1 package main
2 
3 import (
4 	"crypto/tls"
5 	"flag"
6 	"fmt"
7 	"io"
8 	"io/ioutil"
9 	"log"
10 	"net/http"
11 	"path"
12 	"path/filepath"
13 	"regexp"
14 	"strings"
15 
16 	"github.com/andybalholm/cascadia"
17 	irc "github.com/fluffle/goirc/client"
18 	"golang.org/x/net/html"
19 )
20 
21 var (
22 	baseurl      = flag.String("baseurl", "gemini://m2i.omarpolo.com", "base url")
23 	matrixOutDir = flag.String("matrix-out", "", "matrix out directory")
24 
25 	msgRe   = regexp.MustCompile(`https://.*/[^\s]+\.(txt|png|jpg|jpeg|gif)`)
26 	channel = "#gemini-it"
27 
28 	tooLongRe = regexp.MustCompile(`full message at (https://libera.ems.host/.*)[)]`)
29 
30 	httplink = regexp.MustCompile(`https?://[^\s)]+`)
31 )
32 
33 func matrix2gemini(conn *irc.Conn, line *irc.Line) {
34 	matches := msgRe.FindAllString(line.Text(), -1)
35 
36 	// it's not a good idea to defer inside a loop, but we know
37 	// len(matches) is small (usually just 1).  Morover, I like
38 	// living in danger!
39 
40 	for _, link := range matches {
41 		resp, err := http.Get(link)
42 		if err != nil {
43 			conn.Privmsg(
44 				channel,
45 				fmt.Sprintf("failed to download %q: %s", link, err),
46 			)
47 			continue
48 		}
49 		defer resp.Body.Close()
50 
51 		ext := path.Ext(link)
52 		tmpfile, err := ioutil.TempFile(*matrixOutDir, "message-*"+ext)
53 		if err != nil {
54 			conn.Privmsg(channel, fmt.Sprintf("failed to tmpfile: %s", err))
55 			return
56 		}
57 		defer tmpfile.Close()
58 
59 		io.Copy(tmpfile, resp.Body)
60 
61 		conn.Privmsg(
62 			channel,
63 			fmt.Sprintf(
64 				"better: %s/%s",
65 				*baseurl,
66 				filepath.Base(tmpfile.Name()),
67 			),
68 		)
69 	}
70 }
71 
72 func messageTooLong(conn *irc.Conn, line *irc.Line) {
73 	matches := tooLongRe.FindStringSubmatch(line.Text())
74 	if len(matches) != 2 {
75 		return
76 	}
77 
78 	url := matches[1]
79 
80 	resp, err := http.Get(url)
81 	if err != nil {
82 		conn.Privmsg(
83 			channel,
84 			fmt.Sprintf("failed to download %q: %s", url, err),
85 		)
86 		return
87 	}
88 	defer resp.Body.Close()
89 
90 	sb := &strings.Builder{}
91 	if _, err := io.Copy(sb, resp.Body); err != nil {
92 		conn.Privmsg(
93 			channel,
94 			fmt.Sprintf("failed to read body of %q: %s", url, err),
95 		)
96 		return
97 	}
98 
99 	conn.Privmsg(channel, fmt.Sprintf("%s ha detto:", line.Nick))
100 	for _, line := range strings.Split(sb.String(), "\n") {
101 		conn.Privmsg(
102 			channel,
103 			line,
104 		)
105 	}
106 }
107 
108 func stringifyNode(node *html.Node) string {
109 	s := ""
110 
111 	if node.Type == html.TextNode {
112 		return node.Data
113 	}
114 
115 	for child := node.FirstChild; child != nil; child = child.NextSibling {
116 		s += stringifyNode(child)
117 	}
118 
119 	return s
120 }
121 
122 func pagetitle(conn *irc.Conn, line *irc.Line) {
123 	log.Println("text is", line.Text())
124 	matches := httplink.FindAllString(line.Text(), -1)
125 
126 	for _, link := range matches {
127 		log.Println("fetching", link, "...")
128 
129 		resp, err := http.Get(link)
130 		if err != nil {
131 			continue
132 		}
133 		defer resp.Body.Close()
134 
135 		doc, err := html.Parse(resp.Body)
136 		if err != nil {
137 			continue
138 		}
139 
140 		sel := cascadia.MustCompile("head > title")
141 		n := cascadia.Query(doc, sel)
142 
143 		if n == nil {
144 			continue
145 		}
146 
147 		title := stringifyNode(n)
148 		if len(title) > 50 {
149 			title = title[:50]
150 		}
151 		conn.Privmsg(channel, stringifyNode(n))
152 	}
153 }
154 
155 func dostuff(conn *irc.Conn, line *irc.Line) {
156 	matrix2gemini(conn, line)
157 	messageTooLong(conn, line)
158 	pagetitle(conn, line)
159 	// ...
160 }
161 
162 func main() {
163 	flag.Parse()
164 
165 	cfg := irc.NewConfig("gemitbot")
166 	cfg.SSL = true
167 	cfg.SSLConfig = &tls.Config{ServerName: "irc.libera.chat"}
168 	cfg.Server = "irc.libera.chat:7000"
169 	cfg.NewNick = func(n string) string { return n + "^" }
170 
171 	c := irc.Client(cfg)
172 
173 	c.HandleFunc(irc.CONNECTED, func(conn *irc.Conn, line *irc.Line) {
174 		log.Println("connected, joining", channel)
175 		conn.Join(channel)
176 	})
177 
178 	c.HandleFunc(irc.PRIVMSG, dostuff)
179 	c.HandleFunc(irc.ACTION, dostuff)
180 
181 	quit := make(chan bool)
182 
183 	c.HandleFunc(irc.DISCONNECTED, func(conn *irc.Conn, line *irc.Line) {
184 		quit <- true
185 	})
186 
187 	if err := c.Connect(); err != nil {
188 		log.Fatalln("connection error:", err)
189 	}
190 
191 	<-quit
192 }