Marimekko Mosaic

import { type ChartPoint, defineChart, groupBy, mosaicY, rect, select, text } 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 } from "d3-scale";
import { PieChart } from "lucide-react";

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

interface SurveyRow {
    Question: string;
    Response: string;
}

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

const questions = ["Usability", "Performance", "Value", "Support"];
const responses = ["Strongly Disagree", "Disagree", "Neutral", "Agree", "Strongly Agree"];

function generateDemoData(): SurveyRow[] {
    const results: SurveyRow[] = [];

    questions.forEach((q, qIdx) => {
        const count = 50 + qIdx * 25;
        for (let i = 0; i < count; i++) {
            const rIdx = Math.min(4, Math.floor(Math.random() * 3 + qIdx * 0.5));
            results.push({ Question: q, Response: responses[rIdx] });
        }
    });

    return results;
}

function shadcnTooltipContent<TDatum>(points: readonly ChartPoint<TDatum>[]) {
    if (points.length === 0) return { title: "", rows: [] };
    const d = points[0].datum as { xValue: string; yValue: string; proportion?: number };
    if (!d) return { title: "", rows: [] };
    return {
        title: `${d.xValue}: ${d.yValue}`,
        rows: [{ label: "Segment", value: `${d.yValue}`, color: "var(--chart-1)" }],
    };
}

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

    const counts = useMemo(() => {
        return groupBy(data, {
            by: {
                Question: "Question",
                Response: "Response",
            },
            outputs: { count: { reduce: "count" } },
        });
    }, [data]);

    const cells = useMemo(() => {
        return mosaicY(counts, {
            x: "Question",
            y: "Response",
            value: "count",
            yOrder: responses,
        });
    }, [counts]);

    const labels = useMemo(() => {
        return select(cells, {
            by: "xValue",
            select: "first",
        });
    }, [cells]);

    const definition = useMemo(
        () =>
            defineChart(
                {
                    renderer: motionRenderer,
                    marks: [
                        rect(cells, {
                            id: "response-cells",
                            x: "x",
                            x1: "x1",
                            x2: "x2",
                            y: "y",
                            y1: "y1",
                            y2: "y2",
                            color: "yValue",
                            key: (datum: { xValue: string; yValue: string }) => `${datum.xValue}:${datum.yValue}`,
                            inset: 1,
                        }),
                        text(labels, {
                            id: "question-labels",
                            x: "x",
                            y: () => 1.05,
                            text: "Question",
                            key: "xValue",
                            fill: "var(--foreground)",
                            fontSize: 10,
                            fontWeight: 600,
                        }),
                    ],
                    scales: {
                        x: {
                            scale: scaleLinear().domain([0, 1]),
                            axis: {
                                ticks: { format: (v: number) => `${Math.round(v * 100)}%` },
                                label: "Question Share of Total",
                            },
                        },
                        y: {
                            scale: scaleLinear().domain([0, 1.12]),
                            axis: {
                                ticks: { format: (v: number) => `${Math.round(v * 100)}%` },
                                label: "Within-Question Share",
                            },
                        },
                    },
                    color: {
                        domain: responses,
                        range: [
                            "var(--chart-5)",
                            "var(--chart-4)",
                            "var(--chart-3)",
                            "var(--chart-2)",
                            "var(--chart-1)",
                        ],
                    },
                    margin: { top: 28, 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),
                    },
                },
            ),
        [cells, labels],
    );

    return (
        <Card className="w-full max-w-xl">
            <CardHeader>
                <CardTitle>Marimekko Survey Mosaic Chart</CardTitle>
                <CardDescription>
                    Variable-width mosaic chart where column width and height encode 2D survey proportions
                </CardDescription>
            </CardHeader>
            <CardContent>
                <div className="h-[250px] w-full">
                    <Chart
                        definition={definition}
                        renderer={motionRenderer}
                        height={250}
                        ariaLabel="Marimekko Survey Mosaic Chart"
                    />
                </div>
            </CardContent>
            <CardFooter className="flex-col items-start gap-2 text-sm">
                <div className="flex items-center gap-2 leading-none font-medium">
                    Support question represents largest total response volume{" "}
                    <PieChart className="h-4 w-4 text-emerald-500" />
                </div>
                <div className="text-muted-foreground leading-none">
                    Mosaic area maps total counts as column width × row height product
                </div>
            </CardFooter>
        </Card>
    );
}

export default MarimekkoMosaic;