feat: support query single command description

src/main/kotlin/cn/rtast/fancybot/commands/HelpCommand.kt

@@ -22,18 +22,38 @@ class HelpCommand : BaseCommand() {
     override val commandNames = listOf("/help", "/帮助")
 
     override suspend fun executeGroup(listener: OneBotListener, message: GroupMessage, args: List<String>) {
-        val node = NodeMessageChain.Builder()
+        if (args.isEmpty()) {
-        val msg = MessageChain.Builder()
+            val node = NodeMessageChain.Builder()
-        commands.sortedBy { it::class.simpleName }.forEach {
+            val msg = MessageChain.Builder()
-            val description = if (!it::class.hasAnnotation<CommandDescription>()) "暂无描述"
+            commands.sortedBy { it::class.simpleName }.forEach {
-            else it::class.findAnnotation<CommandDescription>()?.description!!
+                val description = if (!it::class.hasAnnotation<CommandDescription>()) "暂无描述"
-            val commandName = it::class.simpleName?.replace("Command", "")!!
+                else it::class.findAnnotation<CommandDescription>()?.description!!
-            val commandNames = it.commandNames.joinToString(",")
+                val commandName = it::class.simpleName?.replace("Command", "")!!
-            msg.addText("[$commandName] [$description] 命令: $commandNames")
+                val commandNames = it.commandNames.joinToString(",")
+                msg.addText("[$commandName] [$description] 命令: $commandNames")
+                    .addNewLine()
+            }
+            msg.addText("共计${commands.size}条命令")
+            node.addMessageChain(msg.build(), message.sender.userId)
+            message.reply(node.build())
+        } else {
+            val commandName = args.first().replace("/", "")
+            val matchedCommand = commands.find {
+                it.commandNames.map { map -> map.replace("/", "") }.contains(commandName)
+            }
+            if (matchedCommand == null) {
+                message.reply("未查询到该命令")
+                return
+            }
+            val description = matchedCommand::class.findAnnotation<CommandDescription>()?.description ?: "暂无描述"
+            val msg = MessageChain.Builder()
+                .addText("命令名称: ${matchedCommand::class.simpleName}")
                 .addNewLine()
+                .addText("指令别名: ${matchedCommand.commandNames.joinToString(",")}")
+                .addNewLine()
+                .addText("指令描述: $description")
+                .build()
+            message.reply(msg)
         }
-        msg.addText("共计${commands.size}条命令")
-        node.addMessageChain(msg.build(), message.sender.userId)
-        message.reply(node.build())
     }
 }