start integration FSM oriented plagubot version

fsm/plugin/src/main/kotlin/FSMPlugin.kt

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+package dev.inmo.plagubot.fsm
+
+import dev.inmo.plagubot.Plugin
+import dev.inmo.tgbotapi.extensions.behaviour_builder.BehaviourContext
+import dev.inmo.tgbotapi.extensions.behaviour_builder.BehaviourContextWithFSM
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.json.JsonObject
+import org.jetbrains.exposed.sql.Database
+import org.koin.core.Koin
+import org.koin.core.module.Module
+
+/**
+ * **ANY REALIZATION OF [FSMPlugin] MUST HAVE CONSTRUCTOR WITH ABSENCE OF INCOMING PARAMETERS**
+ *
+ * Use this interface for your bot. It is possible to use [kotlinx.serialization.SerialName] annotations on your plugins
+ * to set up short name for your plugin. Besides, simple name of your class will be used as key for deserialization
+ * too.
+ */
+@Serializable(FSMPluginSerializer::class)
+interface FSMPlugin : Plugin {
+    suspend fun BehaviourContextWithFSM<*>.setupBotPlugin(koin: Koin) {
+        (this as BehaviourContext).setupBotPlugin(koin)
+    }
+}

fsm/plugin/src/main/kotlin/FSMPluginSerializer.kt

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+package dev.inmo.plagubot.fsm
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+
+@Serializer(FSMPlugin::class)
+class FSMPluginSerializer : KSerializer<FSMPlugin> {
+    override val descriptor: SerialDescriptor
+        get() = String.serializer().descriptor
+
+    override fun deserialize(decoder: Decoder): FSMPlugin {
+        val kclass = Class.forName(decoder.decodeString()).kotlin
+        return (kclass.objectInstance ?: kclass.constructors.first { it.parameters.isEmpty() }.call()) as FSMPlugin
+    }
+
+    override fun serialize(encoder: Encoder, value: FSMPlugin) {
+        encoder.encodeString(
+            value::class.java.canonicalName
+        )
+    }
+}