SV.registerLayout('BinaryTree', {
	defineOptions() {
		return {
			element: {
				default: {
					type: 'binary-tree-node',
					size: [60, 30],
					label: '[data]',
					style: {
						fill: '#b83b5e',
						stroke: '#333',
						cursor: 'pointer',
					},
				},
			},
			link: {
				child: {
					type: 'line',
					sourceAnchor: index => (index === 0 ? 3 : 1),
					targetAnchor: 0,
					style: {
						stroke: '#333',
						lineAppendWidth: 6,
						cursor: 'pointer',
						endArrow: 'default',
						startArrow: {
							path: G6.Arrow.circle(2, -1),
							fill: '#333',
						},
					},
				},
			},
			marker: {
				external: {
					type: 'pointer',
					anchor: 0,
					offset: 14,
					style: {
						fill: '#f08a5d',
					},
					labelOptions: {
						style: {
							fill: '#000099',
						},
					},
				},
			},
			layout: {
				xInterval: 40,
				yInterval: 40,
			},
			behavior: {
				// dragNode: false
			},
		};
	},

	/**
	 * 对子树进行递归布局
	 */
	layoutItem(node, parent, index, layoutOptions) {
		// 次双亲不进行布局
		if (!node) {
			return null;
		}

		let bound = node.getBound(),
			width = bound.width,
			height = bound.height,
			group = new Group(node),
			leftGroup = null,
			rightGroup = null;

		if (node.visited) {
			return null;
		}

		if (node.child && node.child[0]) {
			leftGroup = this.layoutItem(node.child[0], node, 0, layoutOptions);
		}

		if (node.child && node.child[1]) {
			rightGroup = this.layoutItem(node.child[1], node, 1, layoutOptions);
		}

		// 处理左右子树相交问题
		if (leftGroup && rightGroup) {
			let intersection = Bound.intersect(leftGroup.getBound(), rightGroup.getBound()),
				move = 0;

			if (intersection && intersection.width > 0) {
				move = (intersection.width + layoutOptions.xInterval) / 2;
				leftGroup.translate(-move, 0);
				rightGroup.translate(move, 0);
			}
		}

        if (leftGroup) {
            let leftBound = leftGroup.getBound();

            node.set('y', leftBound.y - layoutOptions.yInterval - height);
            node.set('x', leftBound.x + leftBound.width + layoutOptions.xInterval / 2 - width);
        }

        if(rightGroup) {
            let rightBound = rightGroup.getBound();

            node.set('y', rightBound.y - layoutOptions.yInterval - height);
            node.set('x', rightBound.x - layoutOptions.xInterval / 2 - width);
        }

		node.visited = true;

		if (leftGroup) {
			group.add(leftGroup);
		}

		if (rightGroup) {
			group.add(rightGroup);
		}

		return group;
	},

	/**
	 * 布局函数
	 * @param {*} elements
	 * @param {*} layoutOptions
	 */
	layout(elements, layoutOptions) {
		let root = elements[0];
		this.layoutItem(root, null, -1, layoutOptions);
	},
});

[
	{
		id: 6385328,
		data: '',
		external: ['L'],
		root: true,
		after: null,
		next: null,
	},
];