var t = `
<div class="forcegraph h-full w-full overflow-hidden text-gray-200" ref="forcegraph"></div>
`

export default {
  props: [
    'graphData',
    'emphasizeNodeIds',
    'initialTransform',
    'display',
    'forces',
  ],
  emits: ['title-click'],
  data() {
    return {
      zoomTransform: null,
    }
  },
  methods: {
    initGraph() {
      const vm = this;
      vm.$refs.forcegraph.innerHTML = "";

      const links = this.graphData.links.map(d => Object.create(d));
      const nodes = this.graphData.nodes.map(d => Object.create(d));

      const svg = d3.select(vm.$refs.forcegraph).append("svg")
        .style("height", "inherit")
        .style("width", "inherit")
        .attr("viewBox", [-140, -180, 320, 360]);

      const simulation = d3.forceSimulation(nodes)
        .force("link", d3.forceLink(links).id(d => d.id))
        .force("charge", d3.forceManyBody())
        .force("collide", d3.forceCollide())
        .force("center", d3.forceCenter())
        .force("x", d3.forceX())
        .force("y", d3.forceY());

      const link = svg.append("g")
        .classed("link", true)
        .attr("stroke", "currentColor")
        .selectAll("line")
        .data(links)
        .join("line");

      const node = svg.append("g")
        .selectAll("circle")
        .data(nodes)
        .join("circle")
        .attr("r", 2)
        .classed("node", true)
        .classed("node-label", n => (n.isLabel))
        .call(drag(simulation));

      const title = svg.append("g")
        .selectAll("circle")
        .data(nodes)
        .enter()
        .append("text")
        .classed("title", true)
        .on("click", function(event, node) { event.stopPropagation(); vm.$emit('title-click', node.id); })
        .text(node => node.title);

      const zoom = d3.zoom().scaleExtent([0.3, 3]).on('zoom', function(event) {
        svg.selectAll('g').attr('transform', event.transform);
        if (vm.display.scaleTitles.value) scaleTitlesByZoomLevel(event.transform.k);
        vm.zoomTransform = {
          k: event.transform.k,
          x: event.transform.x,
          y: event.transform.y
        }
      });
      svg.call(zoom);

      if (vm.initialTransform) {
        const {k, x, y} = vm.initialTransform;
        const transform = d3.zoomIdentity.translate(x, y).scale(k);
        svg.selectAll('g').attr('transform', transform);
        svg.call(zoom.transform, transform);
        if (vm.display.scaleTitles.value) scaleTitlesByZoomLevel(k);
      }

      simulation.on("tick", () => {
        link
          .attr("x1", d => d.source.x)
          .attr("y1", d => d.source.y)
          .attr("x2", d => d.target.x)
          .attr("y2", d => d.target.y);
        node
          .attr("cx", d => d.x)
          .attr("cy", d => d.y);
        title
          .attr('x', d => d.x + 4).attr('y', d => d.y);
      });

      function drag(simulation) {
        function dragstarted(event, d) {
          if (!event.active) simulation.alphaTarget(0.3).restart();
          d.fx = d.x;
          d.fy = d.y;
        }
        function dragged(event, d) {
          d.fx = event.x;
          d.fy = event.y;
        }
        function dragended(event, d) {
          if (!event.active) simulation.alphaTarget(0);
          d.fx = null;
          d.fy = null;
        }
        return d3.drag()
          .on("start", dragstarted)
          .on("drag", dragged)
          .on("end", dragended);
      }

      function scaleTitlesByZoomLevel(k) {
        const titleSize = k > 0.9 ? 5 - k : 0;
        svg.selectAll('.title').transition().style("font-size", titleSize + "px");
      }

      vm.$watch('display.scaleTitles.value', function(enabled) {
        const k = enabled ? d3.zoomTransform(svg.node()).k : 1;
        scaleTitlesByZoomLevel(k);
      });

      vm.$watch('display.showTitles.value', function(enabled) {
        svg.selectAll('.title').classed("hidden", !enabled);
      });

      function emphasizeNodes(nodeIds) {
        if (nodeIds && nodeIds.length > 0) {
          const linkedNodeIds = Array.from(new Set(vm.graphData.links
            .filter(l => nodeIds.includes(l.source) || nodeIds.includes(l.target))
            .flatMap(l => [l.source, l.target])));

          node.attr("fill-opacity", 0.05);
          title.attr("fill-opacity", 0.15).attr("font-weight", "normal");
          link.attr("stroke", "currentColor").attr("stroke-opacity", 0.15);

          node.filter(n => linkedNodeIds.includes(n.id)).attr("fill-opacity", 0.3);
          title.filter(t => linkedNodeIds.includes(t.id)).attr("fill-opacity", 1);

          node.filter(n => nodeIds.includes(n.id)).attr("fill-opacity", 1);
          title.filter(t => nodeIds.includes(t.id)).attr("fill-opacity", 1).attr("font-weight", "bold");
          link.filter(l => nodeIds.includes(l.source.id) || nodeIds.includes(l.target.id)).attr("stroke-opacity", 1);

        } else {
          node.attr("fill-opacity", 1)
          title.attr("fill-opacity", 1).attr("font-weight", "normal");
          link.attr("stroke", "currentColor").attr("stroke-opacity", 1);
        }
      }

      vm.$watch('emphasizeNodeIds', nodeIds => emphasizeNodes(nodeIds));
      if (this.emphasizeNodeIds?.length > 0) emphasizeNodes(this.emphasizeNodeIds);

      vm.$watch('display.dynamicNodeRadius.value', function(enabled) {
        function getLinkCount(nodeId) {
          return vm.graphData.links.reduce((count, link) => (link.source === nodeId || link.target === nodeId) ? count + 1 : count, 0);
        }

        if (enabled) {
          const totalNodes = vm.graphData.nodes.length;
          const linkCounts = vm.graphData.nodes.map(n => getLinkCount(n.id));
          const maxLinks = Math.max(...linkCounts);

          const minBaseRadius = 1;
          const maxBaseRadius = 5;
          const baseRadius = Math.max(minBaseRadius, Math.min(maxBaseRadius, 5 - totalNodes / 5));

          const minRadiusIncrement = 0.1;
          const maxRadiusIncrement = 0.5;
          const radiusIncrement =  Math.max(minRadiusIncrement, Math.min(maxRadiusIncrement, 5 / maxLinks));

          node.attr("r", n => baseRadius + (getLinkCount(n.id) * radiusIncrement));
        } else {
          node.attr("r", 2);
        }
      });

      vm.$watch('forces.chargeStrength.value', function(value) {
        simulation.force("charge", d3.forceManyBody().strength(value));
        simulation.alpha(1).restart();
      });

      vm.$watch('forces.collideRadius.value', function(value) {
        simulation.force("collide").radius(value);
        simulation.alpha(1).restart();
      });

      vm.$watch('forces.collideStrength.value', function(value) {
        simulation.force("collide").strength(value);
        simulation.alpha(1).restart();
      });

    },
  },
  mounted() {
    this.initGraph();
  },
  template: t
}