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+++ b/doc/specs/inventory.md	Thu Jul 19 12:25:00 2018 +0200
@@ -0,0 +1,52 @@
+# Inventory
+
+This document describes the inventory system in Malikania's Kingdom.
+
+# Synopsis
+
+The inventory is a persistent component where user stores its objects. It can be
+equipments, drinks, foods and so on. As Malikania tries to follow some concepts
+in real life, the inventory has limited size to avoid storing ten thousands of
+objects.
+
+# Slots
+
+Inventory is composed of slots, you can think this as a cell in a grid. The user
+inventory has 16 slots. Each slot can only have one type of object but may have
+multiple amount of the same object in it.
+
+Example:
+
++---+---+---+---+---+---+---+---+
+| E | P | R |   |   |   |   |   |
++---+---+---+---+---+---+---+---+
+|   |   |   |   |   |   |   |   |
++---+---+---+---+---+---+---+---+
+
+Here we have E, P and R types of object which can be anything, a drink, a food
+or an equipment.
+
+Note: equipped gears are not in inventory!
+
+# Amount
+
+Since not all objects are created equal, the amount by type is different. For
+example, one may have dozen of the same biscuit in a slot but only have one
+sword per slot. This means that an item must define a maximum amount.
+
+Example:
+
+- biscuits (A): maximum amount to 64
+- sword (B): maximum amount to 1
+- drinks (C): maximum amount to 8
+
+Then, if user wants to carry 10 drinks (C), 1 sword (B) and 120 biscuits (A),
+the stack will look like:
+
++-----+-----+-----+-----+-----+-----+-----+-----+
+|  A  |  A  |  B  |  C  |  C  |     |     |     |
+| x56 | x64 | x1  | x8  | x2  |     |     |     |
++-----+-----+-----+-----+-----+-----+-----+-----+
+|     |     |     |     |     |     |     |     |
+|     |     |     |     |     |     |     |     |
++-----+-----+-----+-----+-----+-----+-----+-----+