/**
 * upload.js — Generic file upload handler for Portal admin pages.
 *
 * Usage:
 *   setupUpload(inputSelector, uploadType)
 *   - inputSelector: CSS selector for the target input field
 *   - uploadType: "icon" or "background" — determines thumbnail dimensions
 *
 * Adds a hidden file input and a visible "上传图片" button next to the target input.
 * After successful upload, the target input value is set to the returned URL.
 */

(function () {
  "use strict";

  /**
   * Sets up an upload button next to the specified input field.
   * @param {string} inputSelector - CSS selector for the input to fill with the URL
   * @param {string} uploadType - "icon" or "background"
   */
  function setupUpload(inputSelector, uploadType) {
    var input = document.querySelector(inputSelector);
    if (!input) return;

    // Create container for the upload button group
    var wrapper = document.createElement("div");
    wrapper.className = "upload-btn-wrapper";

    // Create the visible upload button
    var btn = document.createElement("button");
    btn.type = "button";
    btn.className = "upload-btn";
    btn.textContent = "上传图片";

    // Create the hidden file input
    var fileInput = document.createElement("input");
    fileInput.type = "file";
    fileInput.accept = "image/jpeg,image/png,image/gif";
    fileInput.style.display = "none";

    // Create status message element
    var status = document.createElement("span");
    status.className = "upload-status";

    // Insert wrapper after the input
    input.parentNode.insertBefore(wrapper, input.nextSibling);
    wrapper.appendChild(btn);
    wrapper.appendChild(fileInput);
    wrapper.appendChild(status);

    // Click button -> open file dialog
    btn.addEventListener("click", function () {
      fileInput.click();
    });

    // File selected -> upload
    fileInput.addEventListener("change", function () {
      if (fileInput.files.length === 0) return;

      var file = fileInput.files[0];

      // Validate file size (5MB)
      if (file.size > 5 * 1024 * 1024) {
        status.textContent = "文件太大，最大允许 5MB";
        status.className = "upload-status upload-error";
        return;
      }

      // Validate file type
      var validTypes = ["image/jpeg", "image/png", "image/gif"];
      if (validTypes.indexOf(file.type) === -1) {
        status.textContent = "不支持的文件格式";
        status.className = "upload-status upload-error";
        return;
      }

      // Start upload
      btn.disabled = true;
      btn.textContent = "上传中...";
      status.textContent = "";
      status.className = "upload-status";

      var formData = new FormData();
      formData.append("file", file);
      formData.append("type", uploadType);

      var xhr = new XMLHttpRequest();
      xhr.open("POST", "/admin/upload", true);

      xhr.onload = function () {
        btn.disabled = false;
        btn.textContent = "上传图片";

        if (xhr.status === 200) {
          try {
            var resp = JSON.parse(xhr.responseText);
            if (resp.url) {
              input.value = resp.url;
              status.textContent = "上传成功！";
              status.className = "upload-status upload-success";

              // If there's a preview element, update it
              var preview = input.parentNode.querySelector(".upload-preview");
              if (preview) {
                preview.src = resp.url + "?thumb=1";
                preview.style.display = "block";
              }
            } else {
              status.textContent = resp.error || "上传失败";
              status.className = "upload-status upload-error";
            }
          } catch (e) {
            status.textContent = "上传失败";
            status.className = "upload-status upload-error";
          }
        } else {
          try {
            var resp = JSON.parse(xhr.responseText);
            status.textContent = resp.error || "上传失败";
          } catch (e) {
            status.textContent = "上传失败 (" + xhr.status + ")";
          }
          status.className = "upload-status upload-error";
        }
      };

      xhr.onerror = function () {
        btn.disabled = false;
        btn.textContent = "上传图片";
        status.textContent = "网络错误";
        status.className = "upload-status upload-error";
      };

      xhr.send(formData);
    });
  }

  // Expose globally
  window.setupUpload = setupUpload;
})();