Files
nanobot/webui/src/components/thread/PromptRail.tsx
T

353 lines
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TypeScript

import { type RefObject, useCallback, useEffect, useMemo, useRef, useState } from "react";
import { cn } from "@/lib/utils";
import type { UIMessage } from "@/lib/types";
import {
findPromptElement,
jumpToPrompt,
type PromptAnchor,
promptTop,
userPromptAnchors,
} from "@/components/thread/promptNavigation";
interface PromptRailProps {
bottomOffset: number;
messages: UIMessage[];
scrollRef: RefObject<HTMLDivElement>;
}
interface MeasuredPrompt extends PromptAnchor {
top: number;
topPercent: number;
}
interface PromptMarker {
answerPreview: string;
count: number;
ids: string[];
label: string;
preview: string;
topPercent: number;
}
const MIN_PROMPTS_FOR_RAIL = 3;
const RAIL_MIN_SCROLL_RANGE_PX = 80;
const DENSE_PROMPT_THRESHOLD = 30;
const DENSE_BUCKET_HEIGHT_PX = 12;
const DENSE_BUCKET_FALLBACK_COUNT = 32;
const DENSE_BUCKET_MAX_COUNT = 42;
const MARKER_MIN_GAP_PX = 9;
const MARKER_BASE_WIDTH_PX = 9;
const MARKER_STACK_GAP_PX = 16;
const RAIL_FALLBACK_HEIGHT_PX = 300;
const MEASURE_RETRY_FRAMES = 4;
const HOVER_MARKER_WIDTHS_PX = [28, 22, 16, 11];
export function PromptRail({
bottomOffset,
messages,
scrollRef,
}: PromptRailProps) {
const railRef = useRef<HTMLDivElement>(null);
const promptAnchors = useMemo(() => userPromptAnchors(messages), [messages]);
const [markers, setMarkers] = useState<PromptMarker[]>([]);
const [activePromptId, setActivePromptId] = useState<string | null>(null);
const [focusedMarkerIndex, setFocusedMarkerIndex] = useState<number | null>(null);
const updateMarkers = useCallback(() => {
const scrollEl = scrollRef.current;
const nextRailHeight = railRef.current?.clientHeight ?? 0;
if (!scrollEl || promptAnchors.length < MIN_PROMPTS_FOR_RAIL) {
setMarkers([]);
setActivePromptId(null);
return;
}
const scrollRange = scrollEl.scrollHeight - scrollEl.clientHeight;
if (scrollRange < RAIL_MIN_SCROLL_RANGE_PX) {
setMarkers([]);
setActivePromptId(null);
return;
}
const measured = measurePrompts(scrollEl, promptAnchors, scrollRange);
const grouped = groupPromptMarkers(measured, nextRailHeight);
setMarkers(distributeMarkerPositions(grouped, nextRailHeight));
setActivePromptId(activePromptForScroll(measured, scrollEl.scrollTop));
}, [promptAnchors, scrollRef]);
useEffect(() => {
let frame = 0;
let remainingFrames = MEASURE_RETRY_FRAMES;
const measure = () => {
updateMarkers();
remainingFrames -= 1;
if (remainingFrames > 0) {
frame = window.requestAnimationFrame(measure);
}
};
measure();
return () => window.cancelAnimationFrame(frame);
}, [bottomOffset, updateMarkers]);
useEffect(() => {
const scrollEl = scrollRef.current;
if (!scrollEl) return undefined;
let frame = 0;
const schedule = () => {
window.cancelAnimationFrame(frame);
frame = window.requestAnimationFrame(updateMarkers);
};
scrollEl.addEventListener("scroll", schedule, { passive: true });
window.addEventListener("resize", schedule);
return () => {
window.cancelAnimationFrame(frame);
scrollEl.removeEventListener("scroll", schedule);
window.removeEventListener("resize", schedule);
};
}, [scrollRef, updateMarkers]);
useEffect(() => {
const scrollEl = scrollRef.current;
if (!scrollEl || typeof ResizeObserver === "undefined") return undefined;
const observer = new ResizeObserver(() => updateMarkers());
observer.observe(scrollEl);
if (scrollEl.firstElementChild) observer.observe(scrollEl.firstElementChild);
return () => observer.disconnect();
}, [scrollRef, updateMarkers]);
if (markers.length === 0) return null;
return (
<div
ref={railRef}
aria-label="User prompt navigation"
className={cn(
"thread-prompt-rail group pointer-events-auto absolute top-3 z-20 w-9 opacity-100",
"transition-opacity duration-200",
"motion-safe:animate-in motion-safe:fade-in-0 motion-safe:duration-200",
)}
onPointerLeave={() => setFocusedMarkerIndex(null)}
style={{ bottom: Math.max(80, bottomOffset) }}
>
{markers.map((marker, index) => {
const active = marker.ids.includes(activePromptId ?? "");
const hoverDistance =
focusedMarkerIndex === null ? null : Math.abs(index - focusedMarkerIndex);
return (
<button
key={marker.ids.join("|")}
type="button"
aria-label={`Jump to prompt: ${marker.label}`}
onClick={() => jumpToPrompt(scrollRef.current, marker.ids[marker.ids.length - 1])}
onBlur={() => setFocusedMarkerIndex(null)}
onFocus={() => setFocusedMarkerIndex(index)}
onPointerEnter={() => setFocusedMarkerIndex(index)}
onPointerLeave={() => setFocusedMarkerIndex(null)}
className={cn(
"group/marker absolute left-0 h-4 w-9 -translate-y-1/2 overflow-visible rounded-sm",
"focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-blue-400/60",
)}
style={{ top: `${marker.topPercent}%` }}
>
<span
aria-hidden
data-testid="prompt-rail-marker"
className={cn(
"absolute left-0 top-1/2 h-0.5 -translate-y-1/2 rounded-full",
"transition-[width,background-color,opacity,height] duration-150",
railMarkerTone(hoverDistance, active),
)}
style={{
height: markerHeight(hoverDistance),
width: markerWidth(hoverDistance),
}}
/>
<span
aria-hidden
className={cn(
"pointer-events-none absolute left-10 top-1/2 z-30 w-[34rem] max-w-[calc(100vw-4rem)] -translate-y-1/2 rounded-[20px] px-4 py-3 text-left",
"border border-border/70 bg-popover/95 text-popover-foreground shadow-[0_18px_45px_rgba(0,0,0,0.12)] backdrop-blur-xl",
"dark:border-white/10 dark:bg-[#2f2f2f]/95 dark:text-white dark:shadow-[0_18px_45px_rgba(0,0,0,0.45)]",
"-translate-x-2 scale-[0.98] opacity-0 transition-[opacity,transform] duration-150",
"group-hover/marker:translate-x-0 group-hover/marker:scale-100 group-hover/marker:opacity-100",
"group-focus-visible/marker:translate-x-0 group-focus-visible/marker:scale-100 group-focus-visible/marker:opacity-100",
)}
>
<span className="line-clamp-2 whitespace-pre-wrap break-words text-[15px] font-semibold leading-6">
{marker.preview}
</span>
{marker.answerPreview ? (
<span className="mt-1.5 line-clamp-3 whitespace-pre-wrap break-words text-[14px] leading-6 text-muted-foreground dark:text-white/55">
{marker.answerPreview}
</span>
) : null}
</span>
</button>
);
})}
</div>
);
}
function measurePrompts(
scrollEl: HTMLElement,
anchors: PromptAnchor[],
scrollRange: number,
): MeasuredPrompt[] {
return anchors.flatMap((anchor) => {
const target = findPromptElement(scrollEl, anchor.id);
if (!target) return [];
const top = Math.max(0, Math.min(scrollRange, promptTop(scrollEl, target) - 16));
return [{
...anchor,
top,
topPercent: clamp((top / scrollRange) * 100, 2, 98),
}];
});
}
function groupPromptMarkers(
measured: MeasuredPrompt[],
railHeight: number,
): PromptMarker[] {
if (measured.length === 0) return [];
if (measured.length >= DENSE_PROMPT_THRESHOLD) {
return bucketPromptMarkers(measured, railHeight);
}
const minGapPercent = railHeight > 0
? (MARKER_MIN_GAP_PX / railHeight) * 100
: 2;
const groups: PromptMarker[] = [];
for (const prompt of measured) {
const last = groups[groups.length - 1];
if (last && prompt.topPercent - last.topPercent < minGapPercent) {
last.count += 1;
last.ids.push(prompt.id);
last.label = groupedPromptLabel(last.count, prompt.label);
last.answerPreview = prompt.answerPreview;
last.preview = prompt.preview;
continue;
}
groups.push({
answerPreview: prompt.answerPreview,
count: 1,
ids: [prompt.id],
label: prompt.label,
preview: prompt.preview,
topPercent: prompt.topPercent,
});
}
return groups;
}
function bucketPromptMarkers(
measured: MeasuredPrompt[],
railHeight: number,
): PromptMarker[] {
const bucketCount = railHeight > 0
? clamp(
Math.floor(railHeight / DENSE_BUCKET_HEIGHT_PX),
1,
DENSE_BUCKET_MAX_COUNT,
)
: DENSE_BUCKET_FALLBACK_COUNT;
const buckets = Array.from({ length: bucketCount }, () => [] as MeasuredPrompt[]);
for (const prompt of measured) {
const bucketIndex = clamp(
Math.floor((prompt.topPercent / 100) * bucketCount),
0,
bucketCount - 1,
);
buckets[bucketIndex].push(prompt);
}
return buckets.flatMap((bucket) => {
if (bucket.length === 0) return [];
const latest = bucket[bucket.length - 1];
const topPercent =
bucket.reduce((sum, prompt) => sum + prompt.topPercent, 0) / bucket.length;
return [{
count: bucket.length,
ids: bucket.map((prompt) => prompt.id),
label: bucket.length === 1
? latest.label
: groupedPromptLabel(bucket.length, latest.label),
answerPreview: latest.answerPreview,
preview: latest.preview,
topPercent,
}];
});
}
function distributeMarkerPositions(markers: PromptMarker[], railHeight: number): PromptMarker[] {
const height = railHeight > 0 ? railHeight : RAIL_FALLBACK_HEIGHT_PX;
if (markers.length <= 1) {
return markers.map((marker) => ({ ...marker, topPercent: 50 }));
}
const availableHeight = Math.max(0, height - MARKER_STACK_GAP_PX);
const stepPx = Math.min(MARKER_STACK_GAP_PX, availableHeight / (markers.length - 1));
const stackHeight = stepPx * (markers.length - 1);
const firstMarkerPx = (height - stackHeight) / 2;
return markers.map((marker, index) => ({
...marker,
topPercent: ((firstMarkerPx + stepPx * index) / height) * 100,
}));
}
function activePromptForScroll(
measured: MeasuredPrompt[],
scrollTop: number,
): string | null {
if (measured.length === 0) return null;
let active = measured[0];
const cursor = scrollTop + 96;
for (const prompt of measured) {
if (prompt.top <= cursor) {
active = prompt;
continue;
}
break;
}
return active.id;
}
function groupedPromptLabel(count: number, latestLabel: string): string {
return `${count} prompts, latest: ${latestLabel}`;
}
function markerWidth(hoverDistance: number | null): number {
if (hoverDistance === null) return MARKER_BASE_WIDTH_PX;
return HOVER_MARKER_WIDTHS_PX[hoverDistance] ?? MARKER_BASE_WIDTH_PX;
}
function markerHeight(hoverDistance: number | null): number {
return hoverDistance === 0 ? 3 : 2;
}
function railMarkerTone(hoverDistance: number | null, active: boolean): string {
if (hoverDistance === 0) {
return "bg-[#222222] opacity-100 dark:bg-white";
}
if (hoverDistance !== null && hoverDistance < HOVER_MARKER_WIDTHS_PX.length) {
return "bg-[#d0d0d0] opacity-100 dark:bg-white/35";
}
if (active) {
return "bg-[#6f6f6f] opacity-100 dark:bg-white/55";
}
return "bg-[#d8d8d8] opacity-100 dark:bg-white/25";
}
function clamp(value: number, min: number, max: number): number {
return Math.max(min, Math.min(max, value));
}