Radar Chart Legend

import { type ChartPoint, defineChart } from "@tanstack/charts";
import { motion } from "@tanstack/charts/motion";
import { angleGrid, focusGroupAngle, polar, radialArea, radialGrid } from "@tanstack/charts/polar";
import { tooltip } from "@tanstack/charts/tooltip";
import { Chart } from "@tanstack/react-charts/core";
import { useMemo } from "react";

import { scaleLinear, scalePoint } from "d3-scale";
import { curveLinearClosed } from "d3-shape";
import { TrendingUp } from "lucide-react";

import { Card, CardContent, CardDescription, CardFooter, CardHeader, CardTitle } from "@/components/ui/card";

function generateDemoData() {
    return [
        { month: "January", desktop: 186, mobile: 80 },
        { month: "February", desktop: 305, mobile: 200 },
        { month: "March", desktop: 237, mobile: 120 },
        { month: "April", desktop: 73, mobile: 190 },
        { month: "May", desktop: 209, mobile: 130 },
        { month: "June", desktop: 214, mobile: 140 },
    ];
}

const twoSeries = ["desktop", "mobile"] as const;
const chartColors = ["var(--chart-1)", "var(--chart-2)"];

const motionRenderer = motion({
    initial: "always",
    transition: { type: "spring", stiffness: 170, damping: 18, mass: 1 },
});

function titleCase(value: string) {
    return value.charAt(0).toUpperCase() + value.slice(1);
}

function shadcnTooltipContent<TDatum>(points: readonly ChartPoint<TDatum>[]) {
    return {
        title: String(points[0]?.xValue ?? ""),
        rows: points.map((point) => ({
            label: titleCase(
                String(point.group ?? point.markId.replace(/-?(bars|lines|areas|slices|values|radar)$/u, "")),
            ),
            value: Number(point.yValue ?? point.xValue ?? 0).toLocaleString("en-US"),
            color: point.color,
        })),
    };
}

export function RadarLegend() {
    const data = useMemo(() => generateDemoData(), []);

    const definition = useMemo(() => {
        const months = data.map((row) => row.month);
        const radiusMax = 320;
        const gridValues = Array.from({ length: 4 }, (_, index) => Math.round((radiusMax * (index + 1)) / 4));

        const guides = [
            radialGrid({
                values: gridValues,
                shape: "polygon",
                stroke: "var(--border)",
                strokeOpacity: 1,
            }),
            angleGrid({
                values: months,
                labels: true,
                labelOffset: 10,
                labelFill: "var(--muted-foreground)",
                labelFontSize: 12,
                stroke: "var(--border)",
                strokeOpacity: 1,
            }),
        ];

        return defineChart(
            {
                renderer: motionRenderer,
                motion: {
                    transition: { type: "spring", stiffness: 170, damping: 18, mass: 1 },
                },
                scales: {
                    x: null,
                    y: null,
                },
                marks: [
                    polar({
                        radiusRatio: 0.76,
                        scales: {
                            angle: { scale: scalePoint<string>().domain(months), wrap: true },
                            radius: { scale: scaleLinear().domain([0, radiusMax]) },
                        },
                        guides,
                        marks: [
                            radialArea(data, {
                                id: "desktop-radar",
                                className: "ts-chart__radar",
                                angle: "month",
                                radius: "desktop",
                                key: "month",
                                z: () => "desktop",
                                curve: curveLinearClosed,
                                fill: chartColors[0],
                                fillOpacity: 0.6,
                                stroke: chartColors[0],
                                strokeOpacity: 1,
                                strokeWidth: 1,
                            }),
                            radialArea(data, {
                                id: "mobile-radar",
                                className: "ts-chart__radar",
                                angle: "month",
                                radius: "mobile",
                                key: "month",
                                z: () => "mobile",
                                curve: curveLinearClosed,
                                fill: chartColors[1],
                                fillOpacity: 1,
                                stroke: chartColors[1],
                                strokeOpacity: 1,
                                strokeWidth: 1,
                            }),
                        ],
                    }),
                ],
                color: { domain: twoSeries, range: chartColors },
                margin: 0,
            },
            {
                focus: focusGroupAngle,
                tooltip: {
                    use: tooltip,
                    motion: { type: "spring", stiffness: 170, damping: 18 },
                    className: "font-sans shadow-none rounded-md bg-popover text-popover-foreground border p-2 text-xs",
                    anchor: "group-center",
                    placement: "auto",
                    sort: "color-domain",
                    content: (points) => shadcnTooltipContent(points),
                },
            },
        );
    }, [data]);

    return (
        <Card className="flex w-full max-w-md flex-col">
            <CardHeader className="items-center pb-4">
                <CardTitle>Cohort Feature Adoption Depth</CardTitle>
                <CardDescription>Usage depth score comparison between Early Adopters and Enterprise</CardDescription>
            </CardHeader>
            <CardContent className="pb-0">
                <div className="mx-auto flex aspect-square max-h-[250px] w-full items-center justify-center">
                    <Chart
                        definition={definition}
                        renderer={motionRenderer}
                        initialWidth={250}
                        height={250}
                        ariaLabel="Cohort Feature Adoption Depth Chart"
                    />
                </div>
                <div className="text-muted-foreground flex items-center justify-center gap-6 pt-4 text-sm">
                    {twoSeries.map((item, index) => (
                        <div key={item} className="flex items-center gap-1.5">
                            <span className="h-2 w-2 rounded-full" style={{ backgroundColor: chartColors[index] }} />
                            <span>{titleCase(item)}</span>
                        </div>
                    ))}
                </div>
            </CardContent>
            <CardFooter className="flex-col gap-2 pt-4 text-sm">
                <div className="flex items-center gap-2 leading-none font-medium">
                    Enterprise feature adoption up by 5.2% this quarter{" "}
                    <TrendingUp className="h-4 w-4 text-emerald-500" />
                </div>
                <div className="text-muted-foreground flex items-center gap-2 leading-none">January - June 2024</div>
            </CardFooter>
        </Card>
    );
}

export default RadarLegend;