package service

import (
	"bufio"
	"encoding/json"
	"fmt"
	"hy2xs-admin/model/vo"
	"hy2xs-admin/util"
	"strconv"
	"strings"
	"time"
)

type journalctlLogLine struct {
	Message            string `json:"MESSAGE"`
	Priority           string `json:"PRIORITY"`
	RealtimeTimestamp  string `json:"__REALTIME_TIMESTAMP"`
}

func ReadHysteriaJournalLogs(numLine int) ([]vo.LogHysteria2Vo, int, error) {
	lines := 100
	if numLine > 0 {
		lines = numLine
	}

	output, err := util.Exec(fmt.Sprintf("journalctl --no-pager -u hysteria-server.service -n %d -o json", lines))
	if err != nil {
		return nil, 0, err
	}

	result := make([]vo.LogHysteria2Vo, 0, lines)
	scanner := bufio.NewScanner(strings.NewReader(output))
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" {
			continue
		}

		item := journalctlLogLine{}
		if err = json.Unmarshal([]byte(line), &item); err != nil {
			continue
		}

		result = append(result, parseHysteriaJournalRecord(item))
	}

	if scanErr := scanner.Err(); scanErr != nil {
		return nil, 0, scanErr
	}

	return result, len(result), nil
}

func ExportHysteriaJournalLogs(numLine int) (string, error) {
	lines := 5000
	if numLine > 0 {
		lines = numLine
	}

	return util.Exec(fmt.Sprintf("journalctl --no-pager -u hysteria-server.service -n %d -o short-iso", lines))
}

func parseHysteriaJournalRecord(item journalctlLogLine) vo.LogHysteria2Vo {
	fallbackTime := convertJournalTimestamp(item.RealtimeTimestamp)
	fallbackLevel := mapJournalPriorityToLevel(item.Priority)

	if strings.TrimSpace(item.Message) == "" {
		return vo.LogHysteria2Vo{
			Level: fallbackLevel,
			Msg:   "",
			Time:  fallbackTime,
		}
	}

	parsed := vo.LogHysteria2Vo{}
	if err := json.Unmarshal([]byte(item.Message), &parsed); err == nil {
		if parsed.Level == "" {
			parsed.Level = fallbackLevel
		}
		if parsed.Time == "" {
			parsed.Time = fallbackTime
		}
		if parsed.Msg == "" {
			parsed.Msg = item.Message
		}
		return parsed
	}

	return vo.LogHysteria2Vo{
		Level: fallbackLevel,
		Msg:   item.Message,
		Time:  fallbackTime,
	}
}

func convertJournalTimestamp(raw string) string {
	if raw == "" {
		return ""
	}

	us, err := strconv.ParseInt(raw, 10, 64)
	if err != nil {
		return ""
	}

	t := time.UnixMicro(us)
	return t.Format("2006-01-02 15:04:05")
}

func mapJournalPriorityToLevel(priority string) string {
	switch strings.TrimSpace(priority) {
	case "0", "1", "2", "3":
		return "error"
	case "4":
		return "warn"
	default:
		return "info"
	}
}