package logger

import (
	"fmt"
	"time"
)

type LogConfig struct {
	Type              string // syslog/stderr/std/file
	Level             string // DEBUG/INFO/WARNING/ERROR/FATAL
	SyslogPriority    string // local0-7
	SyslogSeverity    string
	FileName          string
	FileRotateCount   int
	FileRotateSize    uint64
	FileFlushDuration time.Duration
	RotateByHour      bool
	KeepHours         uint // make sense when RotateByHour is T
}

func initFromConfig(log *Logger,
	sb *syslogBackend,
	fb *FileBackend,
	config LogConfig) error {

	if config.Type == "stderr" || config.Type == "std" {
		log.LogToStderr()
		log.SetSeverity(config.Level)
		return nil
	}

	var err error
	if config.Type == "syslog" {
		if sb, err = NewSyslogBackend(config.SyslogPriority, config.SyslogSeverity); err != nil {
			return err
		}
		log.SetLogging(config.Level, sb)
	} else if config.Type == "file" {
		if fb, err = NewFileBackend(config.FileName); err != nil {
			return err
		}
		log.SetLogging(config.Level, fb)
		fb.Rotate(config.FileRotateCount, config.FileRotateSize)
		fb.SetFlushDuration(config.FileFlushDuration)
		fb.SetRotateByHour(config.RotateByHour)
		fb.SetKeepHours(config.KeepHours)
	} else {
		return fmt.Errorf("unknown log type: %s", config.Type)
	}
	return nil
}

func Init(config LogConfig) error {
	return initFromConfig(&logging, sysback, fileback, config)
}

func NewLoggerFromConfig(config LogConfig) (Logger, error) {
	var log Logger
	var fb *FileBackend = nil
	var sb *syslogBackend = nil
	err := initFromConfig(&log, sb, fb, config)
	return log, err
}