since3-website/modules/landingPage/ui/components/tools/contrast-tool.tsx

"use client"

import { useId, useState } from "react"

import { Button } from "@/components/ui/button"
import { Input } from "@/components/ui/input"
import { Label } from "@/components/ui/label"
import { parseHex, runContrastCheck, type OutputLine } from "@/modules/landingPage/lib/tools"

import { ToolOutput } from "./tool-output"

export function ContrastTool() {
  const id = useId()
  const [fg, setFg] = useState("#767676")
  const [bg, setBg] = useState("#ffffff")
  const [lines, setLines] = useState<OutputLine[] | null>(null)

  // parseHex accepts values without "#" (e.g. "1a1a1a"), but CSS doesn't —
  // build the preview from the parsed RGB channels instead of the raw input
  const fgRgb = parseHex(fg)
  const bgRgb = parseHex(bg)
  const preview =
    fgRgb && bgRgb
      ? { color: `rgb(${fgRgb.join(" ")})`, background: `rgb(${bgRgb.join(" ")})` }
      : undefined

  const onSubmit = (event: React.FormEvent<HTMLFormElement>) => {
    event.preventDefault()
    setLines(runContrastCheck(fg, bg))
  }

  return (
    <form onSubmit={onSubmit} className="grid gap-6">
      <p className="text-ink-300">
        Prüft, ob Text auf einem Hintergrund die WCAG-Kontrastwerte erfüllt, die
        das BFSG verlangt.
      </p>

      <div className="grid gap-4 sm:grid-cols-[1fr_1fr_auto] sm:items-end">
        <div className="grid gap-2.5">
          <Label htmlFor={`${id}-fg`}>Textfarbe</Label>
          <Input
            id={`${id}-fg`}
            value={fg}
            onChange={(event) => setFg(event.target.value)}
            spellCheck={false}
            autoComplete="off"
            className="font-mono"
          />
        </div>
        <div className="grid gap-2.5">
          <Label htmlFor={`${id}-bg`}>Hintergrund</Label>
          <Input
            id={`${id}-bg`}
            value={bg}
            onChange={(event) => setBg(event.target.value)}
            spellCheck={false}
            autoComplete="off"
            className="font-mono"
          />
        </div>
        <div
          aria-hidden="true"
          style={preview}
          className="grid h-12 place-items-center rounded-xl border border-white/10 px-5 text-sm font-medium sm:w-24"
        >
          Aa
        </div>
      </div>

      <div>
        <Button type="submit" variant="solid">
          Kontrast prüfen
        </Button>
      </div>

      <ToolOutput lines={lines} placeholder="Ergebnis erscheint hier." />
    </form>
  )
}