// middleware/permissions.js —— 接口权限 + 数据范围 + 合同类型校验

/**
 * 检查当前用户是否拥有指定权限
 * @param {string} resource - 资源名，如 'customer'
 * @param {string} action   - 操作名，如 'read'
 */
function checkPermission(resource, action) {
  return (req, res, next) => {
    const permName = `${resource}:${action}`
    if (!req.user || !req.user.permissions || !req.user.permissions.includes(permName)) {
      return res.status(403).json({ code: 403, message: '权限不足' })
    }
    next()
  }
}

/**
 * 根据用户部门计算数据范围，挂到 req.scope
 * @param {string} resource - 资源名：customers / contracts / after_sales / employees
 */
function dataScope(resource) {
  return (req, res, next) => {
    const deptName = req.user.departmentName // 如 'franchise_manager'

    // 信息技术部和总经理办公室：全量数据
    if (deptName === 'admin' || deptName === 'general_manager') {
      return next()
    }

    let sql = null, params = []

    switch (resource) {
      case 'customers':
        // 过渡期：招商部和运营部也能看全量加盟商
        break

      case 'contracts':
        if (deptName === 'franchise_manager') {
          sql = 'AND type = ?'
          params = ['franchise']
        } else if (deptName === 'procurement_manager') {
          sql = 'AND type = ?'
          params = ['supply']
        }
        // finance 全量看；operations_manager 无合同权限（checkPermission 已拦截）
        break

      case 'after_sales':
        // 过渡期：运营部看全量售后
        break

      case 'employees':
        if (['franchise_manager', 'operations_manager', 'procurement_manager'].includes(deptName)) {
          sql = 'AND department = ?'
          params = [req.user.departmentDesc] // 如 '招商部'
        }
        // finance 全量看员工
        break
    }

    if (sql) {
      req.scope = { sql, params }
    }
    next()
  }
}

/**
 * 合同创建/修改时校验类型是否匹配部门
 * 招商部只能操作加盟合同，采购部只能操作采购合同
 */
function validateContractType(req, res, next) {
  const deptName = req.user.departmentName
  const type = req.body.type

  // 未传 type 则跳过（路由会默认 'franchise'）
  if (type === undefined) return next()

  // 管理员/总经理/财务不限制
  if (['admin', 'general_manager', 'finance'].includes(deptName)) return next()

  // 采购部只能操作采购合同
  if (deptName === 'procurement_manager' && type !== 'supply') {
    return res.status(403).json({ code: 403, message: '采购部只能操作采购合同' })
  }

  // 招商部只能操作加盟合同
  if (deptName === 'franchise_manager' && type !== 'franchise') {
    return res.status(403).json({ code: 403, message: '招商部只能操作加盟合同' })
  }

  next()
}

module.exports = { checkPermission, dataScope, validateContractType }