1 files changed, 55 insertions, 0 deletions
diff --git a/danmaku/dmmsg/danmu.go b/danmaku/dmmsg/danmu.go
new file mode 100644
index 0000000..2cc5dfa
--- /dev/null
+++ b/danmaku/dmmsg/danmu.go
@@ -0,0 +1,55 @@
+package dmmsg
+
+/*
+Decoder of raw danmaku messages.
+*/
+
+import (
+	"fmt"
+)
+
+type RawDanMuMessage = BaseRawMessage[[]interface{}, interface{}]
+
+type DanMuMessage struct {
+	Content    string
+	SourceUser struct {
+		Nickname string
+		UID      int64
+	}
+}
+
+func (dm DanMuMessage) String() string {
+	return fmt.Sprintf("(user: %v, uid: %v) %v",
+		dm.SourceUser.Nickname, dm.SourceUser.UID, dm.Content)
+}
+
+const kInvalidDanmakuJson = "invalid danmaku JSON document"
+
+func ParseDanmakuMessage(body RawDanMuMessage) (dmm DanMuMessage, err error) {
+	if len(body.Info) != 16 {
+		err = fmt.Errorf("%s: \"info\" length != 16", kInvalidDanmakuJson)
+		return
+	}
+
+	dmm.Content, err = castValue[string](body.Info[1])
+	if err != nil {
+		return
+	}
+
+	userInfo, err := castValue[[]interface{}](body.Info[2])
+
+	var ok bool
+	uid, ok := userInfo[0].(float64)
+	if !ok {
+		err = fmt.Errorf("%s: uid is not a float64: %v", kInvalidDanmakuJson, userInfo[0])
+		return
+	}
+	dmm.SourceUser.UID = int64(uid)
+
+	dmm.SourceUser.Nickname, ok = userInfo[1].(string)
+	if !ok {
+		err = fmt.Errorf("%s: nickname is not a string: %v", kInvalidDanmakuJson, userInfo[1])
+		return
+	}
+	return
+}