package function.builtin.special;

import static testutil.TestUtilities.*;

import org.junit.*;

import function.ArgumentValidator.*;
import table.ExecutionContext;

public class CASETester {

    private ExecutionContext executionContext;

    public CASETester() {
        this.executionContext = ExecutionContext.getInstance();
    }

    @Before
    public void setUp() {
        executionContext.clearContext();
    }

    @After
    public void tearDown() {
        executionContext.clearContext();
    }

    @Test
    public void caseWithOnlySwitchExpression() {
        String input = "(case t)";

        assertSExpressionsMatch(parseString("nil"), evaluateString(input));
    }

    @Test
    public void caseWithEmptyConsequent() {
        String input = "(case :a ((:a)))";

        assertSExpressionsMatch(parseString("nil"), evaluateString(input));
    }

    @Test
    public void caseWithOneClause_Match() {
        String input = "(case :a ((:a) 'banana))";

        assertSExpressionsMatch(parseString("banana"), evaluateString(input));
    }

    @Test
    public void caseWithOneClause_NoMatch() {
        String input = "(case :a ((:b) 'banana))";

        assertSExpressionsMatch(parseString("nil"), evaluateString(input));
    }

    @Test
    public void caseWithSeveralClauses_Match() {
        String input = "(case :a ((:b) 'orange) ((:a) 'banana))";

        assertSExpressionsMatch(parseString("banana"), evaluateString(input));
    }

    @Test
    public void caseWithSeveralClauses_NoMatch() {
        String input = "(case :a ((:b) 'orange) ((:c) 'banana))";

        assertSExpressionsMatch(parseString("nil"), evaluateString(input));
    }

    @Test
    public void caseWithSymbolicKeyList_Match() {
        String input = "(case :a (:a 'orange))";

        assertSExpressionsMatch(parseString("orange"), evaluateString(input));
    }

    @Test
    public void caseWithSymbolicKeyList_NoMatch() {
        String input = "(case :a (:b 'orange))";

        assertSExpressionsMatch(parseString("nil"), evaluateString(input));
    }

    @Test
    public void caseWithEmptyKeyList() {
        String input = "(case nil (() 'orange))";

        assertSExpressionsMatch(parseString("nil"), evaluateString(input));
    }

    @Test
    public void caseWithNil() {
        String input = "(case nil ((nil) 'orange))";

        assertSExpressionsMatch(parseString("orange"), evaluateString(input));
    }

    @Test
    public void caseWithDefaultClause() {
        String input = "(case nil (() 'banana) (t 'orange))";

        assertSExpressionsMatch(parseString("orange"), evaluateString(input));
    }

    @Test
    public void caseWithOutOfOrderDefaultClause() {
        String input = "(case :a (t 'orange) (:a 'banana))";

        assertSExpressionsMatch(parseString("orange"), evaluateString(input));
    }

    @Test
    public void caseWithKeyListContainingT() {
        String input = "(case t ((t) 'banana))";

        assertSExpressionsMatch(parseString("banana"), evaluateString(input));
    }

    @Test
    public void caseWithMultipleMatches_ReturnsFirst() {
        String input = "(case 2 ((0) 'banana) ((1) 'apple) ((2) 'avocado) ((2) 'greenbean))";

        assertSExpressionsMatch(parseString("avocado"), evaluateString(input));
    }

    @Test
    public void caseOnlyEvaluatesFirstMatchingClause() {
        String input = "(case 2 ((0) (setf zero 0)) ((1) (setf one 1)) ((2) (setf two '2)) ((2) (setf two 'two)))";

        evaluateString("(setf zero nil)");
        evaluateString("(setf one nil)");
        evaluateString(input);

        assertSExpressionsMatch(parseString("nil"), evaluateString("zero"));
        assertSExpressionsMatch(parseString("nil"), evaluateString("one"));
        assertSExpressionsMatch(parseString("2"), evaluateString("two"));
    }

    @Test(expected = TooFewArgumentsException.class)
    public void caseWithTooFewArguments() {
        evaluateString("(case)");
    }

    @Test(expected = BadArgumentTypeException.class)
    public void caseWithNonListClause() {
        evaluateString("(case :a t)");
    }

}