// +build go1.16

package funcs_test

import (
	"fmt"
	"strings"
	"testing"
	"testing/fstest"

	"sync"

	"io/fs"

	"github.com/gin-gonic/gin"
	"go.sebtobie.de/httpserver/funcs"
)

const al = "abcdefghijklmnopqrstunwxyz"

type Node struct {
	name     string
	children []*Node
}

func (n *Node) getchildren(dir string, m *sync.Map, wg *sync.WaitGroup) {
	var p = n.name
	if dir != "" {
		p = strings.Join([]string{dir, n.name}, "/")
	}
	if len(n.children) != 0 {
		m.Store(p, &fstest.MapFile{Mode: fs.ModeDir | fs.ModePerm})
		for _, c := range n.children {
			wg.Add(1)
			go c.getchildren(p, m, wg)
		}
	} else {
		m.Store(p, &fstest.MapFile{Data: []byte(p), Mode: fs.ModePerm})
	}
	wg.Done()
}

func getFS(depth, width int) fstest.MapFS {
	var nodes = &Node{
		"",
		createNodes(depth, width),
	}
	var m = sync.Map{}
	var wg = sync.WaitGroup{}
	wg.Add(1)
	go nodes.getchildren("", &m, &wg)
	wg.Wait()
	var fs = make(fstest.MapFS)
	m.Range(func(key, value interface{}) bool {
		fs[key.(string)] = value.(*fstest.MapFile)
		return true
	})
	return fs
}

func name(i int) string {
	var output string
	for {
		if i < 26 {
			output = output + string(al[i])
			break
		}
		output += string(al[i%26])
		i = (i - (i % 26)) / 26
	}
	return output
}

func createNodes(depth, width int) (n []*Node) {
	if depth != 0 {
		for i := 0; i < width; i++ {
			n = append(n, &Node{string(name(i)), createNodes(depth-1, width)})
		}
	}
	return
}

func toMap(routes gin.RoutesInfo) (m map[string]gin.RouteInfo) {
	m = make(map[string]gin.RouteInfo)
	for _, r := range routes {
		m[r.Path] = r
	}
	return
}

func TestStaticFS(t *testing.T) {
	t.Parallel()
	var (
		r               = gin.New()
		rg              = r.Group("")
		fs fstest.MapFS = getFS(5, 10)
	)
	funcs.StaticFS(rg, &fs)
	routes := toMap(r.Routes())
	t.Log(routes)
	for path, node := range fs {
		if node.Mode.IsDir() {
			continue
		}
		_, found := routes["/"+path]
		if !found {
			t.Errorf("Path %s was not handled", path)
		}
	}
}

func BenchmarkStaticFS(b *testing.B) {
	ro := gin.New()
	fs := getFS(52, 2)
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		g := ro.Group(fmt.Sprint(i))
		funcs.StaticFS(g, fs)
	}
}