feat: add restocking bc

Author: vitlinda

restocking/src/main/scala/dev/atedeg/mdm/restocking/Actions.scala

@@ -0,0 +1,16 @@
+package dev.atedeg.mdm.restocking
+
+import cats.data.NonEmptyList
+import cats.syntax.all.*
+
+import dev.atedeg.mdm.utils.given
+
+/**
+ * Given a list of ingredients needed to [[IncomingEvent.ProductionStarted start a production]],
+ * it removes that [[WeightInQuintals quantity]] from the [[Stock stock]].
+ */
+def consumeIngredients(stock: Stock)(ingredients: NonEmptyList[QuintalsOfIngredient]): Stock =
+  ingredients.foldLeft(stock) { case (newStock, QuintalsOfIngredient(q, i)) =>
+    val toSubtract = StockedQuantity(q.n)
+    newStock.updatedWith(i)(oldQuantity => oldQuantity.map(_ - toSubtract))
+  }

restocking/src/main/scala/dev/atedeg/mdm/restocking/Events.scala

@@ -0,0 +1,8 @@
+package dev.atedeg.mdm.restocking
+
+import cats.data.NonEmptyList
+
+enum IncomingEvent:
+  case OrderMilk(quintals: QuintalsOfMilk)
+  case ProductionStarted(ingredients: NonEmptyList[QuintalsOfIngredient])
+

restocking/src/main/scala/dev/atedeg/mdm/restocking/Types.scala

@@ -0,0 +1,38 @@
+package dev.atedeg.mdm.restocking
+
+import dev.atedeg.mdm.products.Ingredient
+import dev.atedeg.mdm.utils.*
+import dev.atedeg.mdm.utils.given
+
+/**
+ * A quantity of milk expressed in quintals.
+ * @note it must be a [[PositiveNumber positive number]].
+ * @example `QuintalsOfMilk(1)` is a valid weight of 110 kg.
+ * @example `QuintalsOfMilk(0)` is not a valid weight.
+ */
+final case class QuintalsOfMilk(quintals: PositiveNumber)
+
+/**
+ * An [[Ingredient ingredient]] and a [[WeightInQuintals weight in quintals]].
+ */
+final case class QuintalsOfIngredient(quintals: WeightInQuintals, ingredient: Ingredient)
+
+/**
+ * A weight expressed in quintals.
+ */
+final case class WeightInQuintals(n: PositiveDecimal)
+
+/**
+ * Quintals of stocked milk.
+ */
+final case class StockedMilk(quintals: NonNegativeDecimal)
+
+/**
+ * The quantity of ingredients in stock.
+ */
+type Stock = Map[Ingredient, StockedQuantity]
+
+/**
+ * A stocked quantity.
+ */
+final case class StockedQuantity(quintals: NonNegativeDecimal) derives Minus