/*
 * This file is part of vospace-rest
 * Copyright (C) 2021 Istituto Nazionale di Astrofisica
 * SPDX-License-Identifier: GPL-3.0-or-later
 */
package it.inaf.oats.vospace;

import it.inaf.ia2.aa.data.User;
import it.inaf.oats.vospace.datamodel.NodeProperties;
import it.inaf.oats.vospace.datamodel.NodeUtils;
import it.inaf.oats.vospace.exception.ContainerNotFoundException;
import it.inaf.oats.vospace.exception.DuplicateNodeException;
import it.inaf.oats.vospace.exception.InternalFaultException;
import it.inaf.oats.vospace.exception.NodeBusyException;
import it.inaf.oats.vospace.exception.NodeNotFoundException;
import it.inaf.oats.vospace.exception.PermissionDeniedException;
import it.inaf.oats.vospace.persistence.NodeDAO;
import java.util.List;
import java.util.Optional;
import javax.servlet.http.HttpServletRequest;
import net.ivoa.xml.vospace.v2.ContainerNode;
import net.ivoa.xml.vospace.v2.Node;
import net.ivoa.xml.vospace.v2.Transfer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.transaction.annotation.Transactional;

@Service
@EnableTransactionManagement
public class MoveService {

    @Autowired
    private NodeDAO nodeDao;

    @Value("${vospace-authority}")
    private String authority;

    @Autowired
    private CreateNodeController createNodeController;

    @Autowired
    private HttpServletRequest servletRequest;
    
    @Transactional(rollbackFor = { Exception.class })
    public void processMoveJob(Transfer transfer) {

        // Get Source Vos Path
        String sourcePath = transfer.getTarget().substring("vos://".length() + authority.length());

        // Get Destination Vos Path (it's in transfer direction)
        String destinationPath = transfer.getDirection().substring("vos://".length() + authority.length());

        // Extract User permissions from servlet request
        User user = (User) servletRequest.getUserPrincipal();

        // Generic common validation for move process job paths
        this.validatePath(sourcePath);
        this.validatePath(destinationPath);

        // Get source node (this locks it with SELECT ... FOR UPDATE)
        Optional<Long> sourceIdOpt = nodeDao.getNodeId(sourcePath);
        if (sourceIdOpt.isEmpty()) {
            throw new NodeNotFoundException(sourcePath);
        }
        Long sourceId = sourceIdOpt.get();

        // Get node branch with root == source. All nodes are locked
        // with SELECT ... FOR UPDATE
        List<Node> sourceBranchNodeList = nodeDao.listNodesInBranch(sourceId, true);

        // Check feasibility of move for source branch
        if (!isWritePermissionsValid(sourceBranchNodeList, user)) {
            throw new PermissionDeniedException(sourcePath);
        }

        if (sourcePath.equals(destinationPath)) {
            return;
        }

        if (!isMoveable(sourceBranchNodeList)) {
            throw new NodeBusyException(sourcePath);
        }

        // Set branch at busy        
        nodeDao.setBranchBusy(sourceId, true);

        // EDGE CASE: a node with the same destination path is created by another
        // process in the database between destination check and move.
        // This applies also to rename.
        // the move process would overwrite it or worse create two nodes with
        // different ids and same vos path
        // possible solution: check for busyness of parent node when creating
        // a new node? May it work and be compliant?
        
        // check if destination node exists before
        if (this.checkNodeExistence(destinationPath)) {
            throw new DuplicateNodeException(destinationPath);
        }

        // Compare source and destination paths parents and see if it's just a rename        
        if (NodeUtils.getParentPath(sourcePath)
                .equals(NodeUtils.getParentPath(destinationPath))) {

            nodeDao.renameNode(sourceId, NodeUtils.getLastPathElement(destinationPath));

        } else {
            
            Long destParentId;
            
            Optional<Long> optDest = nodeDao.getNodeId(NodeUtils.getParentPath(destinationPath));
            if (optDest.isEmpty()) {
                // Try to create parent container(s)
                destParentId = this.createDestination(NodeUtils.getParentPath(destinationPath), user);
            } else {
                Node parentNode = nodeDao.getNodeById(optDest.get(), true)
                        .orElseThrow(()->
                            new NodeNotFoundException(NodeUtils.getParentPath(destinationPath)));

                this.validateDestinationParentNode(parentNode, user);
                destParentId = optDest.get();
            }

            this.moveNode(sourceId, destParentId, NodeUtils.getLastPathElement(destinationPath));
        }

        nodeDao.setBranchBusy(sourceId, false);

    }

    // All nodes must be writable by the user to have a true
    private boolean isWritePermissionsValid(List<Node> list, User user) {
        String userName = user.getName();
        List<String> userGroups = user.getGroups();

        return list.stream().allMatch((n) -> {
            return NodeUtils.checkIfWritable(n, userName, userGroups);
        });

    }

    // All nodes must comply to have a true output            
    private boolean isMoveable(List<Node> list) {
        return list.stream().allMatch((n) -> {
            boolean busy = NodeUtils.getIsBusy(n);
            boolean sticky
                    = Boolean.valueOf(
                            NodeProperties.getNodePropertyByURI(n,
                                    NodeProperties.STICKY_URN));

            return (!busy && !sticky);
        });
    }

    private void moveNode(Long sourceId, Long destParentId, String newNodeName) {
        nodeDao.moveNodeBranch(sourceId, destParentId);
        nodeDao.renameNode(sourceId, newNodeName);
    }

    private void validatePath(String path) {        
        if (path.equals("/")) {            
            throw new IllegalArgumentException("Cannot move root node or to root node");
        }
    }

    private boolean checkNodeExistence(String path) {
        Optional<Long> optNodeId = nodeDao.getNodeId(path);
        return optNodeId.isPresent();
    }
    
    // Returns node id of created destination
    private Long createDestination(String path, User user) {
        List<String> components = NodeUtils.subPathComponents(path);

        for (int i = 0; i < components.size(); i++) {
            if (!this.checkNodeExistence(components.get(i))) {
                ContainerNode node = new ContainerNode();
                node.setUri("vos://" + this.authority + components.get(i));
                createNodeController.createNode(node, user);                
            }
        }
        
        return nodeDao.getNodeId(path).orElseThrow(()-> 
                new InternalFaultException("Unable to create destination at path: "+path));
            
    }

    private void validateDestinationParentNode(Node node, User user) {
        if (!(node instanceof ContainerNode)) {
            throw new ContainerNotFoundException(
                    NodeUtils.getVosPath(node));
        }

        if (!NodeUtils.checkIfWritable(node, user.getName(), user.getGroups())) {
            throw new PermissionDeniedException(NodeUtils.getVosPath(node));
        }
    }

}