const (
	ReasonIdle              = "idle"
	ReasonPoolClosed        = "poolClosed"
	ReasonStale             = "stale"
	ReasonConnectionErrored = "connectionError"
	ReasonTimedOut          = "timeout"
)

const (
	ConnectionClosed   = "ConnectionClosed"
	PoolCreated        = "ConnectionPoolCreated"
	ConnectionCreated  = "ConnectionCreated"
	ConnectionReady    = "ConnectionReady"
	GetFailed          = "ConnectionCheckOutFailed"
	GetSucceeded       = "ConnectionCheckedOut"
	ConnectionReturned = "ConnectionCheckedIn"
	PoolCleared        = "ConnectionPoolCleared"
	PoolClosedEvent    = "ConnectionPoolClosed"
)

type CommandFailedEvent struct {
	CommandFinishedEvent
	Failure string
}

type CommandFinishedEvent struct {
	DurationNanos int64
	CommandName   string
	RequestID     int64
	ConnectionID  string
}

type CommandMonitor struct {
	Started   func(context.Context, *CommandStartedEvent)
	Succeeded func(context.Context, *CommandSucceededEvent)
	Failed    func(context.Context, *CommandFailedEvent)
}

type CommandStartedEvent struct {
	Command      bson.Raw
	DatabaseName string
	CommandName  string
	RequestID    int64
	ConnectionID string
}

type CommandSucceededEvent struct {
	CommandFinishedEvent
	Reply bson.Raw
}

type MonitorPoolOptions struct {
	MaxPoolSize        uint64 `json:"maxPoolSize"`
	MinPoolSize        uint64 `json:"minPoolSize"`
	WaitQueueTimeoutMS uint64 `json:"maxIdleTimeMS"`
}

type PoolEvent struct {
	Type         string              `json:"type"`
	Address      string              `json:"address"`
	ConnectionID uint64              `json:"connectionId"`
	PoolOptions  *MonitorPoolOptions `json:"options"`
	Reason       string              `json:"reason"`
}

type PoolMonitor struct {
	Event func(*PoolEvent)
}

type ServerClosedEvent struct {
	Address    address.Address
	TopologyID primitive.ObjectID // A unique identifier for the topology this server is a part of
}

type ServerDescriptionChangedEvent struct {
	Address             address.Address
	TopologyID          primitive.ObjectID // A unique identifier for the topology this server is a part of
	PreviousDescription description.Server
	NewDescription      description.Server
}

type ServerHeartbeatFailedEvent struct {
	DurationNanos int64
	Failure       error
	ConnectionID  string // The address this heartbeat was sent to with a unique identifier
	Awaited       bool   // If this heartbeat was awaitable
}

type ServerHeartbeatStartedEvent struct {
	ConnectionID string // The address this heartbeat was sent to with a unique identifier
	Awaited      bool   // If this heartbeat was awaitable
}

type ServerHeartbeatSucceededEvent struct {
	DurationNanos int64
	Reply         description.Server
	ConnectionID  string // The address this heartbeat was sent to with a unique identifier
	Awaited       bool   // If this heartbeat was awaitable
}

type ServerMonitor struct {
	ServerDescriptionChanged func(*ServerDescriptionChangedEvent)
	ServerOpening            func(*ServerOpeningEvent)
	ServerClosed             func(*ServerClosedEvent)
	// TopologyDescriptionChanged is called when the topology is locked, so the callback should
	// not attempt any operation that requires server selection on the same client.
	TopologyDescriptionChanged func(*TopologyDescriptionChangedEvent)
	TopologyOpening            func(*TopologyOpeningEvent)
	TopologyClosed             func(*TopologyClosedEvent)
	ServerHeartbeatStarted     func(*ServerHeartbeatStartedEvent)
	ServerHeartbeatSucceeded   func(*ServerHeartbeatSucceededEvent)
	ServerHeartbeatFailed      func(*ServerHeartbeatFailedEvent)
}

type ServerOpeningEvent struct {
	Address    address.Address
	TopologyID primitive.ObjectID // A unique identifier for the topology this server is a part of
}

type TopologyClosedEvent struct {
	TopologyID primitive.ObjectID // A unique identifier for the topology this server is a part of
}

type TopologyDescriptionChangedEvent struct {
	TopologyID          primitive.ObjectID // A unique identifier for the topology this server is a part of
	PreviousDescription description.Topology
	NewDescription      description.Topology
}

type TopologyOpeningEvent struct {
	TopologyID primitive.ObjectID // A unique identifier for the topology this server is a part of
}