package main

import (
	"encoding/json"
	"fmt"
	"net/http"
	"strings"
	"text/template"
	"time"

	"github.com/xlzd/gotp"
)

var addr = "0.0.0.0:8080"

type secret struct {
	S string `json:"secret"`
}
type code struct {
	C string `json:"code"`
	T int    `json:"time"`
}

func calculate(w http.ResponseWriter, r *http.Request) {
	var s secret
	json.NewDecoder(r.Body).Decode(&s)
	totp := gotp.NewDefaultTOTP(s.S).Now()
	c := &code{
		C: totp,
		T: int(30 - time.Now().Unix()%30),
	}
	response, _ := json.Marshal(c)
	w.Header().Set("Content-Type", "application/json")
	w.Write(response)
}

func index(w http.ResponseWriter, r *http.Request) {
	t, _ := template.ParseFiles("templates/index.html")
	t.Execute(w, nil)
}

func main() {
	staticFolder := http.FileServer(http.Dir("./static"))
	http.HandleFunc("/", index)
	http.HandleFunc("/calculate", calculate)
	http.Handle("/static/", http.StripPrefix(strings.TrimRight("/static/", "/"), staticFolder))
	fmt.Println("Listening on ", addr)
	http.ListenAndServe(addr, nil)
}