var LayoutConstants = require('./LayoutConstants');
var LGraphManager = require('./LGraphManager');
var LNode = require('./LNode');
var LEdge = require('./LEdge');
var LGraph = require('./LGraph');
var PointD = require('./util/PointD');
var Transform = require('./util/Transform');
var Emitter = require('./util/Emitter');

function Layout(isRemoteUse) {
  Emitter.call( this );

  //Layout Quality: 0:draft, 1:default, 2:proof
  this.layoutQuality = LayoutConstants.QUALITY;
  //Whether layout should create bendpoints as needed or not
  this.createBendsAsNeeded =
          LayoutConstants.DEFAULT_CREATE_BENDS_AS_NEEDED;
  //Whether layout should be incremental or not
  this.incremental = LayoutConstants.DEFAULT_INCREMENTAL;
  //Whether we animate from before to after layout node positions
  this.animationOnLayout =
          LayoutConstants.DEFAULT_ANIMATION_ON_LAYOUT;
  //Whether we animate the layout process or not
  this.animationDuringLayout = LayoutConstants.DEFAULT_ANIMATION_DURING_LAYOUT;
  //Number iterations that should be done between two successive animations
  this.animationPeriod = LayoutConstants.DEFAULT_ANIMATION_PERIOD;
  /**
   * Whether or not leaf nodes (non-compound nodes) are of uniform sizes. When
   * they are, both spring and repulsion forces between two leaf nodes can be
   * calculated without the expensive clipping point calculations, resulting
   * in major speed-up.
   */
  this.uniformLeafNodeSizes =
          LayoutConstants.DEFAULT_UNIFORM_LEAF_NODE_SIZES;
  /**
   * This is used for creation of bendpoints by using dummy nodes and edges.
   * Maps an LEdge to its dummy bendpoint path.
   */
  this.edgeToDummyNodes = new Map();
  this.graphManager = new LGraphManager(this);
  this.isLayoutFinished = false;
  this.isSubLayout = false;
  this.isRemoteUse = false;

  if (isRemoteUse != null) {
    this.isRemoteUse = isRemoteUse;
  }
}

Layout.RANDOM_SEED = 1;

Layout.prototype = Object.create( Emitter.prototype );

Layout.prototype.getGraphManager = function () {
  return this.graphManager;
};

Layout.prototype.getAllNodes = function () {
  return this.graphManager.getAllNodes();
};

Layout.prototype.getAllEdges = function () {
  return this.graphManager.getAllEdges();
};

Layout.prototype.getAllNodesToApplyGravitation = function () {
  return this.graphManager.getAllNodesToApplyGravitation();
};

Layout.prototype.newGraphManager = function () {
  var gm = new LGraphManager(this);
  this.graphManager = gm;
  return gm;
};

Layout.prototype.newGraph = function (vGraph)
{
  return new LGraph(null, this.graphManager, vGraph);
};

Layout.prototype.newNode = function (vNode)
{
  return new LNode(this.graphManager, vNode);
};

Layout.prototype.newEdge = function (vEdge)
{
  return new LEdge(null, null, vEdge);
};

Layout.prototype.checkLayoutSuccess = function() {
  return (this.graphManager.getRoot() == null)
          || this.graphManager.getRoot().getNodes().length == 0
          || this.graphManager.includesInvalidEdge();
};

Layout.prototype.runLayout = function ()
{
  this.isLayoutFinished = false;
  
  if (this.tilingPreLayout) {
    this.tilingPreLayout();
  }

  this.initParameters();
  var isLayoutSuccessfull;

  if (this.checkLayoutSuccess())
  {
    isLayoutSuccessfull = false;
  }
  else
  {
    isLayoutSuccessfull = this.layout();
  }
  
  if (LayoutConstants.ANIMATE === 'during') {
    // If this is a 'during' layout animation. Layout is not finished yet. 
    // We need to perform these in index.js when layout is really finished.
    return false;
  }
  
  if (isLayoutSuccessfull)
  {
    if (!this.isSubLayout)
    {
      this.doPostLayout();
    }
  }

  if (this.tilingPostLayout) {
    this.tilingPostLayout();
  }

  this.isLayoutFinished = true;

  return isLayoutSuccessfull;
};

/**
 * This method performs the operations required after layout.
 */
Layout.prototype.doPostLayout = function ()
{
  //assert !isSubLayout : "Should not be called on sub-layout!";
  // Propagate geometric changes to v-level objects
  if(!this.incremental){
    this.transform();
  }
  this.update();
};

/**
 * This method updates the geometry of the target graph according to
 * calculated layout.
 */
Layout.prototype.update2 = function () {
  // update bend points
  if (this.createBendsAsNeeded)
  {
    this.createBendpointsFromDummyNodes();

    // reset all edges, since the topology has changed
    this.graphManager.resetAllEdges();
  }

  // perform edge, node and root updates if layout is not called
  // remotely
  if (!this.isRemoteUse)
  {
    // update all edges
    var edge;
    var allEdges = this.graphManager.getAllEdges();
    for (var i = 0; i < allEdges.length; i++)
    {
      edge = allEdges[i];
//      this.update(edge);
    }

    // recursively update nodes
    var node;
    var nodes = this.graphManager.getRoot().getNodes();
    for (var i = 0; i < nodes.length; i++)
    {
      node = nodes[i];
//      this.update(node);
    }

    // update root graph
    this.update(this.graphManager.getRoot());
  }
};

Layout.prototype.update = function (obj) {
  if (obj == null) {
    this.update2();
  }
  else if (obj instanceof LNode) {
    var node = obj;
    if (node.getChild() != null)
    {
      // since node is compound, recursively update child nodes
      var nodes = node.getChild().getNodes();
      for (var i = 0; i < nodes.length; i++)
      {
        update(nodes[i]);
      }
    }

    // if the l-level node is associated with a v-level graph object,
    // then it is assumed that the v-level node implements the
    // interface Updatable.
    if (node.vGraphObject != null)
    {
      // cast to Updatable without any type check
      var vNode = node.vGraphObject;

      // call the update method of the interface
      vNode.update(node);
    }
  }
  else if (obj instanceof LEdge) {
    var edge = obj;
    // if the l-level edge is associated with a v-level graph object,
    // then it is assumed that the v-level edge implements the
    // interface Updatable.

    if (edge.vGraphObject != null)
    {
      // cast to Updatable without any type check
      var vEdge = edge.vGraphObject;

      // call the update method of the interface
      vEdge.update(edge);
    }
  }
  else if (obj instanceof LGraph) {
    var graph = obj;
    // if the l-level graph is associated with a v-level graph object,
    // then it is assumed that the v-level object implements the
    // interface Updatable.

    if (graph.vGraphObject != null)
    {
      // cast to Updatable without any type check
      var vGraph = graph.vGraphObject;

      // call the update method of the interface
      vGraph.update(graph);
    }
  }
};

/**
 * This method is used to set all layout parameters to default values
 * determined at compile time.
 */
Layout.prototype.initParameters = function () {
  if (!this.isSubLayout)
  {
    this.layoutQuality = LayoutConstants.QUALITY;
    this.animationDuringLayout = LayoutConstants.DEFAULT_ANIMATION_DURING_LAYOUT;
    this.animationPeriod = LayoutConstants.DEFAULT_ANIMATION_PERIOD;
    this.animationOnLayout = LayoutConstants.DEFAULT_ANIMATION_ON_LAYOUT;
    this.incremental = LayoutConstants.DEFAULT_INCREMENTAL;
    this.createBendsAsNeeded = LayoutConstants.DEFAULT_CREATE_BENDS_AS_NEEDED;
    this.uniformLeafNodeSizes = LayoutConstants.DEFAULT_UNIFORM_LEAF_NODE_SIZES;
  }

  if (this.animationDuringLayout)
  {
    this.animationOnLayout = false;
  }
};

Layout.prototype.transform = function (newLeftTop) {
  if (newLeftTop == undefined) {
    this.transform(new PointD(0, 0));
  }
  else {
    // create a transformation object (from Eclipse to layout). When an
    // inverse transform is applied, we get upper-left coordinate of the
    // drawing or the root graph at given input coordinate (some margins
    // already included in calculation of left-top).

    var trans = new Transform();
    var leftTop = this.graphManager.getRoot().updateLeftTop();

    if (leftTop != null)
    {
      trans.setWorldOrgX(newLeftTop.x);
      trans.setWorldOrgY(newLeftTop.y);

      trans.setDeviceOrgX(leftTop.x);
      trans.setDeviceOrgY(leftTop.y);

      var nodes = this.getAllNodes();
      var node;

      for (var i = 0; i < nodes.length; i++)
      {
        node = nodes[i];
        node.transform(trans);
      }
    }
  }
};

Layout.prototype.positionNodesRandomly = function (graph) {

  if (graph == undefined) {
    //assert !this.incremental;
    this.positionNodesRandomly(this.getGraphManager().getRoot());
    this.getGraphManager().getRoot().updateBounds(true);
  }
  else {
    var lNode;
    var childGraph;

    var nodes = graph.getNodes();
    for (var i = 0; i < nodes.length; i++)
    {
      lNode = nodes[i];
      childGraph = lNode.getChild();

      if (childGraph == null)
      {
        lNode.scatter();
      }
      else if (childGraph.getNodes().length == 0)
      {
        lNode.scatter();
      }
      else
      {
        this.positionNodesRandomly(childGraph);
        lNode.updateBounds();
      }
    }
  }
};

/**
 * This method returns a list of trees where each tree is represented as a
 * list of l-nodes. The method returns a list of size 0 when:
 * - The graph is not flat or
 * - One of the component(s) of the graph is not a tree.
 */
Layout.prototype.getFlatForest = function ()
{
  var flatForest = [];
  var isForest = true;

  // Quick reference for all nodes in the graph manager associated with
  // this layout. The list should not be changed.
  var allNodes = this.graphManager.getRoot().getNodes();

  // First be sure that the graph is flat
  var isFlat = true;

  for (var i = 0; i < allNodes.length; i++)
  {
    if (allNodes[i].getChild() != null)
    {
      isFlat = false;
    }
  }

  // Return empty forest if the graph is not flat.
  if (!isFlat)
  {
    return flatForest;
  }

  // Run BFS for each component of the graph.

  var visited = new Set();
  var toBeVisited = [];
  var parents = new Map();
  var unProcessedNodes = [];

  unProcessedNodes = unProcessedNodes.concat(allNodes);

  // Each iteration of this loop finds a component of the graph and
  // decides whether it is a tree or not. If it is a tree, adds it to the
  // forest and continued with the next component.

  while (unProcessedNodes.length > 0 && isForest)
  {
    toBeVisited.push(unProcessedNodes[0]);

    // Start the BFS. Each iteration of this loop visits a node in a
    // BFS manner.
    while (toBeVisited.length > 0 && isForest)
    {
      //pool operation
      var currentNode = toBeVisited[0];
      toBeVisited.splice(0, 1);
      visited.add(currentNode);

      // Traverse all neighbors of this node
      var neighborEdges = currentNode.getEdges();

      for (var i = 0; i < neighborEdges.length; i++)
      {
        var currentNeighbor =
                neighborEdges[i].getOtherEnd(currentNode);

        // If BFS is not growing from this neighbor.
        if (parents.get(currentNode) != currentNeighbor)
        {
          // We haven't previously visited this neighbor.
          if (!visited.has(currentNeighbor))
          {
            toBeVisited.push(currentNeighbor);
            parents.set(currentNeighbor, currentNode);
          }
          // Since we have previously visited this neighbor and
          // this neighbor is not parent of currentNode, given
          // graph contains a component that is not tree, hence
          // it is not a forest.
          else
          {
            isForest = false;
            break;
          }
        }
      }
    }

    // The graph contains a component that is not a tree. Empty
    // previously found trees. The method will end.
    if (!isForest)
    {
      flatForest = [];
    }
    // Save currently visited nodes as a tree in our forest. Reset
    // visited and parents lists. Continue with the next component of
    // the graph, if any.
    else
    {
      var temp = [...visited];
      flatForest.push(temp);
      //flatForest = flatForest.concat(temp);
      //unProcessedNodes.removeAll(visited);
      for (var i = 0; i < temp.length; i++) {
        var value = temp[i];
        var index = unProcessedNodes.indexOf(value);
        if (index > -1) {
          unProcessedNodes.splice(index, 1);
        }
      }
      visited = new Set();
      parents = new Map();
    }
  }

  return flatForest;
};

/**
 * This method creates dummy nodes (an l-level node with minimal dimensions)
 * for the given edge (one per bendpoint). The existing l-level structure
 * is updated accordingly.
 */
Layout.prototype.createDummyNodesForBendpoints = function (edge)
{
  var dummyNodes = [];
  var prev = edge.source;

  var graph = this.graphManager.calcLowestCommonAncestor(edge.source, edge.target);

  for (var i = 0; i < edge.bendpoints.length; i++)
  {
    // create new dummy node
    var dummyNode = this.newNode(null);
    dummyNode.setRect(new Point(0, 0), new Dimension(1, 1));

    graph.add(dummyNode);

    // create new dummy edge between prev and dummy node
    var dummyEdge = this.newEdge(null);
    this.graphManager.add(dummyEdge, prev, dummyNode);

    dummyNodes.add(dummyNode);
    prev = dummyNode;
  }

  var dummyEdge = this.newEdge(null);
  this.graphManager.add(dummyEdge, prev, edge.target);

  this.edgeToDummyNodes.set(edge, dummyNodes);

  // remove real edge from graph manager if it is inter-graph
  if (edge.isInterGraph())
  {
    this.graphManager.remove(edge);
  }
  // else, remove the edge from the current graph
  else
  {
    graph.remove(edge);
  }

  return dummyNodes;
};

/**
 * This method creates bendpoints for edges from the dummy nodes
 * at l-level.
 */
Layout.prototype.createBendpointsFromDummyNodes = function ()
{
  var edges = [];
  edges = edges.concat(this.graphManager.getAllEdges());
  edges = [...this.edgeToDummyNodes.keys()].concat(edges);

  for (var k = 0; k < edges.length; k++)
  {
    var lEdge = edges[k];

    if (lEdge.bendpoints.length > 0)
    {
      var path = this.edgeToDummyNodes.get(lEdge);

      for (var i = 0; i < path.length; i++)
      {
        var dummyNode = path[i];
        var p = new PointD(dummyNode.getCenterX(),
                dummyNode.getCenterY());

        // update bendpoint's location according to dummy node
        var ebp = lEdge.bendpoints.get(i);
        ebp.x = p.x;
        ebp.y = p.y;

        // remove the dummy node, dummy edges incident with this
        // dummy node is also removed (within the remove method)
        dummyNode.getOwner().remove(dummyNode);
      }

      // add the real edge to graph
      this.graphManager.add(lEdge, lEdge.source, lEdge.target);
    }
  }
};

Layout.transform = function (sliderValue, defaultValue, minDiv, maxMul) {
  if (minDiv != undefined && maxMul != undefined) {
    var value = defaultValue;

    if (sliderValue <= 50)
    {
      var minValue = defaultValue / minDiv;
      value -= ((defaultValue - minValue) / 50) * (50 - sliderValue);
    }
    else
    {
      var maxValue = defaultValue * maxMul;
      value += ((maxValue - defaultValue) / 50) * (sliderValue - 50);
    }

    return value;
  }
  else {
    var a, b;

    if (sliderValue <= 50)
    {
      a = 9.0 * defaultValue / 500.0;
      b = defaultValue / 10.0;
    }
    else
    {
      a = 9.0 * defaultValue / 50.0;
      b = -8 * defaultValue;
    }

    return (a * sliderValue + b);
  }
};

/**
 * This method finds and returns the center of the given nodes, assuming
 * that the given nodes form a tree in themselves.
 */
Layout.findCenterOfTree = function (nodes)
{
  var list = [];
  list = list.concat(nodes);

  var removedNodes = [];
  var remainingDegrees = new Map();
  var foundCenter = false;
  var centerNode = null;

  if (list.length == 1 || list.length == 2)
  {
    foundCenter = true;
    centerNode = list[0];
  }

  for (var i = 0; i < list.length; i++)
  {
    var node = list[i];
    var degree = node.getNeighborsList().size;
    remainingDegrees.set(node, node.getNeighborsList().size);

    if (degree == 1)
    {
      removedNodes.push(node);
    }
  }

  var tempList = [];
  tempList = tempList.concat(removedNodes);

  while (!foundCenter)
  {
    var tempList2 = [];
    tempList2 = tempList2.concat(tempList);
    tempList = [];

    for (var i = 0; i < list.length; i++)
    {
      var node = list[i];

      var index = list.indexOf(node);
      if (index >= 0) {
        list.splice(index, 1);
      }

      var neighbours = node.getNeighborsList();

      neighbours.forEach(function(neighbour) {
        if (removedNodes.indexOf(neighbour) < 0)
        {
          var otherDegree = remainingDegrees.get(neighbour);
          var newDegree = otherDegree - 1;

          if (newDegree == 1)
          {
            tempList.push(neighbour);
          }

          remainingDegrees.set(neighbour, newDegree);
        }
      });
    }

    removedNodes = removedNodes.concat(tempList);

    if (list.length == 1 || list.length == 2)
    {
      foundCenter = true;
      centerNode = list[0];
    }
  }

  return centerNode;
};

/**
 * During the coarsening process, this layout may be referenced by two graph managers
 * this setter function grants access to change the currently being used graph manager
 */
Layout.prototype.setGraphManager = function (gm)
{
  this.graphManager = gm;
};

module.exports = Layout;