Dual-Handle Interactive Brush Range

import { type ChartPoint, defineChart, dot, lineY } from "@tanstack/charts";
import { brushX } from "@tanstack/charts/interaction/brush";
import { controlledSignal } from "@tanstack/charts/interaction/signal";
import { motion } from "@tanstack/charts/motion";
import { tooltip } from "@tanstack/charts/tooltip";
import { Chart } from "@tanstack/react-charts/core";
import { useMemo, useState } from "react";

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

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

interface StockDatum {
    date: Date;
    close: number;
}

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

function generateDemoData(): StockDatum[] {
    const results: StockDatum[] = [];
    let price = 150;
    const baseDate = new Date(Date.UTC(2024, 0, 1)).getTime();

    for (let i = 0; i < 24; i++) {
        price += Math.sin(i * 0.4) * 6 + (Math.random() - 0.45) * 8;
        results.push({
            date: new Date(baseDate + i * 15 * 24 * 60 * 60 * 1000),
            close: Number(Math.max(100, price).toFixed(2)),
        });
    }
    return results;
}

function shadcnTooltipContent<TDatum>(points: readonly ChartPoint<TDatum>[]) {
    if (points.length === 0) return { title: "", rows: [] };
    const d = points[0].datum as StockDatum;
    if (!d || !d.date) return { title: "", rows: [] };
    const dateObj = d.date instanceof Date ? d.date : new Date(d.date);
    const titleStr = isNaN(dateObj.getTime())
        ? ""
        : dateObj.toLocaleDateString("en-US", { month: "short", day: "numeric", year: "numeric", timeZone: "UTC" });
    return {
        title: titleStr,
        rows: [{ label: "Close Price", value: `$${d.close.toFixed(2)}`, color: "var(--chart-1)" }],
    };
}

export function BrushRangeSelection() {
    const data = useMemo(() => generateDemoData(), []);
    const dates = useMemo(() => data.map((d) => d.date), [data]);
    const fullDomain = useMemo(() => [dates[0], dates[dates.length - 1]], [dates]);

    const [range, setRange] = useState<{ start: Date; end: Date }>({
        start: dates[4],
        end: dates[16],
    });

    const rangeStats = useMemo(() => {
        const startTime = range.start instanceof Date ? range.start.getTime() : new Date(range.start).getTime();
        const endTime = range.end instanceof Date ? range.end.getTime() : new Date(range.end).getTime();
        const sliced = data.filter((d) => {
            const t = d.date instanceof Date ? d.date.getTime() : new Date(d.date).getTime();
            return t >= startTime && t <= endTime;
        });
        if (sliced.length === 0) return { count: 0, avg: 0 };
        const sum = sliced.reduce((acc, curr) => acc + curr.close, 0);
        return { count: sliced.length, avg: sum / sliced.length };
    }, [data, range]);

    const definition = useMemo(
        () =>
            defineChart(
                {
                    renderer: motionRenderer,
                    marks: [
                        lineY(data, {
                            id: "brush-series-line",
                            x: "date",
                            y: "close",
                            stroke: "var(--chart-1)",
                            strokeWidth: 2.5,
                        }),
                        dot(data, {
                            id: "brush-series-points",
                            x: "date",
                            y: "close",
                            fill: "var(--chart-1)",
                            r: 3.5,
                            stroke: "var(--background)",
                            strokeWidth: 1,
                        }),
                    ],
                    scales: {
                        x: {
                            scale: scaleUtc().domain(fullDomain),
                            axis: {
                                ticks: {
                                    format: (v: any) => {
                                        const dateObj = v instanceof Date ? v : new Date(v);
                                        return isNaN(dateObj.getTime())
                                            ? ""
                                            : dateObj.toLocaleDateString("en-US", { month: "short", timeZone: "UTC" });
                                    },
                                },
                            },
                        },
                        y: {
                            scale: scaleLinear,
                            grid: true,
                            axis: { label: "Price ($)" },
                        },
                    },
                    controls: [
                        brushX({
                            id: "monthly-range",
                            range: controlledSignal(range, (next: any) => {
                                if (!next) return;
                                setRange({
                                    start: next.start instanceof Date ? next.start : new Date(next.start),
                                    end: next.end instanceof Date ? next.end : new Date(next.end),
                                });
                            }),
                            values: dates,
                            ariaLabel: "Time range brush handles",
                            selectionStyle: {
                                fill: "var(--chart-1)",
                                fillOpacity: 0.18,
                                stroke: "var(--chart-1)",
                                strokeWidth: 1.5,
                            },
                            handleStyle: {
                                fill: "var(--background)",
                                stroke: "var(--chart-1)",
                                strokeWidth: 2,
                            },
                        }),
                    ],
                    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, dates, fullDomain, range],
    );

    const fmtDate = (d: any) => {
        const dateObj = d instanceof Date ? d : new Date(d);
        return isNaN(dateObj.getTime())
            ? ""
            : dateObj.toLocaleDateString("en-US", { month: "short", day: "numeric", timeZone: "UTC" });
    };

    return (
        <Card className="w-full max-w-xl">
            <CardHeader>
                <CardTitle>Dual-Handle Interactive Brush Range Selection</CardTitle>
                <CardDescription>
                    Drag handles horizontally to select date sub-ranges and compute window aggregations
                </CardDescription>
            </CardHeader>
            <CardContent>
                <div className="h-[250px] w-full">
                    <Chart
                        definition={definition}
                        renderer={motionRenderer}
                        height={250}
                        ariaLabel="Dual-Handle Interactive Brush Range Selection Chart"
                    />
                </div>
            </CardContent>
            <CardFooter className="flex-col items-start gap-2 text-sm">
                <div className="flex items-center gap-2 leading-none font-medium">
                    Selection: {fmtDate(range.start)} → {fmtDate(range.end)} ({rangeStats.count} points, Avg: $
                    {rangeStats.avg.toFixed(2)}) <Sliders className="h-4 w-4 text-emerald-500" />
                </div>
                <div className="text-muted-foreground leading-none">
                    `brushX` mark provides dual handles for active range selection and summary statistics
                </div>
            </CardFooter>
        </Card>
    );
}

export default BrushRangeSelection;