doc patch and lib upd

project/MornyConfiguration.scala

@@ -8,7 +8,7 @@ object MornyConfiguration {
 	val MORNY_CODE_STORE = "https://github.com/Eyre-S/Coeur-Morny-Cono"
 	val MORNY_COMMIT_PATH = "https://github.com/Eyre-S/Coeur-Morny-Cono/commit/%s"
 	
-	val VERSION = "2.0.0-alpha16"
+	val VERSION = "2.0.0-alpha17"
 	val VERSION_DELTA: Option[String] = None
 	val CODENAME = "guanggu"
 	
@@ -16,28 +16,28 @@ object MornyConfiguration {
 	
 	val dependencies: Seq[ModuleID] = Seq(
 		
-		"com.github.spotbugs" % "spotbugs-annotations" % "4.7.3" % Compile,
+		"com.github.spotbugs" % "spotbugs-annotations" % "4.8.2" % Compile,
 		
 		"cc.sukazyo" % "messiva" % "0.2.0",
 		"cc.sukazyo" % "resource-tools" % "0.2.2",
 		
 		"com.github.pengrad" % "java-telegram-bot-api" % "6.2.0",
-		"org.http4s" %% "http4s-dsl"          % "0.23.24",
+		"org.http4s" %% "http4s-dsl"          % "0.23.25",
-		"org.http4s" %% "http4s-circe"        % "0.23.24",
+		"org.http4s" %% "http4s-circe"        % "0.23.25",
-		"org.http4s" %% "http4s-netty-server" % "0.5.11",
+		"org.http4s" %% "http4s-netty-server" % "0.5.12",
 		
-		"com.softwaremill.sttp.client3" %% "core"           % "3.9.0",
+		"com.softwaremill.sttp.client3" %% "core"           % "3.9.2",
-		"com.softwaremill.sttp.client3" %% "okhttp-backend" % "3.9.0",
+		"com.softwaremill.sttp.client3" %% "okhttp-backend" % "3.9.2",
-		"com.squareup.okhttp3" % "okhttp" % "4.11.0" % Runtime,
+		"com.squareup.okhttp3" % "okhttp" % "4.12.0" % Runtime,
 		
 		"org.typelevel" %% "case-insensitive" % "1.4.0",
 		"com.google.code.gson" % "gson" % "2.10.1",
 		"io.circe" %% "circe-core"    % "0.14.6",
 		"io.circe" %% "circe-generic" % "0.14.6",
 		"io.circe" %% "circe-parser"  % "0.14.6",
-		"org.jsoup" % "jsoup" % "1.16.2",
+		"org.jsoup" % "jsoup" % "1.17.2",
 		
-		"com.cronutils" % "cron-utils" % "9.2.0",
+		"com.cronutils" % "cron-utils" % "9.2.1",
 		
 		// used for disable slf4j
 		// due to the slf4j api have been used in the following libraries:
@@ -47,8 +47,8 @@ object MornyConfiguration {
 		"org.scalatest" %% "scalatest"          % "3.2.17" % Test,
 		"org.scalatest" %% "scalatest-freespec" % "3.2.17" % Test,
 		// for test report
-		"com.vladsch.flexmark" % "flexmark"                 % "0.64.0" % Test,
+		"com.vladsch.flexmark" % "flexmark"                 % "0.64.8" % Test,
-		"com.vladsch.flexmark" % "flexmark-profile-pegdown" % "0.64.0" % Test
+		"com.vladsch.flexmark" % "flexmark-profile-pegdown" % "0.64.8" % Test
 		
 	)
 	

src/main/scala/cc/sukazyo/cono/morny/core/MornyCoeur.scala

@@ -5,7 +5,7 @@ import cc.sukazyo.cono.morny.core.MornyCoeur.*
 import cc.sukazyo.cono.morny.core.bot.api.{EventListenerManager, MornyCommandManager, MornyQueryManager}
 import cc.sukazyo.cono.morny.core.bot.api.messages.ThreadingManager
 import cc.sukazyo.cono.morny.core.bot.event.{MornyOnInlineQuery, MornyOnTelegramCommand, MornyOnUpdateTimestampOffsetLock}
-import cc.sukazyo.cono.morny.core.bot.internal.ThreadingManagerImpl
+import cc.sukazyo.cono.morny.core.bot.internal.{ErrorMessageManager, ThreadingManagerImpl}
 import cc.sukazyo.cono.morny.core.http.api.{HttpServer, MornyHttpServerContext}
 import cc.sukazyo.cono.morny.core.http.internal.MornyHttpServerContextImpl
 import cc.sukazyo.cono.morny.reporter.MornyReport
@@ -171,6 +171,7 @@ class MornyCoeur (modules: List[MornyModule])(using val config: MornyConfig)(tes
 	val trusted: MornyTrusted = MornyTrusted()
 	private val _messageThreading: ThreadingManagerImpl = ThreadingManagerImpl(using account)
 	val messageThreading: ThreadingManager = _messageThreading
+	val errorMessageManager: ErrorMessageManager = ErrorMessageManager()
 	
 	val eventManager: EventListenerManager = EventListenerManager()
 	val commands: MornyCommandManager = MornyCommandManager()
@@ -211,6 +212,7 @@ class MornyCoeur (modules: List[MornyModule])(using val config: MornyConfig)(tes
 			
 			DirectMsgClear(),
 			_messageThreading.CancelCommand,
+			errorMessageManager.ShowErrorMessageCommand,
 			
 		)
 	}

src/main/scala/cc/sukazyo/cono/morny/core/bot/api/BotExtension.scala

@@ -0,0 +1,24 @@
+package cc.sukazyo.cono.morny.core.bot.api
+
+import cc.sukazyo.cono.morny.core.MornyCoeur
+import cc.sukazyo.cono.morny.core.bot.api.messages.ErrorMessage
+
+/** Bot extensions for Morny feature.
+  */
+object BotExtension {
+	
+	extension (errorMessage: ErrorMessage[?, ?]) {
+		
+		/** Submit this [[ErrorMessage]] to a [[MornyCoeur]].
+		  * 
+		  * Will send this [[ErrorMessage]] with the basic send config.
+		  *
+		  * @see [[cc.sukazyo.cono.morny.core.bot.internal.ErrorMessageManager.sendErrorMessage]]
+		  * @since 2.0.0
+		  */
+		def submit (using coeur: MornyCoeur): Unit =
+			coeur.errorMessageManager.sendErrorMessage(errorMessage)
+		
+	}
+	
+}

src/main/scala/cc/sukazyo/cono/morny/core/bot/api/EventEnv.scala

@@ -7,38 +7,77 @@ import com.pengrad.telegrambot.model.Update
 
 import scala.collection.mutable
 
+/** A Telegram event context that holds status of the event.
+  *
+  * @param update Associated raw [[Update]] object.
+  */
 class EventEnv (
 	
 	val update: Update
 	
 ) {
 	
+	/** This status contains a [[StackTraceElement]] that shows where the status is set. */
 	trait StateSource (val from: StackTraceElement)
+	/** Available status of the event. */
 	enum State:
+		/** The event is successfully processed by someone event listener. */
 		case OK (_from: StackTraceElement) extends State with StateSource(_from)
+		/** The event is canceled for some reason, it is recommended be ignored. */
 		case CANCELED (_from: StackTraceElement) extends State with StateSource(_from)
 	
 	private val _status: mutable.ListBuffer[State] = mutable.ListBuffer.empty
+	/** [[GivenContext Given Contexts]] associated to the event. Can be used to store and share
+	  * data between event listeners.
+	  * @since 1.3.0
+	  */
 	val givenCxt: GivenContext = GivenContext()
+	/** The [[EpochMillis]] time that bot received this event and preparing to process it.
+	  * @since 1.3.0
+	  */
 	val timeStartup: EpochMillis = System.currentTimeMillis
 	
+	/** If this event is processed.
+	  *
+	  * Not only [[State.OK]] but also [[State.CANCELED]] will been seen as processed.
+	  *
+	  * @since 1.2.0
+	  *
+	  * @return `true` if the event have been processed, `false` otherwise.
+	  */
 	def isEventOk: Boolean = _status.lastOption match
 		case Some(x) if x == State.OK => true
 		case _ => false
 	
+	/** Set the event status to [[State.OK]].
+	  *
+	  * This will push a new [[State.OK]] to the status list.
+	  */
 	//noinspection UnitMethodIsParameterless
 	def setEventOk: Unit =
 		_status += State.OK(StackUtils.getStackTrace(1).head)
 	
+	/** Set the event status to [[State.CANCELED]].
+	  *
+	  * This will push a new [[State.CANCELED]] to the status list.
+	  *
+	  * @since 1.3.0
+	  */
 	//noinspection UnitMethodIsParameterless
 	def setEventCanceled: Unit =
 		_status += State.CANCELED(StackUtils.getStackTrace(1).head)
 	
+	/** Get the last [[State]] set of the event.
+	  * @since 1.3.0
+	  */
 	def state: State|Null =
 		_status.lastOption match
 			case Some(x) => x
 			case None => null
 	
+	/** Get all the status set of the event. The earlier status set is in the left.
+	  * @since 1.3.0
+	  */
 	def status: List[State] =
 		_status.toList
 	

src/main/scala/cc/sukazyo/cono/morny/core/bot/api/messages/ErrorMessage.scala

@@ -0,0 +1,74 @@
+package cc.sukazyo.cono.morny.core.bot.api.messages
+
+import com.pengrad.telegrambot.request.AbstractSendRequest
+
+/** A error message based on Telegram's [[AbstractSendRequest]].
+  *
+  * Contains two types ([[simple]] and [[complex]]) message that
+  * allows to choose one to show in different cases.
+  *
+  * Also there contains a [[context]] (typed with [[MessagingContext.WithMessage]])
+  * that infers the source of this error message, also can be used for
+  * the unique key of one error message.
+  *
+  * There's also a [[ErrorMessage.Types]] enum infers to the two type. You
+  * can use [[getByType]] (or [[getByTypeNormal]]) method to get the specific
+  * type's message of that type.
+  *
+  * @since 2.0.0
+  *
+  * @see [[cc.sukazyo.cono.morny.core.bot.internal.ErrorMessageManager]] This
+  *      ErrorMessage's manager (consumer) implementation by the Morny Coeur.
+  * @see [[cc.sukazyo.cono.morny.core.bot.api.BotExtension.submit]] Simple
+  *      way to consume this.
+  *
+  * @tparam T1 Type of the simple error message
+  * @tparam T2 Type of the complex error message
+  */
+trait ErrorMessage[T1 <: AbstractSendRequest[T1], T2 <: AbstractSendRequest[T2]] {
+	
+	val simple: T1
+	val complex: T2
+	
+	val context: MessagingContext.WithMessage
+	
+	/** Get the simple or complex message by the given [[ErrorMessage.Types]] infer.
+	  *
+	  * This method returns a union type [[T1]] and [[T2]]. This may be
+	  * not useful when you don't care about the specific return types (maybe for
+	  * the most times). You can use [[getByTypeNormal]] instead.
+	  *
+	  * @since 2.0.0
+	  */
+	def getByType (t: ErrorMessage.Types): AbstractSendRequest[T1] | AbstractSendRequest[T2] =
+		t match
+			case ErrorMessage.Types.Simple => simple
+			case ErrorMessage.Types.Complex => complex
+	
+	/** Get the simple or complex message by the given [[ErrorMessage.Types]] infer.
+	  *
+	  * This works exactly the same with the [[getByType]], the only difference is
+	  * this returns with a bit universal type `AbstractSendRequest[?]`.
+	  *
+	  * @see [[getByType]]
+	  * @since 2.0.0
+	  */
+	def getByTypeNormal (t: ErrorMessage.Types): AbstractSendRequest[?] =
+		getByType(t)
+	
+}
+
+object ErrorMessage {
+	
+	enum Types:
+		case Simple
+		case Complex
+	
+	def apply [T1 <: AbstractSendRequest[T1], T2<: AbstractSendRequest[T2]]
+	(_simple: T1, _complex: T2)(using cxt: MessagingContext.WithMessage): ErrorMessage[T1, T2] =
+		new ErrorMessage[T1, T2]:
+			override val simple: T1 = _simple
+			override val complex: T2 = _complex
+			override val context: MessagingContext.WithMessage = cxt
+	
+}

src/main/scala/cc/sukazyo/cono/morny/core/bot/api/messages/MessagingContext.scala

@@ -1,5 +1,6 @@
 package cc.sukazyo.cono.morny.core.bot.api.messages
 
+import cc.sukazyo.cono.morny.util.tgapi.Standardize.*
 import com.pengrad.telegrambot.model.{Chat, Message, User}
 
 /**
@@ -7,37 +8,69 @@ import com.pengrad.telegrambot.model.{Chat, Message, User}
   */
 trait MessagingContext:
 	val bind_chat: Chat
+	def toChatKey: MessagingContext.Key =
+		MessagingContext.Key(this)
 
 /**
   * @since 2.0.0
   */
 object MessagingContext {
 	
-	given String = "aaa"
+	case class Key (chatId: ChatID)
-	
+	object Key:
+		def apply (it: MessagingContext): Key = Key(it.bind_chat.id)
 	def apply (_chat: Chat): MessagingContext =
 		new MessagingContext:
 			override val bind_chat: Chat = _chat
+	
 	trait WithUser extends MessagingContext:
 		val bind_user: User
+		def toChatUserKey: WithUser.Key =
+			WithUser.Key(this)
+	object WithUser:
+		case class Key (chatID: ChatID, userId: UserID)
+		object Key:
+			def apply (it: WithUser): Key = Key(it.bind_chat.id, it.bind_user.id)
+		def apply (_chat: Chat, _user: User): WithUser =
+			new WithUser:
+				override val bind_chat: Chat = _chat
+				override val bind_user: User = _user
 	def apply (_chat: Chat, _user: User): WithUser =
-		new WithUser:
+		WithUser(_chat, _user)
-			override val bind_chat: Chat = _chat
+	
-			override val bind_user: User = _user
 	trait WithMessage extends MessagingContext:
 		val bind_message: Message
+		def toChatMessageKey: WithMessage.Key =
+			WithMessage.Key(this)
+	object WithMessage:
+		case class Key (chatId: ChatID, messageId: MessageID)
+		object Key:
+			def apply (it: WithMessage): Key = Key(it.bind_chat.id, it.bind_message.messageId)
+		def apply (_chat: Chat, _message: Message): WithMessage =
+			new WithMessage:
+				override val bind_chat: Chat = _chat
+				override val bind_message: Message = _message
 	def apply (_chat: Chat, _message: Message): WithMessage =
-		new WithMessage:
+		WithMessage(_chat, _message)
-			override val bind_chat: Chat = _chat
+	
-			override val bind_message: Message = _message
+	trait WithUserAndMessage extends MessagingContext with WithMessage with WithUser:
-	trait WithUserAndMessage extends MessagingContext with WithMessage with WithUser
+		def toChatUserMessageKey: WithUserAndMessage.Key =
+			WithUserAndMessage.Key(this)
+	object WithUserAndMessage:
+		case class Key (chatId: ChatID, userId: UserID, messageId: MessageID)
+		object Key:
+			def apply (it: WithUserAndMessage): Key = Key(it.bind_chat.id, it.bind_user.id, it.bind_message.messageId)
+		def apply (_chat: Chat, _user: User, _message: Message): WithUserAndMessage =
+			new WithUserAndMessage:
+				override val bind_chat: Chat = _chat
+				override val bind_user: User = _user
+				override val bind_message: Message = _message
 	def apply (_chat: Chat, _user: User, _message: Message): WithUserAndMessage =
-		new WithUserAndMessage:
+		WithUserAndMessage(_chat, _user, _message)
-			override val bind_chat: Chat = _chat
-			override val bind_user: User = _user
-			override val bind_message: Message = _message
 	
 	/** Extract a message context from a message (or message event).
+	  * 
+	  * @since 2.0.0
 	  * 
 	  * @param message The message.
 	  * @return The message context, contains the message's belongs chat, sender user and message itself.

src/main/scala/cc/sukazyo/cono/morny/core/bot/command/MornyInformation.scala

@@ -2,6 +2,7 @@ package cc.sukazyo.cono.morny.core.bot.command
 
 import cc.sukazyo.cono.morny.core.{MornyCoeur, MornySystem}
 import cc.sukazyo.cono.morny.core.bot.api.{ICommandAlias, ITelegramCommand}
+import cc.sukazyo.cono.morny.core.bot.api.messages.{ErrorMessage, MessagingContext}
 import cc.sukazyo.cono.morny.data.MornyInformation.*
 import cc.sukazyo.cono.morny.data.TelegramStickers
 import cc.sukazyo.cono.morny.reporter.MornyReport
@@ -36,7 +37,7 @@ class MornyInformation (using coeur: MornyCoeur) extends ITelegramCommand {
 	override def execute (using command: InputCommand, event: Update): Unit = {
 		
 		if (command.args isEmpty) {
-			echoInfo(event.message.chat.id, event.message.messageId)
+			echoInfo(event)
 			return
 		}
 		
@@ -53,9 +54,24 @@ class MornyInformation (using coeur: MornyCoeur) extends ITelegramCommand {
 		
 	}
 	
-	private def echoInfo (chatId: Long, replyTo: Int): Unit = {
+	private def echoInfo (update: Update): Unit = {
+		val cxt = MessagingContext.extract(using update.message)
+		val cxtReplied = Option(update.message.replyToMessage).map(MessagingContext.extract(using _))
+		
+		cxtReplied match
+			case None =>
+			case Some(_cxtReplied) =>
+				// check if theres associated information about error message on the replied context.
+				//   if there really is, that means the replied message is a error message,
+                //   so the error message's complex information will be sent
+				coeur.errorMessageManager.inspectMessage(_cxtReplied.toChatMessageKey) match
+					case None =>
+					case Some(errMessage) =>
+						coeur.errorMessageManager.sendErrorMessage(errMessage, ErrorMessage.Types.Complex, Some(cxt))
+		
+		// if theres no any associated information on the context
 		SendPhoto(
-			chatId,
+			cxt.bind_chat.id,
 			getAboutPic
 		).caption(
 			s"""<b>Morny Cono</b>
@@ -63,8 +79,9 @@ class MornyInformation (using coeur: MornyCoeur) extends ITelegramCommand {
 			   |————————————————
 			   |$getMornyAboutLinksHTML"""
 					.stripMargin
-		).parseMode(ParseMode HTML).replyToMessageId(replyTo)
+		).parseMode(ParseMode HTML).replyToMessageId(cxt.bind_message.messageId)
 			.unsafeExecute
+		
 	}
 	
 	private def echoStickers (using command: InputCommand, event: Update): Unit = {

src/main/scala/cc/sukazyo/cono/morny/core/bot/internal/ErrorMessageManager.scala

@@ -0,0 +1,110 @@
+package cc.sukazyo.cono.morny.core.bot.internal
+
+import cc.sukazyo.cono.morny.core.MornyCoeur
+import cc.sukazyo.cono.morny.core.bot.api.{ICommandAlias, ISimpleCommand}
+import cc.sukazyo.cono.morny.core.bot.api.messages.{ErrorMessage, MessagingContext}
+import cc.sukazyo.cono.morny.util.schedule.{DelayedTask, Scheduler}
+import cc.sukazyo.cono.morny.util.tgapi.InputCommand
+import cc.sukazyo.cono.morny.util.tgapi.TelegramExtensions.Requests.unsafeExecute
+import cc.sukazyo.cono.morny.util.EpochDateTime.DurationMillis
+import com.pengrad.telegrambot.TelegramBot
+import com.pengrad.telegrambot.model.Update
+import com.pengrad.telegrambot.request.{AbstractSendRequest, SendMessage}
+
+class ErrorMessageManager (using coeur: MornyCoeur) {
+	given TelegramBot = coeur.account
+	
+	private val expiresDuration: DurationMillis = 1000 * 60 * 60 * 5 // 5 hours
+	
+	private val errorMessageMap = collection.mutable.Map[MessagingContext.WithMessage.Key, ErrorMessage[?, ?]]()
+	private val errorMessageMapCleaner = Scheduler(isDaemon = true)
+	private def putErrorMessage (key: MessagingContext.WithMessage.Key, message: ErrorMessage[?, ?]): Unit =
+		errorMessageMap.synchronized: // remove an error message after the given expires duration.
+			errorMessageMap += (key -> message)
+			errorMessageMapCleaner ++ DelayedTask("", expiresDuration, {
+				errorMessageMap.remove(key)
+			})
+	
+	/** Send an [[ErrorMessage]] and add this error message to ErrorMessage stash.
+	  *
+	  * This will execute the SendRequest using the default send config.
+	  *
+	  * @since 2.0.0
+	  */
+	def sendErrorMessage (message: ErrorMessage[?, ?]): Unit =
+		// todo: which should be sent using user config
+		val useType = ErrorMessage.Types.Simple
+		sendErrorMessage(message, useType, isNewMessage = true)
+	
+	/** Send an [[ErrorMessage]] and add it to the stash if it is new.
+	  *
+	  * @since 2.0.0
+	  *
+	  * @param message The [[ErrorMessage]] to be sent.
+	  * @param useType Which type of the message should be sent.
+	  * @param injectedSendContext A context that determine where and how the message should
+	  *                            be sent. Currently only the message id in this context will
+	  *                            be used to determine the reply to message.
+	  *
+	  *                            This is part of the API limitation, but due to in normal cases,
+	  *                            the source error message must be in the same chat so it may
+	  *                            make sense.
+	  * @param isNewMessage Is this ErrorMessage is a new error message, otherwise it should be
+	  *                     an existed error message that just calling this method because of
+	  *                     need to be resent some messages.
+	  *
+	  *                     If this is new, the message will be added to the stash, if not, it
+	  *                     should be comes from the stash and will not be added to the stash again.
+	  *
+	  *                     Default is false.
+	  */
+	def sendErrorMessage (
+		message: ErrorMessage[?, ?],
+		useType: ErrorMessage.Types,
+		injectedSendContext: Option[MessagingContext.WithMessage] = None,
+		isNewMessage: Boolean = false
+	): Unit = {
+		val sendMessage = message
+			.getByTypeNormal(useType)
+			.asInstanceOf[AbstractSendRequest[Nothing]]
+		injectedSendContext match
+			case None =>
+			case Some(cxt) =>
+				sendMessage.replyToMessageId(cxt.bind_message.messageId)
+		val response = sendMessage.unsafeExecute
+		if isNewMessage then
+			val key = MessagingContext.extract(using response.message).toChatMessageKey
+			putErrorMessage(key, message)
+	}
+	
+	/** Get the stashed [[ErrorMessage]] associated with the [[MessagingContext.WithMessage.Key message key]].
+	  *
+	  * If the message key does not associated with any error message in the stash, then
+	  * [[None]] will be returned.
+	  *
+	  * Notice that one [[ErrorMessage]] will only be stashed for 5 hours then it will be
+	  * cleaned up from the stash.
+	  *
+	  * @since 2.0.0
+	  */
+	def inspectMessage (messageKey: MessagingContext.WithMessage.Key): Option[ErrorMessage[?, ?]] =
+		errorMessageMap.get(messageKey)
+	
+	object ShowErrorMessageCommand extends ISimpleCommand {
+		override val name: String = "inspect"
+		override val aliases: List[ICommandAlias] = Nil
+		override def execute (using command: InputCommand, event: Update): Unit =
+			val cxt = MessagingContext.extract(using event.message)
+			val cxtReplied = Option(event.message.replyToMessage).map(MessagingContext.extract(using _))
+			errorMessageMap.get(cxtReplied.map(_.toChatMessageKey).orNull) match
+				case Some(msg) =>
+					sendErrorMessage(msg, ErrorMessage.Types.Complex, Some(cxt))
+				case None =>
+					SendMessage(
+						cxt.bind_chat.id,
+						"Not a error message."
+					).replyToMessageId(cxt.bind_message.messageId)
+						.unsafeExecute
+	}
+	
+}

src/main/scala/cc/sukazyo/cono/morny/morny_misc/Testing.scala

@@ -2,12 +2,14 @@ package cc.sukazyo.cono.morny.morny_misc
 
 import cc.sukazyo.cono.morny.core.MornyCoeur
 import cc.sukazyo.cono.morny.core.bot.api.{ICommandAlias, ISimpleCommand}
-import cc.sukazyo.cono.morny.core.bot.api.messages.MessagingContext
+import cc.sukazyo.cono.morny.core.bot.api.messages.{ErrorMessage, MessagingContext}
+import cc.sukazyo.cono.morny.core.bot.api.BotExtension.submit
+import cc.sukazyo.cono.morny.data.TelegramStickers
 import cc.sukazyo.cono.morny.util.tgapi.InputCommand
 import cc.sukazyo.cono.morny.util.tgapi.TelegramExtensions.Requests.unsafeExecute
 import com.pengrad.telegrambot.model.{Message, Update}
 import com.pengrad.telegrambot.model.request.ParseMode
-import com.pengrad.telegrambot.request.SendMessage
+import com.pengrad.telegrambot.request.{SendMessage, SendSticker}
 import com.pengrad.telegrambot.TelegramBot
 
 class Testing (using coeur: MornyCoeur) extends ISimpleCommand {
@@ -32,12 +34,33 @@ class Testing (using coeur: MornyCoeur) extends ISimpleCommand {
 	}
 	
 	private def execute2 (message: Message, previousContext: MessagingContext.WithUserAndMessage): Unit = {
+		
+		if (message.text == "oops")
+			SendMessage(
+				message.chat.id,
+				"A test error message will be generated."
+			).replyToMessageId(message.messageId)
+				.unsafeExecute
+			ErrorMessage(
+				_simple = SendSticker(
+					message.chat.id,
+					TelegramStickers.ID_404
+				).replyToMessageId(message.messageId),
+				_complex = SendMessage(
+					message.chat.id,
+					"Oops: There is just a test error."
+				).replyToMessageId(message.messageId)
+			)(using MessagingContext.extract(using message))
+				.submit
+			return;
+		
 		SendMessage(
 			message.chat.id,
 			// language=html
 			"<b><u>Test command with following input:</u></b>\n" + message.text
 		).replyToMessageId(message.messageId).parseMode(ParseMode HTML)
 			.unsafeExecute
+		
 	}
 	
 }

src/main/scala/cc/sukazyo/cono/morny/util/tgapi/formatting/TelegramParseEscape.scala

@@ -8,6 +8,13 @@ import scala.jdk.CollectionConverters.*
 
 object TelegramParseEscape {
 	
+	/** Encoded a [[String]] that make it can be used as plain texts in Telegram HTML.
+	  *
+	  * This method will just remove `&`, `<` and `>` characters and encode them to
+	  * HTML entities.
+	  *
+	  * @since 1.0.0
+	  */
 	def escapeHtml (input: String): String =
 		var process = input
 		process = process.replaceAll("&", "&amp;")
@@ -15,6 +22,24 @@ object TelegramParseEscape {
 		process = process.replaceAll(">", "&gt;")
 		process
 	
+	/** Transform a [[String]] encoded HTML document/fragment into a Telegram capable
+	  * HTML fragment, make it can be used in sending Telegram message etc.
+	  *
+	  * This method will remove all unsupported HTML tags and attributes. Here is the
+	  * specific rule list of how to process the tags:
+	  *
+	  *  - If the tag is supported by Telegram HTML, it will be kept, and the inner HTML
+	  *    children items will be processed recursively.
+	  *  - If the tag is `<br>`, it will be converted to a newline character (`\n`). If
+	  *    there's any children in the `<br>` tag (which is not allowed in HTML), they
+	  *    will just be ignored.
+	  *  - If the tag is `<img>`, it will be removed. If the `alt` attribute is present,
+	  *    a string `"[$alt]"` will be used as the replacement text.
+	  *  - If the tag is any other tag, it will be removed, and the inner HTML children
+	  *    will be kept and processed recursively.
+	  *
+	  * @since 1.3.0
+	  */
 	def cleanupHtml (input: String): String =
 		import org.jsoup.nodes.*
 		val source = Jsoup.parse(input)
@@ -32,7 +57,7 @@ object TelegramParseEscape {
 //			case _: (DataNode | XmlDeclaration | DocumentType | Comment) => ""
 //			case elem: Element => elem.childNodes.asScala.map(f => toHtmlRaw(f)).mkString("")
 	
-	def cleanupHtml (input: Seq[Node]): List[Node] =
+	private def cleanupHtml (input: Seq[Node]): List[Node] =
 		val result = mutable.ListBuffer.empty[Node]
 		for (i <- input) {
 			import org.jsoup.nodes.*