[F] Prevent race conditions in comment moderation

src/main/kotlin/org/hydev/back/controller/CommentController.kt

@@ -7,8 +7,14 @@ import com.github.kotlintelegrambot.entities.ChatId
 import com.github.kotlintelegrambot.entities.InlineKeyboardMarkup
 import com.github.kotlintelegrambot.entities.ParseMode
 import com.github.kotlintelegrambot.entities.keyboard.InlineKeyboardButton
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
+import javax.annotation.PreDestroy
 import org.hydev.back.*
 import org.hydev.back.ai.HarmLevel
 import org.hydev.back.ai.IHarmClassifier
@@ -24,6 +30,7 @@ import org.springframework.web.bind.annotation.RequestMapping
 import org.springframework.web.bind.annotation.RestController
 import org.springframework.web.util.HtmlUtils
 import java.sql.Date
+import java.util.concurrent.ConcurrentHashMap
 import javax.servlet.http.HttpServletRequest
 
 
@@ -56,6 +63,49 @@ class CommentController(
         return "✅ 已为评论 #$commentId 添加备注：\n$noteContent"
     }
 
+    private val controllerScope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
+
+    @PreDestroy
+    fun onDestroy() {
+        controllerScope.cancel("CommentController 正在关闭，取消所有未完成的审核任务")
+    }
+
+    private val processingCommentIds = ConcurrentHashMap.newKeySet<Long>()
+
+    /**
+     * Acquire the in-process lock for [id], then launch an IO coroutine to run [block].
+     * - Lock taken     → answer callback with a busy alert and return immediately.
+     * - Lock acquired  → silently acknowledge the callback (stops spinner), run [block] on IO dispatcher.
+     * Errors inside [block] are caught, logged, and reported to the admin chat.
+     * The lock is always released in `finally`.
+     */
+    private fun withCommentLock(
+        bot: com.github.kotlintelegrambot.Bot,
+        id: Long,
+        callbackQueryId: String,
+        chatId: ChatId,
+        actionName: String,
+        block: suspend CoroutineScope.() -> Unit
+    ) {
+        if (!processingCommentIds.add(id)) {
+            bot.answerCallbackQuery(callbackQueryId, text = "⚠️ 有人正在处理这条评论，请稍候", showAlert = true)
+            return
+        }
+        bot.answerCallbackQuery(callbackQueryId)
+        controllerScope.launch {
+            try {
+                block()
+            } catch (e: CancellationException) {
+                throw e
+            } catch (e: Exception) {
+                System.err.println("[!] Failed to $actionName comment $id: $e")
+                bot.sendMessage(chatId, "[!] #$id ${actionName}失败: $e")
+            } finally {
+                processingCommentIds.remove(id)
+            }
+        }
+    }
+
     private val actionButtons = mapOf(
         "通过" to "pass",
         "Spoiler 后通过" to "pass-spoiler",
@@ -82,80 +132,82 @@ class CommentController(
         }
 
         if (data == "comment-cancel") {
-            bot.editMessageReplyMarkup(chatId, msgId, inlId, replyMarkup)
+            withCommentLock(bot, id, callbackQuery.id, chatId, "cancel") {
+                bot.editMessageReplyMarkup(chatId, msgId, inlId, replyMarkup)
+            }
             return@callback
         }
 
         if (data.startsWith("comment-confirm-")) {
             val action = data.removePrefix("comment-confirm-")
-            bot.editMessageReplyMarkup(chatId, msgId, inlId, null)
 
             when (action) {
                 // Ban ip
-                "ban" -> {
+                "ban" -> withCommentLock(bot, id, callbackQuery.id, chatId, "ban") {
                     val comment = commentRepo.queryById(id)!!
                     val ip = comment.ip
-                    val entry = Ban(ip = ip, reason = "Bad comment #$id")
-                    banRepo.save(entry)
-
-                    val escapedPersonId = HtmlUtils.htmlEscape(comment.personId)
-                    val escapedContent = HtmlUtils.htmlEscape(comment.content)
-                    val escapedIp = HtmlUtils.htmlEscape(ip)
-                    val escapedOperator = HtmlUtils.htmlEscape(operator)
+                    banRepo.save(Ban(ip = ip, reason = "Bad comment #$id"))
                     val banMessage = """
-                        #$id - $escapedPersonId 收到了新的留言：
+                        #$id - ${HtmlUtils.htmlEscape(comment.personId)} 收到了新的留言：
 
-                        <blockquote expandable><tg-spoiler>$escapedContent</tg-spoiler></blockquote>
+                        <blockquote expandable><tg-spoiler>${HtmlUtils.htmlEscape(comment.content)}</tg-spoiler></blockquote>
 
-                        - 已封禁🚫 $escapedIp by $escapedOperator
+                        - 已封禁🚫 ${HtmlUtils.htmlEscape(ip)} by ${HtmlUtils.htmlEscape(operator)}
                     """.trimIndent()
-
                     println("[-] Comment banned! IP $ip banned by $operator due to Comment $id")
                     bot.editMessageText(chatId, msgId, inlId, banMessage, parseMode = ParseMode.HTML)
                 }
 
                 // Rejected, remove
-                "reject" -> {
+                "reject" -> withCommentLock(bot, id, callbackQuery.id, chatId, "reject") {
                     println("[-] Comment rejected! Comment $id deleted by $operator")
                     bot.editMessageText(chatId, msgId, inlId, "$message\n- 已删除❌ by $operator")
                 }
 
                 // Commit changes
-                "pass", "pass-spoiler" -> {
+                "pass", "pass-spoiler" -> withCommentLock(bot, id, callbackQuery.id, chatId, "pass") {
                     var statusMsgId = 0L
-                    bot.sendMessage(chatId, "正在提交更改...").fold(
-                        { statusMsgId = it.messageId },
-                        { System.err.println("> Failed to send submission message: $it") })
-                    val comment = commentRepo.queryById(id)!!
-
-                    // Spoiler
-                    if (action == "pass-spoiler")
-                        comment.content = "||${comment.content.replace('\n', ' ')}||"
-
-                    // Create commit content
-                    val fPath = "people/${comment.personId}/comments/${date("yyyy-MM-dd")}-C${comment.id}.json"
-                    val cMsg = "[+] Comment added by ${comment.submitter} for ${comment.personId}"
-
-                    // Build JSON content with optional replies
-                    val content = json("id" to comment.id, "content" to comment.content,
-                        "submitter" to comment.submitter, "date" to comment.date,
-                        *comment.note?.let { arrayOf("replies" to listOf(mapOf("content" to it, "submitter" to "Maintainer"))) } ?: arrayOf())
-                    println("[+] Comment approved. Adding Comment $id: $content by $operator")
-
-                    // Write commit
-                    val url = commitDirectly(comment.submitter, DataEdit(fPath, content), cMsg)
-                    bot.deleteMessage(chatId, statusMsgId)
-
-                    // Update database
-                    comment.approved = true
-                    commentRepo.save(comment)
-
-                    // Attach URL
-                    bot.editMessageText(chatId, msgId, inlId, "$message\n- 已通过审核✅ by $operator", replyMarkup =
-                        InlineKeyboardMarkup.createSingleRowKeyboard(
-                            InlineKeyboardButton.Url(text = "查看 Commit", url = url)
+                    try {
+                        val comment = commentRepo.queryById(id)!!
+                        if (comment.approved) {
+                            // Already processed (e.g. approved before this server restarted), notify and bail
+                            bot.sendMessage(chatId, "⚠️ 这条评论 (#$id) 已经被处理过了")
+                            return@withCommentLock
+                        }
+                        bot.sendMessage(chatId, "正在提交更改...").fold(
+                            { statusMsgId = it.messageId },
+                            { System.err.println("> Failed to send submission message: $it") })
+
+                        // Spoiler
+                        if (action == "pass-spoiler")
+                            comment.content = "||${comment.content.replace('\n', ' ')}||"
+
+                        // Create commit content
+                        val fPath = "people/${comment.personId}/comments/${date("yyyy-MM-dd")}-C${comment.id}.json"
+                        val cMsg = "[+] Comment added by ${comment.submitter} for ${comment.personId}"
+
+                        // Build JSON content with optional replies
+                        val content = json("id" to comment.id, "content" to comment.content,
+                            "submitter" to comment.submitter, "date" to comment.date,
+                            *comment.note?.let { arrayOf("replies" to listOf(mapOf("content" to it, "submitter" to "Maintainer"))) } ?: arrayOf())
+                        println("[+] Comment approved. Adding Comment $id: $content by $operator")
+
+                        // Write commit
+                        val url = commitDirectly(comment.submitter, DataEdit(fPath, content), cMsg)
+
+                        // Update database
+                        comment.approved = true
+                        commentRepo.save(comment)
+
+                        // Attach URL
+                        bot.editMessageText(chatId, msgId, inlId, "$message\n- 已通过审核✅ by $operator", replyMarkup =
+                            InlineKeyboardMarkup.createSingleRowKeyboard(
+                                InlineKeyboardButton.Url(text = "查看 Commit", url = url)
+                            )
                         )
-                    )
+                    } finally {
+                        if (statusMsgId != 0L) bot.deleteMessage(chatId, statusMsgId)
+                    }
                 }
             }
             return@callback
@@ -170,7 +222,9 @@ class CommentController(
             )
         } ?: replyMarkup
 
-        bot.editMessageReplyMarkup(chatId, msgId, inlId, confirmMarkup)
+        withCommentLock(bot, id, callbackQuery.id, chatId, "confirm-markup") {
+            bot.editMessageReplyMarkup(chatId, msgId, inlId, confirmMarkup)
+        }
     }
 
     @PostMapping("/add")