main-site/components/themeselector.tsx

import { useUpdateTheme } from "../pages/_app";
import { Fragment, useContext, useState } from 'react';
import { ThemeContext, DefaultTheme } from "styled-components";
import { darkTheme, amoledTheme, lightTheme, amoled2Theme } from './themes';
import { ThemeDropDown, ThemeDropDownButton, ThemeDropDownOption, ThemeDropDownOptions } from "./styles/themedropdown";

const themes = [
  lightTheme,
  darkTheme,
  amoledTheme,
  amoled2Theme,
]

const StyleSelector = () => {
  const updateTheme = useUpdateTheme();
  const currentTheme = useContext(ThemeContext);
  const [selectedTheme, setSelectedTheme] = useState(themes[currentTheme.themeId]);

  const updateThemeWithStorage = (newTheme: DefaultTheme) => {

    if (newTheme.themeId === lightTheme.themeId) {
      updateLightTheme(newTheme);
    }
    else {
      setSelectedTheme(newTheme);
      localStorage.setItem("theme", newTheme.themeId.toString());
      updateTheme(newTheme);
    }
  }

  const updateLightTheme = (newTheme: DefaultTheme) => {
    if (confirm("Really switch to Light Mode?")) {
      setSelectedTheme(newTheme);
      localStorage.setItem("theme", newTheme.themeId.toString());
      updateTheme(newTheme)
    } 
    else {

    }
  }

  const [test, setTest] = useState(false);

  return (

    <ThemeDropDown>
      <ThemeDropDownButton onClick={() => setTest(test => !test)}>{selectedTheme.themeName}</ThemeDropDownButton>
      <ThemeDropDownOptions id="themesDropdown" show={test}>
        {themes.map((theme) => (
          <ThemeDropDownOption active={theme === selectedTheme} key={theme.themeId} onClick={() => updateThemeWithStorage(theme)}>
            {theme.themeName}
          </ThemeDropDownOption>
        ))}
      </ThemeDropDownOptions>
    </ThemeDropDown>
  );
}

{/* <button onClick={() => updateLightTheme(lightTheme)}>Light Style</button>
<button onClick={() => updateThemeWithStorage(darkTheme)}>Dark Style</button>
<button onClick={() => updateThemeWithStorage(amoledTheme)}>Amoled Style</button>
<button onClick={() => updateThemeWithStorage(amoled2Theme)}>Amoled 2 Style</button> */}

export function getTheme(themeId: number): DefaultTheme {
  let theme: DefaultTheme;

  switch (themeId) {
    case 0:
      theme = lightTheme;
      break;
    case 1:
      theme = darkTheme;
      break;
    case 2:
      theme = amoledTheme;
      break;
    case 3:
      theme = amoled2Theme;
      break;
    default:
      theme = darkTheme
  }

  return theme;
}

export default StyleSelector;