/*******************************************************************************
 * Copyright (c) 2010, 2014 Sonatype, Inc.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Sonatype, Inc. - initial API and implementation
 *******************************************************************************/
package org.eclipse.aether.transfer;

import org.eclipse.aether.RepositoryException;

/**
 * Thrown in case of a checksum failure during an artifact/metadata download.
 */
public class ChecksumFailureException
    extends RepositoryException
{

    private final String expected;

    private final String actual;

    private final boolean retryWorthy;

    /**
     * Creates a new exception with the specified expected and actual checksum. The resulting exception is
     * {@link #isRetryWorthy() retry-worthy}.
     * 
     * @param expected The expected checksum as declared by the hosting repository, may be {@code null}.
     * @param actual The actual checksum as computed from the local bytes, may be {@code null}.
     */
    public ChecksumFailureException( String expected, String actual )
    {
        super( "Checksum validation failed, expected " + expected + " but is " + actual );
        this.expected = expected;
        this.actual = actual;
        retryWorthy = true;
    }

    /**
     * Creates a new exception with the specified detail message. The resulting exception is not
     * {@link #isRetryWorthy() retry-worthy}.
     * 
     * @param message The detail message, may be {@code null}.
     */
    public ChecksumFailureException( String message )
    {
        this( false, message, null );
    }

    /**
     * Creates a new exception with the specified cause. The resulting exception is not {@link #isRetryWorthy()
     * retry-worthy}.
     * 
     * @param cause The exception that caused this one, may be {@code null}.
     */
    public ChecksumFailureException( Throwable cause )
    {
        this( "Checksum validation failed" + getMessage( ": ", cause ), cause );
    }

    /**
     * Creates a new exception with the specified detail message and cause. The resulting exception is not
     * {@link #isRetryWorthy() retry-worthy}.
     * 
     * @param message The detail message, may be {@code null}.
     * @param cause The exception that caused this one, may be {@code null}.
     */
    public ChecksumFailureException( String message, Throwable cause )
    {
        this( false, message, cause );
    }

    /**
     * Creates a new exception with the specified retry flag, detail message and cause.
     * 
     * @param retryWorthy {@code true} if the exception is retry-worthy, {@code false} otherwise.
     * @param message The detail message, may be {@code null}.
     * @param cause The exception that caused this one, may be {@code null}.
     */
    public ChecksumFailureException( boolean retryWorthy, String message, Throwable cause )
    {
        super( message, cause );
        expected = actual = "";
        this.retryWorthy = retryWorthy;
    }

    /**
     * Gets the expected checksum for the downloaded artifact/metadata.
     * 
     * @return The expected checksum as declared by the hosting repository or {@code null} if unknown.
     */
    public String getExpected()
    {
        return expected;
    }

    /**
     * Gets the actual checksum for the downloaded artifact/metadata.
     * 
     * @return The actual checksum as computed from the local bytes or {@code null} if unknown.
     */
    public String getActual()
    {
        return actual;
    }

    /**
     * Indicates whether the corresponding download is retry-worthy.
     * 
     * @return {@code true} if retrying the download might solve the checksum failure, {@code false} if the checksum
     *         failure is non-recoverable.
     */
    public boolean isRetryWorthy()
    {
        return retryWorthy;
    }

}