1 package main
2 
3 import (
4 	"bufio"
5 	"context"
6 	"errors"
7 	"regexp"
8 	"strings"
9 
10 	gemini "git.sr.ht/~adnano/go-gemini"
11 )
12 
13 var (
14 	ErrNoTitle = errors.New(`no title found`)
15 
16 	title1 = regexp.MustCompile(`^#[^#]`)
17 	title2 = regexp.MustCompile(`^##[^#]`)
18 	title3 = regexp.MustCompile(`^###`)
19 )
20 
21 func geminiTitle(url string) (string, error) {
22 	client := gemini.Client{}
23 	ctx := context.Background()
24 	resp, err := client.Get(ctx, url)
25 	if err != nil {
26 		return "", err
27 	}
28 	defer resp.Body.Close()
29 
30 	if resp.Status != 20 || !strings.HasPrefix(resp.Meta, "text/gemini") {
31 		return "", ErrNoTitle
32 	}
33 
34 	var t2, t3 string
35 
36 	scanner := bufio.NewScanner(resp.Body)
37 	for scanner.Scan() {
38 		line := scanner.Text()
39 
40 		switch {
41 		case title1.MatchString(line):
42 			return line, nil
43 		case title2.MatchString(line) && t2 == "":
44 			t2 = line
45 		case title3.MatchString(line) && t3 == "":
46 			t3 = line
47 		}
48 	}
49 
50 	if t2 != "" {
51 		return t2, nil
52 	}
53 
54 	if t3 != "" {
55 		return t3, nil
56 	}
57 
58 	return "", ErrNoTitle
59 }