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package main

import (
	"crypto/ed25519"
	"encoding/base64"
	"encoding/gob"
	"errors"
	"net/http"
	"os"
	"strings"
)

type user struct {
	dhtVal []byte
	phase  int64
}

var users map[string]user

// Verify that a body was signed by this ID
func verify(id string, body []byte) error {
	b, err := base64.RawURLEncoding.DecodeString(id)
	if err != nil {
		return err
	}
	if len(body) < ed25519.SignatureSize {
		return errors.New("body too short")
	}
	message := body[:len(body)-ed25519.SignatureSize]
	sig := body[len(body)-ed25519.SignatureSize:]
	if !ed25519.Verify(ed25519.PublicKey(b), message, sig) {
		return errors.New("signature verification failed")
	}
	return nil
}

// Persist a user's data to disk
func persist(id string) {
	writer, err := os.Open(dataDir + "/" + id + "/gob")
	if err != nil {
		return
	}
	enc := gob.NewEncoder(writer)
	enc.Encode(users[id])
}

// Handle user configuration changes
func userHandler(w http.ResponseWriter, r *http.Request) {
	id := r.URL.Fragment[6:]
	// Resolve ID to server list
	val := dhtGet(id, "")
	if verify(id, val) != nil {
		w.WriteHeader(http.StatusNotFound)
		return
	}
	// Check if server list contains this server
	message := string(val[:len(val)-ed25519.SignatureSize])
	if !strings.Contains(message, me) {
		// Delete user if they are no longer associated with this server
		delete(users, id)
		err := os.RemoveAll(id)
		if err != nil {
			w.WriteHeader(http.StatusNotFound)
			return
		}
		w.WriteHeader(http.StatusOK)
		return
	}
	//valSplit := strings.Split(message, "\n")
	//servers := valSplit[1:len(valSplit)-1]

	if _, ok := users[id]; !ok {
		// Add user
		users[id] = user{
			dhtVal: val,
		}
		os.Mkdir(id, 0755)
		persist(id)
	}
}