line-pod/src/index.ts

import { ChartwerkPod, VueChartwerkPodMixin, TimeFormat, CrosshairOrientation, BrushOrientation, yAxisOrientation } from '@chartwerk/core';
import { LineTimeSerie, LineOptions } from './types';

import { LineSeries } from './models/line_series';

import * as d3 from 'd3';
import * as _ from 'lodash';

const METRIC_CIRCLE_RADIUS = 1.5;
const CROSSHAIR_CIRCLE_RADIUS = 3;
const CROSSHAIR_BACKGROUND_RAIDUS = 9;
const CROSSHAIR_BACKGROUND_OPACITY = 0.3;

export class LinePod extends ChartwerkPod<LineTimeSerie, LineOptions> {
  lineGenerator = null;
  areaGenerator = null;
  lineGeneratorY1 = null;
  areaGeneratorY1 = null;

  constructor(_el: HTMLElement, _series: LineTimeSerie[] = [], _options: LineOptions = {}) {
    super(_el, _series, _options);
    this.series = new LineSeries(_series);
  }

  renderMetrics(): void {
    this.clearAllMetrics();

    this.updateCrosshair();
    this.initLineGenerator();
    this.initAreaGenerator();

    if(!this.series.isSeriesAvailable) {
      this.renderNoDataPointsMessage();
      return;
    }
    for(const serie of this.series.visibleSeries) {
      this._renderMetric(serie);
    }
  }

  clearAllMetrics(): void {
    // TODO: temporary hack before it will be implemented in core.
    this.chartContainer.selectAll('.metric-el').remove();
  }

  initLineGenerator(): void {
    this.lineGenerator = d3.line()
      .x(d => this.state.xScale(d[0]))
      .y(d => this.state.yScale(d[1]));
    this.lineGeneratorY1 = d3.line()
      .x(d => this.state.xScale(d[0]))
      .y(d => this.state.y1Scale(d[1]));
  }

  initAreaGenerator(): void {
    this.areaGenerator = d3.area()
      .x(d => this.state.xScale(d[0]))
      .y1(d => this.state.yScale(d[1]))
      .y0(d => this.height);
    this.areaGeneratorY1 = d3.area()
      .x(d => this.state.xScale(d[0]))
      .y1(d => this.state.y1Scale(d[1]))
      .y0(d => this.height);
  }

  getRenderGenerator(renderArea: boolean, yOrientation: yAxisOrientation): any {
    if(renderArea) {
      return yOrientation === yAxisOrientation.LEFT ? this.areaGenerator : this.areaGeneratorY1;
    }
    return yOrientation === yAxisOrientation.LEFT ? this.lineGenerator : this.areaGeneratorY1;
  }

  _renderDots(serie: LineTimeSerie): void {
    this.metricContainer.selectAll(null)
      .data(serie.datapoints)
      .enter()
      .append('circle')
      .attr('class', `metric-circle-${serie.idx} metric-el ${serie.class}`)
      .attr('fill', serie.color)
      .attr('r', METRIC_CIRCLE_RADIUS)
      .style('pointer-events', 'none')
      .attr('cx', d => this.state.xScale(d[0]))
      .attr('cy', d => this.state.yScale(d[1]));
  }

  _renderLines(serie: LineTimeSerie): void {
    const fillColor = serie.renderArea ? serie.color : 'none';
    const fillOpacity = serie.renderArea ? 0.5 : 'none';

    this.metricContainer
      .append('path')
      .datum(serie.datapoints)
      .attr('class', `metric-path-${serie.idx} metric-el ${serie.class}`)
      .attr('fill', fillColor)
      .attr('fill-opacity', fillOpacity)
      .attr('stroke', serie.color)
      .attr('stroke-width', 1)
      .attr('stroke-opacity', 0.7)
      .attr('pointer-events', 'none')
      .style('stroke-dasharray', serie.dashArray)
      .attr('d', this.getRenderGenerator(serie.renderArea, serie.yOrientation));
  }

  _renderMetric(serie: LineTimeSerie): void {
    if(serie.renderLines === true) {
      this._renderLines(serie);
    }

    if(serie.renderDots === true) {
      this._renderDots(serie);
    }
  }

  updateCrosshair(): void {
    this.crosshair.selectAll('circle').remove();
    // Core doesn't know anything about crosshair circles, It is only for line pod
    this.appendCrosshairCircles();
  }

  appendCrosshairCircles(): void {
    // circle for each serie
    this.series.visibleSeries.forEach((serie: LineTimeSerie, serieIdx: number) => {
      this.appendCrosshairCircle(serieIdx);
    });
  }

  appendCrosshairCircle(serieIdx: number): void {
    // TODO: cx, cy - hacks to hide circles after zoom out(can be replaced with display: none)
    this.crosshair.append('circle')
      .attr('class', `crosshair-circle-${serieIdx} crosshair-background`)
      .attr('r', CROSSHAIR_BACKGROUND_RAIDUS)
      .attr('cx', -CROSSHAIR_BACKGROUND_RAIDUS)
      .attr('cy', -CROSSHAIR_BACKGROUND_RAIDUS)
      .attr('clip-path', `url(#${this.rectClipId})`)
      .attr('fill', this.series.visibleSeries[serieIdx].color)
      .style('opacity', CROSSHAIR_BACKGROUND_OPACITY)
      .style('pointer-events', 'none');

    this.crosshair
      .append('circle')
      .attr('cx', -CROSSHAIR_CIRCLE_RADIUS)
      .attr('cy', -CROSSHAIR_CIRCLE_RADIUS)
      .attr('class', `crosshair-circle-${serieIdx}`)
      .attr('clip-path', `url(#${this.rectClipId})`)
      .attr('fill', this.series.visibleSeries[serieIdx].color)
      .attr('r', CROSSHAIR_CIRCLE_RADIUS)
      .style('pointer-events', 'none');
  }

  public renderSharedCrosshair(values: { x?: number, y?: number }): void {
    this.onMouseOver(); // TODO: refactor to use it once
    const eventX = this.state.xScale(values.x);
    const eventY = this.state.yScale(values.y);
    this.moveCrosshairLine(eventX, eventY);
    const datapoints = this.findAndHighlightDatapoints(values.x, values.y);

    this.options.callbackSharedCrosshairMove({
      datapoints: datapoints,
      eventX, eventY
    });
  }

  public hideSharedCrosshair(): void {
    this.crosshair.style('display', 'none');
  }

  moveCrosshairLine(xPosition: number, yPosition: number): void {
    switch(this.options.crosshair.orientation) {
      case CrosshairOrientation.VERTICAL:
        this.crosshair.select('#crosshair-line-x')
          .attr('x1', xPosition)
          .attr('x2', xPosition);
        return;
      case CrosshairOrientation.HORIZONTAL:
        this.crosshair.select('#crosshair-line-y')
          .attr('y1', yPosition)
          .attr('y2', yPosition);
        return;
      case CrosshairOrientation.BOTH:
        this.crosshair.select('#crosshair-line-x')
          .attr('x1', xPosition)
          .attr('x2', xPosition);
        this.crosshair.select('#crosshair-line-y')
          .attr('y1', yPosition)
          .attr('y2', yPosition);
        return;
      default:
        throw new Error(`Unknown type of crosshair orientaion: ${this.options.crosshair.orientation}`);
    }
  }

  moveCrosshairCircle(xPosition: number, yPosition: number, serieIdx: number): void {
    this.crosshair.selectAll(`.crosshair-circle-${serieIdx}`)
      .attr('cx', xPosition)
      .attr('cy', yPosition)
      .style('display', null);
  }

  hideCrosshairCircle(serieIdx: number): void {
    // hide circle for singe serie
    this.crosshair.selectAll(`.crosshair-circle-${serieIdx}`)
      .style('display', 'none');
  }

  getClosestDatapoint(serie: LineTimeSerie, xValue: number, yValue: number): [number, number] {
    // get closest datapoint to the "xValue"/"yValue" in the "serie"
    const datapoints = serie.datapoints;
    const closestIdx = this.getClosestIndex(datapoints, xValue, yValue);
    const datapoint = serie.datapoints[closestIdx];
    return datapoint;
  }

  getClosestIndex(datapoints: [number, number][], xValue: number, yValue: number): number {
    let columnIdx; // 0 for x value, 1 for y value,
    let value; // xValue to y Value
    switch(this.options.crosshair.orientation) {
      case CrosshairOrientation.VERTICAL:
        columnIdx = 0;
        value = xValue;
        break;
      case CrosshairOrientation.HORIZONTAL:
        columnIdx = 1;
        value = yValue;
        break;
      case CrosshairOrientation.BOTH:
        // TODO: maybe use voronoi
        columnIdx = 1;
        value = yValue;
      default:
        throw new Error(`Unknown type of crosshair orientaion: ${this.options.crosshair.orientation}`);
    }

    // TODO: d3.bisect is not the best way. Use binary search
    const bisectIndex = d3.bisector((d: [number, number]) => d[columnIdx]).left;
    let closestIdx = bisectIndex(datapoints, value);

    // TODO: refactor corner cases
    if(closestIdx < 0) {
      return 0;
    }
    if(closestIdx >= datapoints.length) {
      return datapoints.length - 1;
    }
    // TODO: do we realy need it? Binary search should fix it
    if(
      closestIdx > 0 &&
      Math.abs(value - datapoints[closestIdx - 1][columnIdx]) <
      Math.abs(value - datapoints[closestIdx][columnIdx])
    ) {
      closestIdx -= 1;
    }
    return closestIdx;
  }

  getValueInterval(columnIdx: number): number | undefined {
    // columnIdx: 1 for y, 0 for x
    // inverval: x/y value interval between data points
    // TODO: move it to base/state instead of timeInterval
    const intervals = _.map(this.series.visibleSeries, serie => {
      if(serie.datapoints.length < 2) {
        return undefined;
      }
      const start = _.head(serie.datapoints)[columnIdx];
      const end = _.last(serie.datapoints)[columnIdx];
      const range = Math.abs(end - start);
      const interval = range / (serie.datapoints.length - 1);
      return interval;
    });
    return _.max(intervals);
  }

  onMouseMove(): void {
    const eventX = d3.mouse(this.chartContainer.node())[0];
    const eventY = d3.mouse(this.chartContainer.node())[1];
    const xValue = this.state.xScale.invert(eventX); // mouse x position in xScale
    const yValue = this.state.yScale.invert(eventY);
    this.moveCrosshairLine(eventX, eventY);

    const datapoints = this.findAndHighlightDatapoints(xValue, yValue);

    // TDOO: is shift key pressed
    // TODO: need to refactor this object
    this.options.callbackMouseMove({
      x: d3.event.pageX,
      y: d3.event.pageY,
      xVal: xValue,
      yVal: yValue,
      series: datapoints,
      chartX: eventX,
      chartWidth: this.width
    });
  }

  findAndHighlightDatapoints(xValue: number, yValue: number): { value: [number, number], color: string, label: string }[] {
    if(!this.series.isSeriesAvailable) {
      return [];
    }
    let points = []; // datapoints in each metric that is closest to xValue/yValue position
    this.series.visibleSeries.forEach((serie: LineTimeSerie) => {
      const closestDatapoint = this.getClosestDatapoint(serie, xValue, yValue);
      if(_.isNil(closestDatapoint) || _.isNil(closestDatapoint[0])) {
        this.hideCrosshairCircle(serie.idx);
      } else {
        const xPosition = this.state.xScale(closestDatapoint[0]);
        const yPosition = this.state.yScale(closestDatapoint[1]);
        this.moveCrosshairCircle(xPosition, yPosition, serie.idx);
      }

      points.push({
        value: closestDatapoint,
        color: serie.color,
        label: serie.alias || serie.target
      });
    });
    return points;
  }

  onMouseOver(): void {
    this.crosshair.style('display', null);
    this.crosshair.selectAll('.crosshair-circle')
      .style('display', null);
  }

  onMouseOut(): void {
    this.options.callbackMouseOut();
    this.crosshair.style('display', 'none');
  }

  isDoubleClickActive(): boolean {
    return this.options.doubleClickEvent.isActive;
  }

  // methods below rewrite s, (move more methods here)
  protected zoomOut(): void {
    if(d3.event.type === 'dblclick' && !this.isDoubleClickActive()) {
      return;
    }
    // TODO: its not clear, why we use this orientation here. Mb its better to use separate option
    const orientation: BrushOrientation = this.options.mouseZoomEvent.orientation;
    const xInterval = this.state.xValueRange[1] - this.state.xValueRange[0];
    const yInterval = this.state.yValueRange[1] - this.state.yValueRange[0];
    switch(orientation) {
      case BrushOrientation.HORIZONTAL:
        this.state.xValueRange = [this.state.xValueRange[0] - xInterval / 2, this.state.xValueRange[1] + xInterval / 2];
        break;
      case BrushOrientation.VERTICAL:
        this.state.yValueRange = [this.state.yValueRange[0] - yInterval / 2, this.state.yValueRange[1] + yInterval / 2];
        break;
      case BrushOrientation.RECTANGLE:
        this.state.xValueRange = [this.state.xValueRange[0] - xInterval / 2, this.state.xValueRange[1] + xInterval / 2];
        this.state.yValueRange = [this.state.yValueRange[0] - yInterval / 2, this.state.yValueRange[1] + yInterval / 2];
        break;
      case BrushOrientation.SQUARE:
        this.state.xValueRange = [this.state.xValueRange[0] - xInterval / 2, this.state.xValueRange[1] + xInterval / 2];
        this.state.yValueRange = [this.state.yValueRange[0] - yInterval / 2, this.state.yValueRange[1] + yInterval / 2];
        break;
      default:
        throw new Error(`Unknown type of orientation: ${orientation}, path: options.zoomEvents.mouse.zoom.orientation`);;
    }

    // TODO: it shouldn't be here. Add smth like vue watchers in core components. Optimize!
    this.renderMetrics();
    this.renderXAxis();
    this.renderYAxis();
    this.renderGrid();
    this.onMouseOver();

    let xAxisMiddleValue: number = this.state.xScale.invert(this.width / 2);
    let yAxisMiddleValue: number = this.state.yScale.invert(this.height / 2);
    const centers = {
      x: xAxisMiddleValue,
      y: yAxisMiddleValue
    }
    this.options.callbackZoomOut(centers);
  }
}

// it is used with Vue.component, e.g.: Vue.component('chartwerk-line-pod', VueChartwerkLinePod)
export const VueChartwerkLinePod = {
  // alternative to `template: '<div class="chartwerk-line-pod" :id="id" />'`
  render(createElement) {
    return createElement(
      'div',
      {
        class: { 'chartwerk-line-pod': true },
        attrs: { id: this.id }
      }
    );
  },
  mixins: [VueChartwerkPodMixin],
  methods: {
    render() {
      if(this.pod === undefined) {
        this.pod = new LinePod(document.getElementById(this.id), this.series, this.options);
        this.pod.render();
      } else {
        this.pod.updateData(this.series, this.options);
      }
    },
    renderSharedCrosshair(values) {
      this.pod.renderSharedCrosshair(values);
    },
    hideSharedCrosshair() {
      this.pod.hideSharedCrosshair();
    }
  }
};

export { LineTimeSerie, LineOptions, TimeFormat };