package mail

import (
	"bufio"
	"bytes"
	"context"
	"os/exec"
	"regexp"
	"strings"
	"time"
)

type LogEntry struct {
	Timestamp string `json:"timestamp"`
	Priority  string `json:"priority"`
	Message   string `json:"message"`
}

func GetLogs(hours int, filter string) ([]LogEntry, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	args := []string{
		"-u", "postfix",
		"--since", formatDuration(hours),
		"--no-pager",
	}

	cmd := exec.CommandContext(ctx, "/usr/bin/journalctl", args...)
	var out bytes.Buffer
	cmd.Stdout = &out

	if err := cmd.Run(); err != nil {
		return nil, err
	}

	var entries []LogEntry
	scanner := bufio.NewScanner(&out)
	priorityRegex := regexp.MustCompile(`\[([^\]]+)\]`)

	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())

		if strings.Contains(line, "-- No entries") || line == "" {
			continue
		}

		if filter != "" && !strings.Contains(strings.ToLower(line), strings.ToLower(filter)) {
			continue
		}

		parts := strings.SplitN(line, " ", 4)
		if len(parts) < 4 {
			continue
		}

		timestamp := parts[0] + " " + parts[1]

		matches := priorityRegex.FindStringSubmatch(parts[2])
		priority := "info"
		if len(matches) > 1 {
			priority = matches[1]
		} else if strings.Contains(parts[2], "err") {
			priority = "err"
		} else if strings.Contains(parts[2], "warning") || strings.Contains(parts[2], "warn") {
			priority = "warning"
		}

		message := parts[3]

		if filter != "" && !strings.Contains(strings.ToLower(message), strings.ToLower(filter)) {
			continue
		}

		entries = append(entries, LogEntry{
			Timestamp: timestamp,
			Priority:  priority,
			Message:   message,
		})
	}

	if entries == nil {
		entries = []LogEntry{}
	}

	return entries, nil
}

func formatDuration(hours int) string {
	return time.Now().Add(-time.Duration(hours) * time.Hour).Format("2006-01-02 15:04:05")
}