nagix/chartjs-plugin-style

'use strict';

import Chart from 'chart.js';
import styleHelpers from '../helpers/helpers.style';

var helpers = Chart.helpers;

/**
 * Ported from Chart.js 2.7.3.
 *
 * Helper method to merge the opacity into a color
 * For Chart.js 2.7.3 backward compatibility
 */
function mergeOpacity(colorString, opacity) {
    // opacity is not used in Chart.js 2.8 or later
    if (opacity === undefined) {
        return colorString;
    }
    var color = helpers.color(colorString);
    return color.alpha(opacity * color.alpha()).rgbaString();
}

var Tooltip = Chart.Tooltip;

export default Tooltip.extend({

    initialize: function() {
        var me = this;

        Tooltip.prototype.initialize.apply(me, arguments);

        styleHelpers.mergeStyle(me._model, me._options);
    },

    update: function() {
        var me = this;

        Tooltip.prototype.update.apply(me, arguments);

        styleHelpers.mergeStyle(me._model, me._options);

        return me;
    },

    drawBackground: function(pt, vm, ctx, tooltipSize, opacity) {
        var me = this;
        var args = arguments;
        var chart = me._chart;
        var options = helpers.extend({}, vm, {
            bevelHighlightColor: mergeOpacity(vm.bevelHighlightColor, opacity),
            bevelShadowColor: mergeOpacity(vm.bevelShadowColor, opacity),
            innerGlowColor: mergeOpacity(vm.innerGlowColor, opacity),
            outerGlowColor: mergeOpacity(vm.outerGlowColor, opacity)
        });

        var drawCallback = function() {
            Tooltip.prototype.drawBackground.apply(me, args);
        };

        styleHelpers.drawShadow(chart, vm, drawCallback);

        if (styleHelpers.opaque(vm.backgroundColor)) {
            styleHelpers.drawBackground(vm, drawCallback);
            styleHelpers.drawBevel(chart, options, drawCallback);
        }

        styleHelpers.drawInnerGlow(chart, options, drawCallback);
        styleHelpers.drawOuterGlow(chart, options, drawCallback);

        styleHelpers.drawBorder(vm, drawCallback);
    }
});