(function () {
  const boot = window.MaalFlows || {};
  const apiBase = (boot.apiBase || "").replace(/\/$/, "") || new URL(document.currentScript.src).origin;
  const siteKey = boot.siteKey || "9b-plus";
  const lang = (boot.lang || document.documentElement.lang || navigator.language || "cs").slice(0, 2).toLowerCase();
  const storageKey = `maalflows:${siteKey}`;
  const session = loadSession();
  const allowedImageTypes = new Set(["image/jpeg", "image/png", "image/webp", "image/gif", "image/avif"]);
  const maxAttachmentBytes = 3_000_000;
  let lastActivityAt = Date.now();

  fetch(`${apiBase}/api/widget/config?siteKey=${encodeURIComponent(siteKey)}`)
    .then((res) => res.json())
    .then((config) => mount(config))
    .catch(() => {});

  function mount(config) {
    const site = config.site;
    const settings = site.settings;
    const copy = localized(settings, lang);
    const host = document.createElement("div");
    host.id = "maalflows-widget";
    document.body.append(host);
    const root = host.attachShadow({ mode: "open" });

    root.innerHTML = `
      <style>${styles(settings)}</style>
      <button class="mf-launcher" type="button" aria-label="${copy.title}">
        <span></span>
      </button>
      <section class="mf-panel" aria-live="polite">
        <header>
          <strong>${escapeHtml(copy.title)}</strong>
          <small>${escapeHtml(site.isOnline ? copy.intro : copy.offlineIntro)}</small>
          <button class="mf-close" type="button" aria-label="Close">×</button>
        </header>
        <div class="mf-messages"></div>
        <div class="mf-typing" hidden>Operator pise...</div>
        <form class="mf-form">
          <div class="mf-composer">
            <textarea name="message" rows="3" placeholder="${escapeHtml(copy.placeholder)}"></textarea>
            <button class="mf-send" type="submit" aria-label="${escapeHtml(copy.sendLabel)}" title="${escapeHtml(copy.sendLabel)}">
              <svg viewBox="0 0 24 24" aria-hidden="true">
                <path d="M3.7 20.3 21 12 3.7 3.7l2.5 7.1L14 12l-7.8 1.2-2.5 7.1Z"></path>
              </svg>
            </button>
          </div>
          <label class="mf-dropzone" tabindex="0">
            <input name="attachments" type="file" accept=".jpg,.jpeg,.png,.webp,.gif,.avif,image/jpeg,image/png,image/webp,image/gif,image/avif" multiple>
            <svg viewBox="0 0 24 24" aria-hidden="true">
              <path d="M4 17.5V6.5A2.5 2.5 0 0 1 6.5 4h11A2.5 2.5 0 0 1 20 6.5v11a2.5 2.5 0 0 1-2.5 2.5h-11A2.5 2.5 0 0 1 4 17.5Zm3.3-1.2 2.9-3.4 2 2.4 2.7-3.2 3.1 4.2H7.3Zm1-6.8a1.7 1.7 0 1 0 0-3.4 1.7 1.7 0 0 0 0 3.4Z"></path>
            </svg>
            <span>Pridat fotku nebo pretahnout</span>
          </label>
          <div class="mf-attachment-list"></div>
          <p class="mf-note" hidden></p>
          <a class="mf-powered" href="https://app.black-week.cz" target="_blank" rel="noopener noreferrer">Powered by MaalFlows</a>
        </form>
      </section>
    `;

    const panel = root.querySelector(".mf-panel");
    const launcher = root.querySelector(".mf-launcher");
    const close = root.querySelector(".mf-close");
    const { soundButton, infoButton } = createHeaderActions(root, close);
    const form = root.querySelector(".mf-form");
    const messages = root.querySelector(".mf-messages");
    const typing = root.querySelector(".mf-typing");
    const dropzone = root.querySelector(".mf-dropzone");
    const attachmentList = root.querySelector(".mf-attachment-list");
    let selectedFiles = [];
    renderSoundState(soundButton);

    launcher.addEventListener("click", () => {
      panel.classList.toggle("open");
      if (panel.classList.contains("open")) {
        launcher.classList.remove("mf-notify");
        scrollMessagesToBottom(messages);
      }
    });
    close.addEventListener("click", () => panel.classList.remove("open"));
    soundButton.addEventListener("click", () => {
      session.soundMuted = !session.soundMuted;
      saveSession();
      renderSoundState(soundButton);
    });
    infoButton.addEventListener("click", () => {
      root.querySelector(".mf-gdpr").hidden = !root.querySelector(".mf-gdpr").hidden;
    });

    form.message.addEventListener("input", debounce(() => {
      if (!session.conversationId) return;
      fetch(`${apiBase}/api/widget/conversations/${session.conversationId}/typing`, { method: "POST" }).catch(() => {});
    }, 700));

    form.message.addEventListener("keydown", (event) => {
      if (event.key !== "Enter" || event.shiftKey) return;
      event.preventDefault();
      form.requestSubmit();
    });

    form.attachments.addEventListener("change", () => {
      selectedFiles = mergeImageFiles(selectedFiles, [...form.attachments.files]);
      renderSelectedFiles(attachmentList, selectedFiles);
      form.attachments.value = "";
    });

    dropzone.addEventListener("keydown", (event) => {
      if (event.key === "Enter" || event.key === " ") {
        event.preventDefault();
        form.attachments.click();
      }
    });

    for (const eventName of ["dragenter", "dragover"]) {
      dropzone.addEventListener(eventName, (event) => {
        event.preventDefault();
        dropzone.classList.add("dragging");
      });
    }

    for (const eventName of ["dragleave", "drop"]) {
      dropzone.addEventListener(eventName, (event) => {
        event.preventDefault();
        dropzone.classList.remove("dragging");
      });
    }

    dropzone.addEventListener("drop", (event) => {
      selectedFiles = mergeImageFiles(selectedFiles, [...event.dataTransfer.files]);
      renderSelectedFiles(attachmentList, selectedFiles);
    });

    attachmentList.addEventListener("click", (event) => {
      const removeButton = event.target.closest("[data-remove]");
      if (!removeButton) return;
      selectedFiles.splice(Number(removeButton.dataset.remove), 1);
      renderSelectedFiles(attachmentList, selectedFiles);
    });

    form.addEventListener("submit", async (event) => {
      event.preventDefault();
      const body = await payloadFromForm(form, selectedFiles);
      if (!body.message.trim() && !body.attachments.length) return;
      const submitButton = root.querySelector(".mf-send");
      submitButton.disabled = true;

      const url = session.conversationId
        ? `${apiBase}/api/widget/conversations/${session.conversationId}/messages`
        : `${apiBase}/api/widget/conversations`;
      try {
        const data = await postJson(url, withVisitorContext(body));
        session.conversationId = data.conversation.id;
        saveSession();
        form.message.value = "";
        selectedFiles = [];
        renderSelectedFiles(attachmentList, selectedFiles);
        renderConversation(messages, data);
        connectEvents(messages, typing, panel, launcher, settings);
      } catch {
        showFormError(root, "Zpravu se nepodarilo odeslat. Zkuste to prosim znovu.");
      } finally {
        submitButton.disabled = false;
      }
    });

    rememberPage();
    trackVisitorActivity(root);
    pingVisitor();
    setInterval(pingVisitor, 25_000);
    document.addEventListener("visibilitychange", () => {
      if (!document.hidden) {
        noteActivity();
        pingVisitor();
      }
    });
    if (session.conversationId) {
      loadExistingConversation(messages).finally(() => connectEvents(messages, typing, panel, launcher, settings));
    }
  }

  async function payloadFromForm(form, selectedFiles) {
    const fd = new FormData(form);
    return {
      message: fd.get("message") || "",
      attachments: await Promise.all(selectedFiles.slice(0, 3).map(fileToPayload))
    };
  }

  function connectEvents(messages, typing, panel, launcher, settings) {
    if (session.events || !session.conversationId) return;
    session.events = new EventSource(`${apiBase}/api/widget/conversations/${session.conversationId}/events`);
    session.events.addEventListener("message", (event) => {
      const data = JSON.parse(event.data);
      if (data.type === "typing" && data.actor === "admin") {
        typing.hidden = false;
        clearTimeout(connectEvents.typingTimer);
        connectEvents.typingTimer = setTimeout(() => { typing.hidden = true; }, 1800);
      }
      if (data.type === "message:new") {
        renderConversation(messages, data.payload);
        const eventMessages = data.payload?.messages || [];
        const lastMessage = eventMessages[eventMessages.length - 1];
        if (settings.notifications?.pulseOnAdminReply !== false && lastMessage?.senderType === "admin" && !panel.classList.contains("open")) {
          launcher.classList.add("mf-notify");
          playNotifySound();
        }
      }
    });
  }

  function createHeaderActions(root, closeButton) {
    const actions = document.createElement("div");
    actions.className = "mf-header-actions";
    const soundButton = document.createElement("button");
    soundButton.className = "mf-sound";
    soundButton.type = "button";
    soundButton.innerHTML = `
      <svg class="mf-sound-on" viewBox="0 0 24 24" aria-hidden="true">
        <path d="M4 9v6h4l5 4V5L8 9H4Zm12.2-1.8-1.4 1.4A4.9 4.9 0 0 1 16 12c0 1.3-.5 2.5-1.2 3.4l1.4 1.4A6.9 6.9 0 0 0 18 12c0-1.8-.7-3.5-1.8-4.8Zm2.6-2.6-1.4 1.4A8.8 8.8 0 0 1 20 12a8.8 8.8 0 0 1-2.6 6l1.4 1.4A10.8 10.8 0 0 0 22 12c0-2.9-1.2-5.5-3.2-7.4Z"></path>
      </svg>
      <svg class="mf-sound-off" viewBox="0 0 24 24" aria-hidden="true">
        <path d="M4 9v6h4l5 4V5L8 9H4Zm12.4 3 2.3-2.3-1.4-1.4-2.3 2.3-2.3-2.3-1.4 1.4 2.3 2.3-2.3 2.3 1.4 1.4 2.3-2.3 2.3 2.3 1.4-1.4-2.3-2.3Z"></path>
      </svg>
    `;
    const infoButton = document.createElement("button");
    infoButton.className = "mf-info";
    infoButton.type = "button";
    infoButton.setAttribute("aria-label", "GDPR informace");
    infoButton.title = "GDPR informace";
    infoButton.innerHTML = `<svg viewBox="0 0 24 24" aria-hidden="true"><path d="M11 10h2v7h-2v-7Zm0-3h2v2h-2V7Zm1-5a10 10 0 1 0 0 20 10 10 0 0 0 0-20Zm0 18a8 8 0 1 1 0-16 8 8 0 0 1 0 16Z"></path></svg>`;
    closeButton.innerHTML = `<svg viewBox="0 0 24 24" aria-hidden="true"><path d="M6.7 8.7 12 14l5.3-5.3 1.4 1.4L12 16.8l-6.7-6.7 1.4-1.4Z"></path></svg>`;
    closeButton.setAttribute("aria-label", "Zmensit chat");
    closeButton.title = "Zmensit chat";
    closeButton.before(actions);
    actions.append(soundButton, infoButton, closeButton);
    const gdpr = document.createElement("p");
    gdpr.className = "mf-gdpr";
    gdpr.hidden = true;
    gdpr.textContent = "Odeslanim zpravy nam predavate udaje potrebne pro odpoved. Historii chatu uchovavame pro zakaznickou podporu.";
    root.querySelector(".mf-form").prepend(gdpr);
    return { soundButton, infoButton };
  }

  function renderSoundState(button) {
    button.classList.toggle("muted", Boolean(session.soundMuted));
    button.setAttribute("aria-label", session.soundMuted ? "Zapnout zvuk" : "Vypnout zvuk");
    button.title = session.soundMuted ? "Zapnout zvuk" : "Vypnout zvuk";
  }

  function playNotifySound() {
    if (session.soundMuted) return;
    const AudioCtor = window.AudioContext || window.webkitAudioContext;
    if (!AudioCtor) return;
    const audio = new AudioCtor();
    const gain = audio.createGain();
    gain.gain.value = 0.04;
    gain.connect(audio.destination);
    [0, 0.12].forEach((offset, index) => {
      const osc = audio.createOscillator();
      osc.type = "sine";
      osc.frequency.value = index ? 980 : 760;
      osc.connect(gain);
      osc.start(audio.currentTime + offset);
      osc.stop(audio.currentTime + offset + 0.09);
    });
    setTimeout(() => audio.close().catch(() => {}), 420);
  }

  async function loadExistingConversation(messages) {
    try {
      const data = await fetchJson(`${apiBase}/api/widget/conversations/${session.conversationId}?visitorToken=${encodeURIComponent(session.visitorToken)}`);
      renderConversation(messages, data);
    } catch {
      session.conversationId = null;
      saveSession();
    }
  }

  function renderConversation(messages, data) {
    messages.innerHTML = "";
    let lastAdminName = null;
    for (const message of data.messages) {
      addMessage(messages, message.senderType, message.senderName, message.body, message.attachments || [], lastAdminName);
      if (message.senderType === "admin") lastAdminName = message.senderName || "Operator";
      else lastAdminName = null;
    }
    scrollMessagesToBottom(messages);
  }

  function addMessage(messages, sender, senderName, body, attachments, lastAdminName) {
    if (sender === "admin" && (senderName || "Operator") !== lastAdminName) {
      const label = document.createElement("div");
      label.className = "mf-operator-label";
      label.textContent = `${senderName || "Operator"} odpovida`;
      messages.append(label);
    }
    const item = document.createElement("article");
    item.className = `mf-message ${sender}`;
    item.innerHTML = `${body ? `<p>${escapeHtml(body)}</p>` : ""}${attachments.map((a) => `<a class="mf-photo" href="${apiBase}${a.url}" target="_blank" rel="noreferrer"><img src="${apiBase}${a.url}" alt="${escapeHtml(a.name)}"></a>`).join("")}`;
    messages.append(item);
    for (const image of item.querySelectorAll("img")) {
      image.addEventListener("load", () => scrollMessagesToBottom(messages), { once: true });
      image.addEventListener("error", () => scrollMessagesToBottom(messages), { once: true });
    }
    scrollMessagesToBottom(messages);
  }

  function scrollMessagesToBottom(messages) {
    const scroll = () => {
      messages.scrollTop = messages.scrollHeight;
      messages.lastElementChild?.scrollIntoView({ block: "end" });
    };
    scroll();
    requestAnimationFrame(scroll);
    setTimeout(scroll, 80);
    setTimeout(scroll, 240);
  }

  function mergeImageFiles(currentFiles, incomingFiles) {
    const nextFiles = [...currentFiles];
    for (const file of incomingFiles) {
      if (!isAllowedImageFile(file)) continue;
      const exists = nextFiles.some((item) => item.name === file.name && item.size === file.size && item.lastModified === file.lastModified);
      if (!exists) nextFiles.push(file);
      if (nextFiles.length === 3) break;
    }
    return nextFiles;
  }

  function renderSelectedFiles(container, files) {
    container.innerHTML = files.map((file, index) => `
      <span class="mf-attachment-chip">
        <span>${escapeHtml(file.name)}</span>
        <button type="button" data-remove="${index}" aria-label="Odebrat fotku">×</button>
      </span>
    `).join("");
  }

  function withVisitorContext(body) {
    return {
      ...body,
      siteKey,
      visitorToken: session.visitorToken,
      currentUrl: location.href,
      referrer: document.referrer,
      browsingHistory: rememberPage(),
      lastActivityAt: new Date(lastActivityAt).toISOString(),
      language: navigator.language,
      timezone: Intl.DateTimeFormat().resolvedOptions().timeZone,
      device: {
        userAgent: navigator.userAgent,
        platform: navigator.platform,
        viewport: `${innerWidth}x${innerHeight}`
      }
    };
  }

  function pingVisitor() {
    postJson(`${apiBase}/api/widget/visitors/ping`, withVisitorContext({})).catch(() => {});
  }

  function trackVisitorActivity(root) {
    const passive = { passive: true, capture: true };
    for (const eventName of ["pointerdown", "keydown", "mousemove", "touchstart", "scroll"]) {
      document.addEventListener(eventName, noteActivity, passive);
      root.addEventListener(eventName, noteActivity, passive);
    }
  }

  function noteActivity() {
    const now = Date.now();
    if (now - lastActivityAt < 1_000) return;
    lastActivityAt = now;
  }

  function showFormError(root, message) {
    const note = root.querySelector(".mf-note");
    note.textContent = message;
    note.hidden = false;
    note.classList.add("error");
    clearTimeout(showFormError.timer);
    showFormError.timer = setTimeout(() => {
      note.textContent = "";
      note.hidden = true;
      note.classList.remove("error");
    }, 3500);
  }

  function isAllowedImageFile(file) {
    return allowedImageTypes.has(file.type) && file.size > 0 && file.size <= maxAttachmentBytes;
  }

  function localized(settings, language) {
    const pick = (obj) => obj?.[language] || obj?.en || obj?.cs || "";
    return {
      title: pick(settings.title),
      intro: pick(settings.intro),
      offlineIntro: pick(settings.offlineIntro),
      placeholder: pick(settings.placeholder),
      sendLabel: pick(settings.sendLabel)
    };
  }

  function styles(settings) {
    const c = settings.colors;
    const desktop = settings.desktop;
    const mobile = settings.mobile;
    return `
      :host { all: initial; font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; color: ${c.text}; }
      * { box-sizing: border-box; }
      button, input, textarea { font: inherit; }
      .mf-launcher {
        position: fixed; z-index: 2147483000; ${desktop.side}: ${desktop.sideOffsetPx}px; bottom: ${desktop.bottomPx}px;
        width: 58px; height: 58px; border: 0; border-radius: 50%; background: ${c.brand}; color: ${c.brandText};
        box-shadow: 0 12px 30px rgb(0 0 0 / 22%); cursor: pointer;
      }
      .mf-launcher span, .mf-launcher span:before, .mf-launcher span:after { display: block; background: ${c.brandText}; height: 3px; border-radius: 4px; content: ""; }
      .mf-launcher span { width: 26px; margin: 0 auto; }
      .mf-launcher span:before { transform: translateY(-8px); }
      .mf-launcher span:after { transform: translateY(5px); width: 18px; }
      .mf-launcher.mf-notify { animation: mfPulse 1.15s ease-out infinite; }
      .mf-panel {
        position: fixed; z-index: 2147483001; ${desktop.side}: ${desktop.sideOffsetPx}px; bottom: ${desktop.bottomPx + 72}px;
        width: min(${desktop.widthPx}px, calc(100vw - 24px)); max-height: min(680px, calc(100vh - 110px)); display: none;
        background: ${c.surface}; border: 1px solid #dfe6e2; border-radius: 8px; overflow: hidden; box-shadow: 0 18px 50px rgb(0 0 0 / 18%);
      }
      .mf-panel.open { display: grid; grid-template-rows: auto minmax(130px, 1fr) auto auto; }
      header { position: relative; display: grid; gap: 3px; background: ${c.brand}; color: ${c.brandText}; padding: 15px 122px 15px 16px; }
      header strong { font-size: 16px; }
      header small { opacity: .92; font-size: 13px; line-height: 1.35; }
      .mf-header-actions { position: absolute; top: 9px; right: 9px; display: flex; gap: 6px; }
      .mf-close, .mf-sound, .mf-info { width: 30px; height: 30px; display: grid; place-items: center; border: 0; border-radius: 6px; background: rgb(255 255 255 / 16%); color: ${c.brandText}; cursor: pointer; padding: 0; }
      .mf-close svg, .mf-sound svg, .mf-info svg { width: 19px; height: 19px; fill: currentColor; }
      .mf-sound .mf-sound-off { display: none; }
      .mf-sound.muted .mf-sound-on { display: none; }
      .mf-sound.muted .mf-sound-off { display: block; }
      .mf-messages { padding: 14px; overflow: auto; display: flex; flex-direction: column; gap: 10px; }
      .mf-message { max-width: 86%; padding: 9px 11px; border-radius: 8px; background: #f1f5f2; color: ${c.text}; }
      .mf-message.admin { align-self: flex-start; background: #eef7f4; }
      .mf-message.visitor { align-self: flex-end; background: ${c.brand}; color: ${c.brandText}; }
      .mf-operator-label { align-self: flex-start; margin: 4px 0 -4px; color: ${c.muted}; font-size: 12px; font-weight: 700; }
      .mf-message p { margin: 0; white-space: pre-wrap; }
      .mf-message a { color: inherit; display: inline-block; margin-top: 6px; }
      .mf-photo img { display: block; width: min(180px, 100%); max-height: 130px; object-fit: cover; border-radius: 6px; }
      .mf-typing { padding: 0 14px 8px; color: ${c.muted}; font-size: 13px; }
      .mf-form { border-top: 1px solid #dfe6e2; padding: 12px; display: grid; gap: 9px; }
      .mf-composer { display: grid; grid-template-columns: minmax(0, 1fr) 48px; gap: 9px; align-items: stretch; }
      input, textarea { width: 100%; border: 1px solid #dfe6e2; border-radius: 6px; padding: 9px 10px; color: ${c.text}; background: white; }
      textarea { resize: vertical; min-height: 72px; }
      .mf-send { width: 48px; min-height: 72px; height: 100%; display: grid; place-items: center; border: 0; border-radius: 6px; background: ${c.brand}; color: ${c.brandText}; cursor: pointer; }
      .mf-send:disabled { opacity: .55; cursor: wait; }
      .mf-send svg { width: 22px; height: 22px; fill: currentColor; transform: translateX(1px); }
      .mf-dropzone { min-height: 64px; border: 1px dashed #b9c9c1; border-radius: 8px; display: flex; align-items: center; justify-content: center; gap: 8px; padding: 13px 12px; color: ${c.muted}; background: #f8fbf9; font-size: 12px; cursor: pointer; text-align: center; }
      .mf-dropzone.dragging { border-color: ${c.brand}; background: #eef8f4; color: ${c.text}; }
      .mf-dropzone input { display: none; }
      .mf-dropzone svg { width: 18px; height: 18px; fill: currentColor; flex: 0 0 auto; }
      .mf-attachment-list { display: flex; flex-wrap: wrap; gap: 6px; }
      .mf-attachment-chip { max-width: 100%; display: inline-flex; align-items: center; gap: 6px; border: 1px solid #dfe6e2; border-radius: 999px; background: #f8fbf9; color: ${c.text}; padding: 5px 5px 5px 9px; font-size: 12px; }
      .mf-attachment-chip span { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; max-width: 210px; }
      .mf-attachment-chip button { width: 22px; height: 22px; border: 0; border-radius: 50%; background: #e8eee9; color: ${c.text}; cursor: pointer; padding: 0; }
      .mf-note { margin: 0; color: ${c.muted}; font-size: 11px; line-height: 1.3; }
      .mf-note.error { color: #b42318; }
      .mf-gdpr { margin: 0; padding: 9px 10px; border: 1px solid #dfe6e2; border-radius: 8px; background: #f8fbf9; color: ${c.muted}; font-size: 11px; line-height: 1.35; }
      .mf-powered { justify-self: center; color: ${c.muted}; font-size: 11px; text-decoration: none; }
      .mf-powered:hover { color: ${c.brand}; text-decoration: underline; }
      @keyframes mfPulse {
        0% { box-shadow: 0 12px 30px rgb(0 0 0 / 22%), 0 0 0 0 rgb(15 143 111 / 42%); transform: scale(1); }
        70% { box-shadow: 0 12px 30px rgb(0 0 0 / 22%), 0 0 0 14px rgb(15 143 111 / 0%); transform: scale(1.04); }
        100% { box-shadow: 0 12px 30px rgb(0 0 0 / 22%), 0 0 0 0 rgb(15 143 111 / 0%); transform: scale(1); }
      }
      @media (max-width: 640px) {
        .mf-launcher { ${mobile.side}: ${mobile.sideOffsetPx}px; bottom: ${mobile.bottomPx}px; }
        .mf-panel { ${mobile.side}: ${mobile.sideOffsetPx}px; bottom: ${mobile.bottomPx + 68}px; width: min(${mobile.widthPx}px, calc(100vw - 24px)); max-height: calc(100vh - 96px); }
      }
    `;
  }

  function rememberPage() {
    const entry = { url: location.href, title: document.title, at: new Date().toISOString() };
    session.history = (session.history || []).filter((item) => item.url !== entry.url).concat(entry).slice(-20);
    saveSession();
    return session.history;
  }

  function loadSession() {
    try {
      const existing = JSON.parse(localStorage.getItem(storageKey) || "{}");
      return { visitorToken: existing.visitorToken || randomId(), conversationId: existing.conversationId || null, history: existing.history || [], soundMuted: Boolean(existing.soundMuted) };
    } catch {
      return { visitorToken: randomId(), conversationId: null, history: [], soundMuted: false };
    }
  }

  function saveSession() {
    localStorage.setItem(storageKey, JSON.stringify({
      visitorToken: session.visitorToken,
      conversationId: session.conversationId,
      history: session.history || [],
      soundMuted: Boolean(session.soundMuted)
    }));
  }

  function postJson(url, payload) {
    return fetch(url, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(payload)
    }).then((res) => {
      if (!res.ok) throw new Error(`HTTP ${res.status}`);
      return res.json();
    });
  }

  function fetchJson(url) {
    return fetch(url).then((res) => {
      if (!res.ok) throw new Error(`HTTP ${res.status}`);
      return res.json();
    });
  }

  function fileToPayload(file) {
    return new Promise((resolve) => {
      const reader = new FileReader();
      reader.onload = () => resolve({ name: file.name, type: file.type, size: file.size, dataBase64: reader.result });
      reader.readAsDataURL(file);
    });
  }

  function debounce(fn, delay) {
    let timer;
    return (...args) => {
      clearTimeout(timer);
      timer = setTimeout(() => fn(...args), delay);
    };
  }

  function escapeHtml(value) {
    return String(value ?? "").replace(/[&<>"']/g, (char) => ({
      "&": "&amp;",
      "<": "&lt;",
      ">": "&gt;",
      '"': "&quot;",
      "'": "&#039;"
    })[char]);
  }

  function randomId() {
    return `vis_${Math.random().toString(16).slice(2)}${Date.now().toString(16)}`;
  }
})();