/*
 * Copyright (C) 2007 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.base;

import static com.google.common.base.StandardSystemProperty.JAVA_SPECIFICATION_VERSION;
import static com.google.common.base.Throwables.getStackTraceAsString;
import static com.google.common.base.Throwables.lazyStackTrace;
import static com.google.common.base.Throwables.lazyStackTraceIsLazy;
import static com.google.common.base.Throwables.throwIfInstanceOf;
import static com.google.common.base.Throwables.throwIfUnchecked;
import static com.google.common.truth.Truth.assertThat;
import static java.util.Arrays.asList;
import static java.util.regex.Pattern.quote;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.Iterables;
import com.google.common.primitives.Ints;
import com.google.common.testing.NullPointerTester;
import java.util.List;
import junit.framework.TestCase;

/**
 * Unit test for {@link Throwables}.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible(emulated = true)
public class ThrowablesTest extends TestCase {
  public void testThrowIfUnchecked_Unchecked() {
    try {
      throwIfUnchecked(new SomeUncheckedException());
      fail();
    } catch (SomeUncheckedException expected) {
    }
  }

  public void testThrowIfUnchecked_Error() {
    try {
      throwIfUnchecked(new SomeError());
      fail();
    } catch (SomeError expected) {
    }
  }

  @SuppressWarnings("ThrowIfUncheckedKnownChecked")
  public void testThrowIfUnchecked_Checked() {
    throwIfUnchecked(new SomeCheckedException());
  }

  @GwtIncompatible // propagateIfPossible
  public void testPropagateIfPossible_NoneDeclared_NoneThrown() {
    Sample sample =
        new Sample() {
          @Override
          public void noneDeclared() {
            try {
              methodThatDoesntThrowAnything();
            } catch (Throwable t) {
              Throwables.propagateIfPossible(t);
              throw new SomeChainingException(t);
            }
          }
        };

    // Expect no exception to be thrown
    sample.noneDeclared();
  }

  @GwtIncompatible // propagateIfPossible
  public void testPropagateIfPossible_NoneDeclared_UncheckedThrown() {
    Sample sample =
        new Sample() {
          @Override
          public void noneDeclared() {
            try {
              methodThatThrowsUnchecked();
            } catch (Throwable t) {
              Throwables.propagateIfPossible(t);
              throw new SomeChainingException(t);
            }
          }
        };

    // Expect the unchecked exception to propagate as-is
    try {
      sample.noneDeclared();
      fail();
    } catch (SomeUncheckedException expected) {
    }
  }

  @GwtIncompatible // propagateIfPossible
  public void testPropagateIfPossible_NoneDeclared_UndeclaredThrown() {
    Sample sample =
        new Sample() {
          @Override
          public void noneDeclared() {
            try {
              methodThatThrowsUndeclaredChecked();
            } catch (Throwable t) {
              Throwables.propagateIfPossible(t);
              throw new SomeChainingException(t);
            }
          }
        };

    // Expect the undeclared exception to have been chained inside another
    try {
      sample.noneDeclared();
      fail();
    } catch (SomeChainingException expected) {
    }
  }

  @GwtIncompatible // propagateIfPossible(Throwable, Class)
  public void testPropagateIfPossible_OneDeclared_NoneThrown() throws SomeCheckedException {
    Sample sample =
        new Sample() {
          @Override
          public void oneDeclared() throws SomeCheckedException {
            try {
              methodThatDoesntThrowAnything();
            } catch (Throwable t) {
              // yes, this block is never reached, but for purposes of illustration
              // we're keeping it the same in each test
              Throwables.propagateIfPossible(t, SomeCheckedException.class);
              throw new SomeChainingException(t);
            }
          }
        };

    // Expect no exception to be thrown
    sample.oneDeclared();
  }

  @GwtIncompatible // propagateIfPossible(Throwable, Class)
  public void testPropagateIfPossible_OneDeclared_UncheckedThrown() throws SomeCheckedException {
    Sample sample =
        new Sample() {
          @Override
          public void oneDeclared() throws SomeCheckedException {
            try {
              methodThatThrowsUnchecked();
            } catch (Throwable t) {
              Throwables.propagateIfPossible(t, SomeCheckedException.class);
              throw new SomeChainingException(t);
            }
          }
        };

    // Expect the unchecked exception to propagate as-is
    try {
      sample.oneDeclared();
      fail();
    } catch (SomeUncheckedException expected) {
    }
  }

  @GwtIncompatible // propagateIfPossible(Throwable, Class)
  public void testPropagateIfPossible_OneDeclared_CheckedThrown() {
    Sample sample =
        new Sample() {
          @Override
          public void oneDeclared() throws SomeCheckedException {
            try {
              methodThatThrowsChecked();
            } catch (Throwable t) {
              Throwables.propagateIfPossible(t, SomeCheckedException.class);
              throw new SomeChainingException(t);
            }
          }
        };

    // Expect the checked exception to propagate as-is
    try {
      sample.oneDeclared();
      fail();
    } catch (SomeCheckedException expected) {
    }
  }

  @GwtIncompatible // propagateIfPossible(Throwable, Class)
  public void testPropagateIfPossible_OneDeclared_UndeclaredThrown() throws SomeCheckedException {
    Sample sample =
        new Sample() {
          @Override
          public void oneDeclared() throws SomeCheckedException {
            try {
              methodThatThrowsUndeclaredChecked();
            } catch (Throwable t) {
              Throwables.propagateIfPossible(t, SomeCheckedException.class);
              throw new SomeChainingException(t);
            }
          }
        };

    // Expect the undeclared exception to have been chained inside another
    try {
      sample.oneDeclared();
      fail();
    } catch (SomeChainingException expected) {
    }
  }

  @GwtIncompatible // propagateIfPossible(Throwable, Class, Class)
  public void testPropagateIfPossible_TwoDeclared_NoneThrown()
      throws SomeCheckedException, SomeOtherCheckedException {
    Sample sample =
        new Sample() {
          @Override
          public void twoDeclared() throws SomeCheckedException, SomeOtherCheckedException {
            try {
              methodThatDoesntThrowAnything();
            } catch (Throwable t) {
              Throwables.propagateIfPossible(
                  t, SomeCheckedException.class, SomeOtherCheckedException.class);
              throw new SomeChainingException(t);
            }
          }
        };

    // Expect no exception to be thrown
    sample.twoDeclared();
  }

  @GwtIncompatible // propagateIfPossible(Throwable, Class, Class)
  public void testPropagateIfPossible_TwoDeclared_UncheckedThrown()
      throws SomeCheckedException, SomeOtherCheckedException {
    Sample sample =
        new Sample() {
          @Override
          public void twoDeclared() throws SomeCheckedException, SomeOtherCheckedException {
            try {
              methodThatThrowsUnchecked();
            } catch (Throwable t) {
              Throwables.propagateIfPossible(
                  t, SomeCheckedException.class, SomeOtherCheckedException.class);
              throw new SomeChainingException(t);
            }
          }
        };

    // Expect the unchecked exception to propagate as-is
    try {
      sample.twoDeclared();
      fail();
    } catch (SomeUncheckedException expected) {
    }
  }

  @GwtIncompatible // propagateIfPossible(Throwable, Class, Class)
  public void testPropagateIfPossible_TwoDeclared_CheckedThrown() throws SomeOtherCheckedException {
    Sample sample =
        new Sample() {
          @Override
          public void twoDeclared() throws SomeCheckedException, SomeOtherCheckedException {
            try {
              methodThatThrowsChecked();
            } catch (Throwable t) {
              Throwables.propagateIfPossible(
                  t, SomeCheckedException.class, SomeOtherCheckedException.class);
              throw new SomeChainingException(t);
            }
          }
        };

    // Expect the checked exception to propagate as-is
    try {
      sample.twoDeclared();
      fail();
    } catch (SomeCheckedException expected) {
    }
  }

  @GwtIncompatible // propagateIfPossible(Throwable, Class, Class)
  public void testPropagateIfPossible_TwoDeclared_OtherCheckedThrown() throws SomeCheckedException {
    Sample sample =
        new Sample() {
          @Override
          public void twoDeclared() throws SomeCheckedException, SomeOtherCheckedException {
            try {
              methodThatThrowsOtherChecked();
            } catch (Throwable t) {
              Throwables.propagateIfPossible(
                  t, SomeCheckedException.class, SomeOtherCheckedException.class);
              throw new SomeChainingException(t);
            }
          }
        };

    // Expect the checked exception to propagate as-is
    try {
      sample.twoDeclared();
      fail();
    } catch (SomeOtherCheckedException expected) {
    }
  }

  public void testThrowIfUnchecked_null() throws SomeCheckedException {
    try {
      throwIfUnchecked(null);
      fail();
    } catch (NullPointerException expected) {
    }
  }

  @GwtIncompatible // propagateIfPossible
  public void testPropageIfPossible_null() throws SomeCheckedException {
    Throwables.propagateIfPossible(null);
  }

  @GwtIncompatible // propagateIfPossible(Throwable, Class)
  public void testPropageIfPossible_OneDeclared_null() throws SomeCheckedException {
    Throwables.propagateIfPossible(null, SomeCheckedException.class);
  }

  @GwtIncompatible // propagateIfPossible(Throwable, Class, Class)
  public void testPropageIfPossible_TwoDeclared_null() throws SomeCheckedException {
    Throwables.propagateIfPossible(null, SomeCheckedException.class, SomeUncheckedException.class);
  }

  @GwtIncompatible // propagate
  public void testPropagate_NoneDeclared_NoneThrown() {
    Sample sample =
        new Sample() {
          @Override
          public void noneDeclared() {
            try {
              methodThatDoesntThrowAnything();
            } catch (Throwable t) {
              throw Throwables.propagate(t);
            }
          }
        };

    // Expect no exception to be thrown
    sample.noneDeclared();
  }

  @GwtIncompatible // propagate
  public void testPropagate_NoneDeclared_UncheckedThrown() {
    Sample sample =
        new Sample() {
          @Override
          public void noneDeclared() {
            try {
              methodThatThrowsUnchecked();
            } catch (Throwable t) {
              throw Throwables.propagate(t);
            }
          }
        };

    // Expect the unchecked exception to propagate as-is
    try {
      sample.noneDeclared();
      fail();
    } catch (SomeUncheckedException expected) {
    }
  }

  @GwtIncompatible // propagate
  public void testPropagate_NoneDeclared_ErrorThrown() {
    Sample sample =
        new Sample() {
          @Override
          public void noneDeclared() {
            try {
              methodThatThrowsError();
            } catch (Throwable t) {
              throw Throwables.propagate(t);
            }
          }
        };

    // Expect the error to propagate as-is
    try {
      sample.noneDeclared();
      fail();
    } catch (SomeError expected) {
    }
  }

  @GwtIncompatible // propagate
  public void testPropagate_NoneDeclared_CheckedThrown() {
    Sample sample =
        new Sample() {
          @Override
          public void noneDeclared() {
            try {
              methodThatThrowsChecked();
            } catch (Throwable t) {
              throw Throwables.propagate(t);
            }
          }
        };

    // Expect the undeclared exception to have been chained inside another
    try {
      sample.noneDeclared();
      fail();
    } catch (RuntimeException expected) {
      assertThat(expected).hasCauseThat().isInstanceOf(SomeCheckedException.class);
    }
  }

  @GwtIncompatible // throwIfInstanceOf
  public void testThrowIfInstanceOf_Unchecked() throws SomeCheckedException {
    throwIfInstanceOf(new SomeUncheckedException(), SomeCheckedException.class);
  }

  @GwtIncompatible // throwIfInstanceOf
  public void testThrowIfInstanceOf_CheckedDifferent() throws SomeCheckedException {
    throwIfInstanceOf(new SomeOtherCheckedException(), SomeCheckedException.class);
  }

  @GwtIncompatible // throwIfInstanceOf
  public void testThrowIfInstanceOf_CheckedSame() {
    try {
      throwIfInstanceOf(new SomeCheckedException(), SomeCheckedException.class);
      fail();
    } catch (SomeCheckedException expected) {
    }
  }

  @GwtIncompatible // throwIfInstanceOf
  public void testThrowIfInstanceOf_CheckedSubclass() {
    try {
      throwIfInstanceOf(new SomeCheckedException() {}, SomeCheckedException.class);
      fail();
    } catch (SomeCheckedException expected) {
    }
  }

  @GwtIncompatible // throwIfInstanceOf
  public void testPropagateIfInstanceOf_NoneThrown() throws SomeCheckedException {
    Sample sample =
        new Sample() {
          @Override
          public void oneDeclared() throws SomeCheckedException {
            try {
              methodThatDoesntThrowAnything();
            } catch (Throwable t) {
              Throwables.propagateIfInstanceOf(t, SomeCheckedException.class);
              throw Throwables.propagate(t);
            }
          }
        };

    // Expect no exception to be thrown
    sample.oneDeclared();
  }

  @GwtIncompatible // throwIfInstanceOf
  public void testPropagateIfInstanceOf_DeclaredThrown() {
    Sample sample =
        new Sample() {
          @Override
          public void oneDeclared() throws SomeCheckedException {
            try {
              methodThatThrowsChecked();
            } catch (Throwable t) {
              Throwables.propagateIfInstanceOf(t, SomeCheckedException.class);
              throw Throwables.propagate(t);
            }
          }
        };

    // Expect declared exception to be thrown as-is
    try {
      sample.oneDeclared();
      fail();
    } catch (SomeCheckedException expected) {
    }
  }

  @GwtIncompatible // throwIfInstanceOf
  public void testPropagateIfInstanceOf_UncheckedThrown() throws SomeCheckedException {
    Sample sample =
        new Sample() {
          @Override
          public void oneDeclared() throws SomeCheckedException {
            try {
              methodThatThrowsUnchecked();
            } catch (Throwable t) {
              Throwables.propagateIfInstanceOf(t, SomeCheckedException.class);
              throw Throwables.propagate(t);
            }
          }
        };

    // Expect unchecked exception to be thrown as-is
    try {
      sample.oneDeclared();
      fail();
    } catch (SomeUncheckedException expected) {
    }
  }

  @GwtIncompatible // throwIfInstanceOf
  public void testPropagateIfInstanceOf_UndeclaredThrown() throws SomeCheckedException {
    Sample sample =
        new Sample() {
          @Override
          public void oneDeclared() throws SomeCheckedException {
            try {
              methodThatThrowsOtherChecked();
            } catch (Throwable t) {
              Throwables.propagateIfInstanceOf(t, SomeCheckedException.class);
              throw Throwables.propagate(t);
            }
          }
        };

    // Expect undeclared exception wrapped by RuntimeException to be thrown
    try {
      sample.oneDeclared();
      fail();
    } catch (RuntimeException expected) {
      assertThat(expected).hasCauseThat().isInstanceOf(SomeOtherCheckedException.class);
    }
  }

  @GwtIncompatible // throwIfInstanceOf
  public void testThrowIfInstanceOf_null() throws SomeCheckedException {
    try {
      throwIfInstanceOf(null, SomeCheckedException.class);
      fail();
    } catch (NullPointerException expected) {
    }
  }

  @GwtIncompatible // throwIfInstanceOf
  public void testPropageIfInstanceOf_null() throws SomeCheckedException {
    Throwables.propagateIfInstanceOf(null, SomeCheckedException.class);
  }

  public void testGetRootCause_NoCause() {
    SomeCheckedException exception = new SomeCheckedException();
    assertSame(exception, Throwables.getRootCause(exception));
  }

  public void testGetRootCause_SingleWrapped() {
    SomeCheckedException cause = new SomeCheckedException();
    SomeChainingException exception = new SomeChainingException(cause);
    assertSame(cause, Throwables.getRootCause(exception));
  }

  public void testGetRootCause_DoubleWrapped() {
    SomeCheckedException cause = new SomeCheckedException();
    SomeChainingException exception = new SomeChainingException(new SomeChainingException(cause));
    assertSame(cause, Throwables.getRootCause(exception));
  }

  public void testGetRootCause_Loop() {
    Exception cause = new Exception();
    Exception exception = new Exception(cause);
    cause.initCause(exception);
    try {
      Throwables.getRootCause(cause);
      fail("Should have throw IAE");
    } catch (IllegalArgumentException expected) {
      assertThat(expected).hasCauseThat().isSameAs(cause);
    }
  }

  private static class SomeError extends Error {}

  private static class SomeCheckedException extends Exception {}

  private static class SomeOtherCheckedException extends Exception {}

  private static class SomeUncheckedException extends RuntimeException {}

  private static class SomeUndeclaredCheckedException extends Exception {}

  private static class SomeChainingException extends RuntimeException {
    public SomeChainingException(Throwable cause) {
      super(cause);
    }
  }

  static class Sample {
    void noneDeclared() {}

    void oneDeclared() throws SomeCheckedException {}

    void twoDeclared() throws SomeCheckedException, SomeOtherCheckedException {}
  }

  static void methodThatDoesntThrowAnything() {}

  static void methodThatThrowsError() {
    throw new SomeError();
  }

  static void methodThatThrowsUnchecked() {
    throw new SomeUncheckedException();
  }

  static void methodThatThrowsChecked() throws SomeCheckedException {
    throw new SomeCheckedException();
  }

  static void methodThatThrowsOtherChecked() throws SomeOtherCheckedException {
    throw new SomeOtherCheckedException();
  }

  static void methodThatThrowsUndeclaredChecked() throws SomeUndeclaredCheckedException {
    throw new SomeUndeclaredCheckedException();
  }

  @GwtIncompatible // getStackTraceAsString(Throwable)
  public void testGetStackTraceAsString() {
    class StackTraceException extends Exception {
      StackTraceException(String message) {
        super(message);
      }
    }

    StackTraceException e = new StackTraceException("my message");

    String firstLine = quote(e.getClass().getName() + ": " + e.getMessage());
    String secondLine = "\\s*at " + ThrowablesTest.class.getName() + "\\..*";
    String moreLines = "(?:.*\n?)*";
    String expected = firstLine + "\n" + secondLine + "\n" + moreLines;
    assertThat(getStackTraceAsString(e)).matches(expected);
  }

  public void testGetCausalChain() {
    SomeUncheckedException sue = new SomeUncheckedException();
    IllegalArgumentException iae = new IllegalArgumentException(sue);
    RuntimeException re = new RuntimeException(iae);
    IllegalStateException ex = new IllegalStateException(re);

    assertEquals(asList(ex, re, iae, sue), Throwables.getCausalChain(ex));
    assertSame(sue, Iterables.getOnlyElement(Throwables.getCausalChain(sue)));

    List<Throwable> causes = Throwables.getCausalChain(ex);
    try {
      causes.add(new RuntimeException());
      fail("List should be unmodifiable");
    } catch (UnsupportedOperationException expected) {
    }
  }

  public void testGetCasualChainNull() {
    try {
      Throwables.getCausalChain(null);
      fail("Should have throw NPE");
    } catch (NullPointerException expected) {
    }
  }

  public void testGetCasualChainLoop() {
    Exception cause = new Exception();
    Exception exception = new Exception(cause);
    cause.initCause(exception);
    try {
      Throwables.getCausalChain(cause);
      fail("Should have throw IAE");
    } catch (IllegalArgumentException expected) {
      assertThat(expected).hasCauseThat().isSameAs(cause);
    }
  }

  @GwtIncompatible // Throwables.getCauseAs(Throwable, Class)
  public void testGetCauseAs() {
    SomeCheckedException cause = new SomeCheckedException();
    SomeChainingException thrown = new SomeChainingException(cause);

    assertThat(thrown).hasCauseThat().isSameAs(cause);
    assertThat(Throwables.getCauseAs(thrown, SomeCheckedException.class)).isSameAs(cause);
    assertThat(Throwables.getCauseAs(thrown, Exception.class)).isSameAs(cause);

    try {
      Throwables.getCauseAs(thrown, IllegalStateException.class);
      fail("Should have thrown CCE");
    } catch (ClassCastException expected) {
      assertThat(expected).hasCauseThat().isSameAs(thrown);
    }
  }

  @AndroidIncompatible // No getJavaLangAccess in Android (at least not in the version we use).
  @GwtIncompatible // lazyStackTraceIsLazy()
  public void testLazyStackTraceWorksInProd() {
    // TODO(b/64442212): Remove this guard once lazyStackTrace() works in Java 9+.
    Integer javaVersion = Ints.tryParse(JAVA_SPECIFICATION_VERSION.value());
    if (javaVersion != null && javaVersion >= 9) {
      return;
    }
    // Obviously this isn't guaranteed in every environment, but it works well enough for now:
    assertTrue(lazyStackTraceIsLazy());
  }

  @GwtIncompatible // lazyStackTrace(Throwable)
  public void testLazyStackTrace() {
    Exception e = new Exception();
    StackTraceElement[] originalStackTrace = e.getStackTrace();

    assertThat(lazyStackTrace(e)).containsExactly((Object[]) originalStackTrace).inOrder();

    try {
      lazyStackTrace(e).set(0, null);
      fail();
    } catch (UnsupportedOperationException expected) {
    }

    // Now we test a property that holds only for the lazy implementation.

    if (!lazyStackTraceIsLazy()) {
      return;
    }

    e.setStackTrace(new StackTraceElement[0]);
    assertThat(lazyStackTrace(e)).containsExactly((Object[]) originalStackTrace).inOrder();
  }

  @GwtIncompatible // lazyStackTrace
  private void doTestLazyStackTraceFallback() {
    assertFalse(lazyStackTraceIsLazy());

    Exception e = new Exception();

    assertThat(lazyStackTrace(e)).containsExactly((Object[]) e.getStackTrace()).inOrder();

    try {
      lazyStackTrace(e).set(0, null);
      fail();
    } catch (UnsupportedOperationException expected) {
    }

    e.setStackTrace(new StackTraceElement[0]);
    assertThat(lazyStackTrace(e)).isEmpty();
  }

  @GwtIncompatible // NullPointerTester
  public void testNullPointers() {
    new NullPointerTester().testAllPublicStaticMethods(Throwables.class);
  }
}