Premium KPI Sparklines

import { areaY, d3Curve, defineChart, lineY } from "@tanstack/charts";
import { motion } from "@tanstack/charts/motion";
import { Chart } from "@tanstack/react-charts/core";
import { useMemo } from "react";

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

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

interface SparklineDatum {
    id: number;
    period: number;
    value: number;
}

interface KpiMetric {
    id: string;
    label: string;
    value: string;
    trend: string;
    trendDirection: "up" | "down";
    surface: "area" | "line";
    colorToken: string;
    rows: SparklineDatum[];
}

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

const smoothCurve = d3Curve(curveMonotoneX);

function generateKpiMetrics(): KpiMetric[] {
    const generateRows = (base: number, volatility: number) => {
        const rows: SparklineDatum[] = [];
        let val = base;
        for (let i = 1; i <= 12; i++) {
            val += Math.sin(i * 0.6) * volatility + (Math.random() - 0.4) * (volatility * 0.8);
            rows.push({ id: i, period: i, value: Math.max(10, val) });
        }
        return rows;
    };

    return [
        {
            id: "revenue",
            label: "Monthly Recurring Revenue",
            value: "$124,500",
            trend: "+12.4%",
            trendDirection: "up",
            surface: "area",
            colorToken: "var(--chart-1)",
            rows: generateRows(100, 15),
        },
        {
            id: "customers",
            label: "Active Subscriptions",
            value: "1,420",
            trend: "+8.1%",
            trendDirection: "up",
            surface: "area",
            colorToken: "var(--chart-2)",
            rows: generateRows(1200, 60),
        },
        {
            id: "churn",
            label: "User Churn Rate",
            value: "1.82%",
            trend: "-0.4%",
            trendDirection: "down",
            surface: "line",
            colorToken: "var(--chart-3)",
            rows: generateRows(2.2, 0.3),
        },
    ];
}

function KpiCard({ metric }: { metric: KpiMetric }) {
    const definition = useMemo(() => {
        const values = metric.rows.map((r) => r.value);
        const minimum = Math.min(...values);
        const maximum = Math.max(...values);
        const pad = Math.max((maximum - minimum) * 0.15, 0.1);
        const baseline = minimum - pad;

        const line = lineY(metric.rows, {
            id: `${metric.id}-line`,
            x: "period",
            y: "value",
            key: "id",
            stroke: metric.colorToken,
            strokeWidth: 2.2,
            curve: smoothCurve,
        });

        const marks =
            metric.surface === "area"
                ? [
                      areaY(metric.rows, {
                          id: `${metric.id}-area`,
                          x: "period",
                          y: "value",
                          y1: baseline,
                          key: "id",
                          fill: `url(#${metric.id}-fill)`,
                          fillOpacity: 1,
                          curve: smoothCurve,
                      }),
                      line,
                  ]
                : [line];

        return defineChart({
            renderer: motionRenderer,
            marks,
            gradients:
                metric.surface === "area"
                    ? [
                          {
                              id: `${metric.id}-fill`,
                              x1: 0,
                              y1: 0,
                              x2: 0,
                              y2: 1,
                              stops: [
                                  { offset: 0, color: metric.colorToken, opacity: 0.3 },
                                  { offset: 1, color: metric.colorToken, opacity: 0 },
                              ],
                          },
                      ]
                    : [],
            scales: {
                x: {
                    scale: scalePoint<number>()
                        .domain(metric.rows.map((r) => r.period))
                        .padding(0.05),
                    axis: false,
                },
                y: {
                    scale: scaleLinear().domain([baseline, maximum + pad]),
                    axis: false,
                },
            },
            margin: { top: 4, right: 4, bottom: 4, left: 4 },
            theme: {
                foreground: "transparent",
                grid: "transparent",
                background: "transparent",
            },
        });
    }, [metric]);

    return (
        <Card className="flex flex-col justify-between p-4">
            <CardHeader className="flex-row items-center justify-between space-y-0 p-0 pb-2">
                <CardTitle className="text-muted-foreground text-xs font-medium">{metric.label}</CardTitle>
                <div
                    className={`flex items-center text-xs font-semibold ${
                        metric.trendDirection === "up" ? "text-emerald-500" : "text-amber-500"
                    }`}>
                    {metric.trendDirection === "up" ? (
                        <TrendingUp className="mr-1 h-3.5 w-3.5" />
                    ) : (
                        <TrendingDown className="mr-1 h-3.5 w-3.5" />
                    )}
                    {metric.trend}
                </div>
            </CardHeader>
            <CardContent className="space-y-2 p-0">
                <div className="text-2xl font-bold tracking-tight">{metric.value}</div>
                <div className="h-[60px] w-full">
                    <Chart
                        definition={definition}
                        renderer={motionRenderer}
                        height={60}
                        ariaLabel={`${metric.label} sparkline trend`}
                    />
                </div>
            </CardContent>
        </Card>
    );
}

export function PremiumKpiSparklines() {
    const metrics = useMemo(() => generateKpiMetrics(), []);

    return (
        <div className="grid w-full max-w-xl grid-cols-1 gap-4 sm:grid-cols-3">
            {metrics.map((metric) => (
                <KpiCard key={metric.id} metric={metric} />
            ))}
        </div>
    );
}

export default PremiumKpiSparklines;