package testsupport.matchers;

import com.jnape.palatable.lambda.adt.Either;

import org.hamcrest.Description;

import org.hamcrest.Matcher;

import org.hamcrest.TypeSafeMatcher;

import static com.jnape.palatable.lambda.functions.builtin.fn1.Constantly.constantly;

import static com.jnape.palatable.lambda.io.IO.io;

public final class RightMatcher<L, R> extends TypeSafeMatcher<Either<L, R>> {

private final Matcher<R> rMatcher;

private RightMatcher(Matcher<R> rMatcher) {

this.rMatcher = rMatcher;

}

@Override

protected boolean matchesSafely(Either<L, R> actual) {

return actual.match(constantly(false), rMatcher::matches);

}

@Override

public void describeTo(Description description) {

description.appendText("Right value of ");

rMatcher.describeTo(description);

}

@Override

protected void describeMismatchSafely(Either<L, R> item, Description mismatchDescription) {

mismatchDescription.appendText("was ");

item.peek(l -> io(() -> mismatchDescription.appendValue(item)),

r -> io(() -> {

mismatchDescription.appendText("Right value of ");

rMatcher.describeMismatch(r, mismatchDescription);

}));

}

public static <L, R> RightMatcher<L, R> isRightThat(Matcher<R> rMatcher) {

return new RightMatcher<>(rMatcher);

}

}