{% extends "base.html" %}
{% load static %}
{% block header %}
<style>
    svg {
        /* width: 50%;
        height: 50%; */
        width: 25%;
        height: 25%;
        display: block;
        margin: auto;
    }
  </style>
{% endblock %}

{% block content %}
<div class="card mb-0">
    <div class="card-header">
        <h3 class="mb-0">{{ skill.short_label }}</h3>
        <h4 class="card-title"> {{ skill.notation }}</h4>
    </div>
    <div class="card-body pb-0 mb-0">
        <div class="row mr-1 ml-1 pb-0 mb-0">
            <svg></svg>
        </div>
    </div>
</div>
{% endblock %}

{% block footerscript %}
<script src="{% static "js/plugins/D3-dag/d3_7.6.1.min.js" %}"></script>
<script src="{% static "js/plugins/D3-dag/d3-dag_0.11.1.min.js" %}"></script>
<script>
    function compute_font_size(string)
    {
        number_of_spaces = string.split(/ /g).length - 1;
        number_of_tiny_char = (string.split(/f/g).length - 1)
            + (string.split(/i/g).length - 1)
            + (string.split(/j/g).length - 1)
            + (string.split(/l/g).length - 1)
            + (string.split(/t/g).length - 1)
            + (string.split(/\//g).length - 1)
            + (string.split(/,/g).length - 1)
            + (string.split(/\(/g).length - 1)
            + (string.split(/\)/g).length - 1)
        number_of_small_char = (string.split(/r/g).length - 1);
        number_of_big_char = (string.split(/½/g).length - 1)
            + (string.split(/¾/g).length - 1)
            + (string.split(/B/g).length - 1)
            + (string.split(/H/g).length - 1)
            + (string.split(/O/g).length - 1)
            + (string.split(/R/g).length - 1)
            + (string.split(/T/g).length - 1)
            + (string.split(/</g).length - 1);
        return string.length
            + (number_of_big_char / 2)
            - (
                number_of_spaces
                + (number_of_tiny_char / 1.5)
                + (number_of_small_char / 2)
            );
    }

    function define_font_size(string)
    {
        return (1 / compute_font_size(string)) * 80;
    }

    (async () => {
        const data = [
            {% for key, value in node_dict.items %}
            {
                "id": "{{ key.id }}",
                "label": "{% autoescape off %}{{ key.short_label }}{% endautoescape %}",
                "parentIds": [
                    {% for prerequisite in value %}"{{ prerequisite.id }}", {% endfor %}
                ]
            },{% endfor %}
        ]

        const dag = d3.dagStratify()(data);
        const nodeRadius = 30;
        const layout = d3
            //
            // Base layout
            .sugiyama()
            //
            // Layering
            .layering(d3.layeringSimplex())                      // Simplex (shortest edges)
            // .layering(d3.layeringLongestPath())                  // Longest Path (minimum height)
            // .layering(d3.layeringCoffmanGraham())                // Coffman Graham (constrained width)
            //
            // Decrossing
            .decross(d3.decrossOpt())                               // Optimal (can be very slow)
            // .decross(d3.decrossTwoLayer().order(d3.twolayerAgg()))  // Two Layer Agg (fast)
            // .decross(d3.decrossTwoLayer().order(d3.twolayerOpt()))  // Two Layer Opt (can be very slow)
            //
            // Coords
            // .coord(d3.coordCenter())                                 // Center (fast)
            .coord(d3.coordGreedy())                                 // Greedy (fast)
            // .coord(d3.coordQuad())                                   // Quadradtic (can be slow)
            // .coord(d3.coordTopological())                            //
            .nodeSize(
                (node) => [(node ? 3.6 : 0.25) * nodeRadius, 3 * nodeRadius]
            ); // set node size instead of constraining to fit
            // .nodeSize((node) => {
            //     const size = node ? base : 5;
            //     return [1.2 * size, size];
            // });
            // .attr("r", function(d) {return d.name.length * 2.5;})
        const { width, height } = layout(dag);

        // --------------------------------
        // This code only handles rendering
        // --------------------------------
        const svgSelection = d3.select("svg");
        svgSelection.attr("viewBox", [0, 0, width, height].join(" "));
        const defs = svgSelection.append("defs"); // For gradients

        const steps = dag.size();
        const interp = d3.interpolateRainbow;
        const colorMap = new Map();
        for (const [i, node] of [...dag].entries()) {
            colorMap.set(node.data.id, interp(i / steps));
        }

        // How to draw edges
        const line = d3
            .line()
            .curve(d3.curveCatmullRom)
            .x((d) => d.x)
            .y((d) => d.y);

        // Plot edges
        svgSelection
            .append("g")
            .selectAll("path")
            .data(dag.links())
            .enter()
            .append("path")
            .attr("d", ({ points }) => line(points))
            .attr("fill", "none")
            .attr("stroke-width", 3)
            .attr("stroke", ({ source, target }) => {
                // encodeURIComponents for spaces, hope id doesn't have a `--` in it
                const gradId = encodeURIComponent(`${source.data.id}--${target.data.id}`);
                const grad = defs
                    .append("linearGradient")
                    .attr("id", gradId)
                    .attr("gradientUnits", "userSpaceOnUse")
                    .attr("x1", source.x)
                    .attr("x2", target.x)
                    .attr("y1", source.y)
                    .attr("y2", target.y);
                grad
                    .append("stop")
                    .attr("offset", "0%")
                    .attr("stop-color", colorMap.get(source.data.id));
                grad
                    .append("stop")
                    .attr("offset", "100%")
                    .attr("stop-color", colorMap.get(target.data.id));
                return `url(#${gradId})`;
            });

        // Select nodes
        const nodes = svgSelection
            .append("g")
            .selectAll("g")
            .data(dag.descendants())
            .enter()
            .append("g")
            .attr("transform", ({ x, y }) => `translate(${x}, ${y})`);

        // Plot node circles
        nodes
            .append("circle")
            .attr("r", nodeRadius)
            .attr("fill", (n) => colorMap.get(n.data.id));

        // Add text to nodes
        nodes
            .append("text")
            .text((d) => d.data.label)
            .attr("font-size", function(d) {return Math.min(define_font_size(d.data.label), 24);})
            .attr("font-weight", "bold")
            .attr("font-family", "sans-serif")
            .attr("text-anchor", "middle")
            .attr("alignment-baseline", "middle")
            .attr("fill", "white");
    })();
</script>
{% endblock %}