package backend

import (
	"crypto/rand"
	"encoding/gob"
	"fmt"
	"io"
	"os"

	"github.com/gorilla/sessions"
)

type (
	CookieStore struct{ sessions.CookieStore }
	Session     struct{ sessions.Session }
)

func NewKey() ([]byte, error) {
	key := make([]byte, 32)

	if _, err := io.ReadFull(rand.Reader, key); err != nil {
		return nil, fmt.Errorf("error generating key: %v", err)
	}

	return key, nil
}

func SaveKey(key []byte, filename string) error {
	file, err := os.Create(filename)
	if err != nil {
		return fmt.Errorf("error creating key file: %v", err)
	}
	defer file.Close()
	file.Chmod(0600)

	if err = gob.NewEncoder(file).Encode(key); err != nil {
		return fmt.Errorf("error ecoding key: %v", err)
	}

	return nil
}

func LoadKey(filename string) ([]byte, error) {
	file, err := os.Open(filename)
	if err != nil {
		return nil, fmt.Errorf("error opening key file: %v", err)
	}
	defer file.Close()

	key := make([]byte, 32)
	if err = gob.NewDecoder(file).Decode(&key); err != nil {
		return nil, fmt.Errorf("error decoding key: %v", err)
	}

	return key, nil
}

func NewCookieStore(key []byte) *CookieStore {
	store := sessions.NewCookieStore(key)
	store.Options.Secure = true
	store.Options.HttpOnly = true
	return &CookieStore{*store}
}