odoo.define('website_animate.o_animate_frontend', function (require) {
'use strict';

var publicWidget = require('web.public.widget');

var WebsiteAnimate = {
    win   : {},
    items : {},

    offsetRatio : 0.3,  // Dynamic offset ratio: 0.3 = (element's height/3)
    offsetMin   : 10,   // Minimum offset for small elements (in pixels)

    // Retrieve animable elements and attach handlers.
    start: function () {
        var self   = this;
        self.$scrollingElement = $().getScrollingElement();
        self.items = $(".o_animate");
        self.items.each(function () {
            var $el = $(this);
            // Set all monitored elements to initial state
            self.reset_animation($el);
        });
        setTimeout(function () {
            self.attach_handlers();
        });
    },

    // Bind events and define the scrolling function
    attach_handlers: function () {
        var self = this;
        var lastScroll = 0;

        $(window)
        .on("resize.o_animate", function () {
            self.win.h = $(window).height();
            $(window).trigger("scroll");
        })
        .trigger("resize");

        self.$scrollingElement
        .on("scroll.o_animate, slid.bs.carousel", (_.throttle(function () {
            // _.throttle -> Limit the number of times the scroll function
            // can be called in a given period. (http://underscorejs.org/#throttle)
            var windowTop    = $(window).scrollTop();
            var windowBottom = windowTop + self.win.h;

            // Handle reverse scrolling
            var direction = (windowTop < lastScroll) ? -1 : 1;
            lastScroll = windowTop;

            self.items.each(function () {
                var $el       = $(this);
                var elHeight  = $el.height();
                var elOffset  = direction * Math.max((elHeight * self.offsetRatio), self.offsetMin);
                var state     = $el.css("animation-play-state");

                // We need to offset for the change in position from some animation
                // So we get the top value by not taking CSS transforms into calculations
                var elTop = self.getElementOffsetTop($el[0]) - $().getScrollingElement().scrollTop();

                var visible = windowBottom > (elTop + elOffset) && windowTop < (elTop + elHeight - elOffset);

                if ( visible && (state === "paused") ) {
                    $el.addClass("o_visible");
                    self.start_animation($el);
                } else if ( !(visible) && $el.hasClass("o_animate_both_scroll") && (state === "running") ) {
                    $el.removeClass("o_visible");
                    self.reset_animation($el);
                }
            });
        },100)))
        .trigger("scroll");
    },

    // Set elements to initial state
    reset_animation: function ($el) {
        var self = this;
        var anim_name = $el.css("animation-name");

        $el
        .css({"animation-name" : "dummy-none", "animation-play-state" : ""})
        .removeClass("o_animated o_animating");

        self._toggleOverflowXHidden(false);

        // force the browser to redraw using setTimeout
        setTimeout(function () {
            $el.css({"animation-name" : anim_name, "animation-play-state" : "paused"});
        },0);
    },

    // Start animation and/or update element's state
    start_animation: function ($el) {
        var self = this;
        // force the browser to redraw using setTimeout
        setTimeout(function () {
            self._toggleOverflowXHidden(true);
            $el
            .css({"animation-play-state": "running"})
            .addClass("o_animating")
            .one('webkitAnimationEnd oanimationend msAnimationEnd animationend', function (e) {
                $el.addClass("o_animated").removeClass("o_animating");
                self._toggleOverflowXHidden(false);
                $(window).trigger("resize");
            });
        });
    },

    // show/hide the horizontal scrollbar (on the #wrapwrap)
    _toggleOverflowXHidden: function (add) {
        if (add) {
            this.$scrollingElement[0].classList.add('o_wanim_overflow_x_hidden');
        } else if (!this.$scrollingElement.find('.o_animating').length) {
            this.$scrollingElement[0].classList.remove('o_wanim_overflow_x_hidden');
        }
    },

    // Get element top offset by not taking CSS transforms into calculations
    getElementOffsetTop: function (el) {
        // Loop through the DOM tree and add its parent's offset to get page offset
        var top = 0;
        do {
            top += el.offsetTop || 0;
            el = el.offsetParent;
        } while (el);
        return top;
    },
};

publicWidget.registry.WebsiteAnimate = publicWidget.Widget.extend({
    selector: '#wrapwrap',
    disabledInEditableMode: false,

    /**
     * @override
     */
    start: function () {
        // By default, elements are hidden by the css of o_animate.
        // render alements  + // We will trigger the animation then pause it in state 0.
        WebsiteAnimate.start();
        // Then we render all the elements, the ones which are invisible
        // in state 0 (like fade_in for example) will stay invisible.
        $(".o_animate").css("visibility", "visible");

        return this._super.apply(this, arguments);
    },
    /**
     * @override
     */
    destroy: function () {
        WebsiteAnimate.$scrollingElement[0].classList.remove('o_wanim_overflow_x_hidden');
        this._super.apply(this, arguments);
    },
});

// Backward compatibility for enark animation system
publicWidget.registry.o_animate = publicWidget.Widget.extend({
    selector: '.o_animation',

    destroy: function () {
        this._super.apply(this, arguments);

        // Convert old classes to the new animation system
        var old_animation_classes = "o_animation o_displayed o_displayed_top o_displayed_middle o_displayed_bottom o_visible o_visible_top o_visible_middle o_visible_bottom";
        $(".o_fade_in").addClass("o_animate o_anim_fade_in").removeClass("o_fade_in");
        $(".o_fade_in_down").addClass("o_animate o_anim_fade_in_down").removeClass("o_fade_in_down");
        $(".o_fade_in_left").addClass("o_animate o_anim_fade_in_left").removeClass("o_fade_in_left");
        $(".o_fade_in_right").addClass("o_animate o_anim_fade_in_right").removeClass("o_fade_in_right");
        $(".o_fade_in_up").addClass("o_animate o_anim_fade_in_up").removeClass("o_fade_in_up");
        this.$target.removeClass(old_animation_classes);
    },
});

return WebsiteAnimate;
});