things

type Backup struct {
	Things      []Thing
	Channels    []Channel
	Connections []Connection
	Groups      []Group
}

type Channel struct {
	ID       string
	OwnerID  string
	GroupID  string
	Name     string
	Profile  map[string]interface{}
	Metadata map[string]interface{}
}

type ChannelCache interface {
	// Connect channel thing connection.
	Connect(context.Context, string, string) error

	// HasThing checks if thing is connected to channel.
	HasThing(context.Context, string, string) bool

	// Disconnects thing from channel.
	Disconnect(context.Context, string, string) error

	// Removes channel from cache.
	Remove(context.Context, string) error
}

type ChannelRepository interface {
	// Save persists multiple channels. Channels are saved using a transaction. If one channel
	// fails then none will be saved. Successful operation is indicated by non-nil
	// error response.
	Save(ctx context.Context, chs ...Channel) ([]Channel, error)

	// Update performs an update to the existing channel. A non-nil error is
	// returned to indicate operation failure.
	Update(ctx context.Context, c Channel) error

	// RetrieveByID retrieves the channel having the provided identifier, that is owned
	// by the specified user.
	RetrieveByID(ctx context.Context, id string) (Channel, error)

	// RetrieveByOwner retrieves the subset of channels owned by the specified user.
	RetrieveByOwner(ctx context.Context, owner string, pm PageMetadata) (ChannelsPage, error)

	// RetrieveByThing retrieves the channel owned by the specified
	// user and have specified thing connected to it.
	RetrieveByThing(ctx context.Context, owner, thID string) (Channel, error)

	// RetrieveConns retrieves the subset of channels connected to the specified
	// thing.
	RetrieveConns(ctx context.Context, thID string, pm PageMetadata) (ChannelsPage, error)

	// Remove removes the channels having the provided identifiers, that is owned
	// by the specified user.
	Remove(ctx context.Context, owner string, id ...string) error

	// Connect connects a list of things to a channel.
	Connect(ctx context.Context, chID string, thIDs []string) error

	// Disconnect disconnects a list of things from a channel.
	Disconnect(ctx context.Context, chID string, thIDs []string) error

	// RetrieveConnByThingKey retrieves connections IDs by ThingKey
	RetrieveConnByThingKey(ctx context.Context, key string) (Connection, error)

	// RetrieveAll retrieves all channels for all users.
	RetrieveAll(ctx context.Context) ([]Channel, error)

	// RetrieveByAdmin  retrieves all channels for all users with pagination.
	RetrieveByAdmin(ctx context.Context, pm PageMetadata) (ChannelsPage, error)

	// RetrieveAllConnections retrieves all connections between channels and things for all users.
	RetrieveAllConnections(ctx context.Context) ([]Connection, error)
}

type ChannelsPage struct {
	PageMetadata
	Channels []Channel
}

type Connection struct {
	ChannelID string
	ThingID   string
}

type Group struct {
	ID          string
	OwnerID     string
	Name        string
	Description string
	Metadata    GroupMetadata
	CreatedAt   time.Time
	UpdatedAt   time.Time
}

type GroupChannelsPage struct {
	PageMetadata
	Channels []Channel
}

type GroupMetadata map[string]interface{}

type GroupPage struct {
	PageMetadata
	Groups []Group
}

type GroupRepository interface {
	// Save group
	Save(ctx context.Context, g Group) (Group, error)

	// Update a group
	Update(ctx context.Context, g Group) (Group, error)

	// Remove a groups
	Remove(ctx context.Context, groupIDs ...string) error

	// RetrieveByID retrieves group by its id
	RetrieveByID(ctx context.Context, id string) (Group, error)

	// RetrieveByIDs retrieves groups by their ids
	RetrieveByIDs(ctx context.Context, groupIDs []string) (GroupPage, error)

	// RetrieveByOwner retrieves all groups.
	RetrieveByOwner(ctx context.Context, ownerID string, pm PageMetadata) (GroupPage, error)

	// RetrieveGroupThings retrieves page of things that are assigned to a group identified by groupID.
	RetrieveGroupThings(ctx context.Context, groupID string, pm PageMetadata) (GroupThingsPage, error)

	// RetrieveGroupThingsByChannel retrieves page of disconnected things by channel that are assigned to a group same as channel.
	RetrieveGroupThingsByChannel(ctx context.Context, grID, chID string, pm PageMetadata) (GroupThingsPage, error)

	// RetrieveGroupChannels retrieves page of channels that are assigned to a group identified by groupID.
	RetrieveGroupChannels(ctx context.Context, groupID string, pm PageMetadata) (GroupChannelsPage, error)

	// RetrieveAll retrieves all groups.
	RetrieveAll(ctx context.Context) ([]Group, error)

	// RetrieveByAdmin retrieves all groups with pagination.
	RetrieveByAdmin(ctx context.Context, pm PageMetadata) (GroupPage, error)
}

type GroupThingsPage struct {
	PageMetadata
	Things []Thing
}

type Identity struct {
	ID    string
	Email string
}

type Metadata map[string]interface{}

type Notifier struct {
	Protocol  string   `json:"protocol"`
	Contacts  []string `json:"contacts"`
	Subtopics []string `json:"subtopics"`
}

type Page struct {
	PageMetadata
	Things []Thing
}

type PageMetadata struct {
	Total        uint64
	Offset       uint64                 `json:"offset,omitempty"`
	Limit        uint64                 `json:"limit,omitempty"`
	Name         string                 `json:"name,omitempty"`
	Order        string                 `json:"order,omitempty"`
	Dir          string                 `json:"dir,omitempty"`
	Metadata     map[string]interface{} `json:"metadata,omitempty"`
	Disconnected bool                   // Used for connected or disconnected lists
}

type Profile struct {
	ContentType string      `json:"content_type"`
	Write       bool        `json:"write"`
	Notify      bool        `json:"notify"`
	Webhook     bool        `json:"webhook"`
	Transformer Transformer `json:"transformer"`
	Notifier    Notifier    `json:"notifier"`
}

type Service interface {
	// CreateThings adds things to the user identified by the provided key.
	CreateThings(ctx context.Context, token string, things ...Thing) ([]Thing, error)

	// UpdateThing updates the thing identified by the provided ID, that
	// belongs to the user identified by the provided key.
	UpdateThing(ctx context.Context, token string, thing Thing) error

	// UpdateKey updates key value of the existing thing. A non-nil error is
	// returned to indicate operation failure.
	UpdateKey(ctx context.Context, token, id, key string) error

	// ViewThing retrieves data about the thing identified with the provided
	// ID, that belongs to the user identified by the provided key.
	ViewThing(ctx context.Context, token, id string) (Thing, error)

	// ListThings retrieves data about subset of things that belongs to the
	// user identified by the provided key.
	ListThings(ctx context.Context, token string, pm PageMetadata) (Page, error)

	// ListThingsByIDs retrieves data about subset of things that are identified
	ListThingsByIDs(ctx context.Context, ids []string) (Page, error)

	// ListThingsByChannel retrieves data about subset of things that are
	// connected or not connected to specified channel and belong to the user identified by
	// the provided key.
	ListThingsByChannel(ctx context.Context, token, chID string, pm PageMetadata) (Page, error)

	// RemoveThings removes the things identified with the provided IDs, that
	// belongs to the user identified by the provided key.
	RemoveThings(ctx context.Context, token string, id ...string) error

	// CreateChannels adds channels to the user identified by the provided key.
	CreateChannels(ctx context.Context, token string, channels ...Channel) ([]Channel, error)

	// UpdateChannel updates the channel identified by the provided ID, that
	// belongs to the user identified by the provided key.
	UpdateChannel(ctx context.Context, token string, channel Channel) error

	// ViewChannel retrieves data about the channel identified by the provided
	// ID, that belongs to the user identified by the provided key.
	ViewChannel(ctx context.Context, token, id string) (Channel, error)

	// ListChannels retrieves data about subset of channels that belongs to the
	// user identified by the provided key.
	ListChannels(ctx context.Context, token string, pm PageMetadata) (ChannelsPage, error)

	// ViewChannelByThing retrieves data about channel that have
	// specified thing connected or not connected to it and belong to the user identified by
	// the provided key.
	ViewChannelByThing(ctx context.Context, token, thID string) (Channel, error)

	// RemoveChannels removes the things identified by the provided IDs, that
	// belongs to the user identified by the provided key.
	RemoveChannels(ctx context.Context, token string, ids ...string) error

	// ViewChannelProfile retrieves channel profile.
	ViewChannelProfile(ctx context.Context, chID string) (Profile, error)

	// Connect connects a list of things to a channel.
	Connect(ctx context.Context, token, chID string, thIDs []string) error

	// Disconnect disconnects a list of things from a channel.
	Disconnect(ctx context.Context, token, chID string, thIDs []string) error

	// GetConnByKey determines whether the channel can be accessed using the
	// provided key and returns thing's id if access is allowed.
	GetConnByKey(ctx context.Context, key string) (Connection, error)

	// IsChannelOwner determines whether the channel can be accessed by
	// the given user and returns error if it cannot.
	IsChannelOwner(ctx context.Context, owner, chanID string) error

	// IsThingOwner determines whether the thing can be accessed by
	// the given user and returns error if it cannot.
	IsThingOwner(ctx context.Context, token, thingID string) error

	// Identify returns thing ID for given thing key.
	Identify(ctx context.Context, key string) (string, error)

	// Backup retrieves all things, channels and connections for all users. Only accessible by admin.
	Backup(ctx context.Context, token string) (Backup, error)

	// Restore adds things, channels and connections from a backup. Only accessible by admin.
	Restore(ctx context.Context, token string, backup Backup) error

	// CreateGroups adds groups to the user identified by the provided key.
	CreateGroups(ctx context.Context, token string, groups ...Group) ([]Group, error)

	// UpdateGroup updates the group identified by the provided ID.
	UpdateGroup(ctx context.Context, token string, g Group) (Group, error)

	// ViewGroup retrieves data about the group identified by ID.
	ViewGroup(ctx context.Context, token, id string) (Group, error)

	// ListGroups retrieves groups.
	ListGroups(ctx context.Context, token string, pm PageMetadata) (GroupPage, error)

	// ListGroupsByIDs retrieves groups by their IDs.
	ListGroupsByIDs(ctx context.Context, ids []string) ([]Group, error)

	// ListGroupThings retrieves page of things that are assigned to a group identified by groupID.
	ListGroupThings(ctx context.Context, token string, groupID string, pm PageMetadata) (GroupThingsPage, error)

	// ListGroupThingsByChannel retrieves page of disconnected things by channel that are assigned to a group same as channel.
	ListGroupThingsByChannel(ctx context.Context, token, grID, chID string, pm PageMetadata) (GroupThingsPage, error)

	// ViewThingGroup retrieves group that thing belongs to.
	ViewThingGroup(ctx context.Context, token, thingID string) (Group, error)

	// RemoveGroups removes the groups identified with the provided IDs.
	RemoveGroups(ctx context.Context, token string, ids ...string) error

	// ListGroupChannels retrieves page of channels that are assigned to a group identified by groupID.
	ListGroupChannels(ctx context.Context, token, groupID string, pm PageMetadata) (GroupChannelsPage, error)

	// ViewChannelGroup retrieves group that channel belongs to.
	ViewChannelGroup(ctx context.Context, token, channelID string) (Group, error)
}

type Thing struct {
	ID       string
	OwnerID  string
	GroupID  string
	Name     string
	Key      string
	Metadata Metadata
}

type ThingCache interface {
	// Save stores pair thing key, thing id.
	Save(context.Context, string, string) error

	// ID returns thing ID for given key.
	ID(context.Context, string) (string, error)

	// Removes thing from cache.
	Remove(context.Context, string) error
}

type ThingRepository interface {
	// Save persists multiple things. Things are saved using a transaction. If one thing
	// fails then none will be saved. Successful operation is indicated by non-nil
	// error response.
	Save(ctx context.Context, ths ...Thing) ([]Thing, error)

	// Update performs an update to the existing thing. A non-nil error is
	// returned to indicate operation failure.
	Update(ctx context.Context, t Thing) error

	// UpdateKey updates key value of the existing thing. A non-nil error is
	// returned to indicate operation failure.
	UpdateKey(ctx context.Context, owner, id, key string) error

	// RetrieveByID retrieves the thing having the provided identifier, that is owned
	// by the specified user.
	RetrieveByID(ctx context.Context, id string) (Thing, error)

	// RetrieveByKey returns thing ID for given thing key.
	RetrieveByKey(ctx context.Context, key string) (string, error)

	// RetrieveByOwner retrieves the subset of things owned by the specified user
	RetrieveByOwner(ctx context.Context, owner string, pm PageMetadata) (Page, error)

	// RetrieveByIDs retrieves the subset of things specified by given thing ids.
	RetrieveByIDs(ctx context.Context, thingIDs []string, pm PageMetadata) (Page, error)

	// RetrieveByChannel retrieves the subset of things owned by the specified
	// user and connected or not connected to specified channel.
	RetrieveByChannel(ctx context.Context, owner, chID string, pm PageMetadata) (Page, error)

	// Remove removes the things having the provided identifiers, that is owned
	// by the specified user.
	Remove(ctx context.Context, owner string, ids ...string) error

	// RetrieveAll retrieves all things for all users.
	RetrieveAll(ctx context.Context) ([]Thing, error)

	// RetrieveByAdmin retrieves all things for all users with pagination.
	RetrieveByAdmin(ctx context.Context, pm PageMetadata) (Page, error)
}

type Transformer struct {
	ValueFields  []string `json:"value_fields"`
	TimeField    string   `json:"time_field"`
	TimeFormat   string   `json:"time_format"`
	TimeLocation string   `json:"time_location"`
}