1 files changed, 59 insertions, 0 deletions
diff --git a/src/main/kotlin/repo/item/SBItemProperty.kt b/src/main/kotlin/repo/item/SBItemProperty.kt
new file mode 100644
index 0000000..55b8f01
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+++ b/src/main/kotlin/repo/item/SBItemProperty.kt
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+package moe.nea.firmament.repo.item
+
+import io.github.moulberry.repo.data.NEUItem
+import net.minecraft.item.ItemStack
+import moe.nea.firmament.repo.ItemCache.asItemStack
+import moe.nea.firmament.util.compatloader.CompatLoader
+
+/**
+ * A property of a skyblock item. Not every skyblock item must have this property, but some should.
+ *
+ * Access to this class should be limited to [State.bindWith] and [SBItemData.getData].
+ * @see State
+ */
+abstract class SBItemProperty<T> {
+	data class BoundState<T>(val property: State<T>, val data: T) {
+		fun applyTo(store: SBItemData) {
+			store.set(property, data)
+		}
+	}
+
+	// TODO: Actually implement and make use of this method.
+	/**
+	 * Extract this property's state from a [NEUItem]. If this method returns something, it may be equivalent to [fromStack] with the neu item resolved to an item stack according to [asItemStack], but *should not* instantiate an item stack. This method may return null to indicate that it needs a fully constructed item stack to extract a property. This method return one value and then later return another value from [fromStack], but behaviour is generally discouraged.
+	 */
+	open fun fromNeuItem(neuItem: NEUItem, store: SBItemData): T? {
+		return null
+	}
+
+	/**
+	 * Extract this property's state from an [ItemStack]. This should be fully reversible (i.e. all info used to in [fromStack] needs to be set by [State.applyToStack].
+	 */
+	abstract fun fromStack(stack: ItemStack, store: SBItemData): T?
+
+	/**
+	 * A property of a skyblock item that carriers state. Unlike a plain [SBItemProperty] these modifiers can be used
+	 * to change the state of an item, including its rendering as a vanilla [ItemStack].
+	 */
+	abstract class State<T> : SBItemProperty<T>() {
+		abstract fun applyToStack(stack: ItemStack, store: SBItemData, value: T?): ItemStack
+		fun bindWith(data: T) = BoundState(this, data)
+	}
+
+	/**
+	 * The order of this property relative to other properties. Lower values get computed first, so higher values may
+	 * rely on their data being stored already (if that item stack has any of that data), and they can overwrite the
+	 * rendering of the lower states.
+	 */
+	open val order: Int get() = 0
+
+	companion object {
+		val loader = CompatLoader<SBItemProperty<*>>(SBItemProperty::class)
+		val allProperties by lazy {
+			loader.allValidInstances.sortedBy { it.order }
+		}
+		val allStates by lazy {
+			allProperties.filterIsInstance<State<*>>()
+		}
+	}
+}