'use strict';

var defaults = require('../core/core.defaults');
var Element = require('../core/core.element');

defaults._set('global', {
	elements: {
		rectangle: {
			backgroundColor: defaults.global.defaultColor,
			borderColor: defaults.global.defaultColor,
			borderSkipped: 'bottom',
			borderWidth: 0
		}
	}
});

function isVertical(bar) {
	return bar._view.width !== undefined;
}

/**
 * Helper function to get the bounds of the bar regardless of the orientation
 * @param bar {Chart.Element.Rectangle} the bar
 * @return {Bounds} bounds of the bar
 * @private
 */
function getBarBounds(bar) {
	var vm = bar._view;
	var x1, x2, y1, y2;

	if (isVertical(bar)) {
		// vertical
		var halfWidth = vm.width / 2;
		x1 = vm.x - halfWidth;
		x2 = vm.x + halfWidth;
		y1 = Math.min(vm.y, vm.base);
		y2 = Math.max(vm.y, vm.base);
	} else {
		// horizontal bar
		var halfHeight = vm.height / 2;
		x1 = Math.min(vm.x, vm.base);
		x2 = Math.max(vm.x, vm.base);
		y1 = vm.y - halfHeight;
		y2 = vm.y + halfHeight;
	}

	return {
		left: x1,
		top: y1,
		right: x2,
		bottom: y2
	};
}

module.exports = Element.extend({
	draw: function() {
		var ctx = this._chart.ctx;
		var vm = this._view;
		var left, right, top, bottom, signX, signY, borderSkipped;
		var borderWidth = vm.borderWidth;

		if (!vm.horizontal) {
			// bar
			left = vm.x - vm.width / 2;
			right = vm.x + vm.width / 2;
			top = vm.y;
			bottom = vm.base;
			signX = 1;
			signY = bottom > top ? 1 : -1;
			borderSkipped = vm.borderSkipped || 'bottom';
		} else {
			// horizontal bar
			left = vm.base;
			right = vm.x;
			top = vm.y - vm.height / 2;
			bottom = vm.y + vm.height / 2;
			signX = right > left ? 1 : -1;
			signY = 1;
			borderSkipped = vm.borderSkipped || 'left';
		}

		// Canvas doesn't allow us to stroke inside the width so we can
		// adjust the sizes to fit if we're setting a stroke on the line
		if (borderWidth) {
			// borderWidth shold be less than bar width and bar height.
			var barSize = Math.min(Math.abs(left - right), Math.abs(top - bottom));
			borderWidth = borderWidth > barSize ? barSize : borderWidth;
			var halfStroke = borderWidth / 2;
			// Adjust borderWidth when bar top position is near vm.base(zero).
			var borderLeft = left + (borderSkipped !== 'left' ? halfStroke * signX : 0);
			var borderRight = right + (borderSkipped !== 'right' ? -halfStroke * signX : 0);
			var borderTop = top + (borderSkipped !== 'top' ? halfStroke * signY : 0);
			var borderBottom = bottom + (borderSkipped !== 'bottom' ? -halfStroke * signY : 0);
			// not become a vertical line?
			if (borderLeft !== borderRight) {
				top = borderTop;
				bottom = borderBottom;
			}
			// not become a horizontal line?
			if (borderTop !== borderBottom) {
				left = borderLeft;
				right = borderRight;
			}
		}

		ctx.beginPath();
		ctx.fillStyle = vm.backgroundColor;
		ctx.strokeStyle = vm.borderColor;
		ctx.lineWidth = borderWidth;

		// Corner points, from bottom-left to bottom-right clockwise
		// | 1 2 |
		// | 0 3 |
		var corners = [
			[left, bottom],
			[left, top],
			[right, top],
			[right, bottom]
		];

		// Find first (starting) corner with fallback to 'bottom'
		var borders = ['bottom', 'left', 'top', 'right'];
		var startCorner = borders.indexOf(borderSkipped, 0);
		if (startCorner === -1) {
			startCorner = 0;
		}

		function cornerAt(index) {
			return corners[(startCorner + index) % 4];
		}

		// Draw rectangle from 'startCorner'
		var corner = cornerAt(0);
		ctx.moveTo(corner[0], corner[1]);

		for (var i = 1; i < 4; i++) {
			corner = cornerAt(i);
			ctx.lineTo(corner[0], corner[1]);
		}

		ctx.fill();
		if (borderWidth) {
			ctx.stroke();
		}
	},

	height: function() {
		var vm = this._view;
		return vm.base - vm.y;
	},

	inRange: function(mouseX, mouseY) {
		var inRange = false;

		if (this._view) {
			var bounds = getBarBounds(this);
			inRange = mouseX >= bounds.left && mouseX <= bounds.right && mouseY >= bounds.top && mouseY <= bounds.bottom;
		}

		return inRange;
	},

	inLabelRange: function(mouseX, mouseY) {
		var me = this;
		if (!me._view) {
			return false;
		}

		var inRange = false;
		var bounds = getBarBounds(me);

		if (isVertical(me)) {
			inRange = mouseX >= bounds.left && mouseX <= bounds.right;
		} else {
			inRange = mouseY >= bounds.top && mouseY <= bounds.bottom;
		}

		return inRange;
	},

	inXRange: function(mouseX) {
		var bounds = getBarBounds(this);
		return mouseX >= bounds.left && mouseX <= bounds.right;
	},

	inYRange: function(mouseY) {
		var bounds = getBarBounds(this);
		return mouseY >= bounds.top && mouseY <= bounds.bottom;
	},

	getCenterPoint: function() {
		var vm = this._view;
		var x, y;
		if (isVertical(this)) {
			x = vm.x;
			y = (vm.y + vm.base) / 2;
		} else {
			x = (vm.x + vm.base) / 2;
			y = vm.y;
		}

		return {x: x, y: y};
	},

	getArea: function() {
		var vm = this._view;
		return vm.width * Math.abs(vm.y - vm.base);
	},

	tooltipPosition: function() {
		var vm = this._view;
		return {
			x: vm.x,
			y: vm.y
		};
	}
});