package beat

import (
	"errors"
	"time"

	"github.com/elastic/beats/libbeat/common"
)

// Event is the common event format shared by all beats.
// Every event must have a timestamp and provide encodable Fields in `Fields`.
// The `Meta`-fields can be used to pass additional meta-data to the outputs.
// Output can optionally publish a subset of Meta, or ignore Meta.
type Event struct {
	Timestamp time.Time
	Meta      common.MapStr
	Fields    common.MapStr
	Private   interface{} // for beats private use
}

var (
	errNoTimestamp = errors.New("value is no timestamp")
)

func (e *Event) GetValue(key string) (interface{}, error) {
	if key == "@timestamp" {
		return e.Timestamp, nil
	}
	return e.Fields.GetValue(key)
}

func (e *Event) PutValue(key string, v interface{}) (interface{}, error) {
	if key == "@timestamp" {
		switch ts := v.(type) {
		case time.Time:
			e.Timestamp = ts
		case common.Time:
			e.Timestamp = time.Time(ts)
		default:
			return nil, errNoTimestamp
		}
	}

	// TODO: add support to write into '@metadata'?
	return e.Fields.Put(key, v)
}

func (e *Event) Delete(key string) error {
	return e.Fields.Delete(key)
}