stats

type Counter interface {
	// Add increments the Counter by the argument's value.
	Add(uint64)

	// Inc increments the Counter by 1.
	Inc()

	// Set sets an internal counter value which will be written in the next flush.
	// Its use is discouraged as it may break the counter's "always incrementing" semantics.
	Set(uint64)

	// String returns the current value of the Counter as a string.
	String() string

	// Value returns the current value of the Counter as a uint64.
	Value() uint64
}

type FlushableSink interface {
	Sink
	Flush()
}

type Gauge interface {
	// Add increments the Gauge by the argument's value.
	Add(uint64)

	// Sub decrements the Gauge by the argument's value.
	Sub(uint64)

	// Inc increments the Gauge by 1.
	Inc()

	// Dec decrements the Gauge by 1.
	Dec()

	// Set sets the Gauge to a value.
	Set(uint64)

	// String returns the current value of the Gauge as a string.
	String() string

	// Value returns the current value of the Gauge as a uint64.
	Value() uint64
}

type MockSink struct {
	Counters map[string]uint64
	Timers   map[string]uint64
	Gauges   map[string]uint64
	// contains filtered or unexported fields
}

type Scope interface {
	// Scope creates a subscope.
	Scope(name string) Scope

	// ScopeWithTags creates a subscope with Tags to a store or scope. All child scopes and metrics
	// will inherit these tags by default.
	ScopeWithTags(name string, tags map[string]string) Scope

	// Store returns the Scope's backing Store.
	Store() Store

	// NewCounter adds a Counter to a store, or a scope.
	NewCounter(name string) Counter

	// NewCounterWithTags adds a Counter with Tags to a store, or a scope.
	NewCounterWithTags(name string, tags map[string]string) Counter

	// NewPerInstanceCounter adds a Per instance Counter with optional Tags to a store, or a scope.
	NewPerInstanceCounter(name string, tags map[string]string) Counter

	// NewGauge adds a Gauge to a store, or a scope.
	NewGauge(name string) Gauge

	// NewGaugeWithTags adds a Gauge with Tags to a store, or a scope.
	NewGaugeWithTags(name string, tags map[string]string) Gauge

	// NewPerInstanceGauge adds a Per instance Gauge with optional Tags to a store, or a scope.
	NewPerInstanceGauge(name string, tags map[string]string) Gauge

	// NewTimer adds a Timer to a store, or a scope.
	NewTimer(name string) Timer

	// NewTimerWithTags adds a Timer with Tags to a store, or a scope with Tags.
	NewTimerWithTags(name string, tags map[string]string) Timer

	// NewPerInstanceTimer adds a Per instance Timer with optional Tags to a store, or a scope.
	NewPerInstanceTimer(name string, tags map[string]string) Timer
}

type Settings struct {
	// Use statsd as a stats sink.
	UseStatsd bool `envconfig:"USE_STATSD" default:"true"`
	// Address where statsd is running at.
	StatsdHost string `envconfig:"STATSD_HOST" default:"localhost"`
	// Port where statsd is listening at.
	StatsdPort int `envconfig:"STATSD_PORT" default:"8125"`
	// Flushing interval.
	FlushIntervalS int `envconfig:"GOSTATS_FLUSH_INTERVAL_SECONDS" default:"5"`
}

type Sink interface {
	FlushCounter(name string, value uint64)
	FlushGauge(name string, value uint64)
	FlushTimer(name string, value float64)
}

type StatGenerator interface {
	// Runs the StatGenerator to generate Stats.
	GenerateStats()
}

type Store interface {
	// Flush Counters and Gauges to the Sink attached to the Store.
	// To flush the store at a regular interval call the
	//  Start(*time.Ticker)
	// method on it.
	//
	// The store will flush either at the regular interval, or whenever
	//  Flush()
	// is called. Whenever the store is flushed,
	// the store will call
	//  GenerateStats()
	// on all of its stat generators,
	// and flush all the Counters and Gauges registered with it.
	Flush()

	// Start a timer for periodic stat Flushes.
	Start(*time.Ticker)

	// Add a StatGenerator to the Store that programatically generates stats.
	AddStatGenerator(StatGenerator)
	Scope
}

type Timer interface {
	// AddValue flushs the timer with the argument's value.
	AddValue(float64)

	// AllocateSpan allocates a Timespan.
	AllocateSpan() Timespan
}

type Timespan interface {
	// End the Timespan and flush it.
	Complete() time.Duration

	// End the Timespan and flush it. Adds additional time.Duration to the measured time
	CompleteWithDuration(time.Duration)
}