package mongostore

import (
	"context"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/bson/primitive"
	"net/http"
	"time"

	"github.com/gorilla/securecookie"
	"github.com/gorilla/sessions"
	"go.mongodb.org/mongo-driver/mongo"
)

type MongoStore struct {
	client  *mongo.Client
	Codecs  []securecookie.Codec
	Options *sessions.Options

	dbDatabaseName   string
	dbCollectionName string
	dbTimeout        time.Duration
}

func NewMongoStore(client *mongo.Client, dbDatabase, dbCollection string, dbTimeout time.Duration) *MongoStore {
	s := new(MongoStore)
	s.client = client
	s.dbDatabaseName = dbDatabase
	s.dbCollectionName = dbCollection
	s.dbTimeout = dbTimeout
	return s
}

func (s *MongoStore) New(r *http.Request, name string) (*sessions.Session, error) {
	session := sessions.NewSession(s, name)
	options := *s.Options
	session.Options = &options
	session.IsNew = true
	cookie, e := r.Cookie(name)
	if e != nil {
		return nil, e
	}
	e = securecookie.DecodeMulti(name, cookie.Value, &session.ID, s.Codecs...)
	if e != nil {
		return nil, e
	}
	e = s.load(session)
	if e != nil {
		return nil, e
	} else {
		session.IsNew = false
	}
	return session, nil
}

func (s *MongoStore) Get(r *http.Request, name string) (*sessions.Session, error) {
	return sessions.GetRegistry(r).Get(s, name)
}

func (s *MongoStore) Save(r *http.Request, w http.ResponseWriter, session *sessions.Session) error {
	panic("not implemented")
}

func (s *MongoStore) Delete(r *http.Request, w http.ResponseWriter, session *sessions.Session) error {
	panic("not implemented")
}

func (s *MongoStore) Close() error {
	ctx, _ := context.WithTimeout(context.Background(), 3*time.Second)
	return s.client.Disconnect(ctx)
}

func (s *MongoStore) load(session *sessions.Session) error {
	oid, e := primitive.ObjectIDFromHex(session.ID)
	if e != nil {
		return e
	}
	collection := s.client.Database(s.dbDatabaseName).Collection(s.dbCollectionName)
	ctx, _ := context.WithTimeout(context.Background(), s.dbTimeout)
	result := collection.FindOne(ctx, bson.M{"_id": oid})
	ns := new(Session)
	if e := result.Decode(ns); e != nil {
		return e
	}
	if e := securecookie.DecodeMulti(session.Name(), string(ns.Data), &session.Values, s.Codecs...); e != nil {
		return e
	}
	return nil
}