Combine line count and last record query

Author: oissevalt

dice/ext_log.go

@@ -196,7 +196,7 @@ func RegisterBuiltinExtLog(self *Dice) {
 				}
 
 				if name != "" {
-					lines, exists := model.LogLinesCountGet(ctx.Dice.DBLogs, group.GroupID, name)
+					lineCount, lastLine, exists := model.LogGetCountAndLastLine(ctx.Dice.DBLogs, group.GroupID, name)
 
 					if exists {
 						if groupNotActiveCheck() {
@@ -208,15 +208,9 @@ func RegisterBuiltinExtLog(self *Dice) {
 						group.UpdatedAtTime = time.Now().Unix()
 
 						VarSetValueStr(ctx, "$t记录名称", name)
-						VarSetValueInt64(ctx, "$t当前记录条数", lines)
-
-						logEnabledPrompt := DiceFormatTmpl(ctx, "日志:记录_开启_成功")
-						// TODO: 到这里相当于全文 query 了两遍日志。可以优化吗？
-						lastRecord, err := model.LogGetLastLine(ctx.Dice.DBLogs, group.GroupID, name)
-						if err == nil {
-							logEnabledPrompt = fmt.Sprintf("[CQ:reply,id=%v] %s", lastRecord.RawMsgID, logEnabledPrompt)
-						}
+						VarSetValueInt64(ctx, "$t当前记录条数", lineCount)
 
+						logEnabledPrompt := fmt.Sprintf("[CQ:reply,id=%v] %s", lastLine.RawMsgID, DiceFormatTmpl(ctx, "日志:记录_开启_成功"))
 						ReplyToSender(ctx, msg, logEnabledPrompt)
 					} else {
 						VarSetValueStr(ctx, "$t记录名称", name)

dice/model/log.go

@@ -532,3 +532,34 @@ LIMIT 1`
 	}
 	return &record, nil
 }
+
+// LogGetCountAndLastLine performs a specialised union search.
+func LogGetCountAndLastLine(db *sqlx.DB, groupID, logName string) (lineCount int64, lastLine *LogOneItem, exists bool) {
+	logID, err := LogGetIDByGroupIDAndName(db, groupID, logName)
+	if err != nil {
+		return
+	}
+
+	const filterQuery = `
+WITH filtered AS (
+	SELECT id, nickname, im_userid, time, message, is_dice, command_id, command_info, raw_msg_id, user_uniform_id
+	FROM log_items
+	WHERE log_id=$1 AND removed IS NULL
+)
+SELECT COUNT(*) OVER () AS line_count, *
+FROM filtered
+ORDER BY time DESC
+LIMIT 1`
+
+	type QueryResult struct {
+		LineCount int64 `db:"line_count"`
+		LogOneItem
+	}
+
+	var result QueryResult
+	if err = db.Get(&result, filterQuery, logID); err != nil {
+		return
+	}
+
+	return result.LineCount, &result.LogOneItem, true
+}