package main

import (
	"context"
	_ "embed"
	"encoding/json"
	"errors"
	"flag"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/signal"
	"sync"
	"syscall"
)

var (
	Config struct {
		Port      int
		SessionD  string
		Debug     bool
		Semaphore sync.Mutex
	}

	//go:embed template.d/login.html
	htmlLogin []byte
	//go:embed template.d/index.html
	htmlIndex []byte
)

func main() {
	ctx, can := signal.NotifyContext(context.Background(), syscall.SIGINT)
	defer can()

	ctx, cleanup := contextWithCleanup(ctx)
	defer cleanup()

	config(ctx)
	log.Printf("%+v", Config)

	listenAndServe(ctx)
	log.Println("done")
}

func contextWithCleanup(ctx context.Context) (context.Context, func()) {
	m := map[int]func(){}
	ctx = context.WithValue(ctx, "__cleanup__", m)
	return ctx, func() {
		defer func() {
			recover()
		}()
		for _, v := range m {
			v()
		}
	}
}

func contextWithCleanupFunc(ctx context.Context, foo func()) {
	v := ctx.Value("__cleanup__")
	if v == nil {
		panic("cannot get context with cleanup func that doesnt have cleanup init")
	}
	m := v.(map[int]func())
	m[len(m)] = foo
}

func config(ctx context.Context) {
	d, err := os.MkdirTemp(os.TempDir(), "ai.*")
	if err != nil {
		panic(err)
	}
	contextWithCleanupFunc(ctx, func() { os.RemoveAll(d) })

	flag.IntVar(&Config.Port, "p", 37070, "port to listen on")
	flag.StringVar(&Config.SessionD, "d", d, "dir to store sessions")
	flag.BoolVar(&Config.Debug, "debug", false, "debug mode")
	flag.Parse()
}

func listenAndServe(ctx context.Context) {
	wg := &sync.WaitGroup{}
	s := &http.Server{
		Addr:    fmt.Sprintf(":%d", Config.Port),
		Handler: http.HandlerFunc(handle),
	}
	wg.Add(1)
	go func() {
		defer wg.Done()
		if err := s.ListenAndServe(); err != nil && ctx.Err() == nil {
			panic(err)
		}
	}()

	<-ctx.Done()
	s.Close()
	wg.Wait()
}

func handle(w http.ResponseWriter, r *http.Request) {
	if err := _handle(w, r); err != nil {
		u, _, _ := r.BasicAuth()
		log.Printf("%s: %s: %v", u, r.URL.Path, err)
	}
}

func _handle(w http.ResponseWriter, r *http.Request) error {
	u, p, ok := r.BasicAuth()
	if !ok {
		w.Header().Set("WWW-Authenticate", "Basic")
		w.WriteHeader(http.StatusUnauthorized)
		return errors.New("no auth")
	}
	_, _ = u, p

	Config.Semaphore.Lock()
	defer Config.Semaphore.Unlock()

	return errors.New("not impl")
}

type Cookie struct {
	Name string
}

func ParseCookie(r *http.Request) (Cookie, error) {
	cookie, err := r.Cookie("root")
	if err != nil {
		return Cookie{}, err
	}

	var result Cookie
	if err := json.Unmarshal([]byte(cookie.Value), &result); err != nil {
		return Cookie{}, err
	}

	if result.Name == "" {
		return Cookie{}, errors.New("incomplete cookie")
	}

	return result, nil
}

func (cookie Cookie) Serialize(w http.ResponseWriter) {
	b, _ := json.Marshal(cookie)
	c := &http.Cookie{
		Name:  "root",
		Value: string(b),
	}
	http.SetCookie(w, c)
}