formbricks/apps/formbricks-com/components/shared/ThemeSelector.jsx

import { useEffect, useState } from "react";
import { Listbox } from "@headlessui/react";
import clsx from "clsx";

const themes = [
  { name: "Light", value: "light", icon: LightIcon },
  { name: "Dark", value: "dark", icon: DarkIcon },
  { name: "System", value: "system", icon: SystemIcon },
];

function LightIcon(props) {
  return (
    <svg aria-hidden="true" viewBox="0 0 16 16" {...props}>
      <path
        fillRule="evenodd"
        clipRule="evenodd"
        d="M7 1a1 1 0 0 1 2 0v1a1 1 0 1 1-2 0V1Zm4 7a3 3 0 1 1-6 0 3 3 0 0 1 6 0Zm2.657-5.657a1 1 0 0 0-1.414 0l-.707.707a1 1 0 0 0 1.414 1.414l.707-.707a1 1 0 0 0 0-1.414Zm-1.415 11.313-.707-.707a1 1 0 0 1 1.415-1.415l.707.708a1 1 0 0 1-1.415 1.414ZM16 7.999a1 1 0 0 0-1-1h-1a1 1 0 1 0 0 2h1a1 1 0 0 0 1-1ZM7 14a1 1 0 1 1 2 0v1a1 1 0 1 1-2 0v-1Zm-2.536-2.464a1 1 0 0 0-1.414 0l-.707.707a1 1 0 0 0 1.414 1.414l.707-.707a1 1 0 0 0 0-1.414Zm0-8.486A1 1 0 0 1 3.05 4.464l-.707-.707a1 1 0 0 1 1.414-1.414l.707.707ZM3 8a1 1 0 0 0-1-1H1a1 1 0 0 0 0 2h1a1 1 0 0 0 1-1Z"
      />
    </svg>
  );
}

function DarkIcon(props) {
  return (
    <svg aria-hidden="true" viewBox="0 0 16 16" {...props}>
      <path
        fillRule="evenodd"
        clipRule="evenodd"
        d="M7.23 3.333C7.757 2.905 7.68 2 7 2a6 6 0 1 0 0 12c.68 0 .758-.905.23-1.332A5.989 5.989 0 0 1 5 8c0-1.885.87-3.568 2.23-4.668ZM12 5a1 1 0 0 1 1 1 1 1 0 0 0 1 1 1 1 0 1 1 0 2 1 1 0 0 0-1 1 1 1 0 1 1-2 0 1 1 0 0 0-1-1 1 1 0 1 1 0-2 1 1 0 0 0 1-1 1 1 0 0 1 1-1Z"
      />
    </svg>
  );
}

function SystemIcon(props) {
  return (
    <svg aria-hidden="true" viewBox="0 0 16 16" {...props}>
      <path
        fillRule="evenodd"
        clipRule="evenodd"
        d="M1 4a3 3 0 0 1 3-3h8a3 3 0 0 1 3 3v4a3 3 0 0 1-3 3h-1.5l.31 1.242c.084.333.36.573.63.808.091.08.182.158.264.24A1 1 0 0 1 11 15H5a1 1 0 0 1-.704-1.71c.082-.082.173-.16.264-.24.27-.235.546-.475.63-.808L5.5 11H4a3 3 0 0 1-3-3V4Zm3-1a1 1 0 0 0-1 1v4a1 1 0 0 0 1 1h8a1 1 0 0 0 1-1V4a1 1 0 0 0-1-1H4Z"
      />
    </svg>
  );
}

export function ThemeSelector(props) {
  let [selectedTheme, setSelectedTheme] = useState();

  useEffect(() => {
    if (selectedTheme) {
      document.documentElement.setAttribute("data-theme", selectedTheme.value);
    } else {
      setSelectedTheme(
        themes.find((theme) => theme.value === document.documentElement.getAttribute("data-theme"))
      );
    }
  }, [selectedTheme]);

  useEffect(() => {
    let handler = () =>
      setSelectedTheme(themes.find((theme) => theme.value === (window.localStorage.theme ?? "system")));

    window.addEventListener("storage", handler);

    return () => window.removeEventListener("storage", handler);
  }, []);

  return (
    <Listbox as="div" value={selectedTheme} onChange={setSelectedTheme} {...props}>
      <Listbox.Label className="sr-only">Theme</Listbox.Label>
      <Listbox.Button
        className="flex h-6 w-6 items-center justify-center rounded-lg shadow-md shadow-black/5 ring-1 ring-black/5 dark:bg-slate-700 dark:ring-inset dark:ring-white/5"
        aria-label={selectedTheme?.name}>
        <LightIcon className="hidden h-4 w-4 fill-brand [[data-theme=light]_&]:block" />
        <DarkIcon className="hidden h-4 w-4 fill-brand [[data-theme=dark]_&]:block" />
        <LightIcon className="hidden h-4 w-4 fill-slate-400 [:not(.dark)[data-theme=system]_&]:block" />
        <DarkIcon className="hidden h-4 w-4 fill-slate-400 [.dark[data-theme=system]_&]:block" />
      </Listbox.Button>
      <Listbox.Options className="absolute top-full left-1/2 mt-3 w-36 -translate-x-1/2 space-y-1 rounded-xl bg-white p-3 text-sm font-medium shadow-md shadow-black/5 ring-1 ring-black/5 dark:bg-slate-800 dark:ring-white/5">
        {themes.map((theme) => (
          <Listbox.Option
            key={theme.value}
            value={theme}
            className={({ active, selected }) =>
              clsx("flex cursor-pointer select-none items-center rounded-[0.625rem] p-1", {
                "text-brand-dark dark:text-brand-light": selected,
                "text-slate-800 dark:text-slate-100": active && !selected,
                "text-slate-700 dark:text-slate-400": !active && !selected,
                "bg-slate-100 dark:bg-slate-900/40": active,
              })
            }>
            {({ selected }) => (
              <>
                <div className="rounded-md bg-white p-1 shadow ring-1 ring-slate-900/5 dark:bg-slate-700 dark:ring-inset dark:ring-white/5">
                  <theme.icon
                    className={clsx(
                      "h-4 w-4",
                      selected ? "fill-brand-dark dark:fill-brand-light" : "fill-slate-400"
                    )}
                  />
                </div>
                <div className="ml-3">{theme.name}</div>
              </>
            )}
          </Listbox.Option>
        ))}
      </Listbox.Options>
    </Listbox>
  );
}