/*
 * Copyright (C) 2026 Mateusz Gruszczyński @linuxiarz.pl
 * Source-Available Code / Dual-Licensed.
 * 
 * Free for non-commercial and evaluation use under terms of BSL/GPLv3.
 * Commercial or production use requires a valid paid license.
 * See LICENSE file in repository root for details.
 */
const STORAGE_KEY = "rustpad:theme";
const THEMES = new Set(["dark", "light"]);
const systemThemeQuery = window.matchMedia("(prefers-color-scheme: light)");

function systemTheme() {
  return systemThemeQuery.matches ? "light" : "dark";
}

function normalizeTheme(value) {
  return THEMES.has(value) ? value : systemTheme();
}

function updateBrowserChrome(theme) {
  document.documentElement.dataset.theme = theme;
  document.documentElement.style.colorScheme = theme;
  document.querySelector('meta[name="color-scheme"]')?.setAttribute("content", theme);
}

export function getTheme() {
  return normalizeTheme(document.documentElement.dataset.theme);
}

export function applyTheme(value, { persist = true } = {}) {
  const theme = normalizeTheme(value);
  const previousTheme = getTheme();
  updateBrowserChrome(theme);
  if (persist) {
    try { localStorage.setItem(STORAGE_KEY, theme); } catch { }
  }
  if (theme !== previousTheme) {
    window.dispatchEvent(new CustomEvent("rustpad:theme-change", { detail: { theme } }));
  }
  return theme;
}

export function applySessionTheme(session) {
  if (session?.theme) applyTheme(session.theme);
}

window.addEventListener("storage", event => {
  if (event.key !== STORAGE_KEY) return;
  applyTheme(THEMES.has(event.newValue) ? event.newValue : systemTheme(), { persist: false });
});

systemThemeQuery.addEventListener("change", () => {
  try {
    if (THEMES.has(localStorage.getItem(STORAGE_KEY))) return;
  } catch { }
  applyTheme(systemTheme(), { persist: false });
});