// 变更追踪工具
import { MachineryRecord, MachineryChangeHistory } from '../types/machinery';

// 字段名称到中文标签的映射
export const FIELD_LABELS: Record<string, string> = {
  // 基本信息
  name: '设备名称',
  model: '型号规格',
  category: '农机类型',
  usage: '使用场景',
  manufacturer: '生产厂家',
  manufactureDate: '出厂日期',
  purchaseDate: '购买日期',
  
  // 技术参数
  engineNumber: '发动机号',
  chassisNumber: '车架号',
  power: '额定功率',
  weight: '整机重量',
  workingWidth: '工作幅宽',
  
  // 购机信息
  purchasePrice: '购机价格',
  supplier: '供应商',
  invoiceNumber: '发票号码',
  invoiceUrl: '购机发票',
  
  // 保险信息
  insuranceCompany: '保险公司',
  insurancePolicyNumber: '保单号',
  insuranceStartDate: '保险起始日期',
  insuranceEndDate: '保险结束日期',
  insuranceAmount: '保险金额',
  
  // 使用信息
  status: '设备状态',
  currentLocation: '当前位置',
  operator: '操作人员',
  department: '所属部门',
  
  // 保养信息
  maintenanceCycle: '保养周期',
  maintenanceCycleUnit: '保养周期单位',
  
  // 其他信息
  remarks: '备注',
  tags: '标签',
};

// 需要排除的字段（不记录变更）
const EXCLUDED_FIELDS = [
  'id',
  'qrCode',
  'createdAt',
  'updatedAt',
  'createdBy',
  'updatedBy',
];

/**
 * 格式化字段值用于显示
 */
export function formatFieldValue(fieldName: string, value: any): string {
  if (value === null || value === undefined || value === '') {
    return '(空)';
  }
  
  // 日期字段
  if (fieldName.includes('Date') || fieldName.includes('Time')) {
    try {
      return new Date(value).toLocaleDateString('zh-CN');
    } catch {
      return String(value);
    }
  }
  
  // 金额字段
  if (fieldName.includes('Price') || fieldName.includes('Amount')) {
    const num = parseFloat(value);
    return isNaN(num) ? String(value) : `¥${num.toLocaleString()}`;
  }
  
  // 保养周期单位
  if (fieldName === 'maintenanceCycleUnit') {
    const unitMap: Record<string, string> = {
      day: '天',
      month: '月',
      year: '年'
    };
    return unitMap[value] || String(value);
  }
  
  // 数组字段（如标签）
  if (Array.isArray(value)) {
    return value.length > 0 ? value.join(', ') : '(空)';
  }
  
  // 对象字段
  if (typeof value === 'object') {
    return JSON.stringify(value);
  }
  
  // 布尔值
  if (typeof value === 'boolean') {
    return value ? '是' : '否';
  }
  
  return String(value);
}

/**
 * 比较两个值是否相同
 */
function isEqual(oldValue: any, newValue: any): boolean {
  // 处理null/undefined/空字符串的情况
  const isOldEmpty = oldValue === null || oldValue === undefined || oldValue === '';
  const isNewEmpty = newValue === null || newValue === undefined || newValue === '';
  
  if (isOldEmpty && isNewEmpty) return true;
  if (isOldEmpty !== isNewEmpty) return false;
  
  // 数组比较
  if (Array.isArray(oldValue) && Array.isArray(newValue)) {
    if (oldValue.length !== newValue.length) return false;
    return oldValue.every((val, index) => val === newValue[index]);
  }
  
  // 对象比较
  if (typeof oldValue === 'object' && typeof newValue === 'object') {
    return JSON.stringify(oldValue) === JSON.stringify(newValue);
  }
  
  // 基本类型比较
  return oldValue === newValue;
}

/**
 * 追踪农机档案的变更
 * @param oldRecord 旧记录
 * @param newRecord 新记录
 * @param operator 操作人
 * @returns 变更历史记录数组
 */
export function trackMachineryChanges(
  oldRecord: MachineryRecord | undefined,
  newRecord: Partial<MachineryRecord>,
  operator: string
): MachineryChangeHistory[] {
  const changes: MachineryChangeHistory[] = [];
  const timestamp = new Date().toISOString();
  
  // 如果是新建，不记录变更
  if (!oldRecord) {
    return [];
  }
  
  // 遍历新记录的所有字段
  Object.keys(newRecord).forEach((fieldName) => {
    // 跳过排除的字段
    if (EXCLUDED_FIELDS.includes(fieldName)) {
      return;
    }
    
    const oldValue = (oldRecord as any)[fieldName];
    const newValue = (newRecord as any)[fieldName];
    
    // 检查值是否发生变化
    if (!isEqual(oldValue, newValue)) {
      const fieldLabel = FIELD_LABELS[fieldName] || fieldName;
      
      changes.push({
        id: `change-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`,
        machineryId: oldRecord.id,
        fieldName,
        fieldLabel,
        oldValue,
        newValue,
        operator,
        operatedAt: timestamp,
      });
    }
  });
  
  return changes;
}

/**
 * 获取字段的变更描述
 */
export function getChangeDescription(change: MachineryChangeHistory): string {
  const oldValueStr = formatFieldValue(change.fieldName, change.oldValue);
  const newValueStr = formatFieldValue(change.fieldName, change.newValue);
  
  return `将 ${change.fieldLabel} 从 "${oldValueStr}" 修改为 "${newValueStr}"`;
}

/**
 * 按日期分组变更记录
 */
export function groupChangesByDate(
  changes: MachineryChangeHistory[]
): Record<string, MachineryChangeHistory[]> {
  const grouped: Record<string, MachineryChangeHistory[]> = {};
  
  changes.forEach(change => {
    const date = new Date(change.operatedAt).toLocaleDateString('zh-CN');
    if (!grouped[date]) {
      grouped[date] = [];
    }
    grouped[date].push(change);
  });
  
  return grouped;
}

/**
 * 获取变更统计信息
 */
export function getChangeStats(changes: MachineryChangeHistory[]) {
  const stats = {
    total: changes.length,
    byField: {} as Record<string, number>,
    byOperator: {} as Record<string, number>,
    recentChanges: changes
      .sort((a, b) => new Date(b.operatedAt).getTime() - new Date(a.operatedAt).getTime())
      .slice(0, 5),
  };
  
  changes.forEach(change => {
    // 按字段统计
    const field = change.fieldLabel;
    stats.byField[field] = (stats.byField[field] || 0) + 1;
    
    // 按操作人统计
    stats.byOperator[change.operator] = (stats.byOperator[change.operator] || 0) + 1;
  });
  
  return stats;
}