package de.rwu.easydrop.service.processing;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertThrows;

import java.util.ArrayList;
import java.util.List;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;

import de.rwu.easydrop.exception.InvalidCatalogueException;
import de.rwu.easydrop.exception.InvalidOfferException;
import de.rwu.easydrop.model.Offer;
import de.rwu.easydrop.model.Product;
import de.rwu.easydrop.model.ProductCatalogue;
import de.rwu.easydrop.model.ProductPair;

class OfferIdentifierTest {

    @Mock
    private ProductCatalogue mockProductCatalogue;

    private OfferIdentifier offerIdentifier;

    @BeforeEach
    void setUp() {
        MockitoAnnotations.openMocks(this);

        offerIdentifier = new OfferIdentifier();
    }

    @Test
    void runIdentifier_WithValidProductCatalogues_IdentifiesOffers() {
        // Arrange
        List<ProductCatalogue> productCatalogues = new ArrayList<>();
        ProductCatalogue productCatalogue1 = new ProductCatalogue("Catalogue1", "desc");
        ProductCatalogue productCatalogue2 = new ProductCatalogue("Catalogue2", "desc");

        Product product1 = new Product();
        product1.setCurrentPrice(100.0);
        Product product2 = new Product();
        product2.setCurrentPrice(200.0);
        Product product3 = new Product();
        product3.setCurrentPrice(300.0);
        Product product4 = new Product();
        product4.setCurrentPrice(400.0);

        productCatalogue1.addProduct(product1);
        productCatalogue1.addProduct(product2);
        productCatalogue2.addProduct(product3);
        productCatalogue2.addProduct(product4);

        productCatalogues.add(productCatalogue1);
        productCatalogues.add(productCatalogue2);

        // Act
        List<Offer> identifiedOffers = offerIdentifier.runIdentifier(productCatalogues);

        // Assert
        assertEquals(2, identifiedOffers.size());
        assertNotNull(identifiedOffers.get(0).getSourceProduct());
        assertNotNull(identifiedOffers.get(0).getTargetProduct());
        assertNotNull(identifiedOffers.get(1).getSourceProduct());
        assertNotNull(identifiedOffers.get(1).getTargetProduct());
    }

    @Test
    void runIdentifier_WithOneGoodOneBadCatalogue_BadOneIsntIncluded() {
        // Arrange
        List<ProductCatalogue> productCatalogues = new ArrayList<>();
        ProductCatalogue productCatalogue1 = new ProductCatalogue("Catalogue1", "desc");
        ProductCatalogue productCatalogue2 = new ProductCatalogue("Catalogue2", "desc");

        Product product1 = new Product();
        product1.setCurrentPrice(100.0);
        Product product2 = new Product();
        product2.setCurrentPrice(200.0);
        Product product3 = new Product();
        product3.setCurrentPrice(300.0);
        Product product4 = new Product();
        product4.setCurrentPrice(300.0);

        productCatalogue1.addProduct(product1);
        productCatalogue1.addProduct(product2);
        productCatalogue2.addProduct(product3);
        productCatalogue2.addProduct(product4);

        productCatalogues.add(productCatalogue1);
        productCatalogues.add(productCatalogue2);

        // Act
        List<Offer> identifiedOffers = offerIdentifier.runIdentifier(productCatalogues);

        // Assert
        assertEquals(1, identifiedOffers.size()); // Only 1 passed
    }

    @Test
    void getHighestMarginProducts_WithValidProductCatalogue_ReturnsProductPair() {
        // Arrange
        ProductCatalogue productCatalogue = new ProductCatalogue("TestCatalogue", "desc");
        Product product1 = new Product();
        product1.setCurrentPrice(100.0);
        Product product2 = new Product();
        product2.setCurrentPrice(200.0);
        productCatalogue.addProduct(product1);
        productCatalogue.addProduct(product2);

        // Act
        ProductPair productPair = OfferIdentifier.getHighestMarginProducts(productCatalogue);

        // Assert
        assertNotNull(productPair);
        assertNotNull(productPair.getProduct1());
        assertNotNull(productPair.getProduct2());
        assertNotEquals(productPair.getProduct1(), productPair.getProduct2());
    }

    @Test
    void getHighestMarginProducts_SecondProductCheaper() {
        // Arrange
        ProductCatalogue productCatalogue = new ProductCatalogue("TestCatalogue", "desc");
        Product product1 = new Product();
        product1.setCurrentPrice(200.0);
        Product product2 = new Product();
        product2.setCurrentPrice(100.0);
        productCatalogue.addProduct(product1);
        productCatalogue.addProduct(product2);

        // Act
        ProductPair productPair = OfferIdentifier.getHighestMarginProducts(productCatalogue);

        // Assert
        assertNotNull(productPair);
        assertNotNull(productPair.getProduct1());
        assertNotNull(productPair.getProduct2());
        assertNotEquals(productPair.getProduct1(), productPair.getProduct2());
    }

    @Test
    void getHighestMarginProducts_WithCatalogueSizeLessThan2_ThrowsInvalidCatalogueException() {
        // Arrange
        ProductCatalogue productCatalogue = new ProductCatalogue("SmallCatalogue", "desc");

        // Act and Assert
        assertThrows(InvalidCatalogueException.class, () -> {
            OfferIdentifier.getHighestMarginProducts(productCatalogue);
        });
    }

    @Test
    void getHighestMarginProducts_WithZeroPriceMargin_ThrowsInvalidOfferException() {
        // Arrange
        ProductCatalogue productCatalogue = new ProductCatalogue("name", "desc");
        Product product1 = new Product();
        product1.setCurrentPrice(200.0);

        Product product2 = new Product();
        product2.setCurrentPrice(200.0);

        productCatalogue.getProducts().add(product1);
        productCatalogue.getProducts().add(product2);

        // Act and Assert
        InvalidOfferException e = assertThrows(InvalidOfferException.class, () -> {
            OfferIdentifier.getHighestMarginProducts(productCatalogue);
        });

        assertEquals("Price margin is zero!", e.getMessage());
    }
}