Add crafting recipe system

Implements Recipe dataclass, recipe loading from TOML files, and recipe
registry. Recipes define ingredients consumed and result produced for
item crafting.

src/mudlib/crafting.py

@@ -0,0 +1,57 @@
+"""Crafting recipe system."""
+
+import logging
+import tomllib
+from dataclasses import dataclass
+from pathlib import Path
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class Recipe:
+    """A crafting recipe definition."""
+
+    name: str
+    description: str
+    ingredients: list[str]
+    result: str
+
+
+# Module-level registry
+recipes: dict[str, Recipe] = {}
+
+
+def load_recipe(path: Path) -> Recipe:
+    """Load a recipe from TOML.
+
+    Args:
+        path: Path to the recipe TOML file
+
+    Returns:
+        Recipe instance
+    """
+    with open(path, "rb") as f:
+        data = tomllib.load(f)
+    return Recipe(
+        name=data["name"],
+        description=data["description"],
+        ingredients=data["ingredients"],
+        result=data["result"],
+    )
+
+
+def load_recipes(directory: Path) -> dict[str, Recipe]:
+    """Load all recipes from a directory.
+
+    Args:
+        directory: Path to directory containing recipe TOML files
+
+    Returns:
+        Dict of recipes keyed by name
+    """
+    loaded: dict[str, Recipe] = {}
+    for path in sorted(directory.glob("*.toml")):
+        recipe = load_recipe(path)
+        loaded[recipe.name] = recipe
+    return loaded

tests/test_crafting.py

@@ -0,0 +1,99 @@
+"""Tests for the crafting recipe system."""
+
+import tempfile
+from pathlib import Path
+
+import pytest
+
+from mudlib.crafting import Recipe, load_recipe, load_recipes, recipes
+from mudlib.things import thing_templates
+from mudlib.zones import zone_registry
+
+
+@pytest.fixture(autouse=True)
+def _clean_registries():
+    """Snapshot and restore registries to prevent test leakage."""
+    saved_zones = dict(zone_registry)
+    saved_templates = dict(thing_templates)
+    saved_recipes = dict(recipes)
+    zone_registry.clear()
+    thing_templates.clear()
+    recipes.clear()
+    yield
+    zone_registry.clear()
+    zone_registry.update(saved_zones)
+    thing_templates.clear()
+    thing_templates.update(saved_templates)
+    recipes.clear()
+    recipes.update(saved_recipes)
+
+
+def test_load_recipe_from_toml():
+    """Parse a recipe TOML file."""
+    with tempfile.NamedTemporaryFile(mode="w", suffix=".toml", delete=False) as f:
+        f.write("""
+name = "wooden_table"
+description = "Craft a sturdy table from planks and nails"
+ingredients = ["plank", "plank", "plank", "nail", "nail"]
+result = "table"
+""")
+        path = Path(f.name)
+
+    try:
+        recipe = load_recipe(path)
+        assert recipe.name == "wooden_table"
+        assert recipe.description == "Craft a sturdy table from planks and nails"
+        assert recipe.ingredients == ["plank", "plank", "plank", "nail", "nail"]
+        assert recipe.result == "table"
+    finally:
+        path.unlink()
+
+
+def test_load_recipes_directory():
+    """Load all recipes from a directory."""
+    with tempfile.TemporaryDirectory() as tmpdir:
+        tmp_path = Path(tmpdir)
+
+        # Create two recipe files
+        (tmp_path / "table.toml").write_text("""
+name = "wooden_table"
+description = "Craft a table"
+ingredients = ["plank", "plank"]
+result = "table"
+""")
+        (tmp_path / "chair.toml").write_text("""
+name = "wooden_chair"
+description = "Craft a chair"
+ingredients = ["plank"]
+result = "chair"
+""")
+
+        loaded = load_recipes(tmp_path)
+        assert len(loaded) == 2
+        assert "wooden_table" in loaded
+        assert "wooden_chair" in loaded
+        assert loaded["wooden_table"].result == "table"
+        assert loaded["wooden_chair"].result == "chair"
+
+
+def test_recipe_fields():
+    """Verify all recipe fields are populated correctly."""
+    with tempfile.NamedTemporaryFile(mode="w", suffix=".toml", delete=False) as f:
+        f.write("""
+name = "test_recipe"
+description = "A test recipe"
+ingredients = ["item_a", "item_b", "item_c"]
+result = "item_result"
+""")
+        path = Path(f.name)
+
+    try:
+        recipe = load_recipe(path)
+        assert isinstance(recipe, Recipe)
+        assert recipe.name == "test_recipe"
+        assert recipe.description == "A test recipe"
+        assert recipe.ingredients == ["item_a", "item_b", "item_c"]
+        assert recipe.result == "item_result"
+        assert len(recipe.ingredients) == 3
+    finally:
+        path.unlink()