// d3.tip
// Copyright (c) 2013 Justin Palmer
// ES6 / D3 v4 Adaption Copyright (c) 2016 Constantin Gavrilete
// Removal of ES6 for D3 v4 Adaption Copyright (c) 2016 David Gotz
//
// Tooltips for d3.js SVG visualizations

d3.functor = function functor(v) {
    return typeof v === "function" ? v : function () {
        return v;
    };
};

d3.tip = function () {

    var direction = d3_tip_direction,
        offset = d3_tip_offset,
        html = d3_tip_html,
        node = initNode(),
        svg = null,
        point = null,
        target = null

    function tip(vis) {
        svg = getSVGNode(vis)
        point = svg.createSVGPoint()
        document.body.appendChild(node)
    }

    // Public - show the tooltip on the screen
    //
    // Returns a tip
    tip.show = function () {
        var args = Array.prototype.slice.call(arguments)
        if (args[args.length - 1] instanceof SVGElement) target = args.pop()

        var content = html.apply(this, args),
            poffset = offset.apply(this, args),
            dir = direction.apply(this, args),
            nodel = getNodeEl(),
            i = directions.length,
            coords,
            scrollTop = document.documentElement.scrollTop || document.body.scrollTop,
            scrollLeft = document.documentElement.scrollLeft || document.body.scrollLeft

        nodel.html(content)
            .style('position', 'absolute')
            .style('opacity', 1)
            .style('pointer-events', 'all')

        while (i--) nodel.classed(directions[i], false)
        coords = direction_callbacks[dir].apply(this)
        nodel.classed(dir, true)
            .style('top', (coords.top + poffset[0]) + scrollTop + 'px')
            .style('left', (coords.left + poffset[1]) + scrollLeft + 'px')

        return tip
    }

    // Public - hide the tooltip
    //
    // Returns a tip
    tip.hide = function () {
        var nodel = getNodeEl()
        nodel
            .style('opacity', 0)
            .style('pointer-events', 'none')
        return tip
    }

    // Public: Proxy attr calls to the d3 tip container.  Sets or gets attribute value.
    //
    // n - name of the attribute
    // v - value of the attribute
    //
    // Returns tip or attribute value
    tip.attr = function (n, v) {
        if (arguments.length < 2 && typeof n === 'string') {
            return getNodeEl().attr(n)
        } else {
            var args = Array.prototype.slice.call(arguments)
            d3.selection.prototype.attr.apply(getNodeEl(), args)
        }

        return tip
    }

    // Public: Proxy style calls to the d3 tip container.  Sets or gets a style value.
    //
    // n - name of the property
    // v - value of the property
    //
    // Returns tip or style property value
    tip.style = function (n, v) {
        // debugger;
        if (arguments.length < 2 && typeof n === 'string') {
            return getNodeEl().style(n)
        } else {
            var args = Array.prototype.slice.call(arguments);
            if (args.length === 1) {
                var styles = args[0];
                Object.keys(styles).forEach(function (key) {
                    return d3.selection.prototype.style.apply(getNodeEl(), [key, styles[key]]);
                });
            }
        }

        return tip
    }

    // Public: Set or get the direction of the tooltip
    //
    // v - One of n(north), s(south), e(east), or w(west), nw(northwest),
    //     sw(southwest), ne(northeast) or se(southeast)
    //
    // Returns tip or direction
    tip.direction = function (v) {
        if (!arguments.length) return direction
        direction = v == null ? v : d3.functor(v)

        return tip
    }

    // Public: Sets or gets the offset of the tip
    //
    // v - Array of [x, y] offset
    //
    // Returns offset or
    tip.offset = function (v) {
        if (!arguments.length) return offset
        offset = v == null ? v : d3.functor(v)

        return tip
    }

    // Public: sets or gets the html value of the tooltip
    //
    // v - String value of the tip
    //
    // Returns html value or tip
    tip.html = function (v) {
        if (!arguments.length) return html
        html = v == null ? v : d3.functor(v)

        return tip
    }

    // Public: destroys the tooltip and removes it from the DOM
    //
    // Returns a tip
    tip.destroy = function () {
        if (node) {
            getNodeEl().remove();
            node = null;
        }
        return tip;
    }

    function d3_tip_direction() { return 'n' }
    function d3_tip_offset() { return [0, 0] }
    function d3_tip_html() { return ' ' }

    var direction_callbacks = {
        n: direction_n,
        s: direction_s,
        e: direction_e,
        w: direction_w,
        nw: direction_nw,
        ne: direction_ne,
        sw: direction_sw,
        se: direction_se
    };

    var directions = Object.keys(direction_callbacks);

    function direction_n() {
        var bbox = getScreenBBox()
        return {
            top: bbox.n.y - node.offsetHeight,
            left: bbox.n.x - node.offsetWidth / 2
        }
    }

    function direction_s() {
        var bbox = getScreenBBox()
        return {
            top: bbox.s.y,
            left: bbox.s.x - node.offsetWidth / 2
        }
    }

    function direction_e() {
        var bbox = getScreenBBox()
        return {
            top: bbox.e.y - node.offsetHeight / 2,
            left: bbox.e.x
        }
    }

    function direction_w() {
        var bbox = getScreenBBox()
        return {
            top: bbox.w.y - node.offsetHeight / 2,
            left: bbox.w.x - node.offsetWidth
        }
    }

    function direction_nw() {
        var bbox = getScreenBBox()
        return {
            top: bbox.nw.y - node.offsetHeight,
            left: bbox.nw.x - node.offsetWidth
        }
    }

    function direction_ne() {
        var bbox = getScreenBBox()
        return {
            top: bbox.ne.y - node.offsetHeight,
            left: bbox.ne.x
        }
    }

    function direction_sw() {
        var bbox = getScreenBBox()
        return {
            top: bbox.sw.y,
            left: bbox.sw.x - node.offsetWidth
        }
    }

    function direction_se() {
        var bbox = getScreenBBox()
        return {
            top: bbox.se.y,
            left: bbox.e.x
        }
    }

    function initNode() {
        var node = d3.select(document.createElement('div'))
        node
            .style('position', 'absolute')
            .style('top', 0)
            .style('opacity', 0)
            .style('pointer-events', 'none')
            .style('box-sizing', 'border-box')

        return node.node()
    }

    function getSVGNode(el) {
        el = el.node()
        if (el.tagName.toLowerCase() === 'svg')
            return el

        return el.ownerSVGElement
    }

    function getNodeEl() {
        if (node === null) {
            node = initNode();
            // re-add node to DOM
            document.body.appendChild(node);
        };
        return d3.select(node);
    }

    // Private - gets the screen coordinates of a shape
    //
    // Given a shape on the screen, will return an SVGPoint for the directions
    // n(north), s(south), e(east), w(west), ne(northeast), se(southeast), nw(northwest),
    // sw(southwest).
    //
    //    +-+-+
    //    |   |
    //    +   +
    //    |   |
    //    +-+-+
    //
    // Returns an Object {n, s, e, w, nw, sw, ne, se}
    function getScreenBBox() {
        var targetel = target || d3.event.target;

        while ('undefined' === typeof targetel.getScreenCTM && 'undefined' === targetel.parentNode) {
            targetel = targetel.parentNode;
        }

        var bbox = {},
            matrix = targetel.getScreenCTM(),
            tbbox = targetel.getBBox(),
            width = tbbox.width,
            height = tbbox.height,
            x = tbbox.x,
            y = tbbox.y

        point.x = x
        point.y = y
        bbox.nw = point.matrixTransform(matrix)
        point.x += width
        bbox.ne = point.matrixTransform(matrix)
        point.y += height
        bbox.se = point.matrixTransform(matrix)
        point.x -= width
        bbox.sw = point.matrixTransform(matrix)
        point.y -= height / 2
        bbox.w = point.matrixTransform(matrix)
        point.x += width
        bbox.e = point.matrixTransform(matrix)
        point.x -= width / 2
        point.y -= height / 2
        bbox.n = point.matrixTransform(matrix)
        point.y += height
        bbox.s = point.matrixTransform(matrix)

        return bbox
    }

    return tip
};