package main

import (
	"flag"
	"fmt"
	"log"
	"net/http"
	"strconv"
)

type passwordData struct {
	Length     int
	Digits     int
	Symbols    int
	NoUpper    bool
	DenyRepeat bool
	Password   string
}

var d, defaults passwordData

func generatePassword(w http.ResponseWriter, r *http.Request) {
	var err error

	if r.URL.Path != "/" {
		http.Error(w, "404 not found.", http.StatusNotFound)
		return
	}

	switch r.Method {
	case "GET":
		d.Password, err = generate(defaults.Length, defaults.Digits, defaults.Symbols, false, false)
		if err != nil {
			d.Password = "Error: " + err.Error()
			w.WriteHeader(http.StatusInternalServerError)
			w.Write([]byte(d.Password))
			return
		}
		w.WriteHeader(http.StatusOK)
		w.Write([]byte(d.Password))
	case "POST":
		if err = r.ParseForm(); err != nil {
			w.WriteHeader(http.StatusUnprocessableEntity)
			w.Write([]byte(fmt.Sprintf("ParseForm() err: %v", err)))
			return
		}
		d.Length, err = strconv.Atoi(r.FormValue("length"))
		if err != nil {
			d.Length = defaults.Length
		}

		d.Digits, err = strconv.Atoi(r.FormValue("digits"))
		if err != nil {
			d.Digits = defaults.Digits
		}

		d.Symbols, err = strconv.Atoi(r.FormValue("symbols"))
		if err != nil {
			d.Symbols = defaults.Symbols
		}

		if r.FormValue("noupper") == "on" {
			d.NoUpper = true
		}

		if r.FormValue("denyrepeat") == "on" {
			d.DenyRepeat = true
		}

		d.Password, err = generate(d.Length, d.Digits, d.Symbols, d.NoUpper, !d.DenyRepeat)
		if err != nil {
			d.Password = "Error: " + err.Error()
			w.WriteHeader(http.StatusInternalServerError)
			w.Write([]byte(d.Password))
			return
		}
		if d.Length == 0 {
			d.Password = "Error: password can not have zero length"
		}
		w.WriteHeader(http.StatusOK)
		w.Write([]byte(d.Password))
	default:
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte("Sorry, only GET and POST methods are supported."))
	}
}

func checkHealth(w http.ResponseWriter, r *http.Request) {
	w.WriteHeader(http.StatusOK)
	w.Write([]byte("Status:OK"))
}

func main() {

	// Set defaults
	portPtr := flag.Int("listen", 8080, "Specify on which port to listen")
	lengthPtr := flag.Int("length", 16, "Specify the password length")
	digitsPtr := flag.Int("digits", 2, "Specify the the number of digits in the password")
	symbolsPtr := flag.Int("symbols", 2, "Specify the the number of symbols in the password")
	flag.Parse()

	defaults.Length = *lengthPtr
	defaults.Digits = *digitsPtr
	defaults.Symbols = *symbolsPtr

	http.HandleFunc("/", generatePassword)
	http.HandleFunc("/health", checkHealth)

	log.Fatal(http.ListenAndServe(":"+strconv.Itoa(*portPtr), nil))
}