import * as d3 from 'd3';

// d3js module: animated line
export default () => {
  // defaults
  const options = {
    strokewidth: 2,
    duration: 1500,
    endval: 0.10,
    width: 800,
    height: 26,
    round: 1,
    margin: { right: 50 },
    colors: [ '#E3E3E3', '#D0021B' ]
  };

  // start
  const draw = selection => {
    const textWidth = 40;
    const yval = options.strokewidth;
    const yvalText = options.height - options.strokewidth * 2;
    const xval = options.width * options.endval;
    const xvalText = options.endval < 0.51 ? xval : xval - textWidth;

    // add svg
    const svg = selection
      .append('svg')
      .attr('width', options.width)
      .attr('height', options.height);

    // append first line
    svg.append('line')
      .attr('x1', 0)
      .attr('y1', yval)
      .attr('x2', options.width)
      .attr('y2', yval)
      .attr('stroke-width', options.strokewidth)
      .attr('stroke', options.colors[0])
      .attr('stroke-linecap', 'round');

    // append second line
    svg.append('line')
      .attr('x1', 0)
      .attr('y1', yval)
      .attr('x2', 0)
      .attr('y2', yval)
      .attr('stroke-width', options.strokewidth)
      .attr('stroke', options.colors[1])
      .attr('stroke-linecap', 'round')
      .transition()
      .duration(options.duration)
      .attr('x2', xval)
      .attr('y2', yval);

    // append text
    svg.append('text')
      .data([ options.endval * 100 ])
      .text(0)
      .attr('x', 0)
      .attr('y', yvalText)
      .transition()
      .duration(options.duration)
      .attr('x', xvalText)
      .attr('y', yvalText)
      .tween('text', (endval, index, curObj) => {
        const i = d3.interpolate(curObj[index].textContent, endval);

        return t => {
          const val = Math.round(i(t) * options.round) / options.round;
          const localeString = parseFloat(val.toFixed(0)).toLocaleString('de-DE');

          curObj[index].textContent = `${localeString}%`;
        };
      });
  };

  // "setter"
  draw.options = input => {
    Object.assign(options, input);

    return draw;
  };

  return draw;
};