Paginate an array and order by descending "id"

pagination.go

package main

import (
	"fmt"
	"math"
	"sort"
)

type idSorter []article

func (a idSorter) Len() int           { return len(a) }
func (a idSorter) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
func (a idSorter) Less(i, j int) bool { return a[i].id > a[j].id }

type article struct {
	id    int
	title string
}

var perPage = 3
var articles = []article{
	{1, "First"},
	{2, "Second"},
	{3, "Third"},
	{4, "Fourth"},
	{5, "Fifth"},
	{6, "Sixth"},
	{7, "Seventh"},
	{8, "Eighth"},
	{9, "Ninth"},
	{10, "Tenth"},
}

func main() {
	max := maxPagesPagination(len(articles))
	sort.Sort(idSorter(articles))

	for i := 1; i <= max; i++ {
		fmt.Println(paginate(i, len(articles)))
	}

	/* Display result like :
	[{10 Tenth} {9 Ninth} {8 Eighth}]
	[{7 Seventh} {6 Sixth} {5 Fifth}]
	[{4 Fourth} {3 Third} {2 Second}]
	[{1 First}]
	*/
}

// Return max of pages
func maxPagesPagination(total int) int {
	pagesNumber := math.Ceil(float64(total) / float64(perPage))

	return int(pagesNumber)
}

// Return each page content
func paginate(currentPage int, total int) []article {
	firstEntry := (currentPage - 1) * perPage
	lastEntry := firstEntry + perPage

	if lastEntry > total {
		lastEntry = total
	}

	return articles[firstEntry:lastEntry]
}