const getById = (id) => document.getElementById(id);
const docStyle = document.documentElement.style;

const theme_switcher = getById("theme-switcher");
const sections_button = getById("sections-button");
const imgs = document.getElementsByTagName("img");
const sections_menu = document.getElementsByTagName("nav")[0];
const main = document.getElementsByTagName("main")[0];
const isMenuOpen = sections_button.getAttribute("opened") === "true"
const theme = window.localStorage.getItem("theme");
const menuSrc = sections_button.children[0].src

/* Functions */

function changeToDarkTheme() {
  theme_switcher?.setAttribute("title", "turn the light on");
  docStyle.setProperty("--border", "var(--dark-border)");
  docStyle.setProperty("--text", "var(--dark-text)");
  docStyle.setProperty("--bg", "var(--dark-bg)");
  window.localStorage.setItem("theme", "dark");
  for (let i = 0; i < imgs.length; i += 1) {
    imgs[i].src = imgs[i].src.replace("-light", "-dark");
  }
}

function changeToLightTheme() {
  theme_switcher?.setAttribute("title", "turn the light off");
  docStyle.setProperty("--border", "var(--light-border)");
  docStyle.setProperty("--text", "var(--light-text)");
  docStyle.setProperty("--bg", "var(--light-bg)");
  window.localStorage.setItem("theme", "light");
  for (let i = 0; i < imgs.length; i += 1) {
    imgs[i].src = imgs[i].src.replace("-dark", "-light");
  }
}

function closeMenu() {
  sections_button.setAttribute("opened", "false");
  const menuSrc = sections_button.children[0].src
  menuSrc.src = menuSrc.replace("opened", "closed");
  sections_menu.style.display = "none";
}

function openMenu() {
  sections_button.setAttribute("opened", "true");
  menuSrc = menuSrc.replace("closed", "opened");
  sections_menu.style.display = "flex";
  sections_menu.style.flexDirection = "column";
}

/* Listeners */

sections_button.addEventListener("click", () => isMenuOpen ? closeMenu() : openMenu());
window.addEventListener("resize", () => isMenuOpen && closeMenu());
main.addEventListener("click", () => isMenuOpen && closeMenu());

theme_switcher.addEventListener("click", () => {
  const title = theme_switcher.getAttribute("title") ?? "off"
  if (title.indexOf("off") !== -1) changeToDarkTheme();
  else changeToLightTheme();
});

/* Rest */

const userPerfersDark = window?.matchMedia?.("(prefers-color-scheme: dark)").matches
if (!theme && userPerfersDark) changeToDarkTheme();
else theme === "light" ? changeToLightTheme() : changeToDarkTheme();