import { DiagramModel, PointModel } from '@projectstorm/react-diagrams-core';
import * as dagre from 'dagre';
import * as _ from 'lodash';
import { GraphLabel } from 'dagre';
import { Point } from '@projectstorm/geometry';

export interface DagreEngineOptions {
	graph?: GraphLabel;
	/**
	 * Will also layout links
	 */
	includeLinks?: boolean;
}

export class DagreEngine {
	options: DagreEngineOptions;

	constructor(options: DagreEngineOptions = {}) {
		this.options = options;
	}

	redistribute(model: DiagramModel) {
		// Create a new directed graph
		var g = new dagre.graphlib.Graph({
			multigraph: true
		});
		g.setGraph(this.options.graph || {});
		g.setDefaultEdgeLabel(function () {
			return {};
		});

		const processedlinks: { [id: string]: boolean } = {};

		// set nodes
		_.forEach(model.getNodes(), (node) => {
			g.setNode(node.getID(), { width: node.width, height: node.height });
		});

		_.forEach(model.getLinks(), (link) => {
			// set edges
			if (link.getSourcePort() && link.getTargetPort()) {
				processedlinks[link.getID()] = true;
				g.setEdge({
					v: link.getSourcePort().getNode().getID(),
					w: link.getTargetPort().getNode().getID(),
					name: link.getID()
				});
			}
		});

		// layout the graph
		dagre.layout(g);

		g.nodes().forEach((v) => {
			const node = g.node(v);
			model.getNode(v).setPosition(node.x - node.width / 2, node.y - node.height / 2);
		});

		// also include links?
		if (this.options.includeLinks) {
			g.edges().forEach((e) => {
				const edge = g.edge(e);
				const link = model.getLink(e.name);

				const points = [link.getFirstPoint()];
				for (let i = 1; i < edge.points.length - 2; i++) {
					points.push(new PointModel({ link: link, position: new Point(edge.points[i].x, edge.points[i].y) }));
				}
				link.setPoints(points.concat(link.getLastPoint()));
			});
		}
	}
}