From 7de332c2bb5cddf6591b93b16e536b845ea7ab76 Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Tue, 25 Feb 2020 18:16:26 +0100
Subject: plugins/viewtext: linkify plaintext messages

---
 plugins/viewtext/viewer.go | 97 +++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 83 insertions(+), 14 deletions(-)

(limited to 'plugins')

diff --git a/plugins/viewtext/viewer.go b/plugins/viewtext/viewer.go
index cca38a8..9a91f08 100644
--- a/plugins/viewtext/viewer.go
+++ b/plugins/viewtext/viewer.go
@@ -1,21 +1,55 @@
 package koushinviewtext
 
 import (
-	"bytes"
+	"bufio"
 	"fmt"
 	"html/template"
-	"io/ioutil"
+	"net/url"
 	"strings"
 
 	"git.sr.ht/~emersion/koushin"
 	koushinbase "git.sr.ht/~emersion/koushin/plugins/base"
 	"github.com/emersion/go-message"
+	"gitlab.com/golang-commonmark/linkify"
 )
 
 // TODO: dim quotes and "On xxx, xxx wrote:" lines
-// TODO: turn URLs into links
 
-const tpl = `<pre>{{.}}</pre>`
+const (
+	tplStr     = `<pre>{{range .}}{{.}}{{end}}</pre>`
+	linkTplStr = `<a href="{{.Href}}" target="_blank" rel="nofollow noopener">{{.Text}}</a>`
+)
+
+var tpl *template.Template
+
+func init() {
+	tpl = template.Must(template.New("view-text.html").Parse(tplStr))
+	template.Must(tpl.New("view-text-link.html").Parse(linkTplStr))
+}
+
+type linkRenderData struct {
+	Href string
+	Text string
+}
+
+var allowedSchemes = map[string]bool{
+	"http":   true,
+	"https":  true,
+	"mailto": true,
+	"ftp":    true,
+	"sftp":   true,
+	"ftps":   true,
+	"tel":    true,
+}
+
+func executeTemplate(name string, data interface{}) (template.HTML, error) {
+	var sb strings.Builder
+	err := tpl.ExecuteTemplate(&sb, name, data)
+	if err != nil {
+		return "", err
+	}
+	return template.HTML(sb.String()), nil
+}
 
 type viewer struct{}
 
@@ -28,20 +62,55 @@ func (viewer) ViewMessagePart(ctx *koushin.Context, msg *koushinbase.IMAPMessage
 		return nil, koushinbase.ErrViewUnsupported
 	}
 
-	body, err := ioutil.ReadAll(part.Body)
-	if err != nil {
-		return nil, fmt.Errorf("failed to read part body: %v", err)
-	}
+	var tokens []interface{}
+	scanner := bufio.NewScanner(part.Body)
+	for scanner.Scan() {
+		l := scanner.Text()
 
-	t := template.Must(template.New("view-text.html").Parse(tpl))
+		i := 0
+		for _, link := range linkify.Links(l) {
+			href := l[link.Start:link.End]
+			if link.Scheme == "" {
+				href = "https://" + href
+			} else if !strings.HasPrefix(href, link.Scheme) {
+				href = link.Scheme + href
+			}
 
-	var buf bytes.Buffer
-	err = t.Execute(&buf, string(body))
-	if err != nil {
-		return nil, err
+			u, err := url.Parse(href)
+			if err != nil {
+				continue
+			}
+
+			if !allowedSchemes[u.Scheme] {
+				continue
+			}
+
+			// TODO: redirect mailto links to the composer
+
+			if i < link.Start {
+				tokens = append(tokens, l[i:link.Start])
+			}
+			tok, err := executeTemplate("view-text-link.html", linkRenderData{
+				Href: href,
+				Text: l[link.Start:link.End],
+			})
+			if err != nil {
+				return nil, err
+			}
+			tokens = append(tokens, tok)
+			i = link.End
+		}
+		if i < len(l) {
+			tokens = append(tokens, l[i:])
+		}
+
+		tokens = append(tokens, "\n")
+	}
+	if err := scanner.Err(); err != nil {
+		return nil, fmt.Errorf("failed to read part body: %v", err)
 	}
 
-	return template.HTML(buf.String()), nil
+	return executeTemplate("view-text.html", tokens)
 }
 
 func init() {
-- 
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