response/paging.go

package response

import (
	"errors"
	"fmt"
)

type PagingInfo struct {
	HasPreviousPage        bool   `json:"has_previous_page"`
	HasNextPage            bool   `json:"has_next_page"`
	CurrentPage            int    `json:"current_page"`
	PerPage                int    `json:"per_page"`
	TotalData              int    `json:"total_data"`
	LastPage               int    `json:"last_page"`
	From                   int    `json:"from"`
	To                     int    `json:"to"`
	TotalDataInCurrentPage int    `json:"total_data_in_current_page"`
	Label                  string `json:"label"`
}

var ErrPageInfo = errors.New("per_page harus lebih besar dari 0 dan offset tidak boleh negatif")

func NewPagingInfo(currentPage, perPage, offset, totalData int) (*PagingInfo, error) {
	if perPage <= 0 || offset < 0 {
		return nil, ErrPageInfo
	}

	lastPage := totalData / perPage
	if totalData%perPage != 0 {
		lastPage++
	}

	to := min(offset+perPage, totalData)
	from := int(0)
	if to > offset {
		from = offset + 1
	}

	if currentPage > lastPage {
		currentPage = lastPage
	}

	totalDataInCurrentPage := to - offset
	label := fmt.Sprintf("Menampilkan %d sampai %d dari %d data", from, to, totalData)

	return &PagingInfo{
		HasPreviousPage:        currentPage > 1,
		HasNextPage:            currentPage < lastPage,
		CurrentPage:            currentPage,
		PerPage:                perPage,
		TotalData:              totalData,
		LastPage:               lastPage,
		From:                   from,
		To:                     to,
		TotalDataInCurrentPage: totalDataInCurrentPage,
		Label:                  label,
	}, nil
}