var util = require('../../../util');


import Label from './unified/label.js'
import BezierEdgeDynamic from './edges/bezierEdgeDynamic'
import BezierEdgeStatic from './edges/bezierEdgeStatic'
import StraightEdge from './edges/straightEdge'
/**
 * @class Edge
 *
 * A edge connects two nodes
 * @param {Object} properties     Object with options. Must contain
 *                                At least options from and to.
 *                                Available options: from (number),
 *                                to (number), label (string, color (string),
 *                                width (number), style (string),
 *                                length (number), title (string)
 * @param {Network} network       A Network object, used to find and edge to
 *                                nodes.
 * @param {Object} constants      An object with default values for
 *                                example for the color
 */
class Edge {
  constructor(options, body, globalOptions) {
    if (body === undefined) {
      throw "No body provided";
    }

    this.options = util.bridgeObject(globalOptions);
    this.body = body;

    // initialize variables
    this.id = undefined;
    this.fromId = undefined;
    this.toId = undefined;
    this.title = undefined;
    this.value = undefined;
    this.selected = false;
    this.hover = false;
    this.labelDirty = true;
    this.colorDirty = true;

    this.from = undefined; // a node
    this.to   = undefined; // a node

    this.edgeType = undefined;

    this.connected = false;

    this.labelModule = new Label(this.body, this.options);

    this.setOptions(options, true);

    this.controlNodesEnabled = false;
    this.controlNodes = {from: undefined, to: undefined, positions: {}};
    this.connectedNode = undefined;
  }


  /**
   * Set or overwrite options for the edge
   * @param {Object} options  an object with options
   * @param doNotEmit
   */
  setOptions(options, doNotEmit = false) {
    if (!options) {
      return;
    }
    this.colorDirty = true;

    var fields = [
      'id',
      'font',
      'from',
      'hidden',
      'hoverWidth',
      'label',
      'length',
      'line',
      'opacity',
      'physics',
      'scaling',
      'selfReferenceSize',
      'to',
      'value',
      'width',
      'widthMin',
      'widthMax',
      'widthSelectionMultiplier'
    ];
    util.selectiveDeepExtend(fields, this.options, options);
    
    util.mergeOptions(this.options, options, 'smooth');
    util.mergeOptions(this.options, options, 'dashes');

    if (options.arrows !== undefined) {
      util.mergeOptions(this.options.arrows, options.arrows, 'to');
      util.mergeOptions(this.options.arrows, options.arrows, 'middle');
      util.mergeOptions(this.options.arrows, options.arrows, 'from');
    }

    if (options.id !== undefined)   {this.id = options.id;}
    if (options.from !== undefined) {this.fromId = options.from;}
    if (options.to !== undefined)   {this.toId = options.to;}
    if (options.title !== undefined) {this.title = options.title;}
    if (options.value !== undefined) {this.value = options.value;}

    if (options.color !== undefined) {
      if (util.isString(options.color)) {
        this.options.color.color = options.color;
        this.options.color.highlight = options.color;
      }
      else {
        if (options.color.color !== undefined) {
          this.options.color.color = options.color.color;
        }
        if (options.color.highlight !== undefined) {
          this.options.color.highlight = options.color.highlight;
        }
        if (options.color.hover !== undefined) {
          this.options.color.hover = options.color.hover;
        }
      }

      // inherit colors
      if (options.color.inherit === undefined) {
        this.options.color.inherit.enabled = false;
      }
      else {
        util.mergeOptions(this.options.color, options.color, 'inherit');
      }
    }

    // A node is connected when it has a from and to node that both exist in the network.body.nodes.
    this.connect();

    this.labelModule.setOptions(this.options);

    this.updateEdgeType();

    this.edgeType.setOptions(this.options);

  }

  updateEdgeType() {
    if (this.edgeType !== undefined) {
      this.edgeType.cleanup();
    }

    if (this.options.smooth.enabled === true) {
      if (this.options.smooth.dynamic === true) {
        this.edgeType = new BezierEdgeDynamic(this.options, this.body, this.labelModule);
      }
      else {
        this.edgeType = new BezierEdgeStatic(this.options, this.body, this.labelModule);
      }
    }
    else {
      this.edgeType = new StraightEdge(this.options, this.body, this.labelModule);
    }
  }




  /**
   * Enable or disable the physics.
   * @param status
   */
  togglePhysics(status) {
    if (this.options.smooth.enabled == true && this.options.smooth.dynamic == true) {
      if (this.via === undefined) {
        this.via.pptions.physics = status;
      }
    }
    this.options.physics = status;
  }

  /**
   * Connect an edge to its nodes
   */
  connect() {
    this.disconnect();

    this.from = this.body.nodes[this.fromId] || undefined;
    this.to = this.body.nodes[this.toId] || undefined;
    this.connected = (this.from !== undefined && this.to !== undefined);

    if (this.connected === true) {
      this.from.attachEdge(this);
      this.to.attachEdge(this);
    }
    else {
      if (this.from) {
        this.from.detachEdge(this);
      }
      if (this.to) {
        this.to.detachEdge(this);
      }
    }
  }


  /**
   * Disconnect an edge from its nodes
   */
  disconnect() {
    if (this.from) {
      this.from.detachEdge(this);
      this.from = undefined;
    }
    if (this.to) {
      this.to.detachEdge(this);
      this.to = undefined;
    }

    this.connected = false;
  }


  /**
   * get the title of this edge.
   * @return {string} title    The title of the edge, or undefined when no title
   *                           has been set.
   */
  getTitle() {
    return typeof this.title === "function" ? this.title() : this.title;
  }


  /**
   * check if this node is selecte
   * @return {boolean} selected   True if node is selected, else false
   */
  isSelected() {
    return this.selected;
  }



  /**
   * Retrieve the value of the edge. Can be undefined
   * @return {Number} value
   */
  getValue() {
    return this.value;
  }


  /**
   * Adjust the value range of the edge. The edge will adjust it's width
   * based on its value.
   * @param {Number} min
   * @param {Number} max
   * @param total
   */
  setValueRange(min, max, total) {
    if (this.value !== undefined) {
      var scale = this.options.scaling.customScalingFunction(min, max, total, this.value);
      var widthDiff = this.options.scaling.max - this.options.scaling.min;
      if (this.options.scaling.label.enabled == true) {
        var fontDiff = this.options.scaling.label.max - this.options.scaling.label.min;
        this.options.font.size = this.options.scaling.label.min + scale * fontDiff;
      }
      this.options.width = this.options.scaling.min + scale * widthDiff;
    }
  }


  /**
   * Redraw a edge
   * Draw this edge in the given canvas
   * The 2d context of a HTML canvas can be retrieved by canvas.getContext("2d");
   * @param {CanvasRenderingContext2D}   ctx
   */
  draw(ctx) {
    let via = this.edgeType.drawLine(ctx, this.selected, this.hover);
    this.drawArrows(ctx, via);
    this.drawLabel (ctx, via);
  }

  drawArrows(ctx, viaNode) {
    if (this.options.arrows.from.enabled   === true) {this._drawArrowHead(ctx,'from',   viaNode);}
    if (this.options.arrows.middle.enabled === true) {this._drawArrowHead(ctx,'middle', viaNode);}
    if (this.options.arrows.to.enabled     === true) {this._drawArrowHead(ctx,'to',     viaNode);}
  }

  drawLabel(ctx, viaNode) {
    if (this.options.label !== undefined) {
      // set style
      var node1 = this.from;
      var node2 = this.to;
      var selected = (this.from.selected || this.to.selected || this.selected);
      if (node1.id != node2.id) {
        var point = this.edgeType.getPoint(0.5, viaNode);
        ctx.save();

        // if the label has to be rotated:
        if (this.options.font.align !== "horizontal") {
          this.labelModule.calculateLabelSize(ctx,selected,point.x,point.y);
          ctx.translate(point.x, this.labelModule.size.yLine);
          this._rotateForLabelAlignment(ctx);
        }

        // draw the label
        this.labelModule.draw(ctx, point.x, point.y, selected);
        ctx.restore();
      }
      else {
        var x, y;
        var radius = this.options.selfReferenceSize;
        if (node1.width > node1.height) {
          x = node1.x + node1.width * 0.5;
          y = node1.y - radius;
        }
        else {
          x = node1.x + radius;
          y = node1.y - node1.height * 0.5;
        }
        point = this._pointOnCircle(x, y, radius, 0.125);

        this.labelModule.draw(ctx, point.x, point.y, selected);
      }
    }
  }


  /**
   * Check if this object is overlapping with the provided object
   * @param {Object} obj   an object with parameters left, top
   * @return {boolean}     True if location is located on the edge
   */
  isOverlappingWith(obj) {
    if (this.connected) {
      var distMax = 10;
      var xFrom = this.from.x;
      var yFrom = this.from.y;
      var xTo = this.to.x;
      var yTo = this.to.y;
      var xObj = obj.left;
      var yObj = obj.top;

      var dist = this.edgeType.getDistanceToEdge(xFrom, yFrom, xTo, yTo, xObj, yObj);

      return (dist < distMax);
    }
    else {
      return false
    }
  }


  /**
   * Rotates the canvas so the text is most readable
   * @param {CanvasRenderingContext2D} ctx
   * @private
   */
  _rotateForLabelAlignment(ctx) {
    var dy = this.from.y - this.to.y;
    var dx = this.from.x - this.to.x;
    var angleInDegrees = Math.atan2(dy, dx);

    // rotate so label it is readable
    if ((angleInDegrees < -1 && dx < 0) || (angleInDegrees > 0 && dx < 0)) {
      angleInDegrees = angleInDegrees + Math.PI;
    }

    ctx.rotate(angleInDegrees);
  }


  /**
   * Get a point on a circle
   * @param {Number} x
   * @param {Number} y
   * @param {Number} radius
   * @param {Number} percentage. Value between 0 (line start) and 1 (line end)
   * @return {Object} point
   * @private
   */
  _pointOnCircle(x, y, radius, percentage) {
    var angle = percentage * 2 * Math.PI;
    return {
      x: x + radius * Math.cos(angle),
      y: y - radius * Math.sin(angle)
    }
  }



  /**
   *
   * @param ctx
   * @param position
   * @param viaNode
   */
  _drawArrowHead(ctx,position,viaNode) {
    // set style
    ctx.strokeStyle = this.edgeType.getColor(ctx);
    ctx.fillStyle = ctx.strokeStyle;
    ctx.lineWidth = this.edgeType.getLineWidth();

    // set lets
    let angle;
    let length;
    let arrowPos;
    let node1;
    let node2;
    let guideOffset;
    let scaleFactor;

    if (position == 'from') {
      node1 = this.from;
      node2 = this.to;
      guideOffset = 0.1;
      scaleFactor = this.options.arrows.from.scaleFactor;
    }
    else if (position == 'to') {
      node1 = this.to;
      node2 = this.from;
      guideOffset = -0.1;
      scaleFactor = this.options.arrows.to.scaleFactor;
    }
    else {
      node1 = this.to;
      node2 = this.from;
      scaleFactor = this.options.arrows.middle.scaleFactor;
    }

    // if not connected to itself
    if (node1 != node2) {
      if (position !== 'middle') {
        // draw arrow head
        if (this.options.smooth.enabled == true) {
          arrowPos = this.edgeType.findBorderPosition(node1, ctx, {via:viaNode});
          let guidePos = this.edgeType.getPoint(Math.max(0.0,Math.min(1.0,arrowPos.t + guideOffset)), viaNode);
          angle = Math.atan2((arrowPos.y - guidePos.y), (arrowPos.x - guidePos.x));
        }
        else {
          angle = Math.atan2((node1.y - node2.y), (node1.x - node2.x));
          arrowPos = this.edgeType.findBorderPosition(node1, ctx);
        }
      }
      else {
        angle = Math.atan2((node1.y - node2.y), (node1.x - node2.x));
        arrowPos = this.edgeType.getPoint(0.6, viaNode); // this is 0.6 to account for the size of the arrow.
      }
      // draw arrow at the end of the line
      length = (10 + 5 * this.options.width) * scaleFactor;
      ctx.arrow(arrowPos.x, arrowPos.y, angle, length);
      ctx.fill();
      ctx.stroke();
    }
    else {
      // draw circle
      let angle, point;
      let x, y;
      let radius = this.options.selfReferenceSize;
      if (!node1.width) {
        node1.resize(ctx);
      }

      // get circle coordinates
      if (node1.width > node1.height) {
        x = node1.x + node1.width * 0.5;
        y = node1.y - radius;
      }
      else {
        x = node1.x + radius;
        y = node1.y - node1.height * 0.5;
      }


      if (position == 'from') {
        point = this.edgeType.findBorderPosition(x, y, radius, node1, 0.25, 0.6, -1, ctx);
        angle = point.t * -2 * Math.PI + 1.5 * Math.PI + 0.1 * Math.PI;
      }
      else if (position == 'to') {
        point = this.edgeType.findBorderPosition(x, y, radius, node1, 0.6, 0.8, 1, ctx);
        angle = point.t * -2 * Math.PI + 1.5 * Math.PI - 1.1 * Math.PI;
      }
      else {
        point = this.edgeType.findBorderPosition(x,y,radius,0.175);
        angle = 3.9269908169872414; // == 0.175 * -2 * Math.PI + 1.5 * Math.PI + 0.1 * Math.PI;
      }

      // draw the arrowhead
      let length = (10 + 5 * this.options.width) * scaleFactor;
      ctx.arrow(point.x, point.y, angle, length);
      ctx.fill();
      ctx.stroke();
    }
  }

  /**
   * This allows the zoom level of the network to influence the rendering
   *
   * @param scale
   */
  setScale(scale) {
    this.networkScaleInv = 1.0 / scale;
  }

  select() {
    this.selected = true;
  }


  unselect() {
    this.selected = false;
  }





































  //*************************************************************************************************//
  //*************************************************************************************************//
  //*************************************************************************************************//
  //*************************************************************************************************//
  //*********************** MOVE THESE FUNCTIONS TO THE MANIPULATION SYSTEM ************************//
  //*************************************************************************************************//
  //*************************************************************************************************//
  //*************************************************************************************************//
  //*************************************************************************************************//







  /**
   * This function draws the control nodes for the manipulator.
   * In order to enable this, only set the this.controlNodesEnabled to true.
   * @param ctx
   */
  _drawControlNodes(ctx) {
    if (this.controlNodesEnabled == true) {
      if (this.controlNodes.from === undefined && this.controlNodes.to === undefined) {
        var nodeIdFrom = "edgeIdFrom:".concat(this.id);
        var nodeIdTo = "edgeIdTo:".concat(this.id);
        var nodeFromOptions = {
          id: nodeIdFrom,
          shape: 'dot',
          color: {background: '#ff0000', border: '#3c3c3c', highlight: {background: '#07f968'}},
          radius: 7,
          borderWidth: 2,
          borderWidthSelected: 2,
          hidden: false,
          physics: false
        };
        var nodeToOptions = util.deepExtend({},nodeFromOptions);
        nodeToOptions.id = nodeIdTo;

        
        this.controlNodes.from = this.body.functions.createNode(nodeFromOptions);
        this.controlNodes.to = this.body.functions.createNode(nodeToOptions);
      }

      this.controlNodes.positions = {};
      if (this.controlNodes.from.selected == false) {
        this.controlNodes.positions.from = this.getControlNodeFromPosition(ctx);
        this.controlNodes.from.x = this.controlNodes.positions.from.x;
        this.controlNodes.from.y = this.controlNodes.positions.from.y;
      }
      if (this.controlNodes.to.selected == false) {
        this.controlNodes.positions.to = this.getControlNodeToPosition(ctx);
        this.controlNodes.to.x = this.controlNodes.positions.to.x;
        this.controlNodes.to.y = this.controlNodes.positions.to.y;
      }

      this.controlNodes.from.draw(ctx);
      this.controlNodes.to.draw(ctx);
    }
    else {
      this.controlNodes = {from: undefined, to: undefined, positions: {}};
    }
  }

  /**
   * Enable control nodes.
   * @private
   */
  _enableControlNodes() {
    this.fromBackup = this.from;
    this.toBackup = this.to;
    this.controlNodesEnabled = true;
  }


  /**
   * disable control nodes and remove from dynamicEdges from old node
   * @private
   */
  _disableControlNodes() {
    this.fromId = this.from.id;
    this.toId = this.to.id;
    if (this.fromId != this.fromBackup.id) { // from was changed, remove edge from old 'from' node dynamic edges
      this.fromBackup.detachEdge(this);
    }
    else if (this.toId != this.toBackup.id) { // to was changed, remove edge from old 'to' node dynamic edges
      this.toBackup.detachEdge(this);
    }

    this.fromBackup = undefined;
    this.toBackup = undefined;
    this.controlNodesEnabled = false;
  }


  /**
   * This checks if one of the control nodes is selected and if so, returns the control node object. Else it returns undefined.
   * @param x
   * @param y
   * @returns {undefined}
   * @private
   */
  _getSelectedControlNode(x, y) {
    var positions = this.controlNodes.positions;
    var fromDistance = Math.sqrt(Math.pow(x - positions.from.x, 2) + Math.pow(y - positions.from.y, 2));
    var toDistance = Math.sqrt(Math.pow(x - positions.to.x, 2) + Math.pow(y - positions.to.y, 2));

    if (fromDistance < 15) {
      this.connectedNode = this.from;
      this.from = this.controlNodes.from;
      return this.controlNodes.from;
    }
    else if (toDistance < 15) {
      this.connectedNode = this.to;
      this.to = this.controlNodes.to;
      return this.controlNodes.to;
    }
    else {
      return undefined;
    }
  }



  /**
   * this resets the control nodes to their original position.
   * @private
   */
  _restoreControlNodes() {
    if (this.controlNodes.from.selected == true) {
      this.from = this.connectedNode;
      this.connectedNode = undefined;
      this.controlNodes.from.unselect();
    }
    else if (this.controlNodes.to.selected == true) {
      this.to = this.connectedNode;
      this.connectedNode = undefined;
      this.controlNodes.to.unselect();
    }
  }


  /**
   * this calculates the position of the control nodes on the edges of the parent nodes.
   *
   * @param ctx
   * @returns {x: *, y: *}
   */
  getControlNodeFromPosition(ctx) {
    // draw arrow head
    var controlnodeFromPos;
    if (this.options.smooth.enabled == true) {
      controlnodeFromPos = this._findBorderPositionBezier(true, ctx);
    }
    else {
      var angle = Math.atan2((this.to.y - this.from.y), (this.to.x - this.from.x));
      var dx = (this.to.x - this.from.x);
      var dy = (this.to.y - this.from.y);
      var edgeSegmentLength = Math.sqrt(dx * dx + dy * dy);

      var fromBorderDist = this.from.distanceToBorder(ctx, angle + Math.PI);
      var fromBorderPoint = (edgeSegmentLength - fromBorderDist) / edgeSegmentLength;
      controlnodeFromPos = {};
      controlnodeFromPos.x = (fromBorderPoint) * this.from.x + (1 - fromBorderPoint) * this.to.x;
      controlnodeFromPos.y = (fromBorderPoint) * this.from.y + (1 - fromBorderPoint) * this.to.y;
    }

    return controlnodeFromPos;
  }


  /**
   * this calculates the position of the control nodes on the edges of the parent nodes.
   *
   * @param ctx
   * @returns {{from: {x: number, y: number}, to: {x: *, y: *}}}
   */
  getControlNodeToPosition(ctx) {
    // draw arrow head
    var controlnodeToPos;
    if (this.options.smooth.enabled == true) {
      controlnodeToPos = this._findBorderPositionBezier(false, ctx);
    }
    else {
      var angle = Math.atan2((this.to.y - this.from.y), (this.to.x - this.from.x));
      var dx = (this.to.x - this.from.x);
      var dy = (this.to.y - this.from.y);
      var edgeSegmentLength = Math.sqrt(dx * dx + dy * dy);
      var toBorderDist = this.to.distanceToBorder(ctx, angle);
      var toBorderPoint = (edgeSegmentLength - toBorderDist) / edgeSegmentLength;

      controlnodeToPos = {};
      controlnodeToPos.x = (1 - toBorderPoint) * this.from.x + toBorderPoint * this.to.x;
      controlnodeToPos.y = (1 - toBorderPoint) * this.from.y + toBorderPoint * this.to.y;
    }

    return controlnodeToPos;
  }
}

export default Edge;