/*
 * 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.jackrabbit.oak.security.authorization.permission;

import org.apache.jackrabbit.guava.common.collect.ImmutableSet;
import org.apache.jackrabbit.JcrConstants;
import org.apache.jackrabbit.oak.api.CommitFailedException;
import org.apache.jackrabbit.oak.api.PropertyState;
import org.apache.jackrabbit.oak.api.Tree;
import org.apache.jackrabbit.oak.api.Type;
import org.apache.jackrabbit.oak.commons.PathUtils;
import org.apache.jackrabbit.oak.namepath.NamePathMapper;
import org.apache.jackrabbit.oak.plugins.nodetype.ReadOnlyNodeTypeManager;
import org.apache.jackrabbit.oak.plugins.version.ReadWriteVersionManager;
import org.apache.jackrabbit.oak.security.authorization.ProviderCtx;
import org.apache.jackrabbit.oak.spi.commit.CommitHook;
import org.apache.jackrabbit.oak.spi.commit.CommitInfo;
import org.apache.jackrabbit.oak.spi.nodetype.NodeTypeConstants;
import org.apache.jackrabbit.oak.spi.state.DefaultNodeStateDiff;
import org.apache.jackrabbit.oak.spi.state.NodeBuilder;
import org.apache.jackrabbit.oak.spi.state.NodeState;
import org.apache.jackrabbit.oak.spi.state.NodeStateUtils;
import org.apache.jackrabbit.oak.spi.version.VersionConstants;
import org.jetbrains.annotations.NotNull;

import java.util.Collections;

import static org.apache.jackrabbit.oak.plugins.memory.EmptyNodeState.EMPTY_NODE;

/**
 * Commit hook which is responsible for storing the path of the versionable
 * node with every version history. This includes creating the path property
 * for every workspace the version history is represented and updating the
 * path upon moving around a versionable node.
 */
public class VersionablePathHook implements CommitHook {

    private final String workspaceName;
    private final ProviderCtx providerCtx;

    public VersionablePathHook(@NotNull String workspaceName, @NotNull ProviderCtx providerCtx) {
        this.workspaceName = workspaceName;
        this.providerCtx = providerCtx;
    }

    @NotNull
    @Override
    public NodeState processCommit(
            NodeState before, NodeState after, CommitInfo info)
            throws CommitFailedException {
        NodeBuilder rootBuilder = after.builder();
        NodeBuilder vsRoot = rootBuilder.child(NodeTypeConstants.JCR_SYSTEM).child(NodeTypeConstants.JCR_VERSIONSTORAGE);

        ReadWriteVersionManager vMgr = new ReadWriteVersionManager(vsRoot, rootBuilder);
        ReadOnlyNodeTypeManager ntMgr = ReadOnlyNodeTypeManager.getInstance(providerCtx.getRootProvider().createReadOnlyRoot(rootBuilder.getNodeState()), NamePathMapper.DEFAULT);

        after.compareAgainstBaseState(before, new Diff(vMgr, ntMgr, new Node(rootBuilder)));
        return rootBuilder.getNodeState();
    }

    @Override
    public String toString() {
        return "VersionablePathHook : workspaceName = " + workspaceName;
    }

    private final class Diff extends DefaultNodeStateDiff implements VersionConstants {

        private final ReadWriteVersionManager versionManager;
        private final ReadOnlyNodeTypeManager ntMgr;
        private final Node nodeAfter;

        private Diff(@NotNull ReadWriteVersionManager versionManager,
                     @NotNull ReadOnlyNodeTypeManager ntMgr,
                     @NotNull Node node) {
            this.versionManager = versionManager;
            this.ntMgr = ntMgr;
            this.nodeAfter = node;
        }

        @Override
        public boolean propertyAdded(PropertyState after) {
            return setVersionablePath(after);
        }

        @Override
        public boolean propertyChanged(PropertyState before, PropertyState after) {
            return setVersionablePath(after);
        }

        @Override
        public boolean childNodeAdded(String name, NodeState after) {
            return childNodeChanged(name, EMPTY_NODE, after);
        }

        @Override
        public boolean childNodeChanged(
                String name, NodeState before, NodeState after) {
            if (NodeStateUtils.isHidden(name)) {
                // do not traverse into hidden trees
                return true;
            }
            Node node = new Node(nodeAfter, name);
            return after.compareAgainstBaseState(
                    before, new Diff(versionManager, ntMgr, node));
        }

        private boolean setVersionablePath(@NotNull PropertyState after) {
            if (JcrConstants.JCR_VERSIONHISTORY.equals(after.getName()) && nodeAfter.isVersionable(ntMgr)) {
                NodeBuilder vhBuilder = versionManager.getOrCreateVersionHistory(nodeAfter.builder, Collections.emptyMap());
                if (!vhBuilder.hasProperty(JcrConstants.JCR_MIXINTYPES)) {
                    vhBuilder.setProperty(
                            JcrConstants.JCR_MIXINTYPES,
                            ImmutableSet.of(MIX_REP_VERSIONABLE_PATHS),
                            Type.NAMES);
                }

                String versionablePath = nodeAfter.path;
                vhBuilder.setProperty(workspaceName, versionablePath, Type.PATH);
            }
            return true;
        }
    }

    private final class Node {

        private final String path;
        private final NodeBuilder builder;

        private Node(@NotNull NodeBuilder rootBuilder) {
            this.path = "/";
            this.builder = rootBuilder;
        }

        private Node(@NotNull Node parent, @NotNull String name) {
            this.builder = parent.builder.child(name);
            this.path = PathUtils.concat(parent.path, name);
        }

        private boolean isVersionable(@NotNull ReadOnlyNodeTypeManager ntMgr) {
            // this is not 100% correct, because t.getPath() will
            // not return the correct path for node after, but is
            // sufficient to check if it is versionable
            Tree tree = providerCtx.getTreeProvider().createReadOnlyTree(builder.getNodeState());
            return ntMgr.isNodeType(tree, VersionConstants.MIX_VERSIONABLE);
        }
    }
}
