution of this key toward motorVelocity
    this.releaseTime = new Date(); // time when this button was released
    this.pressTime = new Date(); // time when this button was pressed
    this.isPressed = false;
}



// list of last timestamps when various buttons were last pressed


PodMover.prototype.keyPressEvent = function(event) {    
    var keyName = event.text;
    if (event.isShifted) {
        keyName = "SHIFT+" + keyName;
    }
  
    var key = this.controlKeys[keyName];
    if (key != undefined) {
    	key.pressTime = new Date();
        // set the last pressTimestap element to undefined (MUCH faster than removing from the list)
        this.pressTimestamps[keyName] = undefined;
        var msec = key.pressTime.valueOf() - key.releaseTime.valueOf();
        if (!key.isPressed) {
            // add this key's effect to the motorAccumulator
            motorAccumulator = Vec3.sum(motorAccumulator, key.motorContribution);
            key.isPressed = true;
        }
    }
}

PodMover.prototype.keyReleaseEvent = function(event) {
    //printDebug("POD MOVER KEY RELEASE");
    var keyName = event.text;
    if (event.isShifted) {
        keyName = "SHIFT+" + keyName;
    }

    var key = this.controlKeys[keyName];
    if (key != undefined) {
        this.pressTimestamps[keyName] = new Date();
        key.releaseTime = new Date();
        var msec = key.releaseTime.valueOf() - key.pressTime.valueOf();
    }
}

PodMover.prototype.updateMotor = function(deltaTime) {
    var now = new Date();
    for (var keyName in this.pressTimestamps) {
        var t = this.pressTimestamps[keyName];
        if (t != undefined) {
            var msec = now.valueOf() - t.valueOf();
            if (msec > KEY_RELEASE_EXPIRY_MSEC) {
                motorAccumulator = Vec3.subtract(motorAccumulator, this.controlKeys[keyName].motorContribution);
                this.controlKeys[keyName].isPressed = false;
                this.pressTimestamps[keyName] = undefined;
            }
        }
    }

    var motorVelocity = {x:0.0, y:0.0, z:0.0};

    // figure out if we're pushing or braking
    var accumulatorLength = Vec3.length(motorAccumulator);
    var isPushing = false;
    if (accumulatorLength == 0.0) {
        if (!isBraking) {
            isBraking = true;
        }
        isPushing = false;
    } else {
        isPushing = true;
        motorVelocity = Vec3.multiply(AVATAR_SPEED / accumulatorLength, motorAccumulator);
    }

    // compute the timescale
    var motorTimescale = MAX_MOTOR_TIMESCALE;
    if (isBraking) {
        var speed = Vec3.length(MyAvatar.getVelocity());
        if (speed < MIN_BRAKING_SPEED) {
            // we're going slow enough to turn off braking
            // --> we'll drift to a halt, but not so stiffly that we can't be bumped
            isBraking = false;
            motorTimescale = MAX_MOTOR_TIMESCALE;
        } else {
            // we're still braking
            motorTimescale = BRAKING_MOTOR_TIMESCALE;
        }
    } else if (isPushing) {
        motorTimescale = PUSHING_MOTOR_TIMESCALE;
    }

    // apply the motor parameters
    MyAvatar.motorVelocity = motorVelocity;
    MyAvatar.motorTimescale = motorTimescale;
}

PodMover.scriptEnding = function() {
    // disable the motor
    MyAvatar.motorVelocity = {x:0.0, y:0.0, z:0.0}
    MyAvatar.motorTimescale = VERY_LONG_TIME;
}


// init stuff
MyAvatar.motorReferenceFrame = "camera"; // "camera" is default, other options are "avatar" and "world"
MyAvatar.motorTimescale = VERY_LONG_TIME;

// connect callbacks
// Controller.keyPressEvent.connect(keyPressEvent);
// Controller.keyReleaseEvent.connect(keyReleaseEvent);
// Script.update.connect(updateMotor);
// Script.scriptEnding.connect(scriptEnding)