52-Week Token Activity Calendar Heatmap

import { type ChartPoint, cell, defineChart } 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 { scaleBand, scaleOrdinal } from "d3-scale";
import { CalendarDays } from "lucide-react";

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

interface CalendarCellDatum {
    week: number;
    weekday: string;
    level: string;
    dateKey: string;
    tokens: number;
}

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

const weekdays = ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"];
const usageLevels = ["none", "low", "medium", "high", "max"];
const usageColors = ["var(--border)", "var(--chart-1)", "var(--chart-2)", "var(--chart-3)", "var(--chart-4)"];

const months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];

function generateDemoData(): CalendarCellDatum[] {
    const results: CalendarCellDatum[] = [];
    const baseDate = new Date(Date.UTC(2024, 0, 1));

    for (let w = 0; w < 52; w++) {
        for (let d = 0; d < 7; d++) {
            const date = new Date(baseDate.getTime() + (w * 7 + d) * 24 * 60 * 60 * 1000);
            const tokens = Math.floor(Math.random() * 120);
            let level = "none";
            if (tokens > 90) level = "max";
            else if (tokens > 60) level = "high";
            else if (tokens > 30) level = "medium";
            else if (tokens > 5) level = "low";

            results.push({
                week: w,
                weekday: weekdays[d],
                level,
                dateKey: date.toISOString().split("T")[0],
                tokens,
            });
        }
    }
    return results;
}

function shadcnTooltipContent<TDatum>(points: readonly ChartPoint<TDatum>[]) {
    if (points.length === 0) return { title: "", rows: [] };
    const d = points[0].datum as CalendarCellDatum;
    if (!d) return { title: "", rows: [] };
    return {
        title: `${d.dateKey} (${d.weekday})`,
        rows: [{ label: "Token Usage", value: `${d.tokens}k tokens`, color: "var(--chart-1)" }],
    };
}

export function TokenUsageCalendar() {
    const data = useMemo(() => generateDemoData(), []);
    const weekDomain = useMemo(() => Array.from({ length: 52 }, (_, i) => i), []);

    const definition = useMemo(
        () =>
            defineChart(
                {
                    renderer: motionRenderer,
                    marks: [
                        cell(data, {
                            id: "calendar-cells",
                            x: "week",
                            y: "weekday",
                            color: "level",
                            key: "dateKey",
                            radius: 2,
                        }),
                    ],
                    scales: {
                        x: {
                            scale: scaleBand<number>().domain(weekDomain).paddingInner(0.2),
                            axis: {
                                line: false,
                                ticks: {
                                    values: [0, 4, 8, 13, 17, 21, 26, 30, 34, 39, 43, 47],
                                    format: (v: number) => months[Math.floor(v / 4.33)] || "",
                                },
                            },
                        },
                        y: {
                            scale: scaleBand<string>().domain(weekdays).paddingInner(0.2),
                            axis: {
                                line: false,
                                ticks: {
                                    values: ["Mon", "Wed", "Fri"],
                                },
                            },
                        },
                    },
                    color: {
                        scale: scaleOrdinal<string, string>().domain(usageLevels).range(usageColors),
                    },
                    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),
                    },
                },
            ),
        [data, weekDomain],
    );

    return (
        <Card className="w-full max-w-xl">
            <CardHeader>
                <CardTitle>52-Week Token Activity Calendar Heatmap Grid</CardTitle>
                <CardDescription>
                    GitHub/GitLab contribution style matrix tracking daily API token volume
                </CardDescription>
            </CardHeader>
            <CardContent>
                <div className="h-[210px] w-full">
                    <Chart
                        definition={definition}
                        renderer={motionRenderer}
                        height={210}
                        ariaLabel="52-Week Token Activity Calendar Heatmap Grid Chart"
                    />
                </div>
            </CardContent>
            <CardFooter className="flex-col items-start gap-2 text-sm">
                <div className="flex items-center gap-2 leading-none font-medium">
                    Daily token activity intensity mapped across 52 calendar weeks{" "}
                    <CalendarDays className="h-4 w-4 text-emerald-500" />
                </div>
                <div className="text-muted-foreground leading-none">
                    `cell` mark renders discrete categorical grid tiles scaled by ordinal levels
                </div>
            </CardFooter>
        </Card>
    );
}

export default TokenUsageCalendar;