Add initial Matrix->Discord HTML conversion

formatter.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/yuin/goldmark"
+
+	"maunium.net/go/mautrix/event"
+	"maunium.net/go/mautrix/format"
+	"maunium.net/go/mautrix/format/mdext"
+)
+
+var mdRenderer = goldmark.New(format.Extensions, format.HTMLOptions,
+	goldmark.WithExtensions(mdext.EscapeHTML, mdext.SimpleSpoiler, mdext.DiscordUnderline))
+var escapeFixer = regexp.MustCompile(`\\(__[^_]|\*\*[^*])`)
+
+func renderDiscordMarkdown(text string) event.MessageEventContent {
+	text = escapeFixer.ReplaceAllStringFunc(text, func(s string) string {
+		return s[:2] + `\` + s[2:]
+	})
+	return format.RenderMarkdownCustom(text, mdRenderer)
+}
+
+var matrixHTMLParser = &format.HTMLParser{
+	PillConverter:  nil,
+	TabsToSpaces:   4,
+	Newline:        "\n",
+	HorizontalLine: "\n---\n",
+	ItalicConverter: func(s string, context format.Context) string {
+		return fmt.Sprintf("*%s*", s)
+	},
+	UnderlineConverter: func(s string, context format.Context) string {
+		return fmt.Sprintf("__%s__", s)
+	},
+	TextConverter: func(s string, context format.Context) string {
+		return discordMarkdownEscaper.Replace(s)
+	},
+	SpoilerConverter: func(text, reason string, ctx format.Context) string {
+		if reason != "" {
+			return fmt.Sprintf("(%s) ||%s||", reason, text)
+		}
+		return fmt.Sprintf("||%s||", text)
+	},
+}
+
+var discordMarkdownEscaper = strings.NewReplacer(
+	`\`, `\\`,
+	`_`, `\_`,
+	`*`, `\*`,
+	`~`, `\~`,
+	"`", "\\`",
+	`|`, `\|`,
+)
+
+func parseMatrixHTML(content *event.MessageEventContent) string {
+	if content.Format == event.FormatHTML && len(content.FormattedBody) > 0 {
+		return matrixHTMLParser.Parse(content.FormattedBody, make(format.Context))
+	} else {
+		return discordMarkdownEscaper.Replace(content.Body)
+	}
+}

go.mod

@@ -11,7 +11,7 @@ require (
 	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e
 	github.com/yuin/goldmark v1.4.12
 	maunium.net/go/maulogger/v2 v2.3.2
-	maunium.net/go/mautrix v0.11.1-0.20220529105558-04789fc73b32
+	maunium.net/go/mautrix v0.11.1-0.20220529123139-5bc36b2978c1
 )
 
 require (

go.sum

@@ -58,5 +58,5 @@ maunium.net/go/mauflag v1.0.0 h1:YiaRc0tEI3toYtJMRIfjP+jklH45uDHtT80nUamyD4M=
 maunium.net/go/mauflag v1.0.0/go.mod h1:nLivPOpTpHnpzEh8jEdSL9UqO9+/KBJFmNRlwKfkPeA=
 maunium.net/go/maulogger/v2 v2.3.2 h1:1XmIYmMd3PoQfp9J+PaHhpt80zpfmMqaShzUTC7FwY0=
 maunium.net/go/maulogger/v2 v2.3.2/go.mod h1:TYWy7wKwz/tIXTpsx8G3mZseIRiC5DoMxSZazOHy68A=
-maunium.net/go/mautrix v0.11.1-0.20220529105558-04789fc73b32 h1:uAYLJ44nuGvR84XAUYGVrwFRhix30CTKgDIIyVHPD6U=
-maunium.net/go/mautrix v0.11.1-0.20220529105558-04789fc73b32/go.mod h1:CiKpMhAx5QZFHK03jpWb0iKI3sGU8x6+LfsOjDrcO8I=
+maunium.net/go/mautrix v0.11.1-0.20220529123139-5bc36b2978c1 h1:HNntVQh0XVyWDAsSQA/0Rk2++1cGOzmm7tH8xILSsak=
+maunium.net/go/mautrix v0.11.1-0.20220529123139-5bc36b2978c1/go.mod h1:CiKpMhAx5QZFHK03jpWb0iKI3sGU8x6+LfsOjDrcO8I=

portal.go

@@ -3,16 +3,11 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"regexp"
 	"strconv"
 	"strings"
 	"sync"
 	"time"
 
-	"github.com/yuin/goldmark"
-
-	"maunium.net/go/mautrix/format"
-	"maunium.net/go/mautrix/format/mdext"
 	"maunium.net/go/mautrix/util/variationselector"
 
 	"github.com/bwmarrin/discordgo"
@@ -543,17 +538,6 @@ func (portal *Portal) handleDiscordAttachment(intent *appservice.IntentAPI, msgI
 	}
 }
 
-var mdRenderer = goldmark.New(format.Extensions, format.HTMLOptions,
-	goldmark.WithExtensions(mdext.EscapeHTML, mdext.SimpleSpoiler, mdext.DiscordUnderline))
-var escapeFixer = regexp.MustCompile(`\\(__[^_]|\*\*[^*])`)
-
-func renderDiscordMarkdown(text string) event.MessageEventContent {
-	text = escapeFixer.ReplaceAllStringFunc(text, func(s string) string {
-		return s[:2] + `\` + s[2:]
-	})
-	return format.RenderMarkdownCustom(text, mdRenderer)
-}
-
 func (portal *Portal) handleDiscordMessageCreate(user *User, msg *discordgo.Message, thread *Thread) {
 	if portal.MXID == "" {
 		portal.log.Warnln("handle message called without a valid portal")
@@ -947,7 +931,7 @@ func (portal *Portal) handleMatrixMessage(sender *User, evt *event.Event) {
 		if edits != nil {
 			// we don't have anything to save for the update message right now
 			// as we're not tracking edited timestamps.
-			_, err := sender.Session.ChannelMessageEdit(edits.DiscordProtoChannelID(), edits.DiscordID, content.NewContent.Body)
+			_, err := sender.Session.ChannelMessageEdit(edits.DiscordProtoChannelID(), edits.DiscordID, parseMatrixHTML(content.NewContent))
 			if err != nil {
 				portal.log.Errorln("Failed to update message %s: %v", edits.DiscordID, err)
 			}
@@ -982,7 +966,7 @@ func (portal *Portal) handleMatrixMessage(sender *User, evt *event.Event) {
 				}
 			}
 		}
-		sendReq.Content = content.Body
+		sendReq.Content = parseMatrixHTML(content)
 	case event.MsgAudio, event.MsgFile, event.MsgImage, event.MsgVideo:
 		data, err := portal.downloadMatrixAttachment(evt.ID, content)
 		if err != nil {