package fileout

import (
	"encoding/json"

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

func init() {
	outputs.RegisterOutputPlugin("file", FileOutputPlugin{})
}

type FileOutputPlugin struct{}

func (f FileOutputPlugin) NewOutput(
	config *outputs.MothershipConfig,
	topology_expire int,
) (outputs.Outputer, error) {
	output := &fileOutput{}
	err := output.init(config, topology_expire)
	if err != nil {
		return nil, err
	}
	return output, nil
}

type fileOutput struct {
	rotator logp.FileRotator
}

func (out *fileOutput) init(config *outputs.MothershipConfig, topology_expire int) error {
	out.rotator.Path = config.Path
	out.rotator.Name = config.Filename
	if out.rotator.Name == "" {
		out.rotator.Name = config.Index
	}
	logp.Info("File output base filename set to: %v", out.rotator.Name)

	// disable bulk support
	configDisableInt := -1
	config.FlushInterval = &configDisableInt
	config.BulkMaxSize = &configDisableInt

	rotateeverybytes := uint64(config.RotateEveryKb) * 1024
	if rotateeverybytes == 0 {
		rotateeverybytes = 10 * 1024 * 1024
	}
	logp.Info("Rotate every bytes set to: %v", rotateeverybytes)
	out.rotator.RotateEveryBytes = &rotateeverybytes

	keepfiles := config.NumberOfFiles
	if keepfiles == 0 {
		keepfiles = 7
	}
	logp.Info("Number of files set to: %v", keepfiles)

	out.rotator.KeepFiles = &keepfiles

	err := out.rotator.CreateDirectory()
	if err != nil {
		return err
	}

	err = out.rotator.CheckIfConfigSane()
	if err != nil {
		return err
	}

	return nil
}

func (out *fileOutput) PublishEvent(
	trans outputs.Signaler,
	opts outputs.Options,
	event common.MapStr,
) error {
	jsonEvent, err := json.Marshal(event)
	if err != nil {
		// mark as success so event is not sent again.
		outputs.SignalCompleted(trans)

		logp.Err("Fail to convert the event to JSON: %s", err)
		return err
	}

	err = out.rotator.WriteLine(jsonEvent)
	if err != nil {
		if opts.Guaranteed {
			logp.Critical("Unable to write events to file: %s", err)
		} else {
			logp.Err("Error when writing line to file: %s", err)
		}
	}
	outputs.Signal(trans, err)
	return err
}