/*
 * 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.maven.plugin;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.maven.RepositoryUtils;
import org.apache.maven.artifact.Artifact;
import org.apache.maven.model.Plugin;
import org.apache.maven.project.MavenProject;
import org.codehaus.plexus.classworlds.realm.ClassRealm;
import org.codehaus.plexus.classworlds.realm.NoSuchRealmException;
import org.codehaus.plexus.component.annotations.Component;
import org.codehaus.plexus.personality.plexus.lifecycle.phase.Disposable;
import org.eclipse.aether.RepositorySystemSession;
import org.eclipse.aether.graph.DependencyFilter;
import org.eclipse.aether.repository.LocalRepository;
import org.eclipse.aether.repository.RemoteRepository;
import org.eclipse.aether.repository.WorkspaceRepository;

/**
 * Default PluginCache implementation. Assumes cached data does not change.
 */
@Component(role = PluginRealmCache.class)
public class DefaultPluginRealmCache implements PluginRealmCache, Disposable {
    /**
     * CacheKey
     */
    protected static class CacheKey implements Key {

        private final Plugin plugin;

        private final WorkspaceRepository workspace;

        private final LocalRepository localRepo;

        private final List<RemoteRepository> repositories;

        private final ClassLoader parentRealm;

        private final Map<String, ClassLoader> foreignImports;

        private final DependencyFilter filter;

        private final int hashCode;

        public CacheKey(
                Plugin plugin,
                ClassLoader parentRealm,
                Map<String, ClassLoader> foreignImports,
                DependencyFilter dependencyFilter,
                List<RemoteRepository> repositories,
                RepositorySystemSession session) {
            this.plugin = plugin.clone();
            this.workspace = RepositoryUtils.getWorkspace(session);
            this.localRepo = session.getLocalRepository();
            this.repositories = new ArrayList<>(repositories.size());
            for (RemoteRepository repository : repositories) {
                if (repository.isRepositoryManager()) {
                    this.repositories.addAll(repository.getMirroredRepositories());
                } else {
                    this.repositories.add(repository);
                }
            }
            this.parentRealm = parentRealm;
            this.foreignImports =
                    (foreignImports != null) ? foreignImports : Collections.<String, ClassLoader>emptyMap();
            this.filter = dependencyFilter;

            int hash = 17;
            hash = hash * 31 + CacheUtils.pluginHashCode(plugin);
            hash = hash * 31 + Objects.hashCode(workspace);
            hash = hash * 31 + Objects.hashCode(localRepo);
            hash = hash * 31 + RepositoryUtils.repositoriesHashCode(repositories);
            hash = hash * 31 + Objects.hashCode(parentRealm);
            hash = hash * 31 + this.foreignImports.hashCode();
            hash = hash * 31 + Objects.hashCode(dependencyFilter);
            this.hashCode = hash;
        }

        @Override
        public String toString() {
            return plugin.getId();
        }

        @Override
        public int hashCode() {
            return hashCode;
        }

        @Override
        public boolean equals(Object o) {
            if (o == this) {
                return true;
            }

            if (!(o instanceof CacheKey)) {
                return false;
            }

            CacheKey that = (CacheKey) o;

            return parentRealm == that.parentRealm
                    && CacheUtils.pluginEquals(plugin, that.plugin)
                    && Objects.equals(workspace, that.workspace)
                    && Objects.equals(localRepo, that.localRepo)
                    && RepositoryUtils.repositoriesEquals(this.repositories, that.repositories)
                    && Objects.equals(filter, that.filter)
                    && Objects.equals(foreignImports, that.foreignImports);
        }
    }

    protected final Map<Key, CacheRecord> cache = new ConcurrentHashMap<>();

    public Key createKey(
            Plugin plugin,
            ClassLoader parentRealm,
            Map<String, ClassLoader> foreignImports,
            DependencyFilter dependencyFilter,
            List<RemoteRepository> repositories,
            RepositorySystemSession session) {
        return new CacheKey(plugin, parentRealm, foreignImports, dependencyFilter, repositories, session);
    }

    public CacheRecord get(Key key) {
        return cache.get(key);
    }

    public CacheRecord put(Key key, ClassRealm pluginRealm, List<Artifact> pluginArtifacts) {
        Objects.requireNonNull(pluginRealm, "pluginRealm cannot be null");
        Objects.requireNonNull(pluginArtifacts, "pluginArtifacts cannot be null");

        if (cache.containsKey(key)) {
            throw new IllegalStateException("Duplicate plugin realm for plugin " + key);
        }

        CacheRecord record = new CacheRecord(pluginRealm, pluginArtifacts);

        cache.put(key, record);

        return record;
    }

    public void flush() {
        for (CacheRecord record : cache.values()) {
            ClassRealm realm = record.getRealm();
            try {
                realm.getWorld().disposeRealm(realm.getId());
            } catch (NoSuchRealmException e) {
                // ignore
            }
        }
        cache.clear();
    }

    protected static int pluginHashCode(Plugin plugin) {
        return CacheUtils.pluginHashCode(plugin);
    }

    protected static boolean pluginEquals(Plugin a, Plugin b) {
        return CacheUtils.pluginEquals(a, b);
    }

    public void register(MavenProject project, Key key, CacheRecord record) {
        // default cache does not track plugin usage
    }

    public void dispose() {
        flush();
    }
}
