Horizontal Gantt Resource Timeline

import { type ChartPoint, defineChart, rect } from "@tanstack/charts";
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 { scaleBand, scaleUtc } from "d3-scale";
import { GanttChartSquare } from "lucide-react";

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

interface ResourceTask {
    id: string;
    resource: string;
    label: string;
    status: "completed" | "in-progress" | "planned";
    start: Date;
    end: Date;
}

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

const resourceLanes = ["DevOps Team", "Frontend Team", "Backend Team", "Design Team", "QA Security"];
const statuses = ["completed", "in-progress", "planned"] as const;

const statusColors: Record<string, string> = {
    completed: "var(--chart-1)",
    "in-progress": "var(--chart-2)",
    planned: "var(--chart-3)",
};

function generateDemoData(): ResourceTask[] {
    const tasks: ResourceTask[] = [];
    const baseDate = new Date(Date.UTC(2024, 8, 1)).getTime();
    const dayMs = 24 * 60 * 60 * 1000;

    resourceLanes.forEach((lane, lIdx) => {
        for (let t = 0; t < 3; t++) {
            const startDay = lIdx * 3 + t * 8 + Math.floor(Math.random() * 2);
            const duration = 4 + Math.floor(Math.random() * 5);
            tasks.push({
                id: `${lane}-${t}`,
                resource: lane,
                label: `Sprint Task ${lIdx + 1}.${t + 1}`,
                status: statuses[(lIdx + t) % 3],
                start: new Date(baseDate + startDay * dayMs),
                end: new Date(baseDate + (startDay + duration) * dayMs),
            });
        }
    });

    return tasks;
}

function shadcnTooltipContent<TDatum>(points: readonly ChartPoint<TDatum>[]) {
    if (points.length === 0) return { title: "", rows: [] };
    const d = points[0].datum as ResourceTask;
    if (!d) return { title: "", rows: [] };
    const fmt = (dt: any) => {
        if (!dt) return "";
        const dateObj = dt instanceof Date ? dt : new Date(dt);
        return isNaN(dateObj.getTime())
            ? ""
            : dateObj.toLocaleDateString("en-US", { month: "short", day: "numeric", timeZone: "UTC" });
    };
    return {
        title: `${d.resource}: ${d.label}`,
        rows: [
            { label: "Status", value: d.status.toUpperCase(), color: statusColors[d.status] },
            { label: "Schedule Range", value: `${fmt(d.start)} - ${fmt(d.end)}`, color: "var(--foreground)" },
        ],
    };
}

export function ScrollableResourceLanes() {
    const data = useMemo(() => generateDemoData(), []);
    const [focusedTask, setFocusedTask] = useState<ResourceTask | null>(null);

    const fullDomain = useMemo(() => {
        return [new Date(Date.UTC(2024, 8, 1)), new Date(Date.UTC(2024, 9, 15))];
    }, []);

    const definition = useMemo(
        () =>
            defineChart(
                {
                    renderer: motionRenderer,
                    marks: [
                        rect(data, {
                            key: "id",
                            x1: "start",
                            x2: "end",
                            y: "resource",
                            color: "status",
                            inset: 4,
                            radius: 4,
                            stroke: "var(--background)",
                            strokeWidth: 1.5,
                        }),
                    ],
                    scales: {
                        x: {
                            scale: scaleUtc().domain(fullDomain),
                            grid: true,
                            axis: {
                                ticks: {
                                    format: (v: any) => {
                                        const dateObj = v instanceof Date ? v : new Date(v);
                                        return isNaN(dateObj.getTime())
                                            ? ""
                                            : dateObj.toLocaleDateString("en-US", {
                                                  month: "short",
                                                  day: "numeric",
                                                  timeZone: "UTC",
                                              });
                                    },
                                },
                            },
                        },
                        y: {
                            scale: scaleBand<string>().domain(resourceLanes).paddingInner(0.15),
                            grid: false,
                            axis: false,
                        },
                    },
                    color: {
                        domain: ["completed", "in-progress", "planned"],
                        range: ["var(--chart-1)", "var(--chart-2)", "var(--chart-3)"],
                    },
                    margin: { top: 16, right: 24, bottom: 32, left: 110 },
                    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) => {
                            if (points[0]?.datum) setFocusedTask(points[0].datum as ResourceTask);
                            return shadcnTooltipContent(points);
                        },
                    },
                },
            ),
        [data, fullDomain],
    );

    return (
        <Card className="w-full max-w-xl">
            <CardHeader>
                <CardTitle>Horizontal Gantt Resource Timeline Lanes</CardTitle>
                <CardDescription>
                    Multi-team resource scheduling lanes displaying task duration spans and status codes
                </CardDescription>
            </CardHeader>
            <CardContent>
                <div className="h-[260px] w-full overflow-x-auto">
                    <div className="h-full min-w-[500px]">
                        <Chart
                            definition={definition}
                            renderer={motionRenderer}
                            height={260}
                            ariaLabel="Horizontal Gantt Resource Timeline Lanes Chart"
                        />
                    </div>
                </div>
            </CardContent>
            <CardFooter className="flex-col items-start gap-2 text-sm">
                <div className="flex items-center gap-2 leading-none font-medium">
                    {focusedTask
                        ? `Selected: ${focusedTask.resource} - ${focusedTask.label}`
                        : "Hover task blocks to reveal detailed sprint timelines"}{" "}
                    <GanttChartSquare className="h-4 w-4 text-emerald-500" />
                </div>
                <div className="text-muted-foreground leading-none">
                    Band scale Y coordinates pair with UTC timeline X ranges for Gantt task rendering
                </div>
            </CardFooter>
        </Card>
    );
}

export default ScrollableResourceLanes;