Create MessageParser, use in Reader

2026-08-12 13:27:40 +01:00
parent fcac3d5431
commit 25333482c1
2 changed files with 117 additions and 7 deletions
@@ -0,0 +1,83 @@
+package com.shr4pnel.ferretirc.net
+
+import com.shr4pnel.ferretirc.net.messages.ServerMessage
+import io.github.oshai.kotlinlogging.KotlinLogging
+import io.ktor.util.toUpperCasePreservingASCIIRules
+import kotlinx.coroutines.channels.Channel
+
+class MessageParser(val incoming: Channel<String>) {
+    private val logger = KotlinLogging.logger("MessageParser")
+    val incomingParsedMessages = Channel<ServerMessage>()
+
+    private companion object MessageBuilder {
+        sealed interface Command {
+            fun toServerMessage(): ServerMessage
+
+            class NamedCommand(val name: String, val parameters: List<String>) : Command {
+                override fun toServerMessage(): ServerMessage {
+                    return when (name.toUpperCasePreservingASCIIRules()) {
+                        // PONG :PREFIX COMMAND HOSTNAME :TOKEN
+                        "PONG" -> {
+                            val tokenIndex = parameters.indexOfLast { it.contains(":") }
+                            if (tokenIndex != -1) ServerMessage.Pong(
+                                parameters.subList(tokenIndex, parameters.size).joinToString(" ").removePrefix(":")
+                            )
+                            else ServerMessage.Pong()
+                        }
+
+                        else -> ServerMessage.UNIMPLEMENTED("$name ${parameters.joinToString(" ")}")
+                    }
+                }
+            }
+
+            class NumericCommand(val number: Int, val parameters: List<String>?) : Command {
+                override fun toServerMessage(): ServerMessage {
+                    return ServerMessage.UNIMPLEMENTED("$number ${parameters?.joinToString(" ")}")
+                }
+            }
+        }
+
+        private var tags: String? = null
+        private var prefix: String? = null
+        private lateinit var command: Command
+
+        /**
+         * Messages have this format, as rough ABNF:
+         *
+         *   message         ::= ['@' <tags> SPACE] [':' <source> SPACE] <command> <parameters> <crlf>
+         *   SPACE           ::=  %x20 *( %x20 )   ; space character(s)
+         *   crlf            ::=  %x0D %x0A        ; "carriage return" "linefeed"
+         *
+         * The specific parts of an IRC message are:
+         *
+         * tags: Optional metadata on a message, starting with ('@', 0x40).
+         *
+         * source: Optional note of where the message came from, starting with (':', 0x3A).
+         *
+         * command: The specific command this message represents.
+         *
+         * parameters: If it exists, data relevant to this specific command.
+         *
+         * ignoring tags for now ;-;.. still making space for them
+         */
+        fun build(commandList: List<String>): ServerMessage {
+            val tokens = commandList.toMutableList()
+            tags = if (tokens.first().startsWith("@")) tokens.removeFirst() else null
+            prefix = if (tokens.first().startsWith(":")) tokens.removeFirst() else null
+            val commandStr = tokens.removeFirst()
+            command = if (commandStr.toIntOrNull() != null) Command.NumericCommand(commandStr.toInt(), tokens)
+            else Command.NamedCommand(commandStr, tokens)
+
+            return command.toServerMessage()
+        }
+
+        fun build(command: String) = build(command.split(" "))
+    }
+
+    suspend fun start() {
+        for (msg in incoming) {
+            logger.debug { msg }
+            incomingParsedMessages.send(build(msg))
+        }
+    }
+}