import unittest
from unittest.mock import patch, MagicMock
from fastapi.testclient import TestClient
from main import app

class TestMealMathLogic(unittest.TestCase):
    def setUp(self):
        self.client = TestClient(app)
        # Mock user authentication for the calculation endpoint
        self.headers = {"Authorization": "Bearer mock-token"}

    @patch("main.get_user_from_token")
    @patch("main.get_foods_by_ids")
    def test_math_scaling_and_aggregation(self, mock_get_foods, mock_auth):
        # 1. Setup mocks
        mock_auth.return_value = {"id": 1, "username": "testuser"}
        
        # Mock database return for two foods
        mock_get_foods.return_value = [
            {
                "id": 1, "name": "Food A", 
                "calories": 100.0, "protein_g": 10.0, "fat_g": 5.0, "carbs_g": 2.0,
                "fiber_g": 1.0, "sugar_g": 0.5, "cholesterol_mg": 0.0,
                "vitamin_a_iu": 0.0, "vitamin_c_mg": 0.0,
                "calcium_mg": 0.0, "iron_mg": 0.0, "potassium_mg": 0.0, "sodium_mg": 0.0
            },
            {
                "id": 2, "name": "Food B", 
                "calories": 200.0, "protein_g": 20.0, "fat_g": 10.0, "carbs_g": 4.0,
                "fiber_g": 2.0, "sugar_g": 1.0, "cholesterol_mg": 5.0,
                "vitamin_a_iu": 100.0, "vitamin_c_mg": 10.0,
                "calcium_mg": 50.0, "iron_mg": 2.0, "potassium_mg": 300.0, "sodium_mg": 100.0
            }
        ]

        # 2. Test Case: 50g of Food A and 150g of Food B
        # Expected Food A (50g): Cal=50, Pro=5
        # Expected Food B (150g): Cal=300, Pro=30
        # Totals: Cal=350, Pro=35, Weight=200
        
        payload = {
            "items": [
                {"food_id": 1, "amount_g": 50},
                {"food_id": 2, "amount_g": 150}
            ]
        }
        
        response = self.client.post("/api/meal/calculate", json=payload, headers=self.headers)
        
        self.assertEqual(response.status_code, 200)
        data = response.json()
        
        self.assertEqual(data["total_weight_g"], 200.0)
        self.assertEqual(data["macros"]["calories"], 350.0)
        self.assertEqual(data["macros"]["protein_g"], 35.0)
        self.assertEqual(data["macros"]["fat_g"], 17.5) # (5 * 0.5) + (10 * 1.5) = 2.5 + 15 = 17.5
        self.assertEqual(data["macros"]["carbs_g"], 7.0) # (2 * 0.5) + (4 * 1.5) = 1.0 + 6.0 = 7.0

    @patch("main.get_user_from_token")
    @patch("main.get_foods_by_ids")
    def test_precision_rounding(self, mock_get_foods, mock_auth):
        mock_auth.return_value = {"id": 1, "username": "testuser"}
        
        # Mock food with irregular values to trigger rounding
        mock_get_foods.return_value = [
            {
                "id": 1, "name": "Irregular Food", 
                "calories": 123.456, "protein_g": 10.123, "fat_g": 5.555, "carbs_g": 0.0,
                "fiber_g": 0.0, "sugar_g": 0.0, "cholesterol_mg": 0.0,
                "vitamin_a_iu": 0.0, "vitamin_c_mg": 0.0,
                "calcium_mg": 0.0, "iron_mg": 0.0, "potassium_mg": 0.0, "sodium_mg": 0.0
            }
        ]

        # 123g of Food A -> Ratio 1.23
        # Calories: 123.456 * 1.23 = 151.85088 -> Rounded to 151.85
        # Protein: 10.123 * 1.23 = 12.45129 -> Rounded to 12.45
        # Fat: 5.555 * 1.23 = 6.83265 -> Rounded to 6.83
        
        payload = {"items": [{"food_id": 1, "amount_g": 123}]}
        response = self.client.post("/api/meal/calculate", json=payload, headers=self.headers)
        
        data = response.json()
        self.assertEqual(data["macros"]["calories"], 151.85)
        self.assertEqual(data["macros"]["protein_g"], 12.45)
        self.assertEqual(data["macros"]["fat_g"], 6.83)

    @patch("main.get_user_from_token")
    @patch("main.get_foods_by_ids")
    def test_null_value_handling(self, mock_get_foods, mock_auth):
        mock_auth.return_value = {"id": 1, "username": "testuser"}
        
        # Mock food with NULLs
        mock_get_foods.return_value = [
            {
                "id": 1, "name": "Null Food", 
                "calories": None, "protein_g": 10.0, "fat_g": None, "carbs_g": 2.0,
                "fiber_g": None, "sugar_g": None, "cholesterol_mg": None,
                "vitamin_a_iu": None, "vitamin_c_mg": None,
                "calcium_mg": None, "iron_mg": None, "potassium_mg": None, "sodium_mg": None
            }
        ]
        
        payload = {"items": [{"food_id": 1, "amount_g": 100}]}
        response = self.client.post("/api/meal/calculate", json=payload, headers=self.headers)
        
        self.assertEqual(response.status_code, 200)
        data = response.json()
        self.assertEqual(data["macros"]["calories"], 0.0)
        self.assertEqual(data["macros"]["fat_g"], 0.0)
        self.assertEqual(data["extended"]["fiber_g"], 0.0)

if __name__ == "__main__":
    unittest.main()