Todo List

"use client"

import * as React from "react"
import { TaskStatus, TodoItem, TodoList } from "@/components/ui/todo-list"

const FIT_CSS = "html,body{overflow:hidden}[data-fit-small] [data-fit-hide]{display:none!important}"

/**
 * 21st shows a demo in a small frame: about 674 by 421 on a component page, 358 by 224 on a
 * phone and 245 by 139 on a profile card. A demo taller than its frame gets scrollbars, which
 * render white on dark pages. FitFrame fills the frame exactly instead.
 *
 * - "scale": the content shrinks until it fits, centered. For visuals such as orbs.
 * - "crop": the content stays at full size from the top and fades out at the bottom. For text
 *   that streams in, where a changing scale would make the page breathe.
 *
 * `minWidth` lays out a wide demo (a table, a two column panel) at that width and scales it down
 * to the frame, instead of letting it collapse to a narrow layout. The frame centers it, so it
 * shrinks evenly on both sides.
 *
 * Anything marked `data-fit-hide` (state buttons, the chatcn.dev line) drops out in frames
 * shorter than `hideBelow`, so a profile card shows the visual alone.
 */
function FitFrame({
  children,
  mode = "scale",
  hideBelow = 360,
  minWidth,
}: {
  children: React.ReactNode
  mode?: "scale" | "crop"
  hideBelow?: number
  minWidth?: string
}) {
  const content = React.useRef<HTMLDivElement>(null)
  const [cropped, setCropped] = React.useState(false)

  React.useLayoutEffect(() => {
    const el = content.current
    if (!el) return
    const measure = () => {
      const vw = window.innerWidth
      const vh = window.innerHeight
      el.toggleAttribute("data-fit-small", vh < hideBelow)
      // Layout sizes ignore the transform, so measuring never feeds back.
      const w = Math.max(el.offsetWidth, el.scrollWidth)
      const h = Math.max(el.offsetHeight, el.scrollHeight)
      const scale = mode === "scale" ? Math.min(1, vw / w, vh / h) : 1
      el.style.transform = scale < 1 ? `scale(${scale})` : ""
      setCropped(mode === "crop" && h > vh + 1)
    }
    measure()
    const observer = new ResizeObserver(measure)
    observer.observe(el)
    // Content that changes inside a fixed width box (a headline that cycles words) never resizes
    // the box itself, so changes below it measure again on the next frame.
    let frame = 0
    const mutations = new MutationObserver(() => {
      cancelAnimationFrame(frame)
      frame = requestAnimationFrame(measure)
    })
    mutations.observe(el, { subtree: true, childList: true, characterData: true })
    window.addEventListener("resize", measure)
    return () => {
      observer.disconnect()
      mutations.disconnect()
      cancelAnimationFrame(frame)
      window.removeEventListener("resize", measure)
    }
  }, [mode, hideBelow])

  const fade = "linear-gradient(to bottom, #000 calc(100% - 40px), transparent)"
  return (
    <div
      className="flex w-full justify-center overflow-hidden"
      style={{
        height: "100dvh",
        alignItems: mode === "crop" ? "flex-start" : "center",
        maskImage: cropped ? fade : undefined,
        WebkitMaskImage: cropped ? fade : undefined,
      }}
    >
      <style>{FIT_CSS}</style>
      <div
        ref={content}
        className="w-full shrink-0"
        style={{ transformOrigin: mode === "crop" ? "top center" : "center", minWidth }}
      >
        {children}
      </div>
    </div>
  )
}

const ITEMS: Omit<TodoItem, "status">[] = [
  {
    id: "1",
    title: "Read the runs layout and page",
    activeTitle: "Reading the runs layout and page",
  },
  {
    id: "2",
    title: "Stop awaiting getProjects()",
    activeTitle: "Removing the getProjects() await",
  },
  { id: "3", title: "Add RunsHeaderSkeleton", activeTitle: "Adding RunsHeaderSkeleton" },
  { id: "4", title: "Wrap RunsHeader in Suspense", activeTitle: "Wrapping RunsHeader in Suspense" },
  { id: "5", title: "Run pnpm test --filter web", activeTitle: "Running pnpm test --filter web" },
  { id: "6", title: "Run pnpm typecheck", activeTitle: "Running pnpm typecheck" },
  { id: "7", title: "Measure the first paint again", activeTitle: "Measuring the first paint" },
]

/** A todo finishes about every 1.4 s; the list restarts after a pause. */
function TodoListDemo() {
  const [step, setStep] = React.useState(0)
  React.useEffect(() => {
    const id = window.setTimeout(
      () => setStep((s) => (s >= ITEMS.length * 2 + 3 ? 0 : s + 1)),
      step === 0 ? 900 : step % 2 === 1 ? 1100 : 300,
    )
    return () => window.clearTimeout(id)
  }, [step])

  // Odd steps start a todo, even steps finish it.
  const items: TodoItem[] = ITEMS.map((item, i) => {
    let status: TaskStatus = "pending"
    if (step >= i * 2 + 2) status = "done"
    else if (step >= i * 2 + 1) status = "in-progress"
    return { ...item, status }
  })

  return <TodoList items={items} className="w-full max-w-md" />
}

/** The line under each 21st demo that points back to the kit. */
function MoreOn({ slug, children }: { slug: string; children: React.ReactNode }) {
  return (
    <p data-fit-hide className="text-[0.75rem]/[1rem] text-(color:--chatcn-fg-faint) text-center text-balance">
      {children}{" "}
      <a
        href={`https://chatcn.dev/docs/components/${slug}`}
        target="_blank"
        rel="noopener"
        className="text-(color:--chatcn-fg-subtle) hover:text-(color:--chatcn-fg) underline underline-offset-2"
      >
        chatcn.dev
      </a>
    </p>
  )
}

/** The kit's own example, framed for the 21st preview. */
export default function TodoListPreview() {
  return (
    <FitFrame minWidth="34rem">
      <div className="flex w-full flex-col items-center justify-center gap-4 p-6">
        <div className="flex w-full max-w-2xl justify-center">
          <TodoListDemo />
        </div>
        <MoreOn slug="todo-list">An agent's to do list that checks itself off. On</MoreOn>
      </div>
    </FitFrame>
  )
}