/* DbSunburst: Sunburst visualization based on https://observablehq.com/@git-ashish/d3-sunburst-zoomable */
<template>
  <div ref="container" class="db-sunburst"></div>
</template>
<script>
import * as d3 from 'd3';
import log from '../log';

export default {
  name: 'DbSunburstZ',
  props: {
    wdata: {},
    wspec: {},
    dark: {
      type: Boolean,
      default: false
    },
    colorScheme: {
      type: String,
      default: 'interpolateRainbow'
    }
  },
  data() {
    return {
      graph: null,
      svg: null,
      g: null
    };
  },
  mounted() {
    window.addEventListener('resize', this.handleResize);
    this.render();
  },
  beforeDestroy: function() {
    log.info('beforeDestroy!');
    window.removeEventListener('resize', this.handleResize);
  },
  watch: {
    wdata: function() {
      // TODO ???
      // Rendering is triggered when data changed
      // To force re-render if only options changed, call $refs.child.render
      this.render();
    },
    dark: function() {
      this.$nextTick(() => {
        this.render();
      });
    }
  },
  methods: {
    handleResize(/*event*/) {
      this.$nextTick(() => {
        this.sizeSvg();
      });
    },
    // Resize svg efficiently, without re-render, based on current BBox
    sizeSvg() {
      if (this.svg && this.g) {
        const box = this.g.node().getBBox();
        this.svg
          .attr('width', box.width)
          .attr('height', box.height)
          .attr('viewBox', `${box.x} ${box.y} ${box.width} ${box.height}`);
      }
    },
    getColor(i) {
      if (!this.dark) {
        // For Light scheme, get color in straight order
        return d3[this.scheme][Math.max(3, this.overlap)][i + Math.max(0, 3 - this.overlap)];
      } else {
        // For dark scheme, need to take color in reverse order
        let csize = Math.max(3, this.overlap);
        let cidx = csize - 1 - (i + Math.max(0, 3 - this.overlap));
        return d3[this.scheme][csize][cidx];
      }
    },
    partition(data, radius) {
      return d3.partition().size([2 * Math.PI, radius])(
        d3
          .hierarchy(data)
          .sum(d => d.size)
          .sort((a, b) => b.value - a.value)
      );
    },

    // TODO To common utils
    DOMsvg(width, height) {
      let svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
      svg.setAttribute('viewBox', [0, 0, width, height]);
      svg.setAttribute('width', width);
      svg.setAttribute('height', height);
      return svg;
    },

    render() {
      log.info('Rendering d3 SunburstZ ...');

      // Clear whole content of container
      this.svg = null;
      this.g = null;
      while (this.$refs.container.lastChild) {
        this.$refs.container.removeChild(this.$refs.container.lastChild);
      }

      let data = this.wdata.data;

      // These are initial dimensions. It'll scale later after adding to DOM and based on actual BBox of parent
      let radius = 465;
      let width = 930;

      let color = d3.scaleOrdinal().range(d3.quantize(d3[this.colorScheme], data.children.length + 1));

      const root = this.partition(data, radius);
      const aHistory = [];

      let oLastZoomed = root;

      root.each(d => (d.current = d));

      const svg = d3
        .select(this.DOMsvg(width, width))
        .style('width', '100%')
        .style('height', '100%')
        .style('padding', '10px')
        .style('font', '10px Roboto')
        .style('box-sizing', 'border-box');

      const g = svg.append('g');

      let arc = d3
        .arc()
        .startAngle(d => d.x0)
        .endAngle(d => d.x1)
        .padAngle(d => Math.min((d.x1 - d.x0) / 2, 0.005))
        .padRadius(radius / 2)
        .innerRadius(d => d.y0)
        .outerRadius(d => d.y1 - 1);

      let paths = g
        .append('g')
        .attr('fill-opacity', 0.6)
        .selectAll('path')
        .data(root.descendants())
        .enter()
        .append('path')
        .attr('fill', d => {
          while (d.depth > 1) d = d.parent;
          return !d.depth ? 'none' : color(d.data.name);
        })
        .attr('fill-opacity', d => (d.children ? 0.6 : 0.4))
        .attr('d', arc)
        .attr('id', function(d, i) {
          return 'cp-' + i;
        });

      // TODO format - reconsider
      let format = d3.format(',d');

      paths.append('title').text(
        d =>
          `${d
            .ancestors()
            .map(d => d.data.name)
            .reverse()
            .join('/')}\n${format(d.value)}`
      );

      paths
        .filter(d => d.children)
        .style('cursor', 'pointer')
        .on('click', clicked);

      const labels = g
        .append('g')
        .attr('pointer-events', 'none')
        .attr('text-anchor', 'middle')
        .selectAll('text')
        .data(root.descendants().filter(d => d.depth))
        .enter()
        .append('text')
        .attr('transform', d => labelTransform(d))
        .attr('fill-opacity', d => +labelVisible(d))
        .attr('dy', '0.35em')
        .attr('class','db-sunburst-label')
        .attr('clip-path', function(d, i) {
          return 'url(#cp-' + i + ')';
        })
        .text(d => arcText(d, d.data.name));

      function labelVisible(d) {
        return d.x1 - d.x0 > 0 && ((d.y0 + d.y1) / 2) * (d.x1 - d.x0) > 10;
      }

      function labelTransform(d) {
        const x = (((d.x0 + d.x1) / 2) * 180) / Math.PI;
        const y = (d.y0 + d.y1) / 2;
        return `rotate(${x - 90}) translate(${y},0) rotate(${x < 180 ? 0 : 180})`;
      }

      // Label of an arc
      function arcText(d, sKey) {
        // TODO Consider optimizing and using
        /*
        var CHAR_SPACE = 7,
          deltaAngle = d.x1 - d.x0,
          r = Math.max(0, (d.y0 + d.y1) / 2),
          perimeter = r * deltaAngle,
          iMinLength = 3; // minimum length of label
        let iMaxLength = Math.floor(perimeter / CHAR_SPACE);
        iMaxLength = iMaxLength < iMinLength ? 0 : iMaxLength;
        */
        // Need to tune it better
        return sKey; //(sKey || '').toString().slice(0, iMaxLength);
      }

      function clicked(p) {
        /**
         * First time, mark the clicked node as zoomed;
         * Second time, un-mark the node as zoomed.
         * When an already zoomed node is clicked, lets zoom out to its parent or root.
         */
        let target;

        // determine actual node to highlight
        // root will have no parent
        if (p.depth > 1) {
          target = p.bZoomed ? p : p.children ? p : p.parent;
        } else {
          target = p;
        }

        if (target.bZoomed) {
          delete target.bZoomed;
          target = oLastZoomed = aHistory.pop();

          if (!aHistory.length) {
            root.bHighlighted = true;
            target = oLastZoomed = root;
          }
        } else {
          target.bZoomed = true;
          if (oLastZoomed) {
            aHistory.push(oLastZoomed);
          }
          oLastZoomed = target;
        }

        root.each(function(d) {
          d.target = {
            x0: Math.max(0, Math.min(1, (d.x0 - target.x0) / (target.x1 - target.x0))) * 2 * Math.PI,
            x1: Math.max(0, Math.min(1, (d.x1 - target.x0) / (target.x1 - target.x0))) * 2 * Math.PI,
            y0: Math.max(0, d.y0 - target.y0),
            y1: Math.max(0, d.y1 - target.y0)
          };
        });

        const t = g.transition().duration(750);

        // Transition the data on all arcs, even the ones that aren’t visible,
        // so that if this transition is interrupted, entering arcs will start
        // the next transition from the desired position.
        paths
          .transition(t)
          .tween('data', d => {
            const i = d3.interpolate(d.current, d.target);
            return t => (d.current = i(t));
          })
          .attrTween('d', d => () => arc(d.current));

        labels
          .transition(t)
          .attr('fill-opacity', d => +labelVisible(d.target))
          .attrTween('transform', d => () => labelTransform(d.current));
      }

      this.$refs.container.appendChild(svg.node());

      this.svg = svg;
      this.g = g;
      this.sizeSvg();
    }
  }
};
</script>
<style lang="scss">
.db-sunburst {
  width: 100%;
  height: 100%;
  display: block;
  .db-sunburst-label {
    font-size: 16px;
    font-family: 'Roboto', '-apple-system', 'Helvetica Neue', Helvetica, Arial, sans-serif;
  }
}

.db-dark {
  .db-sunburst-label {
    fill: #bdbdbd;
  }
}
</style>