package loggerconfig

import (
	"os"
	"time"

	"git.frostfs.info/TrueCloudLab/frostfs-node/cmd/frostfs-node/config"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/logger"
	"git.frostfs.info/TrueCloudLab/frostfs-observability/logging/lokicore/loki"
)

const (
	// LevelDefault is a default logger level.
	LevelDefault              = "info"
	DestinationDefault        = logger.DestinationStdout
	subsection                = "logger"
	lokiSubsection            = "loki"
	AddressDefault            = "localhost:3100"
	BatchEntriesNumberDefault = 100
	BatchWaitDefault          = time.Second
)

// Level returns the value of "level" config parameter
// from "logger" section.
//
// Returns LevelDefault if the value is not a non-empty string.
func Level(c *config.Config) string {
	v := config.StringSafe(
		c.Sub(subsection),
		"level",
	)
	if v != "" {
		return v
	}

	return LevelDefault
}

// Destination returns the value of "destination" config parameter
// from "logger" section.
//
// Returns DestinationDefault if the value is not a non-empty string.
func Destination(c *config.Config) string {
	v := config.StringSafe(
		c.Sub(subsection),
		"destination",
	)
	if v != "" {
		return v
	}

	return DestinationDefault
}

// ToLokiConfig extracts loki config.
func ToLokiConfig(c *config.Config) loki.Config {
	hostname, _ := os.Hostname()
	return loki.Config{
		Enabled:            config.BoolSafe(c.Sub(subsection).Sub(lokiSubsection), "enabled"),
		BatchWait:          getBatchWait(c),
		BatchEntriesNumber: getBatchEntriesNumber(c),
		Endpoint:           getEndpoint(c),
		Labels: map[string]string{
			"hostname": hostname,
		},
	}
}

func getBatchWait(c *config.Config) time.Duration {
	v := config.DurationSafe(c.Sub(subsection).Sub(lokiSubsection), "max_batch_delay")
	if v > 0 {
		return v
	}

	return BatchWaitDefault
}

func getBatchEntriesNumber(c *config.Config) int {
	v := config.IntSafe(c.Sub(subsection).Sub(lokiSubsection), "max_batch_size")
	if v > 0 {
		return int(v)
	}

	return BatchEntriesNumberDefault
}

func getEndpoint(c *config.Config) string {
	v := config.StringSafe(c.Sub(subsection).Sub(lokiSubsection), "endpoint")
	if v != "" {
		return v
	}

	return AddressDefault
}