Major refactoring to use Koin.

foundation-core/src/main/kotlin/cloud/kubelet/foundation/core/abstraction/Feature.kt

@@ -0,0 +1,31 @@
+package cloud.kubelet.foundation.core.abstraction
+
+import cloud.kubelet.foundation.core.FoundationCorePlugin
+import org.bukkit.command.CommandExecutor
+import org.bukkit.command.TabCompleter
+import org.bukkit.event.Listener
+import org.koin.core.component.KoinComponent
+import org.koin.core.component.inject
+import org.koin.dsl.module
+
+abstract class Feature : KoinComponent, Listener {
+  private val plugin by inject<FoundationCorePlugin>()
+
+  open fun enable() {}
+  open fun disable() {}
+  open fun module() = module {}
+
+  protected fun registerCommandExecutor(name: String, executor: CommandExecutor) {
+    registerCommandExecutor(listOf(name), executor)
+  }
+
+  protected fun registerCommandExecutor(names: List<String>, executor: CommandExecutor) {
+    for (name in names) {
+      val command = plugin.getCommand(name) ?: throw Exception("Failed to get $name command")
+      command.setExecutor(executor)
+      if (executor is TabCompleter) {
+        command.tabCompleter = executor
+      }
+    }
+  }
+}

foundation-core/src/main/kotlin/cloud/kubelet/foundation/core/abstraction/FoundationPlugin.kt

@@ -0,0 +1,54 @@
+package cloud.kubelet.foundation.core.abstraction
+
+import org.bukkit.plugin.java.JavaPlugin
+import org.koin.core.KoinApplication
+import org.koin.core.context.startKoin
+import org.koin.core.context.stopKoin
+import org.koin.core.module.Module
+import org.koin.dsl.module
+
+abstract class FoundationPlugin : JavaPlugin() {
+  private lateinit var pluginModule: Module
+  private lateinit var pluginApplication: KoinApplication
+  protected abstract val features: List<Feature>
+
+  override fun onEnable() {
+    pluginModule = module {
+      single { this@FoundationPlugin }
+      single { server }
+      single { config }
+      single { slF4JLogger }
+    }
+
+    // TODO: If we have another plugin using this class, we may need to use context isolation.
+    //  https://insert-koin.io/docs/reference/koin-core/context-isolation
+    pluginApplication = startKoin {
+      modules(pluginModule)
+      modules(module())
+    }
+
+    features.forEach {
+      pluginApplication.modules(it.module())
+    }
+
+    features.forEach {
+      try {
+        slF4JLogger.info("Enabling feature: ${it.javaClass.simpleName}")
+        it.enable()
+        server.pluginManager.registerEvents(it, this)
+      } catch (e: Exception) {
+        slF4JLogger.error("Failed to enable feature: ${it.javaClass.simpleName}", e)
+      }
+    }
+  }
+
+  override fun onDisable() {
+    features.forEach {
+      it.disable()
+    }
+
+    stopKoin()
+  }
+
+  protected open fun module() = module {}
+}