meeting_memory/frontend_nanobot/src/components/thread/PromptRail.tsx

345 lines
11 KiB
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 {
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 = 16;
const MARKER_MAX_WIDTH_PX = 28;
const MEASURE_RETRY_FRAMES = 4;
const RAIL_REVEAL_MS = 1400;
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 [revealed, setRevealed] = useState(false);
const revealTimeoutRef = useRef<number | null>(null);
const revealTemporarily = useCallback(() => {
setRevealed(true);
if (revealTimeoutRef.current !== null) {
window.clearTimeout(revealTimeoutRef.current);
}
revealTimeoutRef.current = window.setTimeout(() => {
setRevealed(false);
revealTimeoutRef.current = null;
}, RAIL_REVEAL_MS);
}, []);
const updateMarkers = useCallback(() => {
const scrollEl = scrollRef.current;
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);
setMarkers(groupPromptMarkers(measured, railRef.current?.clientHeight ?? 0));
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);
revealTemporarily();
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);
};
}, [revealTemporarily, 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]);
useEffect(() => {
return () => {
if (revealTimeoutRef.current !== null) {
window.clearTimeout(revealTimeoutRef.current);
}
};
}, []);
if (markers.length === 0) return null;
const maxMarkerCount = Math.max(...markers.map((marker) => marker.count));
const activeMarkerIndex = markers.findIndex((marker) =>
marker.ids.includes(activePromptId ?? ""),
);
return (
<div
ref={railRef}
aria-label="User prompt navigation"
className={cn(
"group pointer-events-auto absolute right-4 top-14 z-20 hidden w-8 opacity-70 md:block",
"transition-opacity duration-200 hover:opacity-100",
"motion-safe:animate-in motion-safe:fade-in-0 motion-safe:duration-200",
)}
style={{ bottom: Math.max(80, bottomOffset) }}
>
{markers.map((marker, index) => {
const active = marker.ids.includes(activePromptId ?? "");
const nearActive = activeMarkerIndex < 0 || Math.abs(index - activeMarkerIndex) <= 1;
return (
<button
key={marker.ids.join("|")}
type="button"
aria-label={`Jump to prompt: ${marker.label}`}
onClick={() => jumpToPrompt(scrollRef.current, marker.ids[marker.ids.length - 1])}
className={cn(
"group/marker absolute right-0 h-5 -translate-y-1/2 overflow-visible rounded-full",
"focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-blue-400/60",
)}
style={{
top: `${marker.topPercent}%`,
width: markerWidth(marker.count, maxMarkerCount, active),
}}
>
<span
aria-hidden
className={cn(
"absolute right-0 top-1/2 h-[3px] w-full -translate-y-1/2 rounded-full",
"bg-foreground/20 transition-[background-color,opacity,transform,height] duration-200",
"group-hover/marker:bg-blue-500/70 group-hover/marker:opacity-100 group-hover/marker:scale-x-110",
"group-focus-visible/marker:bg-blue-500 group-focus-visible/marker:opacity-100 group-focus-visible/marker:scale-x-110",
marker.count > 1 && "bg-foreground/30",
active && "h-1 bg-foreground/65 opacity-80 shadow-sm",
!active && nearActive && "opacity-25 group-hover:opacity-55",
!active && !nearActive && !revealed && "opacity-0 group-hover:opacity-40",
!active && !nearActive && revealed && "opacity-35",
)}
/>
<span
aria-hidden
className={cn(
"pointer-events-none absolute right-9 top-1/2 z-30 w-64 -translate-y-1/2 rounded-lg px-3 py-2 text-left",
"bg-background/95 text-xs leading-5 text-foreground shadow-lg ring-1 ring-border/80 backdrop-blur",
"opacity-0 translate-x-1 transition-[opacity,transform] duration-150",
"group-hover/marker:opacity-100 group-hover/marker:translate-x-0",
"group-focus-visible/marker:opacity-100 group-focus-visible/marker:translate-x-0",
)}
>
<span className="block max-h-24 overflow-hidden whitespace-pre-wrap break-words">
{marker.preview}
</span>
</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.preview = groupedPromptPreview(last.count, prompt.preview);
continue;
}
groups.push({
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),
preview: bucket.length === 1
? latest.preview
: groupedPromptPreview(bucket.length, latest.preview),
topPercent,
}];
});
}
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: ${latestLabel}`;
}
function groupedPromptPreview(count: number, latestPreview: string): string {
return `${count} prompts\n\n${latestPreview}`;
}
function markerWidth(count: number, maxCount: number, active: boolean): number {
if (maxCount <= 1) return active ? 34 : MARKER_BASE_WIDTH_PX;
const density = Math.log2(count + 1) / Math.log2(maxCount + 1);
const width = MARKER_BASE_WIDTH_PX
+ (MARKER_MAX_WIDTH_PX - MARKER_BASE_WIDTH_PX) * density;
return Math.round(active ? width + 4 : width);
}
function clamp(value: number, min: number, max: number): number {
return Math.max(min, Math.min(max, value));
}