package polynomial;

import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import static org.junit.Assert.*;

/**
 * A test class for the polynomial.Polynomial class
 * @author Camil Staps, s4498062
 */
public class PolynomialTest {
    
    public PolynomialTest() {
    }
    
    @BeforeClass
    public static void setUpClass() {
    }
    
    @AfterClass
    public static void tearDownClass() {
    }
    
    @Before
    public void setUp() {
    }
    
    @After
    public void tearDown() {
    }

    /**
     * Test of toString method, of class Polynomial.
     */
    @Test
    public void testToString() {
        System.out.println("toString");
        // Test exp=0, exp=1, exp>1, positive & negative integer & floating point coefficients all at once
        assertEquals("3x^5-4x+2.5-3.4x^-7", new Polynomial("3 5 -4 1 2.5 0 -3.4 -7").toString());
        // Test zero polynomial
        assertEquals("", new Polynomial().toString());
    }

    /**
     * Test of minus method, of class Polynomial.
     */
    @Test
    public void testMinus() {
        System.out.println("minus");
        // Test cancelling out and exponents that don't exist in either of the two polynomials all at once
        Polynomial instance = new Polynomial("7 4 -4 2 3 1 5 0");       // 7x^4 - 4x^2 + 3x + 5
        instance.minus(new Polynomial("5 3 4 2 3 1 10 0"));             // 5x^3 + 4x^2 + 3x + 10
        assertEquals(new Polynomial("7 4 -5 3 -8 2 -5 0"), instance);   // 7x^4 - 5x^3 - 8x^2 - 5
        
        // Test minus = plus (times -1) on many small 2-term polynomials
        for (float c1 = -10; c1 < 10; c1 += 2.3)
            for (int exp1 = 5; exp1 < 10; exp1++)
                for (float c2 = -10; c2 < 10; c2 += 2.3)
                    for (int exp2 = 5; exp2 < 10; exp2++) {
                        Polynomial fst = new Polynomial(c1 + " " + exp1 + " " + c2 + " " + exp2);
                        Polynomial snd = new Polynomial(c1 + " " + exp2 + " " + c2 + " " + exp1);
                        Polynomial fst_2 = new Polynomial(fst);
                        Polynomial snd_2 = new Polynomial(snd);
                        fst.minus(snd);
                        snd_2.times(new Polynomial("-1 0"));
                        fst_2.plus(snd_2);
                        assertEquals(true, fst.equals(fst_2));
                    }
        
        // Test associativity for some random polynomials
        Polynomial a = new Polynomial("5 4 2 5 20 8 4 0");
        Polynomial b = new Polynomial("9 2 48 2 10 8 28 2");
        Polynomial c = new Polynomial("3 8 4 20 8 2 4 5 0 0");
        Polynomial a_bc = new Polynomial(a);
        a_bc.minus(b);
        a_bc.minus(c);
        Polynomial a_cb = new Polynomial(a);
        a_cb.minus(c);
        a_cb.minus(b);
        assertEquals(true, a_bc.equals(a_cb));
    }

    /**
     * Test of times method, of class Polynomial.
     */
    @Test
    public void testTimes() {
        System.out.println("times");
        
        // Simple case
        Polynomial instance = new Polynomial("7 1 6 3");
        instance.times(new Polynomial("5 3 4 2"));
        assertEquals(new Polynomial("30 6 24 5 35 4 28 3"), instance);
        
        // Simple case with zero polynomial
        instance = new Polynomial("5 3");
        instance.times(new Polynomial());
        assertEquals(new Polynomial(), instance);
        
        // Advanced case with coefficient 0 in the result
        instance = new Polynomial("4 4 2 3");                           // 4x^4 + 2x^3
        instance.times(new Polynomial("2 2 -4 3"));                     // 2x^2 - 4x^3
        assertEquals(new Polynomial("4 5 -16 7"), instance);            // 4x^5 - 16x^7 (exponent 6 cancels out)
        
        // Test associativity for some random polynomials
        Polynomial a = new Polynomial("5 4 2 5 20 8 4 0");
        Polynomial b = new Polynomial("9 2 48 2 10 8 28 2");
        Polynomial c = new Polynomial("3 8 4 20 8 2 4 5 0 0");
        Polynomial a_bc = new Polynomial(a);
        a_bc.times(b);
        a_bc.times(c);
        Polynomial a_cb = new Polynomial(a);
        a_cb.times(c);
        a_cb.times(b);
        assertEquals(true, a_bc.equals(a_cb));
        
        // Test commutativity
        Polynomial a_b = new Polynomial(a);
        a_b.times(b);
        Polynomial b_a = new Polynomial(b);
        b_a.times(a);
        assertEquals(true, a_b.equals(b_a));
        
        // Test left distributivity
        Polynomial b_plus_c = new Polynomial(b);
        b_plus_c.plus(c);
        Polynomial a_times_b_plus_c = new Polynomial(a);
        a_times_b_plus_c.times(b_plus_c);
        Polynomial a_times_c = new Polynomial(a);
        a_times_c.times(c);
        Polynomial a_times_b_plus_a_times_c = new Polynomial(a);
        a_times_b_plus_a_times_c.times(b);
        a_times_b_plus_a_times_c.plus(a_times_c);
        assertEquals(true, a_times_b_plus_c.equals(a_times_b_plus_a_times_c));
        
        // Test right distributivity
        Polynomial b_plus_c_times_a = new Polynomial(b);
        b_plus_c_times_a.plus(c);
        b_plus_c_times_a.times(a);
        Polynomial c_times_a = new Polynomial(c);
        c_times_a.times(a);
        Polynomial b_times_a_plus_c_times_a = new Polynomial(b);
        b_times_a_plus_c_times_a.times(a);
        b_times_a_plus_c_times_a.plus(c_times_a);
        assertEquals(true, b_plus_c_times_a.equals(b_times_a_plus_c_times_a));
    }

    /**
     * Test of divide method, of class Polynomial.
     */
    @Test
    public void testDivide() {
        System.out.println("divide");
        Polynomial b = null;
        Polynomial instance = new Polynomial();
        instance.divide(b);
        // TODO review the generated test code and remove the default call to fail.
        fail("The test case is a prototype.");
    }

    /**
     * Test of equals method, of class Polynomial.
     */
    @Test
    public void testEquals() {
        System.out.println("equals");
        // Order of terms irrelevant
        assertEquals(true, new Polynomial("4 2 3 5").equals(new Polynomial("3 5 4 2")));
        // Terms with same exponent are added
        assertEquals(true, new Polynomial("5 5 10 5").equals(new Polynomial("15 5")));
        // Simple coefficient 0 removed
        assertEquals(true, new Polynomial("0 7").equals(new Polynomial()));
        // Advanced coefficient 0 removed
        assertEquals(true, new Polynomial("5 10 -5 10").equals(new Polynomial()));
        // Difference in exponent matters
        assertEquals(false, new Polynomial("10 0").equals(new Polynomial("10 1")));
        // Difference in coefficient matters
        assertEquals(false, new Polynomial("10 0").equals(new Polynomial("5 0")));
    }

    /**
     * Test of plus method, of class Polynomial.
     */
    @Test
    public void testPlus_Polynomial() {
        System.out.println("plus");
        // Test cancelling out and exponents that don't exist in either of the two polynomials all at once
        Polynomial instance = new Polynomial("7 4 -4 2 7 1 5 0");       // 7x^4 - 4x^2 + 7x + 5
        instance.plus(new Polynomial("5 3 4 2 3 1 10 0"));              // 5x^3 + 4x^2 + 3x + 10
        assertEquals(new Polynomial("7 4 5 3 10 1 15 0"), instance);    // 7x^4 + 5x^3 + 10x + 15
        
        // Test associativity for some random polynomials
        Polynomial a = new Polynomial("5 4 2 5 20 8 4 0");
        Polynomial b = new Polynomial("9 2 7 5 10 8 28 2");
        Polynomial c = new Polynomial("3 8 4 20 8 2 4 5 0 0");
        Polynomial a_bc = new Polynomial(a);
        a_bc.plus(b);
        a_bc.plus(c);
        Polynomial a_cb = new Polynomial(a);
        a_cb.plus(c);
        a_cb.plus(b);
        assertEquals(true, a_bc.equals(a_cb));
        
        // Test commutativity
        Polynomial a_b = new Polynomial(a);
        a_b.plus(b);
        Polynomial b_a = new Polynomial(b);
        b_a.plus(a);
        assertEquals(true, a_b.equals(b_a));
    }

    /**
     * Test of apply method, of class Polynomial.
     */
    @Test
    public void testApply() {
        System.out.println("apply");
        // Test zero coefficient, floating point coefficient and negative coefficient all at once
        Polynomial instance = new Polynomial("0 7 5 4 0.5 3 9 2 -8 0");
        assertEquals(422654.5, instance.apply(17.0), 0.0);
    }
    
}