// UpsertForm upserts the provided form into the MongoDB database collection and
// creates a gallery based on it.
func UpsertForm(context interface{}, db *db.DB, f *form.Form) error {
	log.Dev(context, "UpsertForm", "Started : Form[%s]", f.ID.Hex())

	var isNewForm bool

	// If there was no ID provided, we should set one. UpsertForm might optionally add
	// a form ID to ensure that we don't duplicate the FormGallery.
	if f.ID.Hex() == "" {
		isNewForm = true
	}

	if err := form.Upsert(context, db, f); err != nil {
		log.Error(context, "UpsertForm", err, "Completed")
		return err
	}

	if isNewForm {

		// Create the new gallery that we will create that is based on the current
		// form ID.
		g := gallery.Gallery{
			FormID: f.ID,
		}

		if err := gallery.Create(context, db, &g); err != nil {
			log.Error(context, "UpsertForm", err, "Completed")
			return err
		}
	}

	log.Dev(context, "UpsertForm", "Completed")
	return nil
}

// Mongo handles session management.
func Mongo(h app.Handler) app.Handler {

	// Check if mongodb is configured.
	dbName, err := cfg.String(cfgMongoDB)
	if err != nil {
		return func(c *app.Context) error {
			log.Dev(c.SessionID, "Mongo", "******> Mongo Not Configured")
			return h(c)
		}
	}

	// Wrap the handlers inside a session copy/close.
	return func(c *app.Context) error {
		mgoDB, err := db.NewMGO("Mongo", dbName)
		if err != nil {
			log.Error(c.SessionID, "Mongo", err, "Method[%s] URL[%s] RADDR[%s]", c.Request.Method, c.Request.URL.Path, c.Request.RemoteAddr)
			return app.ErrDBNotConfigured
		}

		log.Dev(c.SessionID, "Mongo", "******> Capture Mongo Session")
		c.DB = mgoDB
		defer func() {
			log.Dev(c.SessionID, "Mongo", "******> Release Mongo Session")
			mgoDB.CloseMGO("Mongo")
		}()

		return h(c)
	}
}

// newClient creates a new client for an incoming connection.
func newClient(context string, t *TCP, conn net.Conn) *client {
	ipAddress := conn.RemoteAddr().String()
	log.Dev(context, "newClient", "Started : IPAddress[%s]", ipAddress)

	// Ask the user to bind the reader and writer they want to
	// use for this connection.
	r, w := t.ConnHandler.Bind(context, conn)

	c := client{
		context:   context,
		t:         t,
		conn:      conn,
		ipAddress: ipAddress,
		reader:    r,
		writer:    w,
	}

	// Check to see if this connection is ipv6.
	if raddr := conn.RemoteAddr().(*net.TCPAddr); raddr.IP.To4() == nil {
		c.isIPv6 = true
	}

	// Launch a goroutine for this connection.
	c.wg.Add(1)
	go c.read()

	log.Dev(context, "newClient", "Completed")
	return &c
}

// DeleteSubmission deletes a submission as well as updating a form's stats.
func DeleteSubmission(context interface{}, db *db.DB, id, formID string) error {
	log.Dev(context, "DeleteSubmission", "Started : Submission[%s]", id)

	if !bson.IsObjectIdHex(id) {
		log.Error(context, "DeleteSubmission", ErrInvalidID, "Completed")
		return ErrInvalidID
	}

	if !bson.IsObjectIdHex(formID) {
		log.Error(context, "Delete", ErrInvalidID, "Completed")
		return ErrInvalidID
	}

	if err := submission.Delete(context, db, id); err != nil {
		log.Error(context, "DeleteSubmission", err, "Completed")
		return err
	}

	if _, err := form.UpdateStats(context, db, formID); err != nil {
		log.Error(context, "DeleteSubmission", err, "Completed")
		return err
	}

	log.Dev(context, "DeleteSubmission", "Started")
	return nil
}

// New creates a new Pool.
func New(context interface{}, name string, cfg Config) (*Pool, error) {
	log.Dev(context, "New", "Started : Name[%s]", name)

	if cfg.MinRoutines == nil {
		return nil, ErrNilMinRoutines
	}
	if cfg.MinRoutines() <= 0 {
		return nil, ErrInvalidMinRoutines
	}

	if cfg.MaxRoutines == nil {
		return nil, ErrNilMaxRoutines
	}
	if cfg.MaxRoutines() < cfg.MinRoutines() {
		return nil, ErrInvalidMaxRoutines
	}

	p := Pool{
		Config: cfg,
		Name:   name,

		tasks:    make(chan doWork),
		control:  make(chan int),
		kill:     make(chan struct{}),
		shutdown: make(chan struct{}),
	}

	p.manager(context)
	p.add(context, cfg.MinRoutines())

	log.Dev(context, "New", "Completed")
	return &p, nil
}

// GetByName retrieves the document for the specified query mask.
func GetByName(context interface{}, db *db.DB, collection string, field string) (Mask, error) {
	log.Dev(context, "GetByName", "Started : Collection[%s] Field[%s]", collection, field)

	key := "gbn" + collection + field
	if v, found := cache.Get(key); found {
		mask := v.(Mask)
		log.Dev(context, "GetByName", "Completed : CACHE : Mask[%+v]", mask)
		return mask, nil
	}

	var mask Mask
	f := func(c *mgo.Collection) error {
		q := bson.M{"collection": collection, "field": field}
		log.Dev(context, "GetByName", "MGO : db.%s.findOne(%s)", c.Name, mongo.Query(q))
		return c.Find(q).One(&mask)
	}

	if err := db.ExecuteMGO(context, Collection, f); err != nil {
		if err == mgo.ErrNotFound {
			err = ErrNotFound
		}

		log.Error(context, "GetByName", err, "Completed")
		return Mask{}, err
	}

	cache.Set(key, mask, gc.DefaultExpiration)

	log.Dev(context, "GetByName", "Completed : Mask[%+v]", mask)
	return mask, nil
}

// GetByIDs retrieves items by ID from Mongo.
func GetByIDs(context interface{}, db *db.DB, ids []string) ([]Item, error) {
	log.Dev(context, "GetByIDs", "Started : IDs%v", ids)

	// Get the items from Mongo.
	var items []Item
	f := func(c *mgo.Collection) error {
		q := bson.M{"item_id": bson.M{"$in": ids}}
		log.Dev(context, "Find", "MGO : db.%s.find(%s)", c.Name, mongo.Query(q))
		return c.Find(q).All(&items)
	}
	if err := db.ExecuteMGO(context, Collection, f); err != nil {
		if err == mgo.ErrNotFound {
			err = ErrNotFound
		}
		log.Error(context, "GetByIDs", err, "Completed")
		return items, err
	}

	// If we got an unexpected number of items, throw an error.
	if len(ids) < len(items) {
		return nil, fmt.Errorf("Expected %d items, got %d: ", len(ids), len(items))
	}

	log.Dev(context, "GetByIDs", "Completed")
	return items, nil
}

// Midware handles databse session management and manages a MongoDB session.
func Midware(mongoURI *url.URL) web.Middleware {

	// Create the middleware that we can use to create MongoDB sessions with.
	m := func(next web.Handler) web.Handler {

		// Create the handler that will be attached in the middleware chain.
		h := func(c *web.Context) error {

			// Pull in the mongo session from the master session so we can load it
			// onto the request context. It is keyed by the path on the uri.
			db, err := kitdb.NewMGO(c.SessionID, mongoURI.Path)
			if err != nil {
				log.Error(c.SessionID, "mongo : Midware", err, "Method[%s] URL[%s] RADDR[%s]", c.Request.Method, c.Request.URL.Path, c.Request.RemoteAddr)
				return web.ErrDBNotConfigured
			}

			// Load the mongo database onto the request context.
			c.Ctx["DB"] = db

			log.Dev(c.SessionID, "mongo : Midware", "Capture Mongo Session")

			// Close the MongoDB session when the handler returns.
			defer func() {
				log.Dev(c.SessionID, "mongo : Midware", "Release Mongo Session")
				db.CloseMGO(c.SessionID)
			}()

			return next(c)
		}

		return h
	}

	return m
}

// Update updates the form gallery in the MongoDB database
// collection.
func Update(context interface{}, db *db.DB, id string, gallery *Gallery) error {
	log.Dev(context, "Update", "Started : Gallery[%s]", id)

	if !bson.IsObjectIdHex(id) {
		log.Error(context, "Update", ErrInvalidID, "Completed")
		return ErrInvalidID
	}

	if err := gallery.Validate(); err != nil {
		log.Error(context, "Update", err, "Completed")
		return err
	}

	objectID := bson.ObjectIdHex(id)

	gallery.DateUpdated = time.Now()

	f := func(c *mgo.Collection) error {
		log.Dev(context, "Update", "MGO : db.%s.update(%s, %s)", c.Name, mongo.Query(objectID), mongo.Query(gallery))
		return c.UpdateId(objectID, gallery)
	}

	if err := db.ExecuteMGO(context, Collection, f); err != nil {
		log.Error(context, "Update", err, "Completed")
		return err
	}

	log.Dev(context, "Update", "Completed")
	return nil
}

// Auth handles token authentication.
func Auth(h app.Handler) app.Handler {

	// Check if authentication is turned off.
	on, err := cfg.Bool(cfgAuth)
	if err == nil && !on {
		return func(c *app.Context) error {
			log.Dev(c.SessionID, "Auth", "******> Authentication Off")
			return h(c)
		}
	}

	// Turn authentication on.
	return func(c *app.Context) error {
		token := c.Request.Header.Get("Authorization")
		log.Dev(c.SessionID, "Auth", "Started : Token[%s]", token)

		if len(token) < 5 || token[0:5] != "Basic" {
			log.Error(c.SessionID, "Auth", app.ErrNotAuthorized, "Validating token")
			return app.ErrNotAuthorized
		}

		var err error
		if c.User, err = auth.ValidateWebToken(c.SessionID, c.DB, token[6:]); err != nil {
			log.Error(c.SessionID, "Auth", err, "Validating token")
			return app.ErrNotAuthorized
		}

		log.Dev(c.SessionID, "Auth", "Completed")
		return h(c)
	}
}

// GetAll retrieves a list of regexs.
func GetAll(context interface{}, db *db.DB, tags []string) ([]Regex, error) {
	log.Dev(context, "GetAll", "Started : Tags[%v]", tags)

	key := "grs" + strings.Join(tags, "-")
	if v, found := cache.Get(key); found {
		rgxs := v.([]Regex)
		log.Dev(context, "GetAll", "Completed : CACHE : Rgxs[%d]", len(rgxs))
		return rgxs, nil
	}

	var rgxs []Regex
	f := func(c *mgo.Collection) error {
		log.Dev(context, "GetAll", "MGO : db.%s.find({}).sort([\"name\"])", c.Name)
		return c.Find(nil).All(&rgxs)
	}

	if err := db.ExecuteMGO(context, Collection, f); err != nil {
		if err == mgo.ErrNotFound {
			err = ErrNotFound
		}

		log.Error(context, "GetAll", err, "Completed")
		return nil, err
	}

	if rgxs == nil {
		log.Error(context, "GetAll", ErrNotFound, "Completed")
		return nil, ErrNotFound
	}

	cache.Set(key, rgxs, gc.DefaultExpiration)

	log.Dev(context, "GetAll", "Completed : Rgxs[%d]", len(rgxs))
	return rgxs, nil
}

// Remove removes an item into the items collection and remove any
// corresponding quads from the graph database.
func Remove(context interface{}, db *db.DB, graph *cayley.Handle, itemID string) error {
	log.Dev(context, "Remove", "Started : ID[%s]", itemID)

	// Get the item from the items collection.
	items, err := item.GetByIDs(context, db, []string{itemID})
	if err != nil {
		log.Error(context, "Remove", err, "Completed")
		return err
	}

	// Prepare the item map data.
	itmMap := map[string]interface{}{
		"item_id": items[0].ID,
		"type":    items[0].Type,
		"version": items[0].Version,
		"data":    items[0].Data,
	}

	// Remove the corresponding relationships from the graph.
	if err := wire.RemoveFromGraph(context, db, graph, itmMap); err != nil {
		log.Error(context, "Remove", err, "Completed")
		return err
	}

	// Delete the item.
	if err := item.Delete(context, db, itemID); err != nil {
		log.Error(context, "Remove", err, "Completed")
		return err
	}

	log.Dev(context, "Remove", "Completed")
	return nil
}

// Count returns the count of current submissions for a given
// form id in the Form Submissions MongoDB database collection.
func Count(context interface{}, db *db.DB, formID string) (int, error) {
	log.Dev(context, "Count", "Completed : Form[%s]", formID)

	if !bson.IsObjectIdHex(formID) {
		log.Error(context, "Count", ErrInvalidID, "Completed")
		return 0, ErrInvalidID
	}

	formObjectID := bson.ObjectIdHex(formID)

	var count int
	f := func(c *mgo.Collection) error {
		var err error

		q := bson.M{
			"form_id": formObjectID,
		}
		log.Dev(context, "Count", "MGO : db.%s.find(%s).count()", c.Name, mongo.Query(q))
		count, err = c.Find(q).Count()
		return err
	}

	if err := db.ExecuteMGO(context, Collection, f); err != nil {
		log.Error(context, "Count", err, "Completed")
		return 0, err
	}

	log.Dev(context, "Count", "Completed")
	return count, nil
}

// RetrieveMany retrieves a list of Submission's from the MongoDB database collection.
func RetrieveMany(context interface{}, db *db.DB, ids []string) ([]Submission, error) {
	log.Dev(context, "RetrieveMany", "Started")

	var objectIDs = make([]bson.ObjectId, len(ids))

	for i, id := range ids {
		if !bson.IsObjectIdHex(id) {
			log.Error(context, "RetrieveMany", ErrInvalidID, "Completed")
			return nil, ErrInvalidID
		}

		objectIDs[i] = bson.ObjectIdHex(id)
	}

	var submissions []Submission
	f := func(c *mgo.Collection) error {
		q := bson.M{
			"_id": bson.M{
				"$in": objectIDs,
			},
		}
		log.Dev(context, "RetrieveMany", "MGO : db.%s.find(%s)", c.Name, mongo.Query(q))
		return c.Find(q).All(&submissions)
	}

	if err := db.ExecuteMGO(context, Collection, f); err != nil {
		log.Error(context, "RetrieveMany", err, "Completed")
		return nil, err
	}

	log.Dev(context, "RetrieveMany", "Started")
	return submissions, nil
}

// UpdateStatus updates a form submissions status inside the MongoDB database
// collection.
func UpdateStatus(context interface{}, db *db.DB, id, status string) (*Submission, error) {
	log.Dev(context, "UpdateStatus", "Started : Submission[%s]", id)

	if !bson.IsObjectIdHex(id) {
		log.Error(context, "UpdateStatus", ErrInvalidID, "Completed")
		return nil, ErrInvalidID
	}

	objectID := bson.ObjectIdHex(id)

	f := func(c *mgo.Collection) error {
		u := bson.M{
			"$set": bson.M{
				"status":       status,
				"date_updated": time.Now(),
			},
		}
		log.Dev(context, "UpdateStatus", "MGO : db.%s.update(%s, %s)", c.Name, mongo.Query(objectID), mongo.Query(u))
		return c.UpdateId(objectID, u)
	}

	if err := db.ExecuteMGO(context, Collection, f); err != nil {
		log.Error(context, "UpdateStatus", err, "Completed")
		return nil, err
	}

	submission, err := Retrieve(context, db, id)
	if err != nil {
		log.Error(context, "UpdateStatus", err, "Completed")
		return nil, err
	}

	log.Dev(context, "UpdateStatus", "Completed")
	return submission, nil
}

// Do will post the request to be sent by the client worker pool.
func (t *TCP) Do(context interface{}, r *Response) error {
	log.Dev(context, "Do", "Started : Local[ %s ] Remote[ %s ]", join(t.ipAddress, t.port), r.TCPAddr.String())

	// Find the client connection for this IPAddress.
	var c *client
	t.clientsMu.Lock()
	{
		// If this ipaddress and socket does not exist, report an error.
		var ok bool
		if c, ok = t.clients[r.TCPAddr.String()]; !ok {
			err := fmt.Errorf("IP Address disconnected [ %s ]", r.TCPAddr.String())
			log.Error(context, "Do", err, "Completed")

			t.clientsMu.Unlock()
			return err
		}
	}
	t.clientsMu.Unlock()

	// Set the unexported fields.
	r.tcp = t
	r.client = c
	r.context = context

	// Send this to the client work pool for processing.
	t.send.Do(context, r)

	log.Dev(context, "Do", "Completed")
	return nil
}

// Create adds a new Submission based on a given Form into
// the MongoDB database collection.
func Create(context interface{}, db *db.DB, formID string, submission *Submission) error {
	log.Dev(context, "Create", "Started : Form[%s]", formID)

	if !bson.IsObjectIdHex(formID) {
		log.Error(context, "Create", ErrInvalidID, "Completed")
		return ErrInvalidID
	}

	if err := submission.Validate(); err != nil {
		return err
	}

	// FIXME: handle Number field maybe with https://docs.mongodb.com/v3.0/tutorial/create-an-auto-incrementing-field/ to resolve race condition
	count, err := Count(context, db, formID)
	if err != nil {
		log.Error(context, "Create", err, "Completed")
		return err
	}

	submission.Number = count + 1

	f := func(c *mgo.Collection) error {
		log.Dev(context, "Create", "MGO : db.%s.insert(%s)", c.Name, mongo.Query(submission))
		return c.Insert(submission)
	}

	if err := db.ExecuteMGO(context, Collection, f); err != nil {
		log.Error(context, "Create", err, "Completed")
		return err
	}

	log.Dev(context, "Create", "Completed")
	return nil
}

// DecodeWebToken breaks a web token into its parts.
func DecodeWebToken(context interface{}, webToken string) (sessionID string, token string, err error) {
	log.Dev(context, "DecodeWebToken", "Started : WebToken[%s]", webToken)

	// Decode the web token to break it into its parts.
	data, err := base64.StdEncoding.DecodeString(webToken)
	if err != nil {
		log.Error(context, "DecodeWebToken", err, "Completed")
		return "", "", err
	}

	// Split the web token.
	str := strings.Split(string(data), ":")
	if len(str) != 2 {
		err := errors.New("Invalid token")
		log.Error(context, "DecodeWebToken", err, "Completed")
		return "", "", err
	}

	// Pull out the session and token.
	sessionID = str[0]
	token = str[1]

	log.Dev(context, "DecodeWebToken", "Completed : SessionID[%s] Token[%s]", sessionID, token)
	return sessionID, token, nil
}

// UpdateUserPassword updates an existing user's password and token in the database.
func UpdateUserPassword(context interface{}, db *db.DB, u *User, password string) error {
	log.Dev(context, "UpdateUserPassword", "Started : PublicID[%s]", u.PublicID)

	if err := u.Validate(); err != nil {
		log.Error(context, "UpdateUserPassword", err, "Completed")
		return err
	}

	if len(password) < 8 {
		err := errors.New("Invalid password length")
		log.Error(context, "UpdateUserPassword", err, "Completed")
		return err
	}

	newPassHash, err := crypto.BcryptPassword(u.PrivateID + password)
	if err != nil {
		log.Error(context, "UpdateUserPassword", err, "Completed")
		return err
	}

	f := func(c *mgo.Collection) error {
		q := bson.M{"public_id": u.PublicID}
		upd := bson.M{"$set": bson.M{"password": newPassHash, "modified_at": time.Now().UTC()}}
		log.Dev(context, "UpdateUserPassword", "MGO : db.%s.Update(%s, CAN'T SHOW)", c.Name, mongo.Query(q))
		return c.Update(q, upd)
	}

	if err := db.ExecuteMGO(context, Collection, f); err != nil {
		log.Error(context, "UpdateUserPassword", err, "Completed")
		return err
	}

	log.Dev(context, "UpdateUserPassword", "Completed")
	return nil
}

// CreateWebToken return a token and session that can be used to authenticate a user.
func CreateWebToken(context interface{}, db *db.DB, u *User, expires time.Duration) (string, error) {
	log.Dev(context, "CreateWebToken", "Started : PublicID[%s]", u.PublicID)

	// Do we have a valid session right now?
	s, err := session.GetByLatest(context, db, u.PublicID)
	if err != nil && err != mgo.ErrNotFound {
		log.Error(context, "CreateUser", err, "Completed")
		return "", err
	}

	// If we don't have one or it has been expired create
	// a new one.
	if err == mgo.ErrNotFound || s.IsExpired(context) {
		if s, err = session.Create(context, db, u.PublicID, expires); err != nil {
			log.Error(context, "CreateUser", err, "Completed")
			return "", err
		}
	}

	// Set the return arguments though we will explicitly
	// return them. Don't want any confusion.
	token, err := u.WebToken(s.SessionID)
	if err != nil {
		log.Error(context, "CreateUser", err, "Completed")
		return "", err
	}

	log.Dev(context, "CreateWebToken", "Completed : WebToken[%s]", token)
	return token, nil
}