added changes from code submission branch and coin entity

marl_factory_grid/modules/coins/actions.py

@@ -0,0 +1,36 @@
+from typing import Union
+
+from marl_factory_grid.environment.actions import Action
+from marl_factory_grid.utils.results import ActionResult
+
+from marl_factory_grid.modules.coins import constants as d
+
+from marl_factory_grid.environment import constants as c
+
+
+class Collect(Action):
+
+    def __init__(self):
+        """
+        Attempts to reduce coin amount on entity's position. Fails if no coin is found at the at agents' position.
+        """
+        super().__init__(d.COLLECT, d.REWARD_COLLECT_VALID, d.REWARD_COLLECT_FAIL)
+
+    def do(self, entity, state) -> Union[None, ActionResult]:
+        if coin_pile := next((x for x in state.entities.pos_dict[entity.pos] if "coin" in x.name.lower()), None):
+            new_coin_pile_amount = coin_pile.amount - state[d.COIN].collect_amount
+
+            if new_coin_pile_amount <= 0:
+                state[d.COIN].delete_env_object(coin_pile)
+            else:
+                coin_pile.set_new_amount(max(new_coin_pile_amount, c.VALUE_FREE_CELL))
+            valid = c.VALID
+            print_str = f'{entity.name} did just collect some coins at {entity.pos}.'
+            state.print(print_str)
+
+        else:
+            valid = c.NOT_VALID
+            print_str = f'{entity.name} just tried to collect some coins at {entity.pos}, but failed.'
+            state.print(print_str)
+
+        return self.get_result(valid, entity)