(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 copyAll = document.querySelector("#copy-all");
  const openBox = document.querySelector("#open-box");

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

  let latestLinks = [];

  ["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");
    });
  });

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

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

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

    const submit = form.querySelector("button[type='submit']");
    const formData = new FormData(form);
    setLoading(true, submit);

    try {
      const response = await fetch(form.action, {
        method: "POST",
        body: formData,
        headers: {
          Accept: "application/json",
        },
      });

      const payload = await response.json();
      if (!response.ok) {
        throw new Error(payload.error || "Upload failed");
      }

      renderResult(payload);
      form.reset();
      updateSelectedState([]);
    } catch (error) {
      updateStatus(error.message || "Upload failed");
    } finally {
      setLoading(false, submit);
    }
  });

  if (copyAll) {
    copyAll.addEventListener("click", () => {
      copyText(latestLinks.join("\n"), copyAll, "Copied");
    });
  }

  function updateSelectedState(files) {
    const count = files.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.`;
    }
  }

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

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

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

    latestLinks = [payload.boxUrl, payload.zipUrl].concat(payload.files.map((file) => file.url));
    result.hidden = false;
    openBox.href = payload.boxUrl;
    resultMeta.textContent = `${payload.files.length} file${payload.files.length === 1 ? "" : "s"} · expires ${formatDate(payload.expiresAt)}`;

    resultList.replaceChildren();
    payload.files.forEach((file) => {
      const row = document.createElement("div");
      row.className = "result-item";

      const body = document.createElement("span");
      const name = document.createElement("strong");
      name.textContent = file.name;
      const url = document.createElement("code");
      url.textContent = file.url;
      body.append(name, url);

      const copy = document.createElement("button");
      copy.className = "button button-outline";
      copy.type = "button";
      copy.textContent = "Copy";
      copy.addEventListener("click", () => copyText(file.url, copy, "Copied"));

      row.append(body, copy);
      resultList.append(row);
    });

    const zip = document.createElement("div");
    zip.className = "result-item";
    const zipBody = document.createElement("span");
    const zipName = document.createElement("strong");
    zipName.textContent = "Download all as zip";
    const zipUrl = document.createElement("code");
    zipUrl.textContent = payload.zipUrl;
    zipBody.append(zipName, zipUrl);
    const zipCopy = document.createElement("button");
    zipCopy.className = "button button-outline";
    zipCopy.type = "button";
    zipCopy.textContent = "Copy";
    zipCopy.addEventListener("click", () => copyText(payload.zipUrl, zipCopy, "Copied"));
    zip.append(zipBody, zipCopy);
    resultList.append(zip);
  }

  async function copyText(text, button, copiedLabel) {
    if (!text) {
      return;
    }
    await navigator.clipboard.writeText(text);
    const previous = button.textContent;
    button.textContent = copiedLabel;
    setTimeout(() => {
      button.textContent = previous;
    }, 1400);
  }

  function formatDate(value) {
    const date = new Date(value);
    if (Number.isNaN(date.getTime())) {
      return value;
    }
    return date.toLocaleDateString(undefined, {
      month: "short",
      day: "numeric",
      year: "numeric",
    });
  }
})();