/**
 * Draft 欄位操作工具函數
 * 確保 transfer_draft 和 pro_order_detail_items 的操作互不影響
 */

// 解析 draft 欄位，返回標準化的物件格式
function getDraftObject(draft) {
  if (!draft || !draft.trim()) return {};
  try {
    const draftObj = JSON.parse(draft);
    // 確保是物件格式
    if (typeof draftObj === 'object' && !Array.isArray(draftObj)) {
      return draftObj;
    } else if (Array.isArray(draftObj)) {
      // 舊格式：轉換為新格式
      return { transfer_draft: draftObj };
    }
    return {};
  } catch (e) {
    console.error('解析 draft JSON 失敗:', e);
    return {};
  }
}

// 安全地取得 draft 物件中的特定欄位
function getDraftField(draft, fieldName) {
  const draftObj = getDraftObject(draft);
  return draftObj[fieldName] || null;
}

// 安全地更新 draft 物件中的特定欄位，保持其他欄位不變
function updateDraftField(draft, fieldName, newValue) {
  const draftObj = getDraftObject(draft);
  return {
    ...draftObj,
    [fieldName]: newValue
  };
}

// 檢查是否有 transfer_draft 資料
function hasTransferDraft(draft) {
  const transferDraft = getDraftField(draft, 'transfer_draft');
  return transferDraft && Array.isArray(transferDraft) && transferDraft.length > 0;
}

// 檢查是否有 pro_order_detail_items 資料
function hasProOrderDetailItems(draft) {
  const detailItems = getDraftField(draft, 'pro_order_detail_items');
  return detailItems && Array.isArray(detailItems) && detailItems.length > 0;
}

// 清除特定的 draft 欄位
function clearDraftField(draft, fieldName) {
  const draftObj = getDraftObject(draft);
  const newDraftObj = { ...draftObj };
  delete newDraftObj[fieldName];
  return newDraftObj;
}

// 合併兩個 draft 物件
function mergeDraftObjects(draft1, draft2) {
  const obj1 = getDraftObject(draft1);
  const obj2 = getDraftObject(draft2);
  return {
    ...obj1,
    ...obj2
  };
}

// 驗證 draft 物件格式
function validateDraftFormat(draft) {
  if (!draft || !draft.trim()) return { valid: true, format: 'empty' };
  
  try {
    const draftObj = JSON.parse(draft);
    
    if (Array.isArray(draftObj)) {
      return { valid: true, format: 'legacy_array' };
    } else if (typeof draftObj === 'object') {
      const hasTransferDraft = draftObj.transfer_draft && Array.isArray(draftObj.transfer_draft);
      const hasDetailItems = draftObj.pro_order_detail_items && Array.isArray(draftObj.pro_order_detail_items);
      
      if (hasTransferDraft || hasDetailItems) {
        return { 
          valid: true, 
          format: 'new_object',
          hasTransferDraft,
          hasDetailItems
        };
      } else {
        return { valid: false, error: '無效的物件格式' };
      }
    } else {
      return { valid: false, error: '不是有效的 JSON 物件或陣列' };
    }
  } catch (e) {
    return { valid: false, error: 'JSON 解析失敗' };
  }
}

// 取得 draft 的摘要資訊
function getDraftSummary(draft) {
  if (!draft || !draft.trim()) return { hasData: false };
  
  const draftObj = getDraftObject(draft);
  const transferDraft = draftObj.transfer_draft || [];
  const detailItems = draftObj.pro_order_detail_items || [];
  
  return {
    hasData: transferDraft.length > 0 || detailItems.length > 0,
    transferDraftCount: transferDraft.length,
    detailItemsCount: detailItems.length,
    totalReconcileAmount: detailItems.reduce((sum, item) => sum + (Number(item.reconcile) || 0), 0),
    format: validateDraftFormat(draft).format
  };
}

// 將舊格式轉換為新格式
function migrateLegacyFormat(draft) {
  if (!draft || !draft.trim()) return '';
  
  try {
    const draftObj = JSON.parse(draft);
    if (Array.isArray(draftObj)) {
      // 舊格式：轉換為新格式
      const newDraftObj = { transfer_draft: draftObj };
      return JSON.stringify(newDraftObj);
    }
    // 已經是物件格式，直接返回
    return draft;
  } catch (e) {
    console.error('遷移舊格式失敗:', e);
    return draft;
  }
}

// 清理空的 draft 欄位
function cleanEmptyDraft(draft) {
  if (!draft || !draft.trim()) return '';
  
  try {
    const draftObj = JSON.parse(draft);
    const cleaned = {};
    
    if (draftObj.transfer_draft && Array.isArray(draftObj.transfer_draft) && draftObj.transfer_draft.length > 0) {
      cleaned.transfer_draft = draftObj.transfer_draft;
    }
    
    if (draftObj.pro_order_detail_items && Array.isArray(draftObj.pro_order_detail_items) && draftObj.pro_order_detail_items.length > 0) {
      cleaned.pro_order_detail_items = draftObj.pro_order_detail_items;
    }
    
    return Object.keys(cleaned).length > 0 ? JSON.stringify(cleaned) : '';
  } catch (e) {
    console.error('清理 draft 失敗:', e);
    return draft;
  }
}

// 格式化 draft JSON 為可讀字串
function formatDraftJson(draft) {
  if (!draft) return '無記錄';
  try {
    return JSON.stringify(JSON.parse(draft), null, 2);
  } catch(e) {
    return draft;
  }
}

// 使用範例：
/*
// 1. 更新 transfer_draft
const currentDraft = item.draft || '';
const newTransferDraft = [
  { pro_order_detail_num: "123", reconcile: 5000 }
];
const updatedDraft = updateDraftField(currentDraft, 'transfer_draft', newTransferDraft);

// 2. 更新 pro_order_detail_items
const newDetailItems = [
  { 
    pro_order_detail_num: "123", 
    reconcile: 5000,
    activity_name: "法會",
    actitem_name: "護持金"
  }
];
const updatedDraft = updateDraftField(currentDraft, 'pro_order_detail_items', newDetailItems);

// 3. 檢查是否有暫存資料
if (hasTransferDraft(item.draft)) {
  console.log('有暫存資料');
}

// 4. 取得特定欄位
const transferDraft = getDraftField(item.draft, 'transfer_draft');
const detailItems = getDraftField(item.draft, 'pro_order_detail_items');
*/

// 檢查是否有 follower_list（共同支付人清單）
function hasFollowerList(draft) {
  const followerList = getDraftField(draft, 'follower_list');
  return followerList && Array.isArray(followerList) && followerList.length > 0;
}

// 取得 follower_list
function getFollowerList(draft) {
  const followerList = getDraftField(draft, 'follower_list');
  return followerList && Array.isArray(followerList) ? followerList : [];
}

// 更新 follower_list
function updateFollowerList(draft, followerList) {
  return updateDraftField(draft, 'follower_list', followerList);
}

// 如果是在瀏覽器環境中，將函數掛載到全域
if (typeof window !== 'undefined') {
  window.DraftUtils = {
    getDraftObject,
    getDraftField,
    updateDraftField,
    hasTransferDraft,
    hasProOrderDetailItems,
    hasFollowerList,
    getFollowerList,
    updateFollowerList,
    clearDraftField,
    mergeDraftObjects,
    validateDraftFormat,
    getDraftSummary,
    migrateLegacyFormat,
    cleanEmptyDraft,
    formatDraftJson
  };
}

// 如果是在 Node.js 環境中，匯出函數
if (typeof module !== 'undefined' && module.exports) {
  module.exports = {
    getDraftObject,
    getDraftField,
    updateDraftField,
    hasTransferDraft,
    hasProOrderDetailItems,
    hasFollowerList,
    getFollowerList,
    updateFollowerList,
    clearDraftField,
    mergeDraftObjects,
    validateDraftFormat,
    getDraftSummary,
    migrateLegacyFormat,
    cleanEmptyDraft,
    formatDraftJson
  };
}