(function (Highcharts, HighchartsAdapter) {

var UNDEFINED,
	ALIGN_FACTOR,
	ALLOWED_SHAPES,
	Chart = Highcharts.Chart,
	extend = Highcharts.extend,
	each = Highcharts.each;

ALLOWED_SHAPES = ["path", "rect", "circle"];

ALIGN_FACTOR = {
	top: 0,
	left: 0,
	center: 0.5,
	middle: 0.5,
	bottom: 1,
	right: 1
};


// Highcharts helper methods
var inArray = HighchartsAdapter.inArray,
	merge = Highcharts.merge;

function defaultOptions(shapeType) {
	var shapeOptions,
		options;

	options = {
		xAxis: 0,
		yAxis: 0,
		title: {
			style: {},
			text: "",
			x: 0,
			y: 0
		},
		shape: {
			params: {
				stroke: "#000000",
				fill: "transparent",
				strokeWidth: 2
			}
		}
	};

	shapeOptions = {
		circle: {
			params: {
				x: 0,
				y: 0
			}
		}
	};

	if (shapeOptions[shapeType]) {
		options.shape = merge(options.shape, shapeOptions[shapeType]);
	}

	return options;
}

function isArray(obj) {
	return Object.prototype.toString.call(obj) === '[object Array]';
}

function isNumber(n) {
	return typeof n === 'number';
}

function defined(obj) {
	return obj !== UNDEFINED && obj !== null;
}

function translatePath(d, xAxis, yAxis, xOffset, yOffset) {
	var len = d.length,
		i = 0;

	while (i < len) {
		if (typeof d[i] === 'number' && typeof d[i + 1] === 'number') {
			d[i] = xAxis.toPixels(d[i]) - xOffset;
			d[i + 1] = yAxis.toPixels(d[i + 1]) - yOffset;
			i += 2;
		} else {
			i += 1;
		}
	}

	return d;
}


// Define annotation prototype
var Annotation = function () {
	this.init.apply(this, arguments);
};
Annotation.prototype = {
	/* 
	 * Initialize the annotation
	 */
	init: function (chart, options) {
		var shapeType = options.shape && options.shape.type;

		this.chart = chart;
		this.options = merge({}, defaultOptions(shapeType), options);
	},

	/*
	 * Render the annotation
	 */
	render: function (redraw) {
		var annotation = this,
			chart = this.chart,
			renderer = annotation.chart.renderer,
			group = annotation.group,
			title = annotation.title,
			shape = annotation.shape,
			options = annotation.options,
			titleOptions = options.title,
			shapeOptions = options.shape;

		if (!group) {
			group = annotation.group = renderer.g();
		}


		if (!shape && shapeOptions && inArray(shapeOptions.type, ALLOWED_SHAPES) !== -1) {
			shape = annotation.shape = renderer[options.shape.type](shapeOptions.params);
			shape.add(group);
		}

		if (!title && titleOptions) {
			title = annotation.title = renderer.label(titleOptions);
			title.add(group);
		}

		group.add(chart.annotations.group);

		// link annotations to point or series
		annotation.linkObjects();

		if (redraw !== false) {
			annotation.redraw();
		}
	},

	/*
	 * Redraw the annotation title or shape after options update
	 */
	redraw: function () {
		var options = this.options,
			chart = this.chart,
			group = this.group,
			title = this.title,
			shape = this.shape,
			linkedTo = this.linkedObject,
			xAxis = chart.xAxis[options.xAxis],
			yAxis = chart.yAxis[options.yAxis],
			width = options.width,
			height = options.height,
			anchorY = ALIGN_FACTOR[options.anchorY],
			anchorX = ALIGN_FACTOR[options.anchorX],
			resetBBox = false,
			shapeParams,
			linkType,
			series,
			param,
			bbox,
			x,
			y;

		if (linkedTo) {
			linkType = (linkedTo instanceof Highcharts.Point) ? 'point' :
						(linkedTo instanceof Highcharts.Series) ? 'series' : null;

			if (linkType === 'point') {
				options.xValue = linkedTo.x;
				options.yValue = linkedTo.y;
				series = linkedTo.series;
			} else if (linkType === 'series') {
				series = linkedTo;
			}

			if (group.visibility !== series.group.visibility) {
				group.attr({
					visibility: series.group.visibility
				});
			}
		}


		// Based on given options find annotation pixel position
		x = (defined(options.xValue) ? xAxis.toPixels(options.xValue + xAxis.minPointOffset) - xAxis.minPixelPadding : options.x);
		y = defined(options.yValue) ? yAxis.toPixels(options.yValue) : options.y;

		if (isNaN(x) || isNaN(y) || !isNumber(x) || !isNumber(y)) {
			return;
		}


		if (title) {
			title.attr(options.title);
			title.css(options.title.style);
			resetBBox = true;
		}

		if (shape) {
			shapeParams = extend({}, options.shape.params);

			if (options.units === 'values') {
				for (param in shapeParams) {
					if (inArray(param, ['width', 'x']) > -1) {
						shapeParams[param] = xAxis.translate(shapeParams[param]);
					} else if (inArray(param, ['height', 'y']) > -1) {
						shapeParams[param] = yAxis.translate(shapeParams[param]);
					}
				}

				if (shapeParams.width) {
					shapeParams.width -= xAxis.toPixels(0) - xAxis.left;
				}

				if (shapeParams.x) {
					shapeParams.x += xAxis.minPixelPadding;
				}

				if (options.shape.type === 'path') {
					translatePath(shapeParams.d, xAxis, yAxis, x, y);
				}
			}

			// move the center of the circle to shape x/y
			if (options.shape.type === 'circle') {
				shapeParams.x += shapeParams.r;
				shapeParams.y += shapeParams.r;
			}

			resetBBox = true;
			shape.attr(shapeParams);
		}

		group.bBox = null;

		// If annotation width or height is not defined in options use bounding box size
		if (!isNumber(width)) {
			bbox = group.getBBox();
			width = bbox.width;
		}

		if (!isNumber(height)) {
			// get bbox only if it wasn't set before
			if (!bbox) {
				bbox = group.getBBox();
			}

			height = bbox.height;
		}

		// Calculate anchor point
		if (!isNumber(anchorX)) {
			anchorX = ALIGN_FACTOR.center;
		}

		if (!isNumber(anchorY)) {
			anchorY = ALIGN_FACTOR.center;
		}

		// Translate group according to its dimension and anchor point
		x = x - width * anchorX;
		y = y - height * anchorY;

		if (chart.animation && defined(group.translateX) && defined(group.translateY)) {
			group.animate({
				translateX: x,
				translateY: y
			});
		} else {
			group.translate(x, y);
		}
	},

	/*
	 * Destroy the annotation
	 */
	destroy: function () {
		var annotation = this,
			chart = this.chart,
			allItems = chart.annotations.allItems,
			index = allItems.indexOf(annotation);

		if (index > -1) {
			allItems.splice(index, 1);
		}

		each(['title', 'shape', 'group'], function (element) {
			if (annotation[element]) {
				annotation[element].destroy();
				annotation[element] = null;
			}
		});

		annotation.group = annotation.title = annotation.shape = annotation.chart = annotation.options = null;
	},

	/*
	 * Update the annotation with a given options
	 */
	update: function (options, redraw) {
		extend(this.options, options);

		// update link to point or series
		this.linkObjects();

		this.render(redraw);
	},

	linkObjects: function () {
		var annotation = this,
			chart = annotation.chart,
			linkedTo = annotation.linkedObject,
			linkedId = linkedTo && (linkedTo.id || linkedTo.options.id),
			options = annotation.options,
			id = options.linkedTo;

		if (!defined(id)) {
			annotation.linkedObject = null;
		} else if (!defined(linkedTo) || id !== linkedId) {
			annotation.linkedObject = chart.get(id);
		}
	}
};


// Add annotations methods to chart prototype
extend(Chart.prototype, {
	annotations: {
		/*
		 * Unified method for adding annotations to the chart
		 */
		add: function (options, redraw) {
			var annotations = this.allItems,
				chart = this.chart,
				item,
				len;

			if (!isArray(options)) {
				options = [options];
			}

			len = options.length;

			while (len--) {
				item = new Annotation(chart, options[len]);
				annotations.push(item);
				item.render(redraw);
			}
		},

		/**
		 * Redraw all annotations, method used in chart events
		 */
		redraw: function () {
			each(this.allItems, function (annotation) {
				annotation.redraw();
			});
		}
	}
});


// Initialize on chart load
Chart.prototype.callbacks.push(function (chart) {
	var options = chart.options.annotations,
		group;

	group = chart.renderer.g("annotations");
	group.attr({
		zIndex: 7
	});
	group.add();

	// initialize empty array for annotations
	chart.annotations.allItems = [];

	// link chart object to annotations
	chart.annotations.chart = chart;

	// link annotations group element to the chart
	chart.annotations.group = group;

	if (isArray(options) && options.length > 0) {
		chart.annotations.add(chart.options.annotations);
	}

	// update annotations after chart redraw
	Highcharts.addEvent(chart, 'redraw', function () {
		chart.annotations.redraw();
	});
});
}(Highcharts, HighchartsAdapter));