/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package pager

import (
	"reflect"
)

// PageModel page model
type PageModel struct {
	Count int64       `json:"count"`
	List  interface{} `json:"list"`
}

// PageCond page condition
type PageCond struct {
	Page     int
	PageSize int
}

// NewPageModel new page model
func NewPageModel(totalRecords int64, records interface{}) *PageModel {
	sliceValue := reflect.Indirect(reflect.ValueOf(records))
	if sliceValue.Kind() != reflect.Slice {
		panic("not a slice")
	}

	if totalRecords < 0 {
		totalRecords = 0
	}

	return &PageModel{
		Count: totalRecords,
		List:  records,
	}
}

// ValPageAndPageSize validate page pageSize
func ValPageAndPageSize(page, pageSize int) (int, int) {
	if page <= 0 {
		page = 1
	}
	if pageSize <= 0 {
		pageSize = 10
	}
	return page, pageSize
}

// ValPageOutOfRange validate page out of range
func ValPageOutOfRange(total int64, page, pageSize int) bool {
	if total <= 0 {
		return false
	}
	if pageSize <= 0 {
		return true
	}
	totalPages := (total + int64(pageSize) - 1) / int64(pageSize)
	return page < 1 || page > int(totalPages)
}
