package rbac

import (
	"code.fbi.h-da.de/danet/gosdn/controller/interfaces/rbac"
	"code.fbi.h-da.de/danet/gosdn/controller/nucleus/database"
	"code.fbi.h-da.de/danet/gosdn/controller/nucleus/errors"
	"code.fbi.h-da.de/danet/gosdn/controller/store"
	"github.com/google/uuid"
	log "github.com/sirupsen/logrus"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/bson/primitive"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
)

// DatabaseUserStore is used to store users in database
type DatabaseUserStore struct {
	userStoreName string
}

// Add adds an User.
func (s *DatabaseUserStore) Add(userToAdd rbac.User) error {
	client, ctx, cancel := database.GetMongoConnection()
	defer cancel()
	defer client.Disconnect(ctx)

	_, err := client.Database(database.DatabaseName).
		Collection(s.userStoreName).
		InsertOne(ctx, userToAdd)
	if err != nil {
		if mongo.IsDuplicateKeyError(err) {
			return nil
		}

		return errors.ErrCouldNotCreate{StoreName: s.userStoreName}
	}

	return nil
}

// Delete deletes an User.
func (s *DatabaseUserStore) Delete(userToDelete rbac.User) error {
	client, ctx, cancel := database.GetMongoConnection()
	defer cancel()
	defer client.Disconnect(ctx)

	_, err := client.Database(database.DatabaseName).
		Collection(s.userStoreName).
		DeleteOne(ctx, bson.D{primitive.E{Key: "_id", Value: userToDelete.ID().String()}})
	if err != nil {
		return errors.ErrCouldNotFind{ID: userToDelete.ID(), Name: userToDelete.Name()}
	}

	return nil
}

// Get takes a User's UUID or name and returns the User. If the requested
// User does not exist an error is returned.
func (s *DatabaseUserStore) Get(query store.Query) (rbac.LoadedUser, error) {
	var loadedUser rbac.LoadedUser

	if query.ID != uuid.Nil {
		loadedUser, err := s.getByID(query.ID)
		if err != nil {
			return loadedUser, err
		}

		return loadedUser, nil
	}

	loadedUser, err := s.getByName(query.Name)
	if err != nil {
		return loadedUser, err
	}

	return loadedUser, nil
}

func (s *DatabaseUserStore) getByID(idOfUser uuid.UUID) (rbac.LoadedUser, error) {
	var loadedUser rbac.LoadedUser

	client, ctx, cancel := database.GetMongoConnection()
	defer cancel()
	defer client.Disconnect(ctx)

	db := client.Database(database.DatabaseName)
	collection := db.Collection(s.userStoreName)
	result := collection.FindOne(ctx, bson.D{primitive.E{Key: "_id", Value: idOfUser.String()}})
	if result == nil {
		return loadedUser, errors.ErrCouldNotFind{ID: idOfUser}
	}

	err := result.Decode(&loadedUser)
	if err != nil {
		log.Printf("Failed marshalling %v", err)
		return loadedUser, errors.ErrCouldNotMarshall{StoreName: s.userStoreName}
	}

	return loadedUser, nil
}

func (s *DatabaseUserStore) getByName(nameOfUser string) (rbac.LoadedUser, error) {
	var loadedUser rbac.LoadedUser

	client, ctx, cancel := database.GetMongoConnection()
	defer cancel()
	defer client.Disconnect(ctx)

	db := client.Database(database.DatabaseName)
	collection := db.Collection(s.userStoreName)
	result := collection.FindOne(ctx, bson.D{primitive.E{Key: "username", Value: nameOfUser}})
	if result == nil {
		return loadedUser, errors.ErrCouldNotFind{Name: nameOfUser}
	}

	err := result.Decode(&loadedUser)
	if err != nil {
		log.Printf("Failed marshalling %v", err)
		return loadedUser, errors.ErrCouldNotMarshall{StoreName: s.userStoreName}
	}

	return loadedUser, nil
}

// GetAll returns all Users
func (s *DatabaseUserStore) GetAll() ([]rbac.LoadedUser, error) {
	var loadedUsers []rbac.LoadedUser

	client, ctx, cancel := database.GetMongoConnection()
	defer cancel()
	defer client.Disconnect(ctx)
	db := client.Database(database.DatabaseName)
	collection := db.Collection(s.userStoreName)

	cursor, err := collection.Find(ctx, bson.D{})
	if err != nil {
		return nil, err
	}
	defer cursor.Close(ctx)

	err = cursor.All(ctx, &loadedUsers)
	if err != nil {
		log.Printf("Failed marshalling %v", err)

		return nil, errors.ErrCouldNotMarshall{StoreName: s.userStoreName}
	}
	return loadedUsers, nil
}

// Update updates the User.
func (s *DatabaseUserStore) Update(userToUpdate rbac.User) error {
	var updatedLoadedUser rbac.LoadedUser

	client, ctx, cancel := database.GetMongoConnection()
	defer cancel()
	defer client.Disconnect(ctx)

	update := bson.D{primitive.E{Key: "$set", Value: userToUpdate}}

	upsert := false
	after := options.After
	opt := options.FindOneAndUpdateOptions{
		Upsert:         &upsert,
		ReturnDocument: &after,
	}

	err := client.Database(database.DatabaseName).
		Collection(s.userStoreName).
		FindOneAndUpdate(
			ctx, bson.M{"_id": userToUpdate.ID().String()}, update, &opt).
		Decode(&updatedLoadedUser)
	if err != nil {
		log.Printf("Could not update User: %v", err)

		return errors.ErrCouldNotUpdate{StoreName: s.userStoreName}
	}

	return nil
}