var util = require('../../../util');
var Label = require('./shared/Label').default;
var ComponentUtil = require('./shared/ComponentUtil').default;
var CubicBezierEdge = require('./edges/CubicBezierEdge').default;
var BezierEdgeDynamic = require('./edges/BezierEdgeDynamic').default;
var BezierEdgeStatic = require('./edges/BezierEdgeStatic').default;
var StraightEdge = require('./edges/StraightEdge').default;


/**
 * An edge connects two nodes and has a specific direction.
 */
class Edge {
  /**
   * @param {Object} options        values specific to this edge, must contain at least 'from' and 'to'
   * @param {Object} body           shared state from Network instance
   * @param {Object} globalOptions  options from the EdgesHandler instance
   * @param {Object} defaultOptions default options from the EdgeHandler instance. Value and reference are constant
   */
  constructor(options, body, globalOptions, defaultOptions) {
    if (body === undefined) {
      throw new Error("No body provided");
    }

    // Since globalOptions is constant in values as well as reference,
    // Following needs to be done only once.

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

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

    this.baseWidth = this.options.width;
    this.baseFontSize = this.options.font.size;

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

    this.edgeType = undefined;

    this.connected = false;

    this.labelModule = new Label(this.body, this.options, true /* It's an edge label */);
    this.setOptions(options);
  }


  /**
   * Set or overwrite options for the edge
   * @param {Object} options  an object with options
   * @returns {null|boolean} null if no options, boolean if date changed
   */
  setOptions(options) {
    if (!options) {
      return;
    }

    Edge.parseOptions(this.options, options, true, this.globalOptions);

    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)  {
      options.value = parseFloat(options.value);
    }

    let pile = [options, this.options, this.defaultOptions];
    this.chooser = ComponentUtil.choosify('edge', pile);

    // update label Module
    this.updateLabelModule(options);

    let dataChanged = this.updateEdgeType();

    // if anything has been updates, reset the selection width and the hover width
    this._setInteractionWidths();

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

    if (options.hidden !== undefined || options.physics !== undefined) {
      dataChanged = true;
    }

    return dataChanged;
  }


  /**
   *
   * @param {Object} parentOptions
   * @param {Object} newOptions
   * @param {boolean} [allowDeletion=false]
   * @param {Object} [globalOptions={}]
   * @param {boolean} [copyFromGlobals=false]
   */
  static parseOptions(parentOptions, newOptions, allowDeletion = false, globalOptions = {}, copyFromGlobals = false) {
    var fields = [
      'arrowStrikethrough',
      'id',
      'from',
      'hidden',
      'hoverWidth',
      'labelHighlightBold',
      'length',
      'line',
      'opacity',
      'physics',
      'scaling',
      'selectionWidth',
      'selfReferenceSize',
      'to',
      'title',
      'value',
      'width',
      'font',
      'chosen',
      'widthConstraint'
    ];

    // only deep extend the items in the field array. These do not have shorthand.
    util.selectiveDeepExtend(fields, parentOptions, newOptions, allowDeletion);

    // Only copy label if it's a legal value.
    if (ComponentUtil.isValidLabel(newOptions.label)) {
      parentOptions.label = newOptions.label;
    } else {
      parentOptions.label = undefined;
    }

    util.mergeOptions(parentOptions, newOptions, 'smooth', globalOptions);
    util.mergeOptions(parentOptions, newOptions, 'shadow', globalOptions);
    util.mergeOptions(parentOptions, newOptions, 'background', globalOptions);

    if (newOptions.dashes !== undefined && newOptions.dashes !== null) {
      parentOptions.dashes = newOptions.dashes;
    }
    else if (allowDeletion === true && newOptions.dashes === null) {
      parentOptions.dashes = Object.create(globalOptions.dashes); // this sets the pointer of the option back to the global option.
    }

    // set the scaling newOptions
    if (newOptions.scaling !== undefined && newOptions.scaling !== null) {
      if (newOptions.scaling.min !== undefined) {parentOptions.scaling.min = newOptions.scaling.min;}
      if (newOptions.scaling.max !== undefined) {parentOptions.scaling.max = newOptions.scaling.max;}
      util.mergeOptions(parentOptions.scaling, newOptions.scaling, 'label', globalOptions.scaling);
    }
    else if (allowDeletion === true && newOptions.scaling === null) {
      parentOptions.scaling = Object.create(globalOptions.scaling); // this sets the pointer of the option back to the global option.
    }

    // handle multiple input cases for arrows
    if (newOptions.arrows !== undefined && newOptions.arrows !== null) {
      if (typeof newOptions.arrows === 'string') {
        let arrows = newOptions.arrows.toLowerCase();
        parentOptions.arrows.to.enabled     = arrows.indexOf("to")     != -1;
        parentOptions.arrows.middle.enabled = arrows.indexOf("middle") != -1;
        parentOptions.arrows.from.enabled   = arrows.indexOf("from")   != -1;
      }
      else if (typeof newOptions.arrows === 'object') {
        util.mergeOptions(parentOptions.arrows, newOptions.arrows, 'to',     globalOptions.arrows);
        util.mergeOptions(parentOptions.arrows, newOptions.arrows, 'middle', globalOptions.arrows);
        util.mergeOptions(parentOptions.arrows, newOptions.arrows, 'from',   globalOptions.arrows);
      }
      else {
        throw new Error("The arrow newOptions can only be an object or a string. Refer to the documentation. You used:" + JSON.stringify(newOptions.arrows));
      }
    }
    else if (allowDeletion === true && newOptions.arrows === null) {
      parentOptions.arrows = Object.create(globalOptions.arrows); // this sets the pointer of the option back to the global option.
    }

    // handle multiple input cases for color
    if (newOptions.color !== undefined && newOptions.color !== null) {
      let fromColor = newOptions.color;
      let toColor   = parentOptions.color;

      // If passed, fill in values from default options - required in the case of no prototype bridging
      if (copyFromGlobals) {
        util.deepExtend(toColor, globalOptions.color, false, allowDeletion);
      } else {
        // Clear local properties - need to do it like this in order to retain prototype bridges
        for (var i in toColor) {
          if (toColor.hasOwnProperty(i)) {
            delete toColor[i];
          }
        }
      }

      if (util.isString(toColor)) {
        toColor.color     = toColor;
        toColor.highlight = toColor;
        toColor.hover     = toColor;
        toColor.inherit   = false;
        if (fromColor.opacity === undefined) {
          toColor.opacity = 1.0;  // set default
        }
      }
      else {
        let colorsDefined = false;
        if (fromColor.color     !== undefined) {toColor.color     = fromColor.color;     colorsDefined = true;}
        if (fromColor.highlight !== undefined) {toColor.highlight = fromColor.highlight; colorsDefined = true;}
        if (fromColor.hover     !== undefined) {toColor.hover     = fromColor.hover;     colorsDefined = true;}
        if (fromColor.inherit   !== undefined) {toColor.inherit   = fromColor.inherit;}
        if (fromColor.opacity   !== undefined) {toColor.opacity   = Math.min(1,Math.max(0,fromColor.opacity));}

        if (colorsDefined === true) {
          toColor.inherit = false;
        } else {
          if (toColor.inherit === undefined) {
            toColor.inherit = 'from';  // Set default
          }
        }
      }
    }
    else if (allowDeletion === true && newOptions.color === null) {
      parentOptions.color = util.bridgeObject(globalOptions.color); // set the object back to the global options
    }

    if (allowDeletion === true && newOptions.font === null) {
      parentOptions.font = util.bridgeObject(globalOptions.font); // set the object back to the global options
    }
  }


  /**
   *
   * @returns {ArrowOptions}
   */
  getFormattingValues() {
    let toArrow = (this.options.arrows.to === true) || (this.options.arrows.to.enabled === true)
    let fromArrow = (this.options.arrows.from === true) || (this.options.arrows.from.enabled === true)
    let middleArrow = (this.options.arrows.middle === true) || (this.options.arrows.middle.enabled === true)
    let inheritsColor = this.options.color.inherit;
    let values = {
      toArrow: toArrow,
      toArrowScale: this.options.arrows.to.scaleFactor,
      toArrowType: this.options.arrows.to.type,
      middleArrow: middleArrow,
      middleArrowScale: this.options.arrows.middle.scaleFactor,
      middleArrowType: this.options.arrows.middle.type,
      fromArrow: fromArrow,
      fromArrowScale: this.options.arrows.from.scaleFactor,
      fromArrowType: this.options.arrows.from.type,
      arrowStrikethrough: this.options.arrowStrikethrough,
      color: (inheritsColor? undefined : this.options.color.color),
      inheritsColor: inheritsColor,
      opacity: this.options.color.opacity,
      hidden: this.options.hidden,
      length: this.options.length,
      shadow: this.options.shadow.enabled,
      shadowColor: this.options.shadow.color,
      shadowSize: this.options.shadow.size,
      shadowX: this.options.shadow.x,
      shadowY: this.options.shadow.y,
      dashes: this.options.dashes,
      width: this.options.width,
      background: this.options.background.enabled,
      backgroundColor: this.options.background.color,
      backgroundSize: this.options.background.size,
      backgroundDashes: this.options.background.dashes
    };
    if (this.selected || this.hover) {
      if (this.chooser === true) {
        if (this.selected) {
          let selectedWidth = this.options.selectionWidth;
          if (typeof selectedWidth === 'function') {
            values.width = selectedWidth(values.width);
          } else if (typeof selectedWidth === 'number') {
            values.width += selectedWidth;
          }
          values.width = Math.max(values.width, 0.3 / this.body.view.scale);
          values.color = this.options.color.highlight;
          values.shadow = this.options.shadow.enabled;
        } else if (this.hover) {
          let hoverWidth = this.options.hoverWidth;
          if (typeof hoverWidth === 'function') {
            values.width = hoverWidth(values.width);
          } else if (typeof hoverWidth === 'number') {
            values.width += hoverWidth;
          }
          values.width = Math.max(values.width, 0.3 / this.body.view.scale);
          values.color = this.options.color.hover;
          values.shadow = this.options.shadow.enabled;
        }
      } else if (typeof this.chooser === 'function') {
        this.chooser(values, this.options.id, this.selected, this.hover);
        if (values.color !== undefined) {
          values.inheritsColor = false;
        }
        if (values.shadow === false) {
          if ((values.shadowColor !== this.options.shadow.color) ||
              (values.shadowSize !== this.options.shadow.size) ||
              (values.shadowX !== this.options.shadow.x) ||
              (values.shadowY !== this.options.shadow.y)) {
            values.shadow = true;
          }
        }
      }
    } else {
      values.shadow = this.options.shadow.enabled;
      values.width = Math.max(values.width, 0.3 / this.body.view.scale);
    }
    return values;
  }

  /**
   * update the options in the label module
   *
   * @param {Object} options
   */
  updateLabelModule(options) {
    let pile = [
      options,
      this.options,
      this.globalOptions,  // Currently set global edge options
      this.defaultOptions
    ];

    this.labelModule.update(this.options, pile);

    if (this.labelModule.baseSize !== undefined) {
      this.baseFontSize = this.labelModule.baseSize;
    }
  }

  /**
   * update the edge type, set the options
   * @returns {boolean}
   */
  updateEdgeType() {
    let smooth = this.options.smooth;
    let dataChanged = false;
    let changeInType = true;
    if (this.edgeType !== undefined) {
      if ((((this.edgeType instanceof BezierEdgeDynamic) &&
            (smooth.enabled === true) &&
            (smooth.type === 'dynamic'))) ||
          (((this.edgeType instanceof CubicBezierEdge) &&
            (smooth.enabled === true) &&
            (smooth.type === 'cubicBezier'))) ||
          (((this.edgeType instanceof BezierEdgeStatic) &&
            (smooth.enabled === true) &&
            (smooth.type !== 'dynamic') &&
            (smooth.type !== 'cubicBezier'))) ||
          (((this.edgeType instanceof StraightEdge) &&
            (smooth.type.enabled === false)))) {
        changeInType = false;
      }
      if (changeInType === true) {
        dataChanged = this.cleanup();
      }
    }
    if (changeInType === true) {
      if (smooth.enabled === true) {
        if (smooth.type === 'dynamic') {
          dataChanged = true;
          this.edgeType = new BezierEdgeDynamic(this.options, this.body, this.labelModule);
        } else if (smooth.type === 'cubicBezier') {
          this.edgeType = new CubicBezierEdge(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);
      }
    } else { // if nothing changes, we just set the options.
      this.edgeType.setOptions(this.options);
    }
    return dataChanged;
  }

  /**
   * 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);
      }
    }

    this.edgeType.connect();
  }


  /**
   * 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 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.options.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 {number} total
   */
  setValueRange(min, max, total) {
    if (this.options.value !== undefined) {
      var scale = this.options.scaling.customScalingFunction(min, max, total, this.options.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;
    }
    else {
      this.options.width = this.baseWidth;
      this.options.font.size = this.baseFontSize;
    }

    this._setInteractionWidths();
    this.updateLabelModule();
  }

  /**
   *
   * @private
   */
  _setInteractionWidths() {
    if (typeof this.options.hoverWidth === 'function') {
      this.edgeType.hoverWidth = this.options.hoverWidth(this.options.width);
    } else {
      this.edgeType.hoverWidth = this.options.hoverWidth + this.options.width;
    }
    if (typeof this.options.selectionWidth === 'function') {
      this.edgeType.selectionWidth = this.options.selectionWidth(this.options.width);
    } else {
      this.edgeType.selectionWidth = this.options.selectionWidth + this.options.width;
    }
  }


  /**
   * 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 values = this.getFormattingValues();
    if (values.hidden) {
      return;
    }

    // get the via node from the edge type
    let viaNode = this.edgeType.getViaNode();
    let arrowData = {};

    // restore edge targets to defaults
    this.edgeType.fromPoint = this.edgeType.from;
    this.edgeType.toPoint = this.edgeType.to;

    // from and to arrows give a different end point for edges. we set them here
    if (values.fromArrow) {
      arrowData.from = this.edgeType.getArrowData(ctx, 'from', viaNode, this.selected, this.hover, values);
      if (values.arrowStrikethrough === false)
        this.edgeType.fromPoint = arrowData.from.core;
    }
    if (values.toArrow) {
      arrowData.to = this.edgeType.getArrowData(ctx, 'to', viaNode, this.selected, this.hover, values);
      if (values.arrowStrikethrough === false)
        this.edgeType.toPoint = arrowData.to.core;
    }

    // the middle arrow depends on the line, which can depend on the to and from arrows so we do this one lastly.
    if (values.middleArrow) {
      arrowData.middle = this.edgeType.getArrowData(ctx,'middle', viaNode, this.selected, this.hover, values);
    }

    // draw everything
    this.edgeType.drawLine(ctx, values, this.selected, this.hover, viaNode);
    this.drawArrows(ctx, arrowData, values);
    this.drawLabel(ctx, viaNode);
  }

  /**
   *
   * @param {CanvasRenderingContext2D} ctx
   * @param {Object} arrowData
   * @param {ArrowOptions} values
   */
  drawArrows(ctx, arrowData, values) {
    if (values.fromArrow) {
      this.edgeType.drawArrowHead(ctx, values, this.selected, this.hover, arrowData.from);
    }
    if (values.middleArrow) {
      this.edgeType.drawArrowHead(ctx, values, this.selected, this.hover, arrowData.middle);
    }
    if (values.toArrow) {
      this.edgeType.drawArrowHead(ctx, values, this.selected, this.hover, arrowData.to);
    }
  }

  /**
   *
   * @param {CanvasRenderingContext2D} ctx
   * @param {Node} viaNode
   */
  drawLabel(ctx, viaNode) {
    if (this.options.label !== undefined) {
      // set style
      var node1 = this.from;
      var node2 = this.to;

      if (this.labelModule.differentState(this.selected, this.hover)) {
        this.labelModule.getTextSize(ctx, this.selected, this.hover);
      }

      if (node1.id != node2.id) {
        this.labelModule.pointToSelf = false;
        var point = this.edgeType.getPoint(0.5, viaNode);
        ctx.save();

        let rotationPoint = this._getRotation(ctx);
        if (rotationPoint.angle != 0) {
          ctx.translate(rotationPoint.x, rotationPoint.y);
          ctx.rotate(rotationPoint.angle);
        }

        // draw the label
        this.labelModule.draw(ctx, point.x, point.y, this.selected, this.hover);

/*
        // Useful debug code: draw a border around the label
        // This should **not** be enabled in production!
        var size = this.labelModule.getSize();; // ;; intentional so lint catches it
        ctx.strokeStyle = "#ff0000";
        ctx.strokeRect(size.left, size.top, size.width, size.height);
        // End  debug code
*/

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


  /**
   * Determine all visual elements of this edge instance, in which the given
   * point falls within the bounding shape.
   *
   * @param {point} point
   * @returns {Array.<edgeClickItem|edgeLabelClickItem>} list with the items which are on the point
   */
  getItemsOnPoint(point) {
    var ret = [];

    if (this.labelModule.visible()) {
      let rotationPoint = this._getRotation();
      if (ComponentUtil.pointInRect(this.labelModule.getSize(), point, rotationPoint)) {
        ret.push({edgeId:this.id, labelId:0});
      }
    }

    let obj = {
      left: point.x,
      top: point.y
    };

    if (this.isOverlappingWith(obj)) {
      ret.push({edgeId:this.id});
    }

    return ret;
  }


  /**
   * 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
    }
  }


  /** 
   * Determine the rotation point, if any.
   *
   * @param {CanvasRenderingContext2D} [ctx] if passed, do a recalculation of the label size
   * @returns {rotationPoint} the point to rotate around and the angle in radians to rotate
   * @private
   */
  _getRotation(ctx) {
    let viaNode = this.edgeType.getViaNode();
    let point = this.edgeType.getPoint(0.5, viaNode);

    if (ctx !== undefined) {
      this.labelModule.calculateLabelSize(ctx, this.selected, this.hover, point.x, point.y);
    }

    let ret = {
      x: point.x,
      y: this.labelModule.size.yLine,
      angle: 0
    };

    if (!this.labelModule.visible()) {
      return ret;  // Don't even bother doing the atan2, there's nothing to draw
    }

    if (this.options.font.align === "horizontal") {
      return ret;  // No need to calculate angle
    }

    var dy = this.from.y - this.to.y;
    var dx = this.from.x - this.to.x;
    var angle = Math.atan2(dy, dx);  // radians

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

    return ret;
  }


  /**
   * 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)
    }
  }

  /**
   * Sets selected state to true
   */
  select() {
    this.selected = true;
  }

  /**
   * Sets selected state to false
   */
  unselect() {
    this.selected = false;
  }


  /**
   * cleans all required things on delete
   * @returns {*}
   */
  cleanup() {
    return this.edgeType.cleanup();
  }


  /**
   * Remove edge from the list and perform necessary cleanup.
   */
  remove() {
    this.cleanup();
    this.disconnect();
    delete this.body.edges[this.id];
  }


  /**
   * Check if both connecting nodes exist
   * @returns {boolean}
   */
  endPointsValid() {
    return this.body.nodes[this.fromId] !== undefined
        && this.body.nodes[this.toId]   !== undefined;
  }
}

export default Edge;