package function.builtin;

import static org.junit.Assert.assertTrue;
import static testutil.TestUtilities.evaluateString;
import static testutil.TypeAssertions.*;

import java.io.*;

import org.junit.*;

import environment.RuntimeEnvironment;
import error.ErrorManager;
import function.ArgumentValidator.*;

public class LOADTester {

    private ByteArrayOutputStream outputStream;
    private ByteArrayOutputStream errorOutputStream;

    private void assertWarningMessagePrinted() {
        assertTrue(outputStream.toByteArray().length > 0);
        assertTrue(errorOutputStream.toByteArray().length == 0);
    }

    private void assertErrorMessagePrinted() {
        assertTrue(errorOutputStream.toByteArray().length > 0);
        assertTrue(outputStream.toByteArray().length == 0);
    }

    private void assertNothingPrinted() {
        assertTrue(outputStream.toByteArray().length == 0);
        assertTrue(outputStream.toByteArray().length == 0);
    }

    @Before
    public void setUp() {
        this.outputStream = new ByteArrayOutputStream();
        this.errorOutputStream = new ByteArrayOutputStream();
        RuntimeEnvironment.getInstance().setOutput(new PrintStream(outputStream));
        RuntimeEnvironment.getInstance().setErrorOutput(new PrintStream(errorOutputStream));
        RuntimeEnvironment.getInstance().setErrorManager(new ErrorManager());
    }

    @Test
    public void loadGoodFile_ReturnsTAndPrintsNothing() {
        String input = "(load \"test/function/builtin/test-files/load-good.lisp\")";

        assertT(evaluateString(input));
        assertNothingPrinted();
    }

    @Test
    public void loadBadFile_ReturnsNilAndPrintsError() {
        String input = "(load \"test/function/builtin/test-files/load-bad.lisp\")";

        assertNil(evaluateString(input));
        assertErrorMessagePrinted();
    }

    @Test
    public void loadNonExistentFile_ReturnsNilAndPrintsError() {
        String input = "(load \"doesNotExist.lisp\")";

        assertNil(evaluateString(input));
        assertWarningMessagePrinted();
    }

    @Test(expected = BadArgumentTypeException.class)
    public void testLoadWithBadArgumentType() {
        evaluateString("(load '1)");
    }

    @Test(expected = TooManyArgumentsException.class)
    public void testLoadWithTooManyArguments() {
        evaluateString("(load \"1\" \"2\")");
    }

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

}