// Sticky Plugin v1.0.4 for jQuery
// =============
// Author: Anthony Garand
// Improvements by German M. Bravo (Kronuz) and Ruud Kamphuis (ruudk)
// Improvements by Leonardo C. Daronco (daronco)
// Created: 02/14/2011
// Date: 07/20/2015
// Website: http://stickyjs.com/
// Description: Makes an element on the page stick on the screen as you scroll
//              It will only set the 'top' and 'position' of your element, you
//              might need to adjust the width in some cases.

(function (factory) {
    if (typeof define === 'function' && define.amd) {
        // AMD. Register as an anonymous module.
        define(['jquery'], factory);
    } else if (typeof module === 'object' && module.exports) {
        // Node/CommonJS
        module.exports = factory(require('jquery'));
    } else {
        // Browser globals
        factory(jQuery);
    }
}(function ($) {
    var slice = Array.prototype.slice; // save ref to original slice()
    var splice = Array.prototype.splice; // save ref to original slice()

    var defaults = {
            topSpacing: 0,
            bottomSpacing: 0,
            className: 'is-sticky',
            wrapperClassName: 'sticky-wrapper',
            center: false,
            getWidthFrom: '',
            widthFromWrapper: true, // works only when .getWidthFrom is empty
            responsiveWidth: false,
            zIndex: 'auto'
        },
        $window = $(window),
        $document = $(document),
        sticked = [],
        windowHeight = $window.height(),
        scroller = throttle(function() {
            var scrollTop = $window.scrollTop(),
                documentHeight = $document.height(),
                dwh = documentHeight - windowHeight,
                extra = (scrollTop > dwh) ? dwh - scrollTop : 0;

            for (var i = 0, l = sticked.length; i < l; i++) {
                var s = sticked[i],
                    elementTop = s.stickyWrapper.offset().top,
                    etse = elementTop - s.topSpacing - extra;

                //update height in case of dynamic content
                s.stickyWrapper.css('height', s.stickyElement.outerHeight());

                if (scrollTop <= etse) {
                    if (s.currentTop !== null) {
                        s.stickyElement
                            .css({
                                'width': '',
                                'position': '',
                                'top': '',
                                'z-index': ''
                            });
                        s.stickyElement.parent().removeClass(s.className).css('height','');;
                        s.stickyElement.trigger('sticky-end', [s]);
                        s.currentTop = null;
                    }
                }
                else {
                    var newTop = documentHeight - s.stickyElement.outerHeight()
                        - s.topSpacing - s.bottomSpacing - scrollTop - extra;
                    if (newTop < 0) {
                        newTop = newTop + s.topSpacing;
                    } else {
                        newTop = s.topSpacing;
                    }
                    if (s.currentTop !== newTop) {
                        var newWidth;
                        if (s.getWidthFrom) {
                            newWidth = $(s.getWidthFrom).width() || null;
                        } else if (s.widthFromWrapper) {
                            newWidth = s.stickyWrapper.width();
                        }
                        if (newWidth == null) {
                            newWidth = s.stickyElement.width();
                        }
                        s.stickyElement
                            .css('width', newWidth)
                            .css('position', 'fixed')
                            .css('top', newTop)
                            .css('z-index', s.zIndex);

                        s.stickyElement.parent().addClass(s.className);

                        if (s.currentTop === null) {
                            s.stickyElement.trigger('sticky-start', [s]);
                        } else {
                            // sticky is started but it have to be repositioned
                            s.stickyElement.trigger('sticky-update', [s]);
                        }

                        if (s.currentTop === s.topSpacing && s.currentTop > newTop || s.currentTop === null && newTop < s.topSpacing) {
                            // just reached bottom || just started to stick but bottom is already reached
                            s.stickyElement.trigger('sticky-bottom-reached', [s]);
                        } else if(s.currentTop !== null && newTop === s.topSpacing && s.currentTop < newTop) {
                            // sticky is started && sticked at topSpacing && overflowing from top just finished
                            s.stickyElement.trigger('sticky-bottom-unreached', [s]);
                        }

                        s.currentTop = newTop;
                    }

                    // Check if sticky has reached end of container and stop sticking
                    var stickyWrapperContainer = s.stickyWrapper.parent();
                    var unstick = (s.stickyElement.offset().top + s.stickyElement.outerHeight() >= stickyWrapperContainer.offset().top + stickyWrapperContainer.outerHeight()) && (s.stickyElement.offset().top <= s.topSpacing);

                    if( unstick ) {
                        s.stickyElement
                            .css('position', 'absolute')
                            .css('top', '')
                            .css('bottom', 0)
                            .css('z-index', '');
                    } else {
                        s.stickyElement
                            .css('position', 'fixed')
                            .css('top', newTop)
                            .css('bottom', '')
                            .css('z-index', s.zIndex);
                    }
                }
            }
        },10),
        resizer = throttle(function() {
            windowHeight = $window.height();

            for (var i = 0, l = sticked.length; i < l; i++) {
                var s = sticked[i];
                var newWidth = null;
                if (s.getWidthFrom) {
                    if (s.responsiveWidth) {
                        newWidth = $(s.getWidthFrom).width();
                    }
                } else if(s.widthFromWrapper) {
                    newWidth = s.stickyWrapper.width();
                }
                if (newWidth != null) {
                    s.stickyElement.css('width', newWidth);
                }
            }
        },10),
        methods = {
            init: function(options) {
                return this.each(function() {
                    var o = $.extend({}, defaults, options);
                    var stickyElement = $(this);

                    var stickyId = stickyElement.attr('id');
                    var wrapperId = stickyId ? stickyId + '-' + defaults.wrapperClassName : defaults.wrapperClassName;
                    var wrapper = $('<div></div>')
                        .attr('id', wrapperId)
                        .addClass(o.wrapperClassName);

                    stickyElement.wrapAll(function() {
                        if ($(this).parent("#" + wrapperId).length == 0) {
                            return wrapper;
                        }
                    });

                    var stickyWrapper = stickyElement.parent();

                    if (o.center) {
                        stickyWrapper.css({width:stickyElement.outerWidth(),marginLeft:"auto",marginRight:"auto"});
                    }

                    if (stickyElement.css("float") === "right") {
                        stickyElement.css({"float":"none"}).parent().css({"float":"right"});
                    }

                    o.stickyElement = stickyElement;
                    o.stickyWrapper = stickyWrapper;
                    o.currentTop    = null;

                    sticked.push(o);

                    methods.setWrapperHeight(this);
                    methods.setupChangeListeners(this);
                });
            },

            setWrapperHeight: function(stickyElement) {
                var element = $(stickyElement);
                var stickyWrapper = element.parent();
                if (stickyWrapper) {
                    stickyWrapper.css('height', element.outerHeight());
                }
            },

            setupChangeListeners: function(stickyElement) {
                if (window.MutationObserver) {
                    var mutationObserver = new window.MutationObserver(function(mutations) {
                        if (mutations[0].addedNodes.length || mutations[0].removedNodes.length) {
                            methods.setWrapperHeight(stickyElement);
                        }
                    });
                    mutationObserver.observe(stickyElement, {subtree: true, childList: true});
                } else {
                    if (window.addEventListener) {
                        stickyElement.addEventListener('DOMNodeInserted', function() {
                            methods.setWrapperHeight(stickyElement);
                        }, false);
                        stickyElement.addEventListener('DOMNodeRemoved', function() {
                            methods.setWrapperHeight(stickyElement);
                        }, false);
                    } else if (window.attachEvent) {
                        stickyElement.attachEvent('onDOMNodeInserted', function() {
                            methods.setWrapperHeight(stickyElement);
                        });
                        stickyElement.attachEvent('onDOMNodeRemoved', function() {
                            methods.setWrapperHeight(stickyElement);
                        });
                    }
                }
            },
            update: scroller,
            unstick: function(options) {
                return this.each(function() {
                    var that = this;
                    var unstickyElement = $(that);

                    var removeIdx = -1;
                    var i = sticked.length;
                    while (i-- > 0) {
                        if (sticked[i].stickyElement.get(0) === that) {
                            splice.call(sticked,i,1);
                            removeIdx = i;
                        }
                    }
                    if(removeIdx !== -1) {
                        unstickyElement.unwrap();
                        unstickyElement
                            .css({
                                'width': '',
                                'position': '',
                                'top': '',
                                'float': '',
                                'z-index': ''
                            })
                        ;
                    }
                });
            }
        };

    // should be more efficient than using $window.scroll(scroller) and $window.resize(resizer):
    if (window.addEventListener) {
        window.addEventListener('scroll', scroller, false);
        window.addEventListener('resize', resizer, false);
    } else if (window.attachEvent) {
        window.attachEvent('onscroll', scroller);
        window.attachEvent('onresize', resizer);
    }

    $.fn.sticky = function(method) {
        if (methods[method]) {
            return methods[method].apply(this, slice.call(arguments, 1));
        } else if (typeof method === 'object' || !method ) {
            return methods.init.apply( this, arguments );
        } else {
            $.error('Method ' + method + ' does not exist on jQuery.sticky');
        }
    };

    $.fn.unstick = function(method) {
        if (methods[method]) {
            return methods[method].apply(this, slice.call(arguments, 1));
        } else if (typeof method === 'object' || !method ) {
            return methods.unstick.apply( this, arguments );
        } else {
            $.error('Method ' + method + ' does not exist on jQuery.sticky');
        }
    };


    //@todo Remove debounce in future release
    function debounce(func, wait, immediate) {
        var timeout;
        return function() {
            var context = this, args = arguments;
            var later = function() {
                timeout = null;
                if (!immediate) func.apply(context, args);
            };
            var callNow = immediate && !timeout;
            clearTimeout(timeout);
            timeout = setTimeout(later, wait);
            if (callNow) func.apply(context, args);
        };
    };

    function throttle (callback, limit) {
        var wait = false;                  // Initially, we're not waiting
        return function () {               // We return a throttled function
            if (!wait) {                   // If we're not waiting
                callback.call();           // Execute users function
                wait = true;               // Prevent future invocations
                setTimeout(function () {   // After a period of time
                    wait = false;          // And allow future invocations
                    callback.call();
                }, limit);
            }
        }
    }

    $(function() {
        setTimeout(scroller, 0);
    });
}));
