"use client";
import { useEffect, useRef, useState } from "react";
import { motion } from "motion/react";
import { RotateCcw, Square } from "lucide-react";
import { cn } from "@/lib/utils";
import { useAnimationLoop } from "@/hooks/use-animation-loop";
export type StreamChunking = "word" | "character";
export type StreamCaret = "bar" | "block" | "none";
export interface StreamProps {
text?: string;
tokensPerSecond?: number;
jitter?: number;
chunking?: StreamChunking;
blurAmount?: number;
thinkingMs?: number;
caret?: StreamCaret;
caretColor?: string;
autoReplay?: boolean;
paused?: boolean;
reducedMotion?: boolean;
className?: string;
}
type Phase = "thinking" | "streaming" | "done" | "stopped";
const WINDOW = 24;
const DEFAULT_TEXT =
"The registry is the single source of truth here: every tunable prop is declared once as a schema entry, and that one declaration drives both the controls panel you are reading and the props table below it. Nothing is documented twice, so nothing can drift. The code tab reads the shipped source straight from disk, strips the comments on the way out, and serves exactly what the copy button puts on your clipboard.";
const splitTokens = (text: string, chunking: StreamChunking): string[] => {
if (chunking === "character") return Array.from(text);
return text.match(/\S+\s*/g) ?? [];
};
const Stream = ({
text = DEFAULT_TEXT,
tokensPerSecond = 18,
jitter = 0.35,
chunking = "word",
blurAmount = 6,
thinkingMs = 1200,
caret = "bar",
caretColor = "#a78bfa",
autoReplay = true,
paused = false,
reducedMotion = false,
className,
}: StreamProps) => {
const containerRef = useRef<HTMLDivElement | null>(null);
const live = useRef({
tokensPerSecond,
jitter,
blurAmount,
thinkingMs,
autoReplay,
paused,
reducedMotion,
});
live.current = {
tokensPerSecond,
jitter,
blurAmount,
thinkingMs,
autoReplay,
paused,
reducedMotion,
};
const tokens = splitTokens(text, chunking);
const [phase, setPhase] = useState<Phase>("thinking");
const [count, setCount] = useState(0);
const clock = useRef({
phase: "thinking" as Phase,
count: 0,
tokenTotal: tokens.length,
thinkingLeft: thinkingMs / 1000,
untilNext: 0,
replayLeft: 0,
});
clock.current.tokenTotal = tokens.length;
const loop = useAnimationLoop({
target: containerRef,
halted: paused,
onFrame: ({ dt }) => {
const c = clock.current;
const L = live.current;
if (c.phase === "thinking") {
c.thinkingLeft -= dt;
if (c.thinkingLeft <= 0) {
c.phase = "streaming";
c.untilNext = 0;
setPhase("streaming");
}
return;
}
if (c.phase === "streaming") {
c.untilNext -= dt;
let emitted = 0;
while (c.untilNext <= 0 && c.count < c.tokenTotal && emitted < 6) {
c.count++;
emitted++;
const base = 1 / Math.max(L.tokensPerSecond, 0.5);
const wobble = 1 + L.jitter * (Math.random() * 2 - 1);
const stall =
Math.random() < L.jitter * 0.05 ? base * (4 + Math.random() * 8) : 0;
c.untilNext += base * Math.max(wobble, 0.25) + stall;
}
if (emitted > 0) setCount(c.count);
if (c.count >= c.tokenTotal) {
c.phase = "done";
c.replayLeft = 2.6;
setPhase("done");
}
return;
}
if (c.phase === "done" && L.autoReplay) {
c.replayLeft -= dt;
if (c.replayLeft <= 0) {
c.phase = "thinking";
c.count = 0;
c.thinkingLeft = L.thinkingMs / 1000;
setPhase("thinking");
setCount(0);
}
return;
}
return false;
},
});
useEffect(() => {
loop.start();
}, [paused, autoReplay, loop]);
useEffect(() => {
const c = clock.current;
c.phase = "thinking";
c.count = 0;
c.thinkingLeft = live.current.thinkingMs / 1000;
setPhase("thinking");
setCount(0);
loop.start();
}, [text, chunking, loop]);
const stop = () => {
const c = clock.current;
if (c.phase !== "streaming" && c.phase !== "thinking") return;
c.phase = "stopped";
setPhase("stopped");
};
const regenerate = () => {
const c = clock.current;
c.phase = "thinking";
c.count = 0;
c.thinkingLeft = live.current.thinkingMs / 1000;
setPhase("thinking");
setCount(0);
loop.start();
};
const generating = phase === "thinking" || phase === "streaming";
const windowStart = Math.max(0, count - WINDOW);
const settledText = tokens.slice(0, windowStart).join("");
const liveTokens = tokens.slice(windowStart, count);
const caretEl =
caret !== "none" && phase === "streaming" ? (
<motion.span
aria-hidden
className="ml-px inline-block align-baseline"
style={{
width: caret === "block" ? "0.55em" : "2px",
height: "1.1em",
marginBottom: "-0.2em",
background: caretColor,
}}
animate={reducedMotion ? { opacity: 1 } : { opacity: [1, 1, 0, 0] }}
transition={
reducedMotion
? undefined
: { duration: 0.9, repeat: Infinity, ease: "linear" }
}
/>
) : null;
return (
<div
ref={containerRef}
className={cn(
"flex h-full w-full flex-col gap-4 rounded-lg border border-hairline bg-panel p-5",
className,
)}
>
<div className="relative min-h-0 flex-1 overflow-hidden">
<div
aria-hidden
className="invisible text-sm leading-relaxed"
>
{text}
</div>
{phase === "thinking" ? (
<div className="absolute inset-0 flex flex-col gap-2.5 pt-1">
{[0.92, 0.98, 0.62].map((w, i) => (
<div
key={i}
className="relative h-3.5 overflow-hidden rounded bg-raised"
style={{ width: `${w * 100}%` }}
>
{!reducedMotion && (
<motion.div
className="absolute inset-y-0 w-1/2"
style={{
background:
"linear-gradient(105deg, transparent, color-mix(in oklab, var(--sg-ink) 12%, transparent), transparent)",
}}
initial={{ x: "-110%" }}
animate={{ x: "310%" }}
transition={{
duration: 1.3,
repeat: Infinity,
ease: "linear",
delay: i * 0.18,
}}
/>
)}
</div>
))}
</div>
) : (
<p className="absolute inset-0 overflow-hidden text-sm leading-relaxed text-ink">
<span>{settledText}</span>
{liveTokens.map((token, i) => (
<motion.span
key={windowStart + i}
className="inline"
initial={
reducedMotion
? false
: { opacity: 0, y: 2, filter: `blur(${blurAmount}px)` }
}
animate={{ opacity: 1, y: 0, filter: "blur(0px)" }}
transition={{ duration: 0.3, ease: "easeOut" }}
>
{token}
</motion.span>
))}
{caretEl}
</p>
)}
</div>
<div className="flex items-center gap-2">
{generating ? (
<button
type="button"
onClick={stop}
className="inline-flex items-center gap-1.5 rounded-md border border-hairline bg-raised px-2.5 py-1.5 font-mono text-xs text-ink-dim transition-colors hover:text-ink focus-visible:outline-2 focus-visible:outline-accent"
>
<Square className="size-3" fill="currentColor" />
Stop
</button>
) : (
<button
type="button"
onClick={regenerate}
className="inline-flex items-center gap-1.5 rounded-md border border-hairline bg-raised px-2.5 py-1.5 font-mono text-xs text-ink-dim transition-colors hover:text-ink focus-visible:outline-2 focus-visible:outline-accent"
>
<RotateCcw className="size-3" />
Regenerate
</button>
)}
<span className="font-mono text-[10px] uppercase tracking-widest text-ink-mute">
{phase === "thinking" && "thinking…"}
{phase === "streaming" && `${count}/${tokens.length} tokens`}
{phase === "done" && "complete"}
{phase === "stopped" && "stopped"}
</span>
</div>
</div>
);
};
export default Stream;