Vector Field

import { type ChartPoint, defineChart, vector } 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, scaleSqrt } from "d3-scale";
import { Compass } from "lucide-react";

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

interface VectorDatum {
    x: number;
    y: number;
    u: number;
    v: number;
}

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

function generateDemoData(): VectorDatum[] {
    const results: VectorDatum[] = [];
    for (let x = -5; x <= 5; x += 1) {
        for (let y = -5; y <= 5; y += 1) {
            const u = -y * 1.5;
            const v = x * 1.5;
            results.push({ x, y, u, v });
        }
    }
    return results;
}

function shadcnTooltipContent<TDatum>(points: readonly ChartPoint<TDatum>[]) {
    if (points.length === 0) return { title: "", rows: [] };
    const d = points[0].datum as VectorDatum;
    if (!d) return { title: "", rows: [] };
    const speedVal = Math.hypot(d.u, d.v).toFixed(1);
    const angleDeg = ((Math.atan2(d.u, d.v) * 180) / Math.PI).toFixed(0);
    return {
        title: `Grid Position (${d.x}, ${d.y})`,
        rows: [
            { label: "Velocity Magnitude", value: `${speedVal} m/s`, color: "var(--chart-1)" },
            { label: "Direction Angle", value: `${angleDeg}°`, color: "var(--foreground)" },
        ],
    };
}

export function VectorField() {
    const data = useMemo(() => generateDemoData(), []);
    const speedScale = useMemo(() => scaleSqrt().domain([0, 15]).range([2, 16]), []);

    const definition = useMemo(
        () =>
            defineChart(
                {
                    renderer: motionRenderer,
                    marks: [
                        vector(data, {
                            id: "wind-vectors",
                            x: "x",
                            y: "y",
                            length: (row: VectorDatum) => speedScale(Math.hypot(row.u, row.v)),
                            rotate: (row: VectorDatum) => (Math.atan2(row.u, row.v) * 180) / Math.PI,
                            stroke: "var(--chart-1)",
                            strokeWidth: 1.5,
                        }),
                    ],
                    scales: {
                        x: { scale: scaleLinear, grid: true, axis: { label: "Longitude X" } },
                        y: { scale: scaleLinear, grid: true, axis: { label: "Latitude Y" } },
                    },
                    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, speedScale],
    );

    return (
        <Card className="w-full max-w-xl">
            <CardHeader>
                <CardTitle>Rotational Velocity Vector Field</CardTitle>
                <CardDescription>
                    Directional vector arrows mapping circulation and flow field magnitude
                </CardDescription>
            </CardHeader>
            <CardContent>
                <div className="h-[250px] w-full">
                    <Chart
                        definition={definition}
                        renderer={motionRenderer}
                        height={250}
                        ariaLabel="Rotational Velocity Vector Field Chart"
                    />
                </div>
            </CardContent>
            <CardFooter className="flex-col items-start gap-2 text-sm">
                <div className="flex items-center gap-2 leading-none font-medium">
                    Counter-clockwise vortex circulation around origin (0,0){" "}
                    <Compass className="h-4 w-4 text-emerald-500" />
                </div>
                <div className="text-muted-foreground leading-none">
                    Arrow length indicates vector speed; rotation angle represents directional heading
                </div>
            </CardFooter>
        </Card>
    );
}

export default VectorField;