import ch.bfh.CalculatorLexer;
import ch.bfh.parser.ExpressionParser;
import org.junit.Test;
import static org.junit.Assert.assertEquals;

public class ExpressionParserTest {

    // Only testing correct expressions first
    @Test
    public void emptyExpression() {
        CalculatorLexer cl = new CalculatorLexer();
        cl.initLexer("");
        ExpressionParser ep = new ExpressionParser(cl);
        assertEquals(0.0, ep.getValue(), 0.0);
    }

    @Test
    public void oneFactor() {
        CalculatorLexer cl = new CalculatorLexer();
        cl.initLexer("10");
        ExpressionParser ep = new ExpressionParser(cl);
        assertEquals(10.0, ep.getValue(), 0.0);
    }

    @Test
    public void oneParenthesisedFactor() {
        CalculatorLexer cl = new CalculatorLexer();
        cl.initLexer("(10)");
        ExpressionParser ep = new ExpressionParser(cl);
        assertEquals(10.0, ep.getValue(), 0.0);
    }

    @Test
    public void oneNegativeFactor() {
        CalculatorLexer cl = new CalculatorLexer();
        cl.initLexer("-10");
        ExpressionParser ep = new ExpressionParser(cl);
        assertEquals(-10.0, ep.getValue(), 0.0);
    }

    @Test
    public void oneNegativeParenthesisedFactor() {
        CalculatorLexer cl = new CalculatorLexer();
        cl.initLexer("-(10)");
        ExpressionParser ep = new ExpressionParser(cl);
        assertEquals(-10.0, ep.getValue(), 0.0);
    }

    @Test
    public void oneNegativeParenthesisedNegativeFactor() {
        CalculatorLexer cl = new CalculatorLexer();
        cl.initLexer("-(-10)");
        ExpressionParser ep = new ExpressionParser(cl);
        assertEquals(10.0, ep.getValue(), 0.0);
    }

    @Test
    public void twoFactorSum() {
        CalculatorLexer cl = new CalculatorLexer();
        cl.initLexer("2+3");
        ExpressionParser ep = new ExpressionParser(cl);
        assertEquals(5.0, ep.getValue(), 0.0);
    }

    @Test
    public void twoFactorSub() {
        CalculatorLexer cl = new CalculatorLexer();
        cl.initLexer("2-3");
        ExpressionParser ep = new ExpressionParser(cl);
        assertEquals(-1.0, ep.getValue(), 0.0);
    }

    @Test
    public void twoFactorSumWithSub() {
        CalculatorLexer cl = new CalculatorLexer();
        cl.initLexer("2--3");
        ExpressionParser ep = new ExpressionParser(cl);
        assertEquals(5.0, ep.getValue(), 0.0);
    }

    @Test
    public void twoFactorSumWithSubParenthesised() {
        CalculatorLexer cl = new CalculatorLexer();
        cl.initLexer("2-(-3)");
        ExpressionParser ep = new ExpressionParser(cl);
        assertEquals(5.0, ep.getValue(), 0.0);
    }

    @Test
    public void twoFactorMul() {
        CalculatorLexer cl = new CalculatorLexer();
        cl.initLexer("2*3");
        ExpressionParser ep = new ExpressionParser(cl);
        assertEquals(6.0, ep.getValue(), 0.0);
    }

    @Test
    public void twoFactorDiv() {
        CalculatorLexer cl = new CalculatorLexer();
        cl.initLexer("11/4");
        ExpressionParser ep = new ExpressionParser(cl);
        assertEquals(2.75, ep.getValue(), 0.0);
    }

    @Test
    public void completeArithmeticOperationWithPriorities() {
        CalculatorLexer cl = new CalculatorLexer();
        cl.initLexer("(4+5)*3/4");
        ExpressionParser ep = new ExpressionParser(cl);
        assertEquals(6.75, ep.getValue(), 0.0);
    }

    //TODO - test error messages

}