/**
 * 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!" );
    }
}