"use strict";
/*
*  Copyright (C) 1998-2017 by Northwoods Software Corporation. All Rights Reserved.
*/

import * as go from "../release/go";

// A custom TreeLayout that requires a "Split" node and a "Merge" node, by category.
// The "Split" node should be the root of a tree-like structure if one excludes links to the "Merge" node.
// This will position the "Merge" node to line up with the "Split" node.

/**
* @constructor
* @extends TreeLayout
* @class
* Assume there is a pair of nodes that "Split" and "Merge",
* along with any number of nodes extending in a tree-structure from the "Split" node.
* You can set all of the TreeLayout properties that you like,
* except that for simplicity this code just works for angle === 0 or angle === 90.
*/
export class ParallelLayout extends go.TreeLayout {
  public isRealtime = false;
  // these are desired for the Parallel Layout:
  public alignment = go.TreeLayout.AlignmentCenterChildren;
  public compaction = go.TreeLayout.CompactionNone;
  public alternateAlignment = go.TreeLayout.AlignmentCenterChildren;
  public alternateCompaction = go.TreeLayout.CompactionNone;

  public makeNetwork(coll: go.Iterable<go.Part>): go.LayoutNetwork {
    var net = super.makeNetwork.call(this, coll);
    // look for and remember the one "Split" node and the one "Merge" node
    for (var it = net.vertexes.iterator; it.next();) {
      var v = it.value;
      // handle asymmetric Groups, where the Placeholder is not centered
      if (v.node instanceof go.Group && v.node.isSubGraphExpanded && v.node.placeholder !== null) {
        v.focus = v.node.placeholder.getDocumentPoint(go.Spot.Center).subtract(v.node.position);
      }
      if (v.node.category === "Split") {
        if (net.splitNode) throw new Error("Split node already exists in " + this + " -- existing: " + net.splitNode + " new: " + v.node);
        net.splitNode = v.node;
      } else if (v.node.category === "Merge") {
        if (net.mergeNode) throw new Error("Merge node already exists in " + this + " -- existing: " + net.mergeNode + " new: " + v.node);
        net.mergeNode = v.node;
      }
    }
    if (net.splitNode || net.mergeNode) {
      if (!net.splitNode) throw new Error("Missing Split node in " + this);
      if (!net.mergeNode) throw new Error("Missing Merge node in " + this);
    }
    // don't lay out the Merge node
    if (net.mergeNode) net.deleteNode(net.mergeNode);
    return net;
  };

  public commitNodes() {
    super.commitNodes.call(this);
    var mergeNode = (this.network as any).mergeNode;
    var splitNode = (this.network as any).splitNode;
    var splitVertex: any = this.network.findVertex(splitNode);
    if (mergeNode && splitVertex) {
      // line up the "Merge" node to the center of the "Split" node
      if (this.angle === 0) {
        mergeNode.position = new go.Point(splitVertex.x + splitVertex.subtreeSize.width + this.layerSpacing,
          splitVertex.centerY - mergeNode.actualBounds.height / 2);
      } else if (this.angle === 90) {
        mergeNode.position = new go.Point(splitVertex.centerX - mergeNode.actualBounds.width / 2,
          splitVertex.y + splitVertex.subtreeSize.height + this.layerSpacing);
      }
    }
  };

  public commitLinks() {
    super.commitLinks.call(this);
    var mergeNode = (this.network as any).mergeNode;
    if (mergeNode) {
      for (var it = mergeNode.findLinksInto(); it.next();) {
        var link = it.value;
        if (this.angle === 0) {
          link.fromSpot = go.Spot.Right;
          link.toSpot = go.Spot.Left;
        } else if (this.angle === 90) {
          link.fromSpot = go.Spot.Bottom;
          link.toSpot = go.Spot.Top;
        }
        if (!link.isOrthogonal) continue;
        // have all of the links coming into the "Merge" node have segments
        // that share a common X (or if angle==90, Y) coordinate
        link.updateRoute();
        if (link.pointsCount >= 6) {
          var pts = link.points.copy();
          var p2 = pts.elt(pts.length - 4);
          var p3 = pts.elt(pts.length - 3);
          if (this.angle === 0) {
            var x = mergeNode.position.x - this.layerSpacing / 2;
            pts.setElt(pts.length - 4, new go.Point(x, p2.y));
            pts.setElt(pts.length - 3, new go.Point(x, p3.y));
          } else if (this.angle === 90) {
            var y = mergeNode.position.y - this.layerSpacing / 2;
            pts.setElt(pts.length - 4, new go.Point(p2.x, y));
            pts.setElt(pts.length - 3, new go.Point(p3.x, y));
          }
          link.points = pts;
        }
      }
    }
  };

}