// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package event

import (
	"fmt"
	"time"
)

// Event holds the information about an event that occurred.
// It combines the event metadata with the user supplied labels.
type Event struct {
	Kind    Kind
	ID      uint64    // unique for this process id of the event
	Parent  uint64    // id of the parent event for this event
	At      time.Time // time at which the event is delivered to the exporter.
	Message string
	Labels  []Label
}

// Kind indicates the type of event.
type Kind byte

const (
	// UnknownKind is the default event kind, a real kind should always be chosen.
	UnknownKind = Kind(iota)
	// LogKind is a Labels kind that indicates a log event.
	LogKind
	// StartKind is a Labels kind that indicates a span start event.
	StartKind
	// EndKind is a Labels kind that indicates a span end event.
	EndKind
	// MetricKind is a Labels kind that indicates a metric record event.
	MetricKind
	// AnnotateKind is a Labels kind that reports label values at a point in time.
	AnnotateKind
)

// Format prints the value in a standard form.
func (e *Event) Format(f fmt.State, verb rune) {
	newPrinter(f).Event(e)
}

func (k Kind) Format(f fmt.State, verb rune) {
	newPrinter(f).Kind(k)
}