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

import Label              from './shared/Label'
import CubicBezierEdge    from './edges/CubicBezierEdge'
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, defaultOptions, edgeOptions) {
    if (body === undefined) {
      throw "No body provided";
    }
    this.options = util.bridgeObject(globalOptions);
    this.globalOptions = globalOptions;
    this.defaultOptions = defaultOptions;
    this.edgeOptions = edgeOptions;
    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
   * @param doNotEmit
   */
  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);
    }

    this.choosify(options);

    // update label Module
    this.updateLabelModule(options);
    this.labelModule.propagateFonts(this.edgeOptions, options, this.defaultOptions);

    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;
  }

  static parseOptions(parentOptions, newOptions, allowDeletion = false, globalOptions = {}) {
    var fields = [
      'arrowStrikethrough',
      'id',
      'from',
      'hidden',
      'hoverWidth',
      'label',
      'labelHighlightBold',
      'length',
      'line',
      'opacity',
      'physics',
      'scaling',
      'selectionWidth',
      'selfReferenceSize',
      'to',
      'title',
      'value',
      'width'
    ];

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

    util.mergeOptions(parentOptions, newOptions, 'smooth', allowDeletion, globalOptions);
    util.mergeOptions(parentOptions, newOptions, 'shadow', allowDeletion, 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', allowDeletion, 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',     allowDeletion, globalOptions.arrows);
        util.mergeOptions(parentOptions.arrows, newOptions.arrows, 'middle', allowDeletion, globalOptions.arrows);
        util.mergeOptions(parentOptions.arrows, newOptions.arrows, 'from',   allowDeletion, 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) {
      // make a copy of the parent object in case this is referring to the global one (due to object create once, then update)
      parentOptions.color = util.deepExtend({}, parentOptions.color, true);
      if (util.isString(newOptions.color)) {
        parentOptions.color.color     = newOptions.color;
        parentOptions.color.highlight = newOptions.color;
        parentOptions.color.hover     = newOptions.color;
        parentOptions.color.inherit   = false;
      }
      else {
        let colorsDefined = false;
        if (newOptions.color.color     !== undefined) {parentOptions.color.color     = newOptions.color.color;     colorsDefined = true;}
        if (newOptions.color.highlight !== undefined) {parentOptions.color.highlight = newOptions.color.highlight; colorsDefined = true;}
        if (newOptions.color.hover     !== undefined) {parentOptions.color.hover     = newOptions.color.hover;     colorsDefined = true;}
        if (newOptions.color.inherit   !== undefined) {parentOptions.color.inherit   = newOptions.color.inherit;}
        if (newOptions.color.opacity   !== undefined) {parentOptions.color.opacity   = Math.min(1,Math.max(0,newOptions.color.opacity));}

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

    // handle the font settings
    if (newOptions.font !== undefined && newOptions.font !== null) {
      Label.parseOptions(parentOptions.font, newOptions);
    }
    else if (allowDeletion === true && newOptions.font === null) {
      parentOptions.font = util.bridgeObject(globalOptions.font); // set the object back to the global options
    }
  }

  choosify(options) {
    this.chooser = true;

    let pile = [options, this.options, this.edgeOptions, this.defaultOptions];

    let chosen = util.topMost(pile, 'chosen');
    if (typeof chosen === 'boolean') {
      this.chooser = chosen;
    } else if (typeof chosen === 'object') {
      let chosenEdge = util.topMost(pile, ['chosen', 'edge']);
      if ((typeof chosenEdge === 'boolean') || (typeof chosenEdge === 'function')) {
        this.chooser = chosenEdge;
      }
    }
  }

  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
    };
    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
   */
  updateLabelModule(options) {
    this.labelModule.setOptions(this.options, true);
    if (this.labelModule.baseSize !== undefined) {
      this.baseFontSize = this.labelModule.baseSize;
    }
    this.labelModule.constrain(this.edgeOptions, options, this.defaultOptions);
    this.labelModule.choosify(this.edgeOptions, options, this.defaultOptions);
  }

  /**
   * 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 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();
  }

  _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);
  }


  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);
    }
  }


  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) {
        this.labelModule.pointToSelf = false;
        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, this.hover, 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, this.hover);
        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, selected, this.hover);
      }
    }
  }


  /**
   * 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)
    }
  }


  select() {
    this.selected = true;
  }


  unselect() {
    this.selected = false;
  }


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

export default Edge;