(function () {
  const form = document.querySelector("#upload-form");
  const dropZone = document.querySelector(".drop-zone");
  const fileInput = document.querySelector("#file-input");
  const fileSummary = document.querySelector("#file-summary");
  const progress = document.querySelector("#upload-progress");
  const uploadStatus = document.querySelector("#upload-status");
  const result = document.querySelector("#upload-result");
  const resultMeta = document.querySelector("#result-meta");
  const resultList = document.querySelector("#result-list");
  const uploadQueue = document.querySelector("#upload-queue");
  const totalProgressBar = document.querySelector("#total-progress-bar");
  const copyURL = document.querySelector("#copy-url");
  const openBox = document.querySelector("#open-box");
  const manageLink = document.querySelector("#manage-link");
  const RESUMABLE_SESSIONS_KEY = "warpbox-resumable-sessions";

  if (!form || !dropZone || !fileInput) {
    return;
  }

  // Remember the last-chosen expiry across uploads (per browser).
  const expirySelect = form.querySelector("[data-expiry-select]");
  if (expirySelect) {
    const EXPIRY_KEY = "warpbox-expiry";
    let saved = null;
    try {
      saved = localStorage.getItem(EXPIRY_KEY);
    } catch (e) {
      saved = null;
    }
    if (saved && expirySelect.querySelector('option[value="' + saved + '"]')) {
      expirySelect.value = saved;
    }
    expirySelect.addEventListener("change", () => {
      try {
        localStorage.setItem(EXPIRY_KEY, expirySelect.value);
      } catch (e) {
        /* ignore persistence failures */
      }
    });
  }

  let latestBoxURL = "";
  let selectedFiles = [];
  let uploadLocked = false;

  ["dragenter", "dragover"].forEach((eventName) => {
    dropZone.addEventListener(eventName, (event) => {
      event.preventDefault();
      dropZone.classList.add("is-dragging");
    });
  });

  ["dragleave", "drop"].forEach((eventName) => {
    dropZone.addEventListener(eventName, (event) => {
      event.preventDefault();
      dropZone.classList.remove("is-dragging");
    });
  });

  document.addEventListener("dragover", (event) => {
    if (event.dataTransfer && Array.from(event.dataTransfer.types || []).includes("Files")) {
      event.preventDefault();
    }
  });

  document.addEventListener("drop", (event) => {
    if (!event.dataTransfer || !event.dataTransfer.files.length) {
      return;
    }
    event.preventDefault();
    if (!dropZone.contains(event.target)) {
      addSelectedFiles(event.dataTransfer.files);
    }
  });

  dropZone.addEventListener("drop", (event) => {
    if (event.dataTransfer && event.dataTransfer.files.length > 0) {
      addSelectedFiles(event.dataTransfer.files);
    }
  });

  fileInput.addEventListener("change", () => {
    addSelectedFiles(fileInput.files);
    fileInput.value = "";
  });

  form.addEventListener("submit", async (event) => {
    event.preventDefault();
    if (selectedFiles.length === 0) {
      updateStatus("Choose at least one file first.");
      return;
    }

    const submit = form.querySelector("button[type='submit']");
    const formData = uploadFormData();
    renderQueue(selectedFiles, "queued");
    setLoading(true, submit);

    try {
      const payload = await uploadResumable(form.action, formData, selectedFiles);
      renderResult(payload);
      form.reset();
      selectedFiles = [];
      fileInput.value = "";
      updateSelectedState();
    } catch (error) {
      updateStatus(error.message || "Upload failed");
    } finally {
      setLoading(false, submit);
    }
  });

  if (copyURL) {
    copyURL.addEventListener("click", () => {
      window.Warpbox.copyText(latestBoxURL, copyURL, "Copied");
    });
  }

  function addSelectedFiles(files) {
    if (uploadLocked) {
      return;
    }
    Array.from(files || []).forEach((file) => {
      if (!selectedFiles.some((existing) => fileIdentity(existing) === fileIdentity(file))) {
        selectedFiles.push(file);
      }
    });
    updateSelectedState();
  }

  function removeSelectedFile(index) {
    if (uploadLocked) {
      return;
    }
    selectedFiles.splice(index, 1);
    updateSelectedState();
  }

  function updateSelectedState() {
    const count = selectedFiles.length || 0;
    const title = dropZone.querySelector(".drop-title");
    if (title) {
      title.textContent = count === 0 ? "Drop files to upload" : count === 1 ? "1 file selected" : `${count} files selected`;
    }
    if (fileSummary) {
      fileSummary.textContent = count === 0 ? "Choose one or more files to begin." : `${count} file${count === 1 ? "" : "s"} ready.`;
    }
    if (count > 0) {
      renderQueue(selectedFiles, "queued");
    } else if (uploadQueue) {
      uploadQueue.hidden = true;
      uploadQueue.replaceChildren();
    }
  }

  function setLoading(isLoading, submit) {
    uploadLocked = isLoading;
    if (progress) {
      progress.hidden = !isLoading;
    }
    if (submit) {
      submit.disabled = isLoading;
      submit.textContent = isLoading ? "Uploading..." : "Upload files";
    }
    updateStatus(isLoading ? "Transferring files..." : "");
    setTotalProgress(isLoading ? 0 : 100);
  }

  function updateStatus(message) {
    if (uploadStatus) {
      uploadStatus.textContent = message;
    }
  }

  function renderResult(payload) {
    if (!result || !resultList || !resultMeta || !openBox) {
      return;
    }

    latestBoxURL = payload.boxUrl;
    result.hidden = false;
    openBox.href = payload.boxUrl;
    resultMeta.textContent = `${payload.files.length} file${payload.files.length === 1 ? "" : "s"} · expires ${window.Warpbox.formatDate(payload.expiresAt)}`;
    if (manageLink) {
      const anchor = manageLink.querySelector("a");
      manageLink.hidden = !payload.manageUrl;
      if (anchor && payload.manageUrl) {
        anchor.href = payload.manageUrl;
      }
    }

    resultList.replaceChildren();
    payload.files.forEach((file) => {
      resultList.append(createFileRow({
        name: file.name,
        meta: `${file.size} · ${file.url}`,
        progress: 100,
        status: "complete",
      }));
    });
  }

  function uploadWithProgress(url, formData, files) {
    return new Promise((resolve, reject) => {
      const request = new XMLHttpRequest();
      request.open("POST", url);
      request.setRequestHeader("Accept", "application/json");

      request.upload.addEventListener("progress", (event) => {
        if (!event.lengthComputable) {
          updateStatus("Uploading...");
          return;
        }
        const percent = Math.round((event.loaded / event.total) * 100);
        updateStatus(`${percent}%`);
        setTotalProgress(percent);
        setFileProgress(files, percent);
      });

      request.addEventListener("load", () => {
        let payload = {};
        try {
          payload = JSON.parse(request.responseText || "{}");
        } catch (error) {
          reject(new Error("Upload response could not be read"));
          return;
        }
        if (request.status < 200 || request.status >= 300) {
          reject(new Error(payload.error || "Upload failed"));
          return;
        }
        setTotalProgress(100);
        setFileProgress(files, 100);
        resolve(payload);
      });

      request.addEventListener("error", () => reject(new Error("Network error during upload")));
      request.addEventListener("abort", () => reject(new Error("Upload aborted")));
      request.send(formData);
    });
  }

  async function uploadResumable(fallbackUrl, formData, files) {
    if (!window.fetch || typeof Blob === "undefined") {
      return uploadWithProgress(fallbackUrl, formData, files);
    }

    updateStatus("Fingerprinting files...");
    const fingerprints = await Promise.all(files.map((file) => fileFingerprint(file)));
    const createPayload = {
      files: files.map((file, index) => ({
        name: file.name,
        size: file.size,
        contentType: file.type || "application/octet-stream",
        fingerprint: fingerprints[index],
      })),
      expiresMinutes: parseInt(formData.get("expires_minutes") || "0", 10) || 0,
      maxDownloads: parseInt(formData.get("max_downloads") || "0", 10) || 0,
      password: formData.get("password") || "",
      obfuscateMetadata: formData.get("obfuscate_metadata") === "on",
      collectionId: formData.get("collection_id") || "",
    };
    const persistable = !createPayload.password;
    let session = persistable ? await findResumableSession(createPayload) : null;
    if (session) {
      session = await addMissingResumableFiles(session, createPayload);
    }
    if (!session || session.status !== "uploading") {
      try {
        session = await createResumableSession(createPayload);
      } catch (error) {
        if ((error.message || "").toLowerCase().includes("resumable uploads are disabled")) {
          return uploadWithProgress(fallbackUrl, formData, files);
        }
        throw error;
      }
      if (persistable) {
        saveResumableSession(session, createPayload);
      }
    }
    const sessionFiles = files.map((file, index) => matchSessionFile(session, createPayload.files[index]));
    if (sessionFiles.some((file) => !file)) {
      throw new Error("Upload session could not match the selected files");
    }

    updateStatus("Uploading...");
    const totalBytes = files.reduce((sum, file) => sum + file.size, 0);
    const completedByFile = new Array(files.length).fill(0);
    sessionFiles.forEach((sessionFile, index) => {
      completedByFile[index] = uploadedBytesForSessionFile(sessionFile, session.chunkSize);
      setSingleFileProgress(index, files[index], percentForBytes(completedByFile[index], files[index].size));
    });
    setTotalProgress(percentForBytes(completedByFile.reduce((sum, bytes) => sum + bytes, 0), totalBytes));

    for (let fileIndex = 0; fileIndex < files.length; fileIndex++) {
      const file = files[fileIndex];
      const sessionFile = sessionFiles[fileIndex];
      const uploaded = new Set(sessionFile.uploadedChunks || []);
      for (let chunkIndex = 0; chunkIndex < sessionFile.chunkCount; chunkIndex++) {
        if (uploaded.has(chunkIndex)) {
          continue;
        }
        const start = chunkIndex * session.chunkSize;
        const end = Math.min(file.size, start + session.chunkSize);
        await uploadChunk(session.sessionId, sessionFile.id, chunkIndex, file.slice(start, end), (loaded) => {
          const currentTotal = completedByFile.reduce((sum, bytes) => sum + bytes, 0) + loaded;
          setTotalProgress(percentForBytes(currentTotal, totalBytes));
          setSingleFileProgress(fileIndex, file, percentForBytes(completedByFile[fileIndex] + loaded, file.size));
          updateStatus(`${percentForBytes(currentTotal, totalBytes)}%`);
        });
        completedByFile[fileIndex] += end - start;
        uploaded.add(chunkIndex);
        sessionFile.uploadedChunks = Array.from(uploaded).sort((a, b) => a - b);
        if (persistable) {
          saveResumableSession(session, createPayload);
        }
      }
      setSingleFileProgress(fileIndex, file, 100);
    }

    const resultPayload = await completeResumableSession(session.sessionId);
    if (persistable) {
      removeResumableSession(session.sessionId);
    }
    setTotalProgress(100);
    setFileProgress(files, 100);
    return resultPayload;
  }

  async function createResumableSession(payload) {
    const response = await fetch("/api/v1/uploads/resumable", {
      method: "POST",
      headers: {
        "Accept": "application/json",
        "Content-Type": "application/json",
      },
      body: JSON.stringify(payload),
    });
    return readUploadJSON(response, "Upload session could not be created");
  }

  async function fetchResumableStatus(sessionID) {
    const response = await fetch(`/api/v1/uploads/resumable/${encodeURIComponent(sessionID)}`, {
      headers: { "Accept": "application/json" },
    });
    return readUploadJSON(response, "Upload session could not be resumed");
  }

  async function addResumableFiles(sessionID, files) {
    const response = await fetch(`/api/v1/uploads/resumable/${encodeURIComponent(sessionID)}/files`, {
      method: "POST",
      headers: {
        "Accept": "application/json",
        "Content-Type": "application/json",
      },
      body: JSON.stringify({ files }),
    });
    return readUploadJSON(response, "Upload session files could not be added");
  }

  function uploadChunk(sessionID, fileID, chunkIndex, chunk, onProgress) {
    return new Promise((resolve, reject) => {
      const request = new XMLHttpRequest();
      request.open("PUT", `/api/v1/uploads/resumable/${encodeURIComponent(sessionID)}/files/${encodeURIComponent(fileID)}/chunks/${chunkIndex}`);
      request.setRequestHeader("Accept", "application/json");
      request.upload.addEventListener("progress", (event) => {
        if (event.lengthComputable && onProgress) {
          onProgress(event.loaded);
        }
      });
      request.addEventListener("load", () => {
        if (request.status < 200 || request.status >= 300) {
          let payload = {};
          try {
            payload = JSON.parse(request.responseText || "{}");
          } catch (error) {
            payload = {};
          }
          reject(new Error(payload.error || "Chunk upload failed"));
          return;
        }
        resolve();
      });
      request.addEventListener("error", () => reject(new Error("Network error during chunk upload")));
      request.addEventListener("abort", () => reject(new Error("Chunk upload aborted")));
      request.send(chunk);
    });
  }

  async function completeResumableSession(sessionID) {
    const response = await fetch(`/api/v1/uploads/resumable/${encodeURIComponent(sessionID)}/complete`, {
      method: "POST",
      headers: { "Accept": "application/json" },
    });
    return readUploadJSON(response, "Upload could not be completed");
  }

  async function readUploadJSON(response, fallback) {
    let payload = {};
    try {
      payload = await response.json();
    } catch (error) {
      payload = {};
    }
    if (!response.ok) {
      throw new Error(payload.error || fallback);
    }
    return payload;
  }

  async function findResumableSession(payload) {
    const records = loadResumableSessions();
    const optionKey = resumableOptionKey(payload);
    const selectedKeys = new Set(payload.files.map((file) => resumableFileKey(file)));
    for (const record of records) {
      if (record.optionKey !== optionKey) {
        continue;
      }
      if (!record.files || !record.files.some((file) => selectedKeys.has(resumableFileKey(file)))) {
        continue;
      }
      const session = await fetchResumableStatus(record.sessionId).catch(() => null);
      if (!session || session.status !== "uploading") {
        removeResumableSession(record.sessionId);
        continue;
      }
      const sessionKeys = new Set(session.files.map((file) => resumableFileKey(file)));
      const sessionHasOnlySelectedFiles = session.files.every((file) => selectedKeys.has(resumableFileKey(file)));
      const selectedContainsSessionFile = Array.from(sessionKeys).some((key) => selectedKeys.has(key));
      if (sessionHasOnlySelectedFiles && selectedContainsSessionFile) {
        return session;
      }
    }
    return null;
  }

  async function addMissingResumableFiles(session, payload) {
    const existing = new Set(session.files.map((file) => resumableFileKey(file)));
    const missing = payload.files.filter((file) => !existing.has(resumableFileKey(file)));
    if (missing.length === 0) {
      return session;
    }
    return addResumableFiles(session.sessionId, missing);
  }

  function matchSessionFile(session, file) {
    const key = resumableFileKey(file);
    return session.files.find((sessionFile) => resumableFileKey(sessionFile) === key) || null;
  }

  function resumableOptionKey(payload) {
    return [
      payload.expiresMinutes,
      payload.maxDownloads,
      payload.obfuscateMetadata ? "1" : "0",
      payload.collectionId || "",
    ].join(":");
  }

  function resumableFileKey(file) {
    return [file.name, file.size, file.fingerprint || ""].join(":");
  }

  function loadResumableSessions() {
    try {
      const value = localStorage.getItem(RESUMABLE_SESSIONS_KEY);
      const records = value ? JSON.parse(value) : [];
      return Array.isArray(records) ? records : [];
    } catch (error) {
      return [];
    }
  }

  function saveResumableSession(session, payload) {
    try {
      const records = loadResumableSessions().filter((record) => record.sessionId !== session.sessionId);
      records.push({
        sessionId: session.sessionId,
        optionKey: resumableOptionKey(payload),
        files: session.files.map((file) => ({
          name: file.name,
          size: file.size,
          fingerprint: file.fingerprint || "",
        })),
        updatedAt: new Date().toISOString(),
      });
      localStorage.setItem(RESUMABLE_SESSIONS_KEY, JSON.stringify(records.slice(-25)));
    } catch (error) {
      /* ignore persistence failures */
    }
  }

  function removeResumableSession(sessionID) {
    try {
      const records = loadResumableSessions().filter((record) => record.sessionId !== sessionID);
      localStorage.setItem(RESUMABLE_SESSIONS_KEY, JSON.stringify(records));
    } catch (error) {
      /* ignore persistence failures */
    }
  }

  function uploadedBytesForSessionFile(file, chunkSize) {
    return (file.uploadedChunks || []).reduce((sum, index) => {
      const start = index * chunkSize;
      const end = Math.min(file.size, start + chunkSize);
      return sum + Math.max(0, end - start);
    }, 0);
  }

  function percentForBytes(bytes, total) {
    if (!total) {
      return 100;
    }
    return Math.max(0, Math.min(100, Math.round((bytes / total) * 100)));
  }

  function renderQueue(files, status) {
    if (!uploadQueue) {
      return;
    }
    uploadQueue.hidden = files.length === 0;
    uploadQueue.replaceChildren();
    files.forEach((file, index) => {
      uploadQueue.append(createFileRow({
        name: file.name,
        meta: window.Warpbox.formatBytes(file.size),
        progress: status === "queued" ? 0 : 100,
        status,
        index,
        removable: status === "queued",
      }));
    });
  }

  function createFileRow(file) {
    const row = document.createElement("div");
    row.className = "result-item upload-file-row";
    row.dataset.fileName = file.name;
    row.dataset.fileIndex = file.index || 0;

    const body = document.createElement("span");
    const name = document.createElement("strong");
    name.className = "file-name";
    name.textContent = file.name;
    name.title = file.name;
    const meta = document.createElement("code");
    meta.textContent = file.meta;
    body.append(name, meta);

    const side = document.createElement("div");
    side.className = "file-progress-side";
    const percent = document.createElement("span");
    percent.className = "file-progress-percent";
    percent.textContent = `${file.progress}%`;
    const bar = document.createElement("div");
    bar.className = "progress file-progress";
    const fill = document.createElement("span");
    fill.style.transform = `scaleX(${file.progress / 100})`;
    bar.append(fill);
    side.append(percent, bar);
    if (file.removable) {
      const remove = document.createElement("button");
      remove.className = "upload-file-remove";
      remove.type = "button";
      remove.setAttribute("aria-label", `Remove ${file.name}`);
      remove.textContent = "×";
      remove.addEventListener("click", () => removeSelectedFile(file.index || 0));
      side.append(remove);
    }

    row.append(body, side);
    return row;
  }

  function uploadFormData() {
    const formData = new FormData(form);
    formData.delete("file");
    selectedFiles.forEach((file) => {
      formData.append("file", file, file.name);
    });
    return formData;
  }

  function fileIdentity(file) {
    return [file.name, file.size, file.lastModified || 0].join(":");
  }

  async function fileFingerprint(file) {
    if (!window.crypto || !window.crypto.subtle || !file.slice || typeof TextEncoder === "undefined") {
      return fileIdentity(file);
    }
    const sampleSize = Math.min(file.size, 1024 * 1024);
    const sample = await file.slice(0, sampleSize).arrayBuffer();
    const metadata = new TextEncoder().encode([file.name, file.size, file.lastModified || 0, sampleSize].join(":"));
    const combined = new Uint8Array(metadata.byteLength + sample.byteLength);
    combined.set(metadata, 0);
    combined.set(new Uint8Array(sample), metadata.byteLength);
    const digest = await window.crypto.subtle.digest("SHA-256", combined);
    return Array.from(new Uint8Array(digest)).map((byte) => byte.toString(16).padStart(2, "0")).join("");
  }

  function setTotalProgress(percent) {
    if (totalProgressBar) {
      totalProgressBar.style.transform = `scaleX(${Math.max(0, Math.min(100, percent)) / 100})`;
    }
  }

  function setFileProgress(files, totalPercent) {
    if (!uploadQueue) {
      return;
    }
    const count = files.length || 1;
    const completedFloat = (Math.max(0, Math.min(100, totalPercent)) / 100) * count;
    uploadQueue.querySelectorAll(".upload-file-row").forEach((row, index) => {
      const progress = Math.max(0, Math.min(100, Math.round((completedFloat - index) * 100)));
      const percent = row.querySelector(".file-progress-percent");
      const fill = row.querySelector(".file-progress span");
      if (percent) {
        percent.textContent = `${progress}%`;
      }
      if (fill) {
        fill.style.transform = `scaleX(${progress / 100})`;
      }
    });
  }

  function setSingleFileProgress(index, file, progress) {
    if (!uploadQueue) {
      return;
    }
    const row = uploadQueue.querySelector(`.upload-file-row[data-file-index="${index}"]`);
    if (!row) {
      return;
    }
    const percent = row.querySelector(".file-progress-percent");
    const fill = row.querySelector(".file-progress span");
    const normalized = Math.max(0, Math.min(100, progress));
    if (percent) {
      percent.textContent = `${normalized}%`;
    }
    if (fill) {
      fill.style.transform = `scaleX(${normalized / 100})`;
    }
  }
})();