package centrifuge

import (
	"time"
)

// Config contains Node configuration options.
type Config struct {
	// Version of server – will be sent to client on connection establishment
	// phase in response to connect request.
	Version string
	// Name of this server Node - must be unique, used as human readable and
	// meaningful node identifier. If not set then os.Hostname will be used.
	Name string
	// LogLevel is a log level to use. By default nothing will be logged.
	LogLevel LogLevel
	// LogHandler is a handler func node will send logs to.
	LogHandler LogHandler
	// NodeInfoMetricsAggregateInterval sets interval for automatic metrics
	// aggregation. It's not reasonable to have it less than one second.
	NodeInfoMetricsAggregateInterval time.Duration
	// ClientPresenceUpdateInterval is an interval how often connected
	// clients must update presence information.
	ClientPresenceUpdateInterval time.Duration
	// ClientPresenceExpireInterval is an interval how long to consider
	// presence info valid after receiving presence ping.
	ClientPresenceExpireInterval time.Duration
	// ClientExpiredCloseDelay is an extra time given to client to refresh
	// its connection in the end of connection TTL. At moment only used for
	// client-side refresh workflow.
	ClientExpiredCloseDelay time.Duration
	// ClientExpiredSubCloseDelay is an extra time given to client to
	// refresh its expiring subscription in the end of subscription TTL.
	// At moment only used for client-side subscription refresh workflow.
	ClientExpiredSubCloseDelay time.Duration
	// ClientStaleCloseDelay is a timeout after which connection will be
	// closed if still not authenticated (i.e. no valid connect command
	// received yet).
	ClientStaleCloseDelay time.Duration
	// ClientChannelPositionCheckDelay defines minimal time from previous
	// client position check in channel. If client does not pass check it will
	// be disconnected with DisconnectInsufficientState.
	ClientChannelPositionCheckDelay time.Duration
	// ClientQueueMaxSize is a maximum size of client's message queue in bytes.
	// After this queue size exceeded Centrifuge closes client's connection.
	ClientQueueMaxSize int
	// ClientChannelLimit sets upper limit of channels each client can subscribe to.
	ClientChannelLimit int
	// UserConnectionLimit limits number of client connections to single Node
	// from user with the same ID. Zero value means unlimited. Anonymous users
	// can't be tracked.
	UserConnectionLimit int
	// ChannelMaxLength is a maximum length of channel name.
	ChannelMaxLength int
	// MetricsNamespace is a Prometheus metrics namespace to use for internal metrics.
	// If not set then default namespace name `centrifuge` will be used.
	MetricsNamespace string
}

const (
	// nodeInfoPublishInterval is an interval how often node must publish
	// node control message.
	nodeInfoPublishInterval = 3 * time.Second
	// nodeInfoCleanInterval is an interval in seconds, how often node must
	// clean information about other running nodes.
	nodeInfoCleanInterval = nodeInfoPublishInterval * 3
	// nodeInfoMaxDelay is an interval in seconds – how many seconds node
	// info considered actual.
	nodeInfoMaxDelay = nodeInfoPublishInterval*2 + time.Second
)

// DefaultConfig is Config initialized with default values for all fields.
var DefaultConfig = Config{
	ChannelMaxLength:                 255,
	NodeInfoMetricsAggregateInterval: 60 * time.Second,
	ClientPresenceUpdateInterval:     25 * time.Second,
	ClientPresenceExpireInterval:     60 * time.Second,
	ClientExpiredCloseDelay:          25 * time.Second,
	ClientExpiredSubCloseDelay:       25 * time.Second,
	ClientStaleCloseDelay:            25 * time.Second,
	ClientChannelPositionCheckDelay:  40 * time.Second,
	ClientQueueMaxSize:               10485760, // 10MB by default
	ClientChannelLimit:               128,
}