/*
 * 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 order = ["assets", "language", "libraries", "access", "files"];
  const resourceParts = new Set();
  const locale = String(document.documentElement.lang || "en").toLowerCase().startsWith("pl") ? "pl" : "en";
  const strings = {
    en: {
      assets: "Preparing the interface", language: "Setting up language",
      libraries: "Starting the editor", access: "Checking access", files: "Opening the note",
      complete: "Ready", error: "The note could not be opened", retry: "Reload page",
      errorDetails: "Check your connection and try again.", progress: "{done} of {total} stages completed",
      timeout: "Still waiting for the note. Check the connection or reload."
    },
    pl: {
      assets: "Przygotowanie interfejsu", language: "Ustawianie j\u0119zyka",
      libraries: "Uruchamianie edytora", access: "Sprawdzanie dost\u0119pu", files: "Otwieranie notatki",
      complete: "Gotowe", error: "Nie uda\u0142o si\u0119 otworzy\u0107 notatki", retry: "Za\u0142aduj ponownie",
      errorDetails: "Sprawd\u017a po\u0142\u0105czenie i spr\u00f3buj ponownie.", progress: "Uko\u0144czono {done} z {total} etap\u00f3w",
      timeout: "Nadal oczekujemy na notatk\u0119. Sprawd\u017a po\u0142\u0105czenie lub od\u015bwie\u017c stron\u0119."
    }
  }[locale];
  const completed = new Set();
  const loadedStyleElements = new WeakSet();
  let loadedStyleCount = 0;
  let readyRequested = false;
  let dismissed = false;
  let failure = "";
  const element = id => document.getElementById(id);

  function update() {
    const overlay = element("app-boot-overlay");
    if (!overlay || dismissed) return;
    const count = completed.size;
    const progress = Math.round((count / order.length) * 100);
    const next = order.find(stage => !completed.has(stage));
    const heading = element("app-boot-heading");
    if (heading) heading.textContent = locale === "pl" ? "Ładowanie…" : "Loading…";
    const stageText = element("app-boot-stage");
    const stageCount = element("app-boot-count");
    const bar = element("app-boot-progress");
    const fill = element("app-boot-progress-fill");
    const retry = element("app-boot-retry");
    if (stageText) stageText.textContent = failure ? strings.error : (next ? strings[next] : strings.complete);
    if (stageCount) stageCount.textContent = failure || strings.progress.replace("{done}", count).replace("{total}", order.length);
    if (bar) bar.setAttribute("aria-valuenow", String(progress));
    if (fill) fill.style.width = `${progress}%`;
    if (retry) { retry.hidden = !failure; retry.textContent = strings.retry; }
    overlay.classList.toggle("has-error", Boolean(failure));
    for (const stage of order) {
      const node = element(`app-boot-step-${stage}`);
      if (!node) continue;
      const isDone = completed.has(stage);
      node.dataset.status = isDone ? "done" : (stage === next && !failure ? "active" : "waiting");
      node.querySelector("span")?.replaceChildren(document.createTextNode(strings[stage]));
    }
    if (readyRequested && count === order.length && !failure) dismiss();
  }

  function dismiss() {
    if (dismissed) return;
    dismissed = true;
    const overlay = element("app-boot-overlay");
    if (!overlay) return;
    overlay.classList.add("is-ready");
    const remove = () => overlay.remove();
    overlay.addEventListener("transitionend", remove, { once: true });
    setTimeout(remove, 300);
  }

  function complete(stage) {
    if (dismissed || failure) return;
    if (stage === "css" || stage === "js") {
      resourceParts.add(stage);
      if (resourceParts.has("css") && resourceParts.has("js")) completed.add("assets");
    } else if (order.includes(stage)) {
      completed.add(stage);
    } else {
      return;
    }
    update();
  }

  function fail(reason) {
    if (dismissed || failure) return;
    const safeMessage = reason instanceof Error ? reason.message : typeof reason === "string" ? reason : "";
    failure = safeMessage && safeMessage.length < 180 ? `${strings.error}: ${safeMessage}` : strings.errorDetails;
    update();
  }

  document.addEventListener("load", event => {
    if (!(event.target instanceof HTMLLinkElement) || !event.target.matches("link[data-rustpad-shell-css]")) return;
    if (loadedStyleElements.has(event.target)) return;
    loadedStyleElements.add(event.target);
    loadedStyleCount += 1;
    const expected = document.querySelectorAll("link[data-rustpad-shell-css]").length;
    if (expected > 0 && loadedStyleCount >= expected) complete("css");
  }, true);
  document.addEventListener("error", event => {
    if (event.target instanceof HTMLLinkElement && event.target.matches("link[data-rustpad-shell-css]")) {
      fail(strings.errorDetails);
    }
  }, true);
  document.addEventListener("DOMContentLoaded", () => {
    element("app-boot-retry")?.addEventListener("click", () => location.reload());
    update();
  }, { once: true });

  const timeout = setTimeout(() => {
    if (!dismissed) fail(strings.timeout);
  }, 45000);

  window.__RUSTPAD_LOADING__ = Object.freeze({
    complete,
    skip: complete,
    ready() { readyRequested = true; update(); if (dismissed) clearTimeout(timeout); },
    fail,
    stageDone(stage) {
      return stage === "css" || stage === "js" ? resourceParts.has(stage) : completed.has(stage);
    }
  });
})();