Roll20 API feature script based on polygon path on the GM layer

featurePath

var featurePath = featurePath || (function(){
    'use strict';
 
    var version = '0.1.1',
    lastUpdate = 1430550687,
    schemaVersion = '0.1.1',
    
    objExtractKeysGraphic = ['id','pageid','layer','width','height','top','left'],
    objExtractKeysPath = ['id','pageid','layer','width','height','top','left','path','stroke'],
    
    activeTrap = function(hazzard, token) {
        var objValues = getObjValue(hazzard, objExtractKeysPath),
            featureMacro =  findObjs({                                                            
                _type: 'macro',   
                name: objValues.stroke
            })[0];
        //DO SOMETHING WITH 'featureMacro'
        log(hazzard)
        log(token)
        log(featureMacro)
    },

    getObjValue = function(obj, keys) {
        return _.reduce( keys || objExtractKeys, function(m,prop){
            m[prop] = obj.get(prop);
            return m;
        }, {});
    },
    
    isPointInPoly = function (poly, pt){
        var c, i, l, j;
        for(c = false, i = -1, l = poly.length, j = l - 1; ++i < l; j = i) {
            ((poly[i].y <= pt.y && pt.y < poly[j].y) || (poly[j].y <= pt.y && pt.y < poly[i].y))
        	&& (pt.x < (poly[j].x - poly[i].x) * (pt.y - poly[i].y) / (poly[j].y - poly[i].y) + poly[i].x)
    		&& (c = !c);
        }
    	return c;
    },
    
    pathChecker = function (obj){ 
        var ObjValues = getObjValue(obj, ['layer', 'path']),
            check = true,
            firstX = false, 
            firstY = false,
            lastX, lastY;
        
        _.each(JSON.parse(ObjValues.path), function(eachPoint) {
            if( false === firstX ) {
                firstX = eachPoint[1];
                firstY = eachPoint[2];
            }
            lastX = eachPoint[1];
            lastY = eachPoint[2];
            if( 3 !== eachPoint.length ) {
                check = false;
                return false;
            }
        });
        if ( (lastX !== firstX) || (lastY !== firstY) ) {
            check = false;
        }
        if ( ('gmlayer' !== ObjValues.layer) ) {
            check = false;
        }
        return check;
    },
    
    registerPath = function(obj) {
        var objValues = getObjValue(obj, objExtractKeysPath),
            goodPath = pathChecker(obj);
        
        if(goodPath){
            obj.set({
                controlledby: 'supportedPath',
                fill: 'transparent'
            });
        }
    },
    
    checkTrap = function(obj) {
        var objValues = getObjValue(obj, objExtractKeysGraphic),
            point = [{x: objValues.left, y: objValues.top}],
            inPoly = false,
            trapId = '',
            currentPageTraps = findObjs({                              
                _pageid: objValues.pageid,                              
                _type: 'path', 
                controlledby: 'supportedPath'
            }),
            checkPath;
        
        _.each(currentPageTraps, function(obj) {
            checkPath = [];
            _.each(JSON.parse(obj.get('path')), function(eachPoint) {
                checkPath.push({
                x: parseInt(eachPoint[1] + (obj.get('left') - (obj.get('width') / 2))),
                y: parseInt(eachPoint[2] + (obj.get('top') - (obj.get('height') / 2)))
                });
            });
            inPoly = isPointInPoly(checkPath, point[0]);
            if(true === inPoly) {
                trapId = obj.get('id')
            }
        });
        if(true === inPoly) {
            activeTrap(getObj('path', trapId),obj);
        }
    },
    
    checkInstall = function() {
        
        if( ! _.has(state,'featurePath') || state.featurePath.version !== schemaVersion) {
            log('featurePath: Resetting state');
            state.featurePath = {
                version: schemaVersion
            };
        }
    },

    handleGraphicChange = function(obj) {
        var objValues = getObjValue(obj, objExtractKeysGraphic),
            playerBookMark = Campaign().get('playerpageid');
        if(('objects' === objValues.layer) && playerBookMark === objValues.pageid) {
            checkTrap(obj);
        }
    },
    
    handlePathAdd = function(obj) {
        var objValues = getObjValue(obj, objExtractKeysPath),
            playerBookMark = Campaign().get('playerpageid');
        if(('gmlayer' === objValues.layer) && playerBookMark === objValues.pageid) {
            registerPath(obj);
        }
    },

    registerEventHandlers = function() {
        on('change:graphic', handleGraphicChange);
        on('add:path', handlePathAdd);
        checkInstall();
    };
    return {
        CheckInstall: checkInstall,
        RegisterEventHandlers: registerEventHandlers
    }; 
}());
 
on('ready',function(){
    'use strict';
    featurePath.RegisterEventHandlers();
});