import random
import threading


class RecipeGenerator:
    """
    Generates recipes based on provided ingredients and dietary requirements.

    The class stores a dictionary of recipes categorized by dietary requirements
    (vegetarian, vegan, gluten-free). It provides methods to generate a
    random recipe matching the given criteria, list supported ingredients and
    dietary requirements. Thread safety is implemented to handle concurrent
    recipe generation.
    """

    def __init__(self):
        """
        Initializes the RecipeGenerator with a predefined set of recipes.
        """
        self.recipes = {
            "vegetarian": [
                {"name": "Vegetable Stir Fry", "ingredients": ["broccoli", "carrot", "bell pepper", "onion", "tofu", "soy sauce"],
                    "instructions": "1. Heat oil in a pan. 2. Add chopped vegetables and tofu. 3. Stir in soy sauce and cook until tender."},
                {"name": "Caprese Salad", "ingredients": ["tomato", "mozzarella cheese", "basil", "balsamic vinegar", "olive oil"],
                    "instructions": "1. Slice tomatoes and mozzarella. 2. Arrange on a plate with basil leaves. 3. Drizzle with olive oil and balsamic vinegar."},
                {"name": "Vegetarian Chili", "ingredients": ["black beans", "kidney beans", "bell pepper", "onion", "tomato", "chili powder"],
                    "instructions": "1. Saute onions and bell peppers. 2. Add tomatoes and beans. 3. Season with chili powder and cook until thickened."}
            ],
            "vegan": [
                {"name": "Vegan Curry", "ingredients": ["coconut milk", "chickpeas", "potato", "carrot", "curry powder", "onion"],
                    "instructions": "1. Cook onions, carrots, and potatoes until tender. 2. Add chickpeas and coconut milk. 3. Simmer with curry powder."},
                {"name": "Quinoa Salad", "ingredients": ["quinoa", "cucumber", "tomato", "red onion", "lemon juice", "olive oil"],
                    "instructions": "1. Cook quinoa according to package instructions. 2. Mix with chopped vegetables. 3. Dress with lemon juice and olive oil."},
                {"name": "Vegan Pasta Primavera", "ingredients": ["pasta", "zucchini", "bell pepper", "cherry tomatoes", "garlic",
                                                                  "olive oil"], "instructions": "1. Cook pasta until al dente. 2. Saute vegetables in olive oil. 3. Toss with cooked pasta."}
            ],
            "gluten-free": [
                {"name": "Grilled Salmon with Asparagus", "ingredients": ["salmon fillet", "asparagus", "lemon", "olive oil", "salt", "pepper"],
                    "instructions": "1. Season salmon with salt and pepper. 2. Grill until cooked through. 3. Serve with grilled asparagus and lemon wedges."},
                {"name": "Quinoa Stuffed Bell Peppers", "ingredients": ["bell peppers", "quinoa", "black beans", "corn", "tomato", "avocado"],
                    "instructions": "1. Cook quinoa according to package instructions. 2. Mix with beans, corn, and diced tomato. 3. Stuff mixture into halved bell peppers and bake until tender."},
                {"name": "Gluten-Free Banana Pancakes", "ingredients": ["banana", "egg", "oat flour", "almond milk", "vanilla extract", "baking powder"],
                    "instructions": "1. Mash bananas and mix with egg, oat flour, almond milk, and vanilla extract. 2. Stir in baking powder. 3. Cook pancakes on a hot griddle until golden brown."}
            ]
        }
        self.lock = threading.Lock()

    def _get_filtered_recipes(self, ingredients, dietary_requirements):
        """
        Filters recipes based on ingredients and dietary requirements.

        Args:
            ingredients (list): A list of ingredients to filter by.
            dietary_requirements (str): The dietary requirement (e.g., "vegetarian").

        Returns:
            list: A list of recipes matching the criteria.
        """
        return [recipe for recipe in self.recipes[dietary_requirements] if all(ingredient in recipe["ingredients"] for ingredient in ingredients)]

    def generate_recipe(self, ingredients, dietary_requirements):
        """
        Generates a random recipe based on ingredients and dietary requirements.

        Args:
            ingredients (list): A list of ingredients.
            dietary_requirements (str): The dietary requirement.

        Returns:
            dict or str: A randomly chosen recipe (dictionary) if found,
                         or a string message if no recipe is found or the
                         dietary requirement is invalid.

        Raises:
            KeyError: If the provided dietary requirement is not in the recipe database.
        """
        with self.lock:  # Ensures thread-safe access to the recipes dictionary.
            try:
                filtered_recipes = self._get_filtered_recipes(
                    ingredients, dietary_requirements)
                if filtered_recipes:
                    return random.choice(filtered_recipes)
                else:
                    return "No recipe found with the given ingredients and dietary requirements."
            except KeyError:
                return "Invalid dietary requirement provided."

    def supported_ingredients(self):
        """
        Returns a set of all unique ingredients supported by the recipe generator.

        Returns:
            set: A set of supported ingredient strings.
        """
        return set(ingredient for recipe_set in self.recipes.values() for recipe in recipe_set for ingredient in recipe["ingredients"])

    def supported_dietary_requirements(self):
        """
        Returns a list of supported dietary requirements.

        Returns:
            list: A list of the supported dietary requirement strings.
        """
        return list(self.recipes.keys())


def main():
    generator = RecipeGenerator()
    print("Supported Ingredients:", generator.supported_ingredients())
    print("Supported Dietary Requirements:",
          generator.supported_dietary_requirements())

    ingredients = ["tofu", "broccoli", "bell pepper", "soy sauce"]
    dietary_requirements = "vegetarian"
    try:
        recipe = generator.generate_recipe(ingredients, dietary_requirements)
        if isinstance(recipe, dict):
            print("\nGenerated Recipe:")
            print("Name:", recipe["name"])
            print("Ingredients:", ", ".join(recipe["ingredients"]))
            print("Instructions:")
            print(recipe["instructions"])
        else:
            print(recipe)
    except Exception as e:
        print(f"An error occurred: {e}")


if __name__ == "__main__":
    main()