/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.ace.client.repository.repository;

import java.io.IOException;
import java.net.URL;
import java.util.List;

import org.apache.ace.client.repository.ObjectRepository;
import org.apache.ace.client.repository.object.ArtifactObject;
import org.apache.ace.client.repository.object.TargetObject;

import org.osgi.annotation.versioning.ProviderType;

/**
 * Interface to a ArtifactRepository. The functionality is defined by the generic AssociationRepository.
 */
@ProviderType
public interface ArtifactRepository extends ObjectRepository<ArtifactObject> {
    static class ArtifactAlreadyExistsException extends IOException {
        private final URL m_url;
        private final String m_filename;

        /**
         * Creates a new {@link ArtifactAlreadyExistsException} instance.
         */
        public ArtifactAlreadyExistsException(URL artifactURL, String filename) {
            m_url = artifactURL;
            m_filename = filename;
        }

        /**
         * @return the filename of the artifact that already exists, can be <code>null</code>.
         */
        public String getFilename() {
            return m_filename;
        }

        /**
         * @return the URL of the already existing artifact, cannot be <code>null</code>.
         */
        public URL getUrl() {
            return m_url;
        }
    }

    /**
     * Gets a list of all ArtifactObject's which are resource processing bundles.
     */
    public List<ArtifactObject> getResourceProcessors();

    /**
     * Tries to import an artifact into storage, while extracting necessary metadata.
     *
     * @param artifact
     *            a URL pointing to the 'physical' artifact.
     * @param upload
     *            Indicates whether this artifact should be uploaded to our own OBR.
     * @return An <code>ArtifactObject</code> representing the passed in artifact, if (a) the artifact is recognized,
     *         (b) there is storage available and (c) there is a resource processor available for this type of artifact.
     * @throws IllegalArgumentException
     *             when the given <tt>artifact</tt> represents an invalid URL;
     * @throws ArtifactAlreadyExistsException
     *             in case the artifact could not be uploaded, as it already exists in the storage;
     * @throws IOException
     *             when there is a problem transferring the <code>artifact</code> to storage.
     */
    public ArtifactObject importArtifact(URL artifact, boolean upload) throws IllegalArgumentException, IOException;

    /**
     * Checks whether an artifact is 'usable', that is, there is a resource processor available for it, if necessary.
     *
     * @param artifact
     *            A URL pointing to an artifact.
     * @return <code>true</code> if the artifact is recognized, and a processor for it is available. <code>false</code>
     *         otherwise, including when the artifact cannot be reached.
     */
    public boolean recognizeArtifact(URL artifact);

    /**
     * Tries to import an artifact into storage, while extracting necessary metadata.
     *
     * @param artifact
     *            a URL pointing to the 'physical' artifact.
     * @param mimetype
     *            a String giving this object's mimetype.
     * @param upload
     *            Indicates whether this artifact should be uploaded to our own OBR.
     * @return An <code>ArtifactObject</code> representing the passed in artifact, if (a) there is storage available and
     *         (b) there is a resource processor available for this type of artifact.
     * @throws IllegalArgumentException
     *             when the <code>artifact</code> cannot be processed.
     * @throws IOException
     *             when there is a problem transferring the <code>artifact</code> to storage.
     */
    public ArtifactObject importArtifact(URL artifact, String mimetype, boolean upload) throws IllegalArgumentException, IOException;

    /**
     * Tries to locate a preprocessor for the passed artifact, an processes it. If no processing needs to be done, the
     * original artifact's URL will be returned.
     *
     * @param artifact
     *            An artifact
     * @param props
     *            A tree of properties objects, to be used for replacement.
     * @param targetID
     *            The targetID of the target for which this artifact is being processed.
     * @param version
     *            The deployment version for which this artifact is being processed.
     * @return A URL to a new, processed artifact, or to the original one, in case nothing needed to be processed.
     * @throws IOException
     *             Thrown if reading the original artifact goes wrong, or storing the processed one.
     */
    public String preprocessArtifact(ArtifactObject artifact, TargetObject target, String targetID, String version) throws IOException;

    /**
     * Indicates whether the template should be processed again, given the properties, and the version to which it
     * should be compared.
     *
     * @param url
     *            A string representing a URL to the original artifact.
     * @param props
     *            A PropertyResolver which can be used to fill in 'holes' in the template.
     * @param targetID
     *            The targetID of the target for which this artifact is being processed.
     * @param version
     *            The deployment version for which this artifact is being processed.
     * @param lastVersion
     *            The deployment version to which the current one should be compared.
     * @param newVersion
     *            The new, potential version.
     * @param obrBase
     *            A base OBR to upload the new artifact to.
     * @return Whether or not a new version has to be created.
     * @throws IOException
     */
    public boolean needsNewVersion(ArtifactObject artifact, TargetObject target, String targetID, String fromVersion);
}