(function(root, factory) {
	if (typeof module === 'object' && module.exports) {
		module.exports = function(d3) {
			d3.contextMenu = factory(d3);
			return d3.contextMenu;
		};
	} else {
		root.d3.contextMenu = factory(root.d3);
	}
}(	this, 
	function(d3) {
		return function (menu, opts) {

			var openCallback,
				closeCallback;

			if (typeof opts === 'function') {
				openCallback = opts;
			} else {
				opts = opts || {};
				openCallback = opts.onOpen;
				closeCallback = opts.onClose;
			}

			// create the div element that will hold the context menu
			d3.selectAll('.d3-context-menu').data([1])
				.enter()
				.append('div')
				.attr('class', 'd3-context-menu');

			// close menu
			d3.select('body').on('click.d3-context-menu', function() {
				d3.select('.d3-context-menu').style('display', 'none');
				if (closeCallback) {
					closeCallback();
				}
			});

			// this gets executed when a contextmenu event occurs
			return function(data, index) {
				var elm = this;

				d3.selectAll('.d3-context-menu').html('');
				var list = d3.selectAll('.d3-context-menu').append('ul');
				list.selectAll('li').data(typeof menu === 'function' ? menu(data) : menu).enter()
					.append('li')
					.html(function(d) {
						return (typeof d.title === 'string') ? d.title : d.title(data);
					})
					.on('click', function(d, i) {
						d.action(elm, data, index);
						d3.select('.d3-context-menu').style('display', 'none');

						if (closeCallback) {
							closeCallback();
						}
					});

				// the openCallback allows an action to fire before the menu is displayed
				// an example usage would be closing a tooltip
				if (openCallback) {
					if (openCallback(data, index) === false) {
						return;
					}
				}

				// display context menu
				d3.select('.d3-context-menu')
					.style('left', (d3.event.pageX - 2) + 'px')
					.style('top', (d3.event.pageY - 2) + 'px')
					.style('display', 'block');

				d3.event.preventDefault();
				d3.event.stopPropagation();
			};
		};
	}
));