/**
 * Created by Simon on 09.05.2017.
 */
//The script is very simple.
// Hand it the object whose position
// should be calculated and set the
// variables curleft and curtop to 0:

function findPos(obj) {
    "use strict";
    var curleft = 0;
    var curtop = 0;
    if (obj.offsetParent) {
        do {
            curleft += obj.offsetLeft;
            curtop += obj.offsetTop;
        } while (obj === obj.offsetParent);
        return [curleft, curtop];
    }
}

function class_By_Y_Position($id, $activeclass, $inactiveclass, $startoffset, $endoffset, $absoluteoffset) {
    // "use strict";
    // Default values
    $startoffset = ( "undefined" !== typeof $startoffset ) ? $startoffset : 0;
    $endoffset = (  "undefined" !== typeof $endoffset  ) ? $endoffset : 0;
    $activeclass = (  "undefined" !== typeof $activeclass  ) ? $activeclass : "active";
    $inactiveclass = (  "undefined" !== typeof $inactiveclass ) ? $inactiveclass : "inactive";
    $absoluteoffset = (  "undefined" !== typeof $absoluteoffset  ) ? $absoluteoffset : false;

    // Variables
    var $elementtop;

    // Get element
    var $el = document.getElementById($id);

    // Get Start & End Pixel From Top
    var $start = 0;
    var $end = 0;

    // Get el position
    var $elementtop = findPos($el)[1];

    var pos = function () {
        console.log("el pos: " + $elementtop);
    };

    $start = $elementtop + $startoffset;


    // What should we do when scrolling occurs
    var runOnScroll = function () {
        var $scrollpos = window.scrollY;

        // Check if we are beyond the startpoint
        if ($scrollpos > $start) {


            // Now Check if it has an end
            if (
                $endoffset != 0 && // If endposition is set
                $scrollpos > ( $end )// And we are beyond that point
            ) {

                //Remove the class
                addClass($el, $inactiveclass);
                removeClass($el, $activeclass);

                //Scroll back the amount of end positioning to avoid jumps
                // Todo maybe better to integrate in another function for scrolling/fixing etc.
                //window.scrollTo(0, $end);

            }

            // In any other case add it
            else {
                removeClass($el, $inactiveclass);
                removeClass($el, 'before');

                addClass($el, $activeclass);
                addClass($el, 'after');
            }
        }

        //In any other case than being beyond start, remove the class
        else {
            addClass($el, $inactiveclass);
            addClass($el, 'before');

            removeClass($el, $activeclass);
            removeClass($el, 'after');
        }
    };

    switch ($absoluteoffset) {
        case true:

            $start = $startoffset;
            $end = $endoffset;

            break;

        case false:
            $start = ( $elementtop + $startoffset );
            $end = ( $elementtop + $endoffset );

            break;
    }
    // And then make each element do something on scroll

    // Trigger events
    window.addEventListener("load", pos);
    window.addEventListener("load", runOnScroll);

    document.addEventListener("resize", pos);
    document.addEventListener("resize", runOnScroll);

    window.addEventListener("scroll", runOnScroll);
}

function getheight($selector) {
    $identifier = $selector.substr(0, 1);

    if ($identifier === ".") {
        return $element = document.getElementsByClassName(
            $selector.substr(1))[0].getBoundingClientRect().height;
    } else if ($identifier === "#") {
        return $element = document.getElementById(
            $selector.substr(1)).getBoundingClientRect().height;
    } else {
        console.log("Error identifying selector type!");
    }
}