utils/pagination/v1/pagination.go

package pagination

import "math"

const (
	DefaultPage = 1
	MinPageSize = 10
	MaxPageSize = 100
)

type Pagination struct {
	Page      int32 `json:"page"`
	PageSize  int32 `json:"page_size"`
	TotalPage int32 `json:"total_page"`
	Total     int32 `json:"total"`
}

type Integer interface {
	~int | ~int32
}

func PageToOffset[T Integer](page, pageSize T) (offset, limit T) {
	if page < DefaultPage {
		page = DefaultPage
	}

	if pageSize <= MinPageSize {
		pageSize = MinPageSize
	}

	if pageSize >= MaxPageSize {
		pageSize = MaxPageSize
	}

	offset = (page - 1) * pageSize
	limit = pageSize
	return
}

func CalcPagination[T Integer, E Integer](page, pageSize T, total E) (res Pagination) {
	if page < DefaultPage {
		page = DefaultPage
	}

	if pageSize <= MinPageSize {
		pageSize = MinPageSize
	}

	if pageSize >= MaxPageSize {
		pageSize = MaxPageSize
	}
	res.Page = int32(page)
	res.PageSize = int32(pageSize)
	res.Total = int32(total)

	res.TotalPage = int32(math.Ceil(float64(res.Total) / float64(res.PageSize)))

	return
}