gamelog.go

package factorio

import (
	"errors"
	"log"
	"regexp"
	"strings"
	"time"

	"github.com/hpcloud/tail"
	"github.com/OpenFactorioServerManager/factorio-server-manager/bootstrap"
)

// TailLog tails the Factorio game log file
func TailLog(filename string) ([]string, error) {
	var result []string

	config := bootstrap.GetConfig()

	t, err := tail.TailFile(config.FactorioLog, tail.Config{Follow: false})
	if err != nil {
		log.Printf("Error tailing log %s", err)
		return result, err
	}

	for line := range t.Lines {
		result = append(result, line.Text)
	}

	result = reformatTimestamps(result)

	return result, nil
}

func getOffset(line string) (string, error) {
	re, _ := regexp.Compile(`^\d+.\d+`)

	if !re.MatchString(line) {
		log.Printf("This line has no offset %v\n", line)
		return "error", errors.New(line)
	}

	offset := re.FindString(line)

	return offset, nil
}

func getStartTime(line string) time.Time {
	re, _ := regexp.Compile(`\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}`)
	date := re.FindString(line)
	startTime, _ := time.Parse(time.RFC3339, strings.Replace(date, " ", "T", 1)+"Z")

	return startTime
}

func replaceTimestampInLine(line string, offset string, startTime time.Time) string {
	offset, err := getOffset(line)
	offsetDuration, _ := time.ParseDuration(offset + "s")
	timestamp := startTime.Add(offsetDuration)

	if err == nil {
		return timestamp.Format("2006-01-02 15:04:05") + ":" + strings.Replace(line, offset, "", 1)
	}

	return line
}

func reformatTimestamps(log []string) []string {
	firstLine := log[0]
	startTime := getStartTime(firstLine)
	var result []string

	for _, line := range log {
		line = strings.TrimLeft(line, " \t")
		offset, _ := getOffset(line)
		result = append(result, replaceTimestampInLine(line, offset, startTime))
	}

	return result
}