package main

import (
	"crypto/rand"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"unicode"

	log "github.com/sirupsen/logrus"
	"golang.org/x/crypto/nacl/secretbox"

	. "git.deuxfleurs.fr/Deuxfleurs/easybridge/connector"
)

const EASYBRIDGE_SYSTEM_PROTOCOL string = "✯◡✯"

func ezbrMxId() string {
	return fmt.Sprintf("@%s:%s", registration.SenderLocalpart, config.MatrixDomain)
}

func ezbrSystemRoom(user_mx_id string) (string, error) {
	return dbGetMxPmRoom(EASYBRIDGE_SYSTEM_PROTOCOL, UserID("Easybridge"), ezbrMxId(), user_mx_id, "easybridge")
}

func ezbrSystemSend(user_mx_id string, msg string) {
	mx_room_id, err := ezbrSystemRoom(user_mx_id)
	if err == nil {
		err = mx.SendMessageAs(mx_room_id, "m.text", msg, ezbrMxId())
	}
	if err != nil {
		log.Warnf("(%s) %s", user_mx_id, msg)
	}
}

func ezbrSystemSendf(user_mx_id string, format string, args ...interface{}) {
	ezbrSystemSend(user_mx_id, fmt.Sprintf(format, args...))
}

// ----

func roomAlias(protocol string, id RoomID) string {
	return fmt.Sprintf("_ezbr__%s__%s", safeStringForId(string(id)), protocol)
}

func userMxId(protocol string, id UserID) string {
	return fmt.Sprintf("_ezbr__%s__%s", safeStringForId(string(id)), protocol)
}

func safeStringForId(in string) string {
	id2 := ""
	for _, c := range in {
		if c == '@' {
			id2 += "__"
		} else if c == ':' {
			id2 += "_"
		} else if unicode.IsDigit(c) || unicode.IsLetter(c) || c == '.' || c == '-' || c == '_' {
			id2 += string(c)
		}
	}
	return id2
}

// ---- Encoding and encryption of account config

func encryptAccountConfig(config map[string]string, key *[32]byte) string {
	bytes, err := json.Marshal(config)
	if err != nil {
		log.Fatal(err)
	}

	var nonce [24]byte
	_, err = rand.Read(nonce[:])
	if err != nil {
		log.Fatal(err)
	}

	crypto := secretbox.Seal([]byte{}, bytes, &nonce, key)
	all := append(nonce[:], crypto...)
	return base64.StdEncoding.EncodeToString(all)
}

func decryptAccountConfig(data string, key *[32]byte) (map[string]string, error) {
	bytes, err := base64.StdEncoding.DecodeString(data)
	if err != nil {
		return nil, err
	}

	var nonce [24]byte
	copy(nonce[:], bytes[:24])

	decoded, ok := secretbox.Open([]byte{}, bytes[24:], &nonce, key)
	if !ok {
		return nil, fmt.Errorf("Invalid key")
	}

	var config map[string]string
	err = json.Unmarshal(decoded, &config)
	return config, err
}