refactor: Add DI and packages

1 files changed, 63 insertions, 0 deletions

diff --git a/src/main/kotlin/moe/nea/ledger/utils/DI.kt b/src/main/kotlin/moe/nea/ledger/utils/DI.kt
new file mode 100644
index 0000000..1114127
--- /dev/null
+++ b/src/main/kotlin/moe/nea/ledger/utils/DI.kt
@@ -0,0 +1,63 @@
+package moe.nea.ledger.utils
+
+import java.lang.reflect.AnnotatedElement
+import java.util.Collections
+import java.util.Stack
+
+@Suppress("UNCHECKED_CAST")
+class DI {
+	private fun <T : Any, C> internalProvide(type: Class<T>, element: AnnotatedElement? = null): T {
+		val provider = providers[type] as BaseDIProvider<T, C>
+		val context = if (element == null) provider.createEmptyContext() else provider.createContext(element)
+		val key = Pair(type, context)
+		val existingValue = values[key]
+		if (existingValue != null) return existingValue as T
+		if (type in injectionStack) {
+			error("Found injection cycle: ${injectionStack.joinToString(" -> ")} -> $type")
+		}
+		injectionStack.push(type)
+		val value = try {
+			provider.provideWithContext(this, context)
+		} catch (ex: Exception) {
+			throw RuntimeException("Could not create instance for type $type", ex)
+		}
+		val cycleCheckCookie = injectionStack.pop()
+		require(cycleCheckCookie == type) { "Unbalanced stack cookie: $cycleCheckCookie != $type" }
+		values[key] = value
+		return value
+	}
+
+	fun <T : Any> provide(type: Class<T>, element: AnnotatedElement? = null): T {
+		return internalProvide<T, Any>(type, element)
+	}
+
+	fun <T : Any> register(type: Class<T>, provider: BaseDIProvider<T, *>) {
+		providers[type] = provider
+	}
+
+	fun registerInjectableClasses(vararg type: Class<*>) {
+		type.forEach { internalRegisterInjectableClass(it) }
+	}
+
+	private fun <T : Any> internalRegisterInjectableClass(type: Class<T>) {
+		register(type, DIProvider.fromInjectableClass(type))
+	}
+
+	fun instantiateAll() {
+		providers.keys.forEach {
+			provide(it, null)
+		}
+	}
+
+	fun getAllInstances(): Collection<Any> =
+		Collections.unmodifiableCollection(values.values)
+
+	fun <T : Any> registerSingleton(value: T) {
+		register(value.javaClass, DIProvider.singeleton(value))
+	}
+
+	private val injectionStack: Stack<Class<*>> = Stack()
+	private val values = mutableMapOf<Pair<Class<*>, *>, Any>()
+	private val providers = mutableMapOf<Class<*>, BaseDIProvider<*, *>>()
+
+}
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