crypto: add full support for json.RawMessage in EncryptMegolmEvent

crypto/encryptmegolm.go

@@ -15,6 +15,8 @@ import (
 	"fmt"
 
 	"github.com/rs/zerolog"
+	"github.com/tidwall/gjson"
+	"go.mau.fi/util/exgjson"
 	"go.mau.fi/util/exzerolog"
 
 	"maunium.net/go/mautrix"
@@ -27,7 +29,24 @@ var (
 	NoGroupSession = errors.New("no group session created")
 )
 
-func getRelatesTo(content interface{}) *event.RelatesTo {
+func getRawJSON[T any](content json.RawMessage, path ...string) *T {
+	value := gjson.GetBytes(content, exgjson.Path(path...))
+	if !value.IsObject() {
+		return nil
+	}
+	var result T
+	err := json.Unmarshal([]byte(value.Raw), &result)
+	if err != nil {
+		return nil
+	}
+	return &result
+}
+
+func getRelatesTo(content any) *event.RelatesTo {
+	contentJSON, ok := content.(json.RawMessage)
+	if ok {
+		return getRawJSON[event.RelatesTo](contentJSON, "m.relates_to")
+	}
 	contentStruct, ok := content.(*event.Content)
 	if ok {
 		content = contentStruct.Parsed
@@ -39,7 +58,11 @@ func getRelatesTo(content interface{}) *event.RelatesTo {
 	return nil
 }
 
-func getMentions(content interface{}) *event.Mentions {
+func getMentions(content any) *event.Mentions {
+	contentJSON, ok := content.(json.RawMessage)
+	if ok {
+		return getRawJSON[event.Mentions](contentJSON, "m.mentions")
+	}
 	contentStruct, ok := content.(*event.Content)
 	if ok {
 		content = contentStruct.Parsed