handlers.go

package internal

import (
	"fmt"
	"log"
	"net/http"
	"strconv"
	"time"

	"github.com/pquerna/otp/totp"
)

func LoginHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method == http.MethodGet {
		w.Header().Set("Content-Type", "text/html")
		_, _ = w.Write([]byte(rendorLoginFormTpl("")))
		return
	}

	if r.Method == http.MethodPost {
		if time.Since(lastLoginAttemptTime) < time.Duration(LoginStopSeconds) * time.Second {

			msg := fmt.Sprintf("Slow down. Hold your horses for %d seconds.", LoginStopSeconds)
			log.Print(msg)

			w.WriteHeader(http.StatusTooManyRequests)
			_, _ = w.Write([]byte(rendorLoginFormTpl(msg)))
			return
		}

		lastLoginAttemptTime = time.Now()

		_ = r.ParseForm()
		code := r.PostForm.Get("code")

		if Password != "" { // check hash with password
			hash :=  r.PostForm.Get("hash")
			hash64, _ := strconv.ParseInt(hash, 10, 32)
			localHash := simpleHash(Password + code)

			if hash64 != localHash {
				log.Println("login failed for hash check")
				w.Header().Set("Content-Type", "text/html")
				_, _ = w.Write([]byte(rendorLoginFormTpl("Login failed")))
				return
			}
		}

		originalURI := r.URL.RawQuery
		if originalURI == "" {
			originalURI = "/"
		}

		if totp.Validate(code, Secret) {
			jwtToken := jwtManager.GenerateToken("0")

			http.SetCookie(w, &http.Cookie{
				Name:       CookieName,
				Value:      jwtToken,
				Path:       "/",
				Domain:     "",
				Expires:    time.Now().Add(time.Second * time.Duration(MaxAge)),
				RawExpires: "",
				MaxAge:     0,
				Secure:     false,
				HttpOnly:   false,
				SameSite:   0,
				Raw:        "",
				Unparsed:   nil,
			})

			log.Print("login success")

			http.Redirect(w, r, originalURI, http.StatusFound)
			return
		}

		log.Print("login failed")

		w.Header().Set("Content-Type", "text/html")
		_, _ = w.Write([]byte(rendorLoginFormTpl("Login failed")))
		return
	}

	w.WriteHeader(http.StatusNotFound)
}

// CheckAuthHandler validate jwt in cookies, response 401 when invalid
func CheckAuthHandler(w http.ResponseWriter, r *http.Request) {
	jwtCookie, err := r.Cookie(CookieName)
	if err != nil {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	jwtToken := jwtCookie.Value

	ok, err := jwtManager.Valid(jwtToken, "0")

	if ok {
		w.WriteHeader(http.StatusOK)
		return
	}

	log.Print("auth failed ", err)
	w.WriteHeader(http.StatusUnauthorized)
}

// simpleHash
func simpleHash(input string) int64 {
	var hash int32 = 0
	for i := 0; i < len(input); i++ {
		char := input[i]
		hash = (hash<<5 + hash) + int32(char)
		hash &= hash
	}
	return int64(hash)
}