/*
 * 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.
 */

let hideTimer;

function toastElement(selector = "#toast") {
  return document.querySelector(selector);
}

function show(element, duration = null) {
  element.classList.add("visible");
  clearTimeout(hideTimer);
  if (duration != null) hideTimer = setTimeout(() => element.classList.remove("visible"), duration);
}

function reset(element) {
  element.className = "toast";
  element.removeAttribute("aria-busy");
  element.removeAttribute("aria-label");
}

function formatBytes(value) {
  const bytes = Math.max(0, Number(value) || 0);
  if (bytes < 1024) return `${Math.round(bytes)} B`;
  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(bytes >= 10240 ? 0 : 1)} KB`;
  if (bytes < 1024 * 1024 * 1024) return `${(bytes / (1024 * 1024)).toFixed(bytes >= 10 * 1024 * 1024 ? 1 : 2)} MB`;
  return `${(bytes / (1024 * 1024 * 1024)).toFixed(2)} GB`;
}

export function toast(message, options = {}) {
  const element = toastElement(options.selector);
  if (!element) return;
  reset(element);
  element.textContent = String(message ?? "");
  show(element, options.duration ?? 1800);
}

export function createUploadToast(filename, options = {}) {
  const element = toastElement(options.selector);
  if (!element) {
    return { start() { }, update() { }, fail() { }, success() { }, dismiss() { } };
  }

  reset(element);
  element.classList.add("toast--upload", "toast--interactive");
  element.setAttribute("aria-live", "polite");
  element.innerHTML = `
    <div class="upload-toast__header">
      <div class="upload-toast__heading">
        <strong class="upload-toast__title">Uploading file</strong>
        <span class="upload-toast__filename"></span>
      </div>
    </div>
    <div class="upload-toast__progress" role="progressbar" aria-label="File upload progress" aria-valuemin="0" aria-valuemax="100" aria-valuenow="0"><span></span></div>
    <div class="upload-toast__meta"><span data-upload-amount>Preparing…</span><span data-upload-speed>—</span></div>
    <p class="upload-toast__error" data-upload-error hidden></p>
    <div class="upload-toast__actions" data-upload-actions hidden>
      <button type="button" class="upload-toast__retry">Retry</button>
      <button type="button" class="upload-toast__dismiss">Dismiss</button>
    </div>`;

  const title = element.querySelector(".upload-toast__title");
  const filenameElement = element.querySelector(".upload-toast__filename");
  const progress = element.querySelector(".upload-toast__progress");
  const progressFill = progress.querySelector("span");
  const amount = element.querySelector("[data-upload-amount]");
  const speedElement = element.querySelector("[data-upload-speed]");
  const errorElement = element.querySelector("[data-upload-error]");
  const actions = element.querySelector("[data-upload-actions]");
  const retryButton = element.querySelector(".upload-toast__retry");
  const dismissButton = element.querySelector(".upload-toast__dismiss");
  let retryHandler = null;

  filenameElement.textContent = String(filename || "file");

  function dismiss() {
    clearTimeout(hideTimer);
    element.classList.remove("visible");
  }

  function start() {
    reset(element);
    element.classList.add("toast--upload", "toast--interactive", "visible");
    element.setAttribute("aria-live", "polite");
    element.setAttribute("aria-busy", "true");
    title.textContent = "Uploading file";
    filenameElement.textContent = String(filename || "file");
    progress.classList.remove("is-error", "is-complete");
    progress.setAttribute("aria-valuenow", "0");
    progressFill.style.width = "0%";
    amount.textContent = "Preparing…";
    speedElement.textContent = "—";
    errorElement.hidden = true;
    errorElement.textContent = "";
    actions.hidden = true;
    retryButton.disabled = false;
    clearTimeout(hideTimer);
  }

  function update({ loaded = 0, total = 0, speed = 0, percent = null, phase = "uploading" } = {}) {
    const normalizedPercent = Number.isFinite(percent)
      ? Math.max(0, Math.min(100, percent))
      : total > 0 ? Math.max(0, Math.min(100, (loaded / total) * 100)) : null;
    if (normalizedPercent != null) {
      progress.setAttribute("aria-valuenow", String(Math.round(normalizedPercent)));
      progressFill.style.width = `${normalizedPercent}%`;
    } else {
      progress.removeAttribute("aria-valuenow");
      progressFill.style.width = "24%";
      progress.classList.add("is-indeterminate");
    }
    amount.textContent = total > 0
      ? `${Math.round(normalizedPercent || 0)}% · ${formatBytes(loaded)} / ${formatBytes(total)}`
      : formatBytes(loaded);
    speedElement.textContent = phase === "processing" ? "Processing…" : speed > 0 ? `${formatBytes(speed)}/s` : "Starting…";
  }

  function fail(message, { retryable = true, onRetry = null } = {}) {
    element.removeAttribute("aria-busy");
    title.textContent = "Upload failed";
    progress.classList.remove("is-indeterminate", "is-complete");
    progress.classList.add("is-error");
    errorElement.textContent = String(message || "Upload failed.");
    errorElement.hidden = false;
    actions.hidden = false;
    retryButton.hidden = !retryable;
    retryHandler = typeof onRetry === "function" ? onRetry : null;
    show(element);
  }

  function success(message = "File uploaded") {
    element.removeAttribute("aria-busy");
    title.textContent = message;
    progress.classList.remove("is-error", "is-indeterminate");
    progress.classList.add("is-complete");
    progress.setAttribute("aria-valuenow", "100");
    progressFill.style.width = "100%";
    amount.textContent = "100%";
    speedElement.textContent = "Complete";
    errorElement.hidden = true;
    actions.hidden = true;
    show(element, 1800);
  }

  retryButton.addEventListener("click", async () => {
    if (!retryHandler) return;
    retryButton.disabled = true;
    await retryHandler();
  });
  dismissButton.addEventListener("click", dismiss);

  start();
  return { start, update, fail, success, dismiss };
}