package error;

import static error.ErrorManager.Severity.*;
import static org.junit.Assert.*;

import java.io.*;
import java.util.*;

import org.junit.*;

import environment.RuntimeEnvironment;
import error.ErrorManager.Severity;

public class ErrorManagerTester {

    private static final String TERMINATED = "terminated";
    private static final String MESSAGE = "message";

    private Set<String> indicatorSet;
    private ByteArrayOutputStream errorOutputStream;
    private ByteArrayOutputStream outputStream;

    private ErrorManager createErrorManagerWithIndicators() {
        RuntimeEnvironment.getInstance().setErrorTerminationFunction(() -> indicatorSet.add(TERMINATED));
        RuntimeEnvironment.getInstance().setErrorOutput(new PrintStream(errorOutputStream));
        RuntimeEnvironment.getInstance().setOutput(new PrintStream(outputStream));

        return new ErrorManager();
    }

    private LispException createLispException(Severity severity) {
        return new LispException() {

            private static final long serialVersionUID = 1L;

            @Override
            public Severity getSeverity() {
                return severity;
            }

            @Override
            public String getMessage() {
                return MESSAGE;
            }
        };
    }

    private void assertTerminated() {
        assertTrue(indicatorSet.contains(TERMINATED));
    }

    private void assertNotTerminated() {
        assertFalse(indicatorSet.contains(TERMINATED));
    }

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

    private void assertWarningMessageWritten() {
        assertTrue(outputStream.toByteArray().length > 0);
    }

    private void assertErrorMessageNotWritten() {
        assertTrue(errorOutputStream.toByteArray().length == 0);
    }

    private void assertErrorMessageWritten() {
        assertTrue(errorOutputStream.toByteArray().length > 0);
    }

    @Before
    public void setUp() {
        this.indicatorSet = new HashSet<>();
        this.errorOutputStream = new ByteArrayOutputStream();
        this.outputStream = new ByteArrayOutputStream();
    }

    @Test
    public void givenCriticalExceptionSeverity_RunsProvidedTerminationFunction() {
        ErrorManager errorManager = createErrorManagerWithIndicators();

        errorManager.handle(createLispException(CRITICAL));
        assertTerminated();
    }

    @Test
    public void givenWarningExceptionSeverity_DoesNotRunProvidedTerminationFunction() {
        ErrorManager errorManager = createErrorManagerWithIndicators();

        errorManager.handle(createLispException(WARNING));
        assertNotTerminated();
    }

    @Test
    public void givenErrorExceptionSeverity_DoesNotRunProvidedTerminationFunction() {
        ErrorManager errorManager = createErrorManagerWithIndicators();

        errorManager.handle(createLispException(ERROR));
        assertNotTerminated();
    }

    @Test
    public void usesOutputToDisplayWarningMessage() {
        ErrorManager errorManager = createErrorManagerWithIndicators();

        errorManager.handle(createLispException(WARNING));
        assertNotTerminated();
        assertErrorMessageNotWritten();
        assertWarningMessageWritten();
    }

    @Test
    public void usesErrorOutputToDisplayErrorMessage() {
        ErrorManager errorManager = createErrorManagerWithIndicators();

        errorManager.handle(createLispException(ERROR));
        assertNotTerminated();
        assertWarningMessageNotWritten();
        assertErrorMessageWritten();
    }

    @Test
    public void noMessageDisplayedBeforeError() {
        createErrorManagerWithIndicators();

        assertNotTerminated();
        assertErrorMessageNotWritten();
    }

    @Test
    public void usesOutputFunctionToDisplayMessages_WithTermination() {
        ErrorManager errorManager = createErrorManagerWithIndicators();

        errorManager.handle(createLispException(CRITICAL));
        assertTerminated();
        assertErrorMessageWritten();
    }

    @Test
    public void severityCoverage() {
        Severity.valueOf(WARNING.toString());
        Severity.valueOf(ERROR.toString());
        Severity.valueOf(CRITICAL.toString());
    }

}