(function () {
  "use strict";

  var DEFAULT_MAX = 200 * 1024 * 1024;
  var BLOCKED_MSG = "Dieser Dateityp ist aus Sicherheitsgründen nicht erlaubt.";

  function ext(name) {
    var i = name.lastIndexOf(".");
    return i >= 0 ? name.slice(i).toLowerCase() : "";
  }

  function formatSize(bytes) {
    if (bytes < 1024) return bytes + " B";
    if (bytes < 1024 * 1024) return (bytes / 1024).toFixed(1) + " KB";
    return (bytes / (1024 * 1024)).toFixed(1) + " MB";
  }

  function escapeHtml(s) {
    var d = document.createElement("div");
    d.textContent = s;
    return d.innerHTML;
  }

  function showStatus(el, type, message) {
    el.hidden = false;
    el.className = "upload-status alert alert-" + type;
    el.textContent = message;
  }

  function isOdt(name) {
    return name && name.toLowerCase().slice(-4) === ".odt";
  }

  function editBtn(file) {
    if (!isOdt(file.original_filename)) return "";
    return ' <a href="/files/' + file.id + '/edit" class="btn btn-sm btn-secondary">Im Browser bearbeiten</a>';
  }

  function buildFileRow(file, mode) {
    var tr = document.createElement("tr");
    tr.dataset.fileId = String(file.id);
    if (mode === "task") {
      tr.innerHTML =
        "<td>" + escapeHtml(file.original_filename) + "</td>" +
        "<td>" + formatSize(file.size_bytes) + "</td>" +
        "<td>" + escapeHtml(file.created_at) + " (" + escapeHtml(file.uploader || "") + ")</td>" +
        '<td class="file-actions"><a href="/files/' + file.id + '/download" class="btn btn-sm btn-primary">Download</a>' +
        editBtn(file) + "</td>";
      return tr;
    }
    var tags = (file.tags || []).map(function (t) {
      return '<span class="tag">' + escapeHtml(t) + "</span>";
    }).join("");
    tr.innerHTML =
      "<td>" + escapeHtml(file.original_filename) + "</td>" +
      "<td>" + escapeHtml(file.category || "–") + "</td>" +
      "<td>" + escapeHtml(file.description || "–") + "</td>" +
      "<td>" + formatSize(file.size_bytes) + "</td>" +
      "<td>" + escapeHtml(file.created_at) + " (" + escapeHtml(file.uploader || "") + ")</td>" +
      "<td>" + tags + "</td>" +
      '<td class="file-actions"><a href="/files/' + file.id + '/download" class="btn btn-sm btn-primary">Download</a>' +
      editBtn(file) + "</td>";
    return tr;
  }

  function parseList(raw) {
    if (!raw) return [];
    return raw.split(",").map(function (s) { return s.trim(); }).filter(Boolean);
  }

  function initWidget(widget) {
    var dropZone = widget.querySelector("[data-drop-zone]");
    var fileInput = widget.querySelector("[data-file-input]");
    var statusEl = widget.querySelector("[data-upload-status]");
    var csrf = widget.dataset.csrf;
    var taskId = widget.dataset.taskId || "";
    var categoryEl = widget.querySelector("[data-upload-category]");
    var descriptionEl = widget.querySelector("[data-upload-description]");
    var tagsEl = widget.querySelector("[data-upload-tags]");
    var listTargetId = widget.dataset.listTarget;
    var listTarget = listTargetId ? document.getElementById(listTargetId) : null;
    var rowMode = widget.dataset.rowMode || "full";
    var emptyState = widget.dataset.emptyState
      ? document.getElementById(widget.dataset.emptyState)
      : null;
    var maxBytes = parseInt(widget.dataset.maxBytes, 10) || DEFAULT_MAX;
    var maxMb = parseInt(widget.dataset.maxMb, 10) || 200;
    var allowed = parseList(widget.dataset.allowed);
    var blocked = parseList(widget.dataset.blocked);
    var uploading = false;
    var queue = [];

    if (!dropZone || !fileInput || !csrf) return;

    if (allowed.length && fileInput) {
      fileInput.setAttribute("accept", allowed.join(","));
    }

    dropZone.addEventListener("click", function (e) {
      if (e.target === fileInput) return;
      fileInput.click();
    });

    dropZone.addEventListener("keydown", function (e) {
      if (e.key === "Enter" || e.key === " ") {
        e.preventDefault();
        fileInput.click();
      }
    });

    ["dragenter", "dragover"].forEach(function (ev) {
      dropZone.addEventListener(ev, function (e) {
        e.preventDefault();
        e.stopPropagation();
        dropZone.classList.add("drop-zone-active");
      });
    });

    ["dragleave", "drop"].forEach(function (ev) {
      dropZone.addEventListener(ev, function (e) {
        e.preventDefault();
        e.stopPropagation();
        dropZone.classList.remove("drop-zone-active");
      });
    });

    dropZone.addEventListener("drop", function (e) {
      var files = e.dataTransfer && e.dataTransfer.files;
      if (files && files.length) enqueue(Array.prototype.slice.call(files));
    });

    fileInput.addEventListener("change", function () {
      if (fileInput.files && fileInput.files.length) {
        enqueue(Array.prototype.slice.call(fileInput.files));
        fileInput.value = "";
      }
    });

    function enqueue(files) {
      files.forEach(function (f) { queue.push(f); });
      processQueue();
    }

    function processQueue() {
      if (uploading || !queue.length) return;
      uploading = true;
      uploadOne(queue.shift()).finally(function () {
        uploading = false;
        processQueue();
      });
    }

    function uploadOne(file) {
      var e = ext(file.name);
      if (blocked.indexOf(e) !== -1) {
        showStatus(statusEl, "error", file.name + ": " + BLOCKED_MSG);
        return Promise.resolve();
      }
      if (allowed.length && allowed.indexOf(e) === -1) {
        showStatus(statusEl, "error", file.name + ": Dateityp nicht erlaubt.");
        return Promise.resolve();
      }
      if (file.size > maxBytes) {
        showStatus(statusEl, "error", file.name + ": zu gross (max. " + maxMb + " MB).");
        return Promise.resolve();
      }

      showStatus(statusEl, "info", "Lade hoch: " + file.name + " …");

      var fd = new FormData();
      fd.append("csrf_token", csrf);
      fd.append("upload", file);
      if (categoryEl) fd.append("category", categoryEl.value);
      if (descriptionEl) fd.append("description", descriptionEl.value);
      if (tagsEl) fd.append("tags", tagsEl.value);
      if (taskId) fd.append("task_id", taskId);

      return fetch("/api/files/upload", { method: "POST", body: fd, credentials: "same-origin" })
        .then(function (r) { return r.json(); })
        .then(function (data) {
          if (data.ok && data.file) {
            showStatus(statusEl, "success", file.name + " erfolgreich hochgeladen.");
            if (listTarget) {
              if (emptyState) emptyState.hidden = true;
              var tbody = listTarget.tagName === "TBODY" ? listTarget : listTarget.querySelector("tbody");
              if (tbody) {
                tbody.insertBefore(buildFileRow(data.file, rowMode), tbody.firstChild);
              }
            }
          } else {
            showStatus(statusEl, "error", (data.message || "Upload fehlgeschlagen.") + " (" + file.name + ")");
          }
        })
        .catch(function () {
          showStatus(statusEl, "error", "Netzwerkfehler beim Upload von " + file.name + ".");
        });
    }
  }

  document.addEventListener("DOMContentLoaded", function () {
    document.querySelectorAll("[data-upload-widget]").forEach(initWidget);
  });
})();