Quantile Ribbon

import { type ChartPoint, areaY, defineChart, groupBy, lineY, quantile } from "@tanstack/charts";
import { motion } from "@tanstack/charts/motion";
import { tooltip } from "@tanstack/charts/tooltip";
import { Chart } from "@tanstack/react-charts/core";
import { useMemo } from "react";

import { scaleLinear, scaleUtc } from "d3-scale";
import { Spline } from "lucide-react";

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

interface IndustryDatum {
    industry: string;
    date: Date;
    unemployed: number;
}

interface QuantileRow {
    date: Date;
    lower: number;
    median: number;
    upper: number;
}

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

function generateDemoData(): IndustryDatum[] {
    const results: IndustryDatum[] = [];
    const industries = ["Trade", "Manufacturing", "Tech", "Services", "Health", "Construction"];
    const dates: Date[] = [];

    for (let m = 0; m < 24; m++) {
        dates.push(new Date(Date.UTC(2023, m, 1)));
    }

    dates.forEach((d) => {
        industries.forEach((ind, idx) => {
            const base = 80 + Math.sin(d.getTime() * 0.000000001 + idx) * 30 + (idx + 1) * 20;
            results.push({
                industry: ind,
                date: d,
                unemployed: Math.max(20, Math.round(base + (Math.random() - 0.5) * 25)),
            });
        });
    });

    return results;
}

function shadcnTooltipContent<TDatum>(points: readonly ChartPoint<TDatum>[]) {
    if (points.length === 0) return { title: "", rows: [] };
    const d = points[0].datum as QuantileRow;
    if (!d || !d.date) return { title: "", rows: [] };
    const dateObj = d.date instanceof Date ? d.date : new Date(d.date);
    const dateStr = isNaN(dateObj.getTime())
        ? ""
        : dateObj.toLocaleDateString("en-US", { month: "short", year: "numeric", timeZone: "UTC" });
    return {
        title: dateStr,
        rows: [
            { label: "90th Percentile (Upper)", value: `${d.upper}k`, color: "var(--chart-1)" },
            { label: "50th Percentile (Median)", value: `${d.median}k`, color: "var(--foreground)" },
            { label: "10th Percentile (Lower)", value: `${d.lower}k`, color: "var(--chart-2)" },
        ],
    };
}

export function QuantileRibbon() {
    const rawData = useMemo(() => generateDemoData(), []);

    const quantileRows = useMemo(() => {
        return groupBy(rawData, {
            by: "date",
            outputs: {
                lower: { value: "unemployed", reduce: quantile(0.1) },
                median: { value: "unemployed", reduce: quantile(0.5) },
                upper: { value: "unemployed", reduce: quantile(0.9) },
            },
        }) as unknown as QuantileRow[];
    }, [rawData]);

    const definition = useMemo(
        () =>
            defineChart(
                {
                    renderer: motionRenderer,
                    marks: [
                        areaY(quantileRows, {
                            id: "quantile-ribbon",
                            x: "date",
                            y1: "lower",
                            y2: "upper",
                            key: (row: QuantileRow) =>
                                row?.date
                                    ? row.date instanceof Date
                                        ? row.date.getTime()
                                        : new Date(row.date).getTime()
                                    : 0,
                            fill: "var(--chart-1)",
                            fillOpacity: 0.25,
                        }),
                        lineY(quantileRows, {
                            id: "median-line",
                            x: "date",
                            y: "median",
                            key: (row: QuantileRow) =>
                                row?.date
                                    ? row.date instanceof Date
                                        ? row.date.getTime()
                                        : new Date(row.date).getTime()
                                    : 0,
                            stroke: "var(--chart-1)",
                            strokeWidth: 2.25,
                        }),
                    ],
                    scales: {
                        x: {
                            scale: scaleUtc,
                            axis: { label: "Timeline Month" },
                        },
                        y: {
                            scale: scaleLinear,
                            grid: true,
                            axis: { label: "Unemployment Range (Thousands)" },
                        },
                    },
                    margin: { top: 24, right: 24, bottom: 32, left: 45 },
                    theme: {
                        foreground: "var(--muted-foreground)",
                        grid: "var(--border)",
                        background: "transparent",
                    },
                },
                {
                    keyboard: true,
                    tooltip: {
                        use: tooltip,
                        className:
                            "font-sans shadow-none rounded-md bg-popover text-popover-foreground border p-2 text-xs",
                        anchor: "pointer",
                        placement: "auto",
                        content: (points) => shadcnTooltipContent(points),
                    },
                },
            ),
        [quantileRows],
    );

    return (
        <Card className="w-full max-w-xl">
            <CardHeader>
                <CardTitle>10th–90th Quantile Distribution Ribbon</CardTitle>
                <CardDescription>
                    Percentile band area chart tracking median line within 10th-90th quantile bounds
                </CardDescription>
            </CardHeader>
            <CardContent>
                <div className="h-[250px] w-full">
                    <Chart
                        definition={definition}
                        renderer={motionRenderer}
                        height={250}
                        ariaLabel="10th–90th Quantile Distribution Ribbon Chart"
                    />
                </div>
            </CardContent>
            <CardFooter className="flex-col items-start gap-2 text-sm">
                <div className="flex items-center gap-2 leading-none font-medium">
                    Ribbon encapsulates 80% central spread across industry metrics{" "}
                    <Spline className="h-4 w-4 text-emerald-500" />
                </div>
                <div className="text-muted-foreground leading-none">
                    Quantile reducer computes robust non-parametric confidence bands
                </div>
            </CardFooter>
        </Card>
    );
}

export default QuantileRibbon;