feat: Add visitor trading detection

1 files changed, 33 insertions, 0 deletions

diff --git a/src/main/kotlin/moe/nea/ledger/ItemChange.kt b/src/main/kotlin/moe/nea/ledger/ItemChange.kt
new file mode 100644
index 0000000..a8bb7e8
--- /dev/null
+++ b/src/main/kotlin/moe/nea/ledger/ItemChange.kt
@@ -0,0 +1,33 @@
+package moe.nea.ledger
+
+data class ItemChange(
+	val itemId: ItemId,
+	val count: Double,
+	val direction: ChangeDirection,
+) {
+	enum class ChangeDirection {
+		GAINED,
+		TRANSFORM,
+		SYNC,
+		CATALYST,
+		LOST;
+	}
+
+	companion object {
+		fun gainCoins(number: Double): ItemChange {
+			return gain(ItemId.COINS, number)
+		}
+
+		fun gain(itemId: ItemId, amount: Number): ItemChange {
+			return ItemChange(itemId, amount.toDouble(), ChangeDirection.GAINED)
+		}
+
+		fun lose(itemId: ItemId, amount: Number): ItemChange {
+			return ItemChange(itemId, amount.toDouble(), ChangeDirection.LOST)
+		}
+
+		fun loseCoins(number: Double): ItemChange {
+			return lose(ItemId.COINS, number)
+		}
+	}
+}
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