'use strict';

const hasOwn = (obj, key) => Object.prototype.hasOwnProperty.call(obj || {}, key);

const toInt = (value, fallback = null) => {
   const num = Number.parseInt(value, 10);
   return Number.isInteger(num) ? num : fallback;
};

const isPositiveInt = value => Number.isInteger(Number(value)) && Number(value) > 0;

const parsePagination = (query = {}) => {
   const page = Math.max(toInt(query.page, 1), 1);
   const pageSize = Math.min(Math.max(toInt(query.pageSize, 20), 1), 5000);
   return {
      page,
      pageSize,
      offset: (page - 1) * pageSize,
      limit: pageSize,
   };
};

const normalizeParentId = value => {
   if (value === null || value === undefined || value === '') return null;
   const parsed = toInt(value);
   if (!parsed || parsed < 1) throw '参数错误: parentId';
   return parsed;
};

const normalizeNullableInt = (value, label = 'value') => {
   if (value === null || value === undefined || value === '') return null;
   const parsed = toInt(value);
   if (!parsed || parsed < 1) throw `参数错误: ${label}`;
   return parsed;
};

const normalizeInsertPosition = (rawPosition, maxPosition) => {
   const parsed = toInt(rawPosition, maxPosition);
   if (!parsed || parsed < 1) return maxPosition;
   if (parsed > maxPosition) return maxPosition;
   return parsed;
};

const normalizeOrderedInput = (items = []) => {
   return (items || [])
      .map((item, index) => ({
         item,
         sortPos: isPositiveInt(item?.position) ? Number(item.position) : index + 1,
         index,
      }))
      .sort((a, b) => a.sortPos - b.sortPos || a.index - b.index)
      .map(entry => entry.item);
};

const ensureCreatedBy = (body = {}) => {
   const createdBy = String(body.createdBy || '').trim();
   if (!createdBy) throw '缺少参数: createdBy';
   return createdBy;
};

const ensureNonEmptyString = (value, label = 'value') => {
   const normalized = String(value || '').trim();
   if (!normalized) throw `missing param: ${label}`;
   return normalized;
};

const ensureObjectPayload = (value, label = 'payload') => {
   if (!value || typeof value !== 'object' || Array.isArray(value)) {
      throw `invalid param: ${label}`;
   }
   return value;
};

module.exports = {
   hasOwn,
   toInt,
   isPositiveInt,
   parsePagination,
   normalizeParentId,
   normalizeNullableInt,
   normalizeInsertPosition,
   normalizeOrderedInput,
   ensureCreatedBy,
   ensureNonEmptyString,
   ensureObjectPayload,
};