/**
 * QR Code 產生器 - Google Drive 上傳模組
 */

/**
 * 上傳圖片到 Google Drive
 * @param {string} base64Image - Base64 編碼的圖片
 * @param {string} filename - 檔案名稱
 * @param {string} folderId - 目標資料夾 ID
 * @returns {Object} 上傳結果
 */
function uploadToDrive(base64Image, filename, folderId) {
  try {
    // 解碼 Base64
    const decoded = Utilities.base64Decode(base64Image);
    const blob = Utilities.newBlob(decoded, 'image/jpeg', filename);
    
    // 取得目標資料夾
    const folder = DriveApp.getFolderById(folderId);
    
    // 檢查是否已存在同名檔案
    const existingFiles = folder.getFilesByName(filename);
    if (existingFiles.hasNext()) {
      // 刪除舊檔案
      const oldFile = existingFiles.next();
      oldFile.setTrashed(true);
    }
    
    // 上傳新檔案
    const file = folder.createFile(blob);
    
    // 設定分享權限（可選：設為任何人可檢視）
    // file.setSharing(DriveApp.Access.ANYONE_WITH_LINK, DriveApp.Permission.VIEW);
    
    return {
      success: true,
      fileId: file.getId(),
      fileName: file.getName(),
      webViewLink: file.getUrl(),
      downloadUrl: 'https://drive.google.com/uc?export=download&id=' + file.getId()
    };
    
  } catch (error) {
    throw new Error('Drive 上傳失敗: ' + error.message);
  }
}

/**
 * 取得資料夾資訊
 * @param {string} folderId - 資料夾 ID
 * @returns {Object} 資料夾資訊
 */
function getFolderInfo(folderId) {
  try {
    const folder = DriveApp.getFolderById(folderId);
    
    // 取得完整路徑
    const path = getFolderPath(folder);
    
    return {
      success: true,
      id: folder.getId(),
      name: folder.getName(),
      path: path,
      url: folder.getUrl()
    };
  } catch (error) {
    return {
      success: false,
      error: '無法存取資料夾: ' + error.message
    };
  }
}

/**
 * 取得資料夾完整路徑
 * @param {Folder} folder - 資料夾物件
 * @returns {string} 完整路徑
 */
function getFolderPath(folder) {
  const pathParts = [folder.getName()];
  let parent = folder.getParents();
  
  while (parent.hasNext()) {
    const parentFolder = parent.next();
    pathParts.unshift(parentFolder.getName());
    parent = parentFolder.getParents();
  }
  
  return pathParts.join(' / ');
}

/**
 * 列出使用者可存取的資料夾（用於下拉選單）
 * @param {string} searchQuery - 搜尋關鍵字（可選）
 * @returns {Array} 資料夾列表
 */
function listFolders(searchQuery) {
  const folders = [];
  let query = 'mimeType = "application/vnd.google-apps.folder"';
  
  if (searchQuery) {
    query += ' and name contains "' + searchQuery + '"';
  }
  
  const iterator = DriveApp.searchFolders(query);
  let count = 0;
  const maxResults = 50;
  
  while (iterator.hasNext() && count < maxResults) {
    const folder = iterator.next();
    folders.push({
      id: folder.getId(),
      name: folder.getName(),
      path: getFolderPath(folder)
    });
    count++;
  }
  
  return folders;
}

/**
 * 建立新資料夾
 * @param {string} folderName - 資料夾名稱
 * @param {string} parentFolderId - 父資料夾 ID（可選，預設為根目錄）
 * @returns {Object} 新資料夾資訊
 */
function createFolder(folderName, parentFolderId) {
  try {
    let parentFolder;
    
    if (parentFolderId) {
      parentFolder = DriveApp.getFolderById(parentFolderId);
    } else {
      parentFolder = DriveApp.getRootFolder();
    }
    
    // 檢查是否已存在同名資料夾
    const existing = parentFolder.getFoldersByName(folderName);
    if (existing.hasNext()) {
      const existingFolder = existing.next();
      return {
        success: true,
        isNew: false,
        id: existingFolder.getId(),
        name: existingFolder.getName(),
        path: getFolderPath(existingFolder),
        message: '資料夾已存在，使用現有資料夾'
      };
    }
    
    // 建立新資料夾
    const newFolder = parentFolder.createFolder(folderName);
    
    return {
      success: true,
      isNew: true,
      id: newFolder.getId(),
      name: newFolder.getName(),
      path: getFolderPath(newFolder),
      message: '已建立新資料夾'
    };
    
  } catch (error) {
    return {
      success: false,
      error: '建立資料夾失敗: ' + error.message
    };
  }
}

/**
 * 檢查資料夾是否有寫入權限
 * @param {string} folderId - 資料夾 ID
 * @returns {boolean} 是否有權限
 */
function checkFolderPermission(folderId) {
  try {
    const folder = DriveApp.getFolderById(folderId);
    // 嘗試取得 editors，如果沒有權限會拋出錯誤
    const access = folder.getAccess(Session.getActiveUser());
    return access === DriveApp.Permission.EDIT || access === DriveApp.Permission.OWNER;
  } catch (error) {
    return false;
  }
}

/**
 * 批次上傳圖片
 * @param {Array} images - 圖片陣列 [{base64, filename}, ...]
 * @param {string} folderId - 目標資料夾 ID
 * @returns {Array} 上傳結果陣列
 */
function uploadToDriveBatch(images, folderId) {
  const results = [];
  const folder = DriveApp.getFolderById(folderId);
  
  for (const image of images) {
    try {
      const decoded = Utilities.base64Decode(image.base64);
      const blob = Utilities.newBlob(decoded, 'image/jpeg', image.filename);
      const file = folder.createFile(blob);
      
      results.push({
        success: true,
        filename: image.filename,
        fileId: file.getId(),
        webViewLink: file.getUrl()
      });
    } catch (error) {
      results.push({
        success: false,
        filename: image.filename,
        error: error.message
      });
    }
  }
  
  return results;
}