plan.py: add commandline parsing

plan.py

@@ -38,7 +38,8 @@ def required_rates(
 
     while remain:
         for dst_name, dst_rate in remain.pop().items():
-            # Append the requested item
+            # Append the requested item to the output rate. We'll add the
+            # inputs just below.
             required_items[dst_name] += dst_rate
 
             # We can't craft resources, so just ignore them.
@@ -148,13 +149,22 @@ def plan(recipes: satisfactory.Cookbook, required: Dict[str, Fraction]):
 def main():
     recipes = satisfactory.Cookbook('data/recipes')
 
-    # Create a list of items we want to make
-    # names = [ 'supercomputer' ]
-    names = recipes.components()
+    import argparse
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "item",
+        nargs="*",
+        type=str,
+        default=recipes.components(),
+        help="The name of an item to produce at full rate"
+    )
+
+    args = parser.parse_args()
 
     # Create an initial name:rate request for all of the target items, then
     # create a plan for their creation.
-    request = [{n: basic_rate(recipes[n]['recipes'][0]) for n in names}]
+    request = [{n: basic_rate(recipes[n]['recipes'][0]) for n in args.item}]
 
     plan(recipes, request)