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 	gemlink  = regexp.MustCompile(`gemini://[^\s)]+`)
32 )
33 
34 func matrix2gemini(conn *irc.Conn, line *irc.Line) {
35 	matches := msgRe.FindAllString(line.Text(), -1)
36 
37 	// it's not a good idea to defer inside a loop, but we know
38 	// len(matches) is small (usually just 1).  Morover, I like
39 	// living in danger!
40 
41 	for _, link := range matches {
42 		resp, err := http.Get(link)
43 		if err != nil {
44 			conn.Privmsg(
45 				channel,
46 				fmt.Sprintf("failed to download %q: %s", link, err),
47 			)
48 			continue
49 		}
50 		defer resp.Body.Close()
51 
52 		ext := path.Ext(link)
53 		tmpfile, err := ioutil.TempFile(*matrixOutDir, "message-*"+ext)
54 		if err != nil {
55 			conn.Privmsg(channel, fmt.Sprintf("failed to tmpfile: %s", err))
56 			return
57 		}
58 		defer tmpfile.Close()
59 
60 		io.Copy(tmpfile, resp.Body)
61 
62 		conn.Privmsg(
63 			channel,
64 			fmt.Sprintf(
65 				"better: %s/%s",
66 				*baseurl,
67 				filepath.Base(tmpfile.Name()),
68 			),
69 		)
70 	}
71 }
72 
73 func messageTooLong(conn *irc.Conn, line *irc.Line) {
74 	matches := tooLongRe.FindStringSubmatch(line.Text())
75 	if len(matches) != 2 {
76 		return
77 	}
78 
79 	url := matches[1]
80 
81 	resp, err := http.Get(url)
82 	if err != nil {
83 		conn.Privmsg(
84 			channel,
85 			fmt.Sprintf("failed to download %q: %s", url, err),
86 		)
87 		return
88 	}
89 	defer resp.Body.Close()
90 
91 	sb := &strings.Builder{}
92 	if _, err := io.Copy(sb, resp.Body); err != nil {
93 		conn.Privmsg(
94 			channel,
95 			fmt.Sprintf("failed to read body of %q: %s", url, err),
96 		)
97 		return
98 	}
99 
100 	conn.Privmsg(channel, fmt.Sprintf("%s ha detto:", line.Nick))
101 	for _, line := range strings.Split(sb.String(), "\n") {
102 		conn.Privmsg(
103 			channel,
104 			line,
105 		)
106 	}
107 }
108 
109 func stringifyNode(node *html.Node) string {
110 	s := ""
111 
112 	if node.Type == html.TextNode {
113 		return node.Data
114 	}
115 
116 	for child := node.FirstChild; child != nil; child = child.NextSibling {
117 		s += stringifyNode(child)
118 	}
119 
120 	return s
121 }
122 
123 func wwwpagetitle(conn *irc.Conn, line *irc.Line) {
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 gempagetitle(conn *irc.Conn, line *irc.Line) {
156 	matches := gemlink.FindAllString(line.Text(), -1)
157 
158 	for _, link := range matches {
159 		log.Println("fetching", link, "...")
160 		title, err := geminiTitle(link)
161 		if err != nil {
162 			continue
163 		}
164 
165 		conn.Privmsg(channel, title)
166 	}
167 }
168 
169 func dostuff(conn *irc.Conn, line *irc.Line) {
170 	matrix2gemini(conn, line)
171 	messageTooLong(conn, line)
172 	wwwpagetitle(conn, line)
173 	gempagetitle(conn, line)
174 	// ...
175 }
176 
177 func main() {
178 	flag.Parse()
179 
180 	cfg := irc.NewConfig("gemitbot")
181 	cfg.SSL = true
182 	cfg.SSLConfig = &tls.Config{ServerName: "irc.libera.chat"}
183 	cfg.Server = "irc.libera.chat:7000"
184 	cfg.NewNick = func(n string) string { return n + "^" }
185 
186 	c := irc.Client(cfg)
187 
188 	c.HandleFunc(irc.CONNECTED, func(conn *irc.Conn, line *irc.Line) {
189 		log.Println("connected, joining", channel)
190 		conn.Join(channel)
191 	})
192 
193 	c.HandleFunc(irc.PRIVMSG, dostuff)
194 	c.HandleFunc(irc.ACTION, dostuff)
195 
196 	quit := make(chan bool)
197 
198 	c.HandleFunc(irc.DISCONNECTED, func(conn *irc.Conn, line *irc.Line) {
199 		quit <- true
200 	})
201 
202 	if err := c.Connect(); err != nil {
203 		log.Fatalln("connection error:", err)
204 	}
205 
206 	<-quit
207 }