package it.inaf.oats.vospace.persistence;

import java.sql.Array;
import net.ivoa.xml.vospace.v2.Node;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Optional;
import java.util.function.Function;
import java.util.stream.Collectors;
import javax.sql.DataSource;
import net.ivoa.xml.vospace.v2.ContainerNode;
import net.ivoa.xml.vospace.v2.DataNode;
import net.ivoa.xml.vospace.v2.Property;
import net.ivoa.xml.vospace.v2.StructuredDataNode;
import net.ivoa.xml.vospace.v2.View;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

/**
 *
 * @author bertocco
 */
@Repository
public class NodeDAO {

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

    private final JdbcTemplate jdbcTemplate;

    @Autowired
    public NodeDAO(DataSource dataSource) {
        jdbcTemplate = new JdbcTemplate(dataSource);
    }

    public void createNode(Node myNode) {

        String nodeURI = myNode.getUri();
        String path = nodeURI.replaceAll("vos://[^/]+", "");
        String parentPath = getParentPath(path);

        String sql = "SELECT path, relative_path from "
                + "node n join node_vos_path p on n.node_id = p.node_id "
                + "where p.vos_path = ?";

        List<NodePaths> paths = jdbcTemplate.query(conn -> {
            PreparedStatement ps = conn.prepareStatement(sql);
            ps.setString(1, parentPath);
            return ps;
        }, (row, index) -> {
            return getPathsFromResultSet(row);
        });

        if (paths.isEmpty()) {
            throw new IllegalStateException("Unable to find parent node during node creation");
        }
        if (paths.size() > 1) {
            throw new IllegalStateException("Multiple ltree parent paths found for " + parentPath);
        }

        StringBuilder sb = new StringBuilder();
        sb.append("INSERT INTO node");
        sb.append(" (name, busy_state, owner_id, creator_id, group_read, group_write,");
        sb.append(" is_public, parent_path, parent_relative_path, type, accept_views, provide_views)");
        sb.append(" VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)");

        jdbcTemplate.update(conn -> {
            PreparedStatement ps = conn.prepareStatement(sb.toString());
            int i = 0;
            ps.setString(++i, getNodeName(myNode));
            ps.setBoolean(++i, getIsBusy(myNode));
            ps.setString(++i, getProperty(myNode, getPropertyURI("creator")));
            ps.setString(++i, getProperty(myNode, getPropertyURI("creator")));
            ps.setArray(++i, fromPropertyToArray(ps, getProperty(myNode, getPropertyURI("groupread"))));
            ps.setArray(++i, fromPropertyToArray(ps, getProperty(myNode, getPropertyURI("groupwrite"))));
            ps.setBoolean(++i, Boolean.valueOf(getProperty(myNode, getPropertyURI("publicread"))));
            ps.setObject(++i, paths.get(0).path, Types.OTHER);
            ps.setObject(++i, paths.get(0).relativePath, Types.OTHER);
            ps.setObject(++i, getDbNodeType(myNode), Types.OTHER);
            ps.setObject(++i, fromViewsToArray(ps, myNode, d -> d.getAccepts()), Types.OTHER);
            ps.setObject(++i, fromViewsToArray(ps, myNode, d -> d.getProvides()), Types.OTHER);
            return ps;
        });
    }

    public Optional<Node> listNode(String path) {

        String sql = "SELECT os.vos_path, n.node_id, type, async_trans, busy_state, creator_id, group_read, group_write,\n"
                + "is_public, content_length, created_on, last_modified, accept_views, provide_views\n"
                + "FROM node n\n"
                + "JOIN node_vos_path os ON n.node_id = os.node_id\n"
                + "WHERE n.path ~ (" + getFirstLevelChildrenSelector(path) + ")::lquery\n"
                + "OR os.vos_path = ? ORDER BY vos_path";

        List<Node> parentAndChildren = jdbcTemplate.query(conn -> {
            PreparedStatement ps = conn.prepareStatement(sql);
            ps.setString(1, path);
            ps.setString(2, path);
            return ps;
        }, (row, index) -> {
            return getNodeFromResultSet(row);
        });

        if (parentAndChildren.isEmpty()) {
            return Optional.empty();
        }

        // Query returns parent as first node
        Node node = parentAndChildren.get(0);

        // Fill children
        if (node instanceof ContainerNode && parentAndChildren.size() > 1) {
            ContainerNode parent = (ContainerNode) node;
            for (int i = 1; i < parentAndChildren.size(); i++) {
                parent.getNodes().add(parentAndChildren.get(i));
            }
        }

        return Optional.of(node);
    }

    private String getFirstLevelChildrenSelector(String path) {
        String select = "(SELECT path FROM node WHERE node_id = (SELECT node_id FROM node_vos_path WHERE vos_path = ?))::varchar || '";

        if (!"/".equals(path)) {
            select += ".";
        }
        select += "*{1}'";
        return select;
    }

    private Node getNodeFromResultSet(ResultSet rs) throws SQLException {

        Node node = getTypedNode(rs.getString("type"));

        if (node instanceof DataNode) {

            DataNode dataNode = (DataNode) node;

            dataNode.setBusy(rs.getBoolean("busy_state"));
            dataNode.setAccepts(getViews(rs.getArray("accept_views")));
            dataNode.setProvides(getViews(rs.getArray("provide_views")));
        }

        node.setUri(getUri(rs.getString("vos_path")));

        List<Property> properties = new ArrayList<>();

        addProperty(getPropertyURI("length"), rs.getString("content_length"),
                properties);

        addProperty(getPropertyURI("btime"), rs.getString("created_on"),
                properties);

        addProperty(getPropertyURI("creator"), rs.getString("creator_id"),
                properties);

        addProperty(getPropertyURI("mtime"), rs.getString("last_modified"),
                properties);

        addProperty(getPropertyURI("groupread"), getGroupsString(rs, "group_read"),
                properties);

        addProperty(getPropertyURI("groupwrite"), getGroupsString(rs, "group_write"),
                properties);

        addProperty(getPropertyURI("publicread"), rs.getString("is_public"),
                properties);

        addProperty("urn:async_trans", rs.getString("async_trans"),
                properties);

        node.setProperties(properties);
        return node;
    }

    private String getPropertyURI(String propertyName) {
        return "ivo://ivoa.net/vospace/core#".concat(propertyName);
    }

    private String getGroupsString(ResultSet rs, String column) throws SQLException {
        Array array = rs.getArray(column);
        if (array == null) {
            return null;
        }
        return String.join(" ", (String[]) array.getArray());
    }

    // If value is null does nothing
    private void addProperty(String uri, String value, List<Property> list) {
        if (value != null) {
            Property prop = new Property();
            prop.setUri(uri);
            prop.setValue(value);
            list.add(prop);
        }
    }

    private Node getTypedNode(String type) {
        Node node;
        switch (type) {
            case "container":
                node = new ContainerNode();
                break;
            case "data":
                node = new DataNode();
                break;
            case "structured":
                node = new StructuredDataNode();
                break;
            default:
                throw new UnsupportedOperationException("Node type " + type + " not supported yet");
        }
        return node;
    }

    private String getUri(String path) {
        return "vos://" + authority + path;
    }

    private NodePaths getPathsFromResultSet(ResultSet rs) throws SQLException {
        NodePaths paths = new NodePaths(rs.getString("path"), rs.getString("relative_path"));
        return paths;
    }

    private String getNodeName(String path) {
        String[] parsedPath = path.split("/");

        return parsedPath[parsedPath.length - 1];
    }

    private String getNodeName(Node myNode) {
        String uri = myNode.getUri();
        return getNodeName(uri);
    }

    private boolean getIsBusy(Node myNode) {

        if (myNode instanceof DataNode) {

            DataNode dataNode = (DataNode) myNode;
            return dataNode.isBusy();
        }

        return false;
    }

    // Copied from CreateNodeController: to be moved in a common utility class
    private String getParentPath(String path) {
        String[] parsedPath = path.split("[/]+");

        if (parsedPath.length < 2 || !parsedPath[0].isEmpty()) {
            throw new IllegalArgumentException();
        }

        StringBuilder sb = new StringBuilder();
        sb.append("/");

        for (int i = 1; i < parsedPath.length - 1; i++) {
            sb.append(parsedPath[i]);
            if (i < parsedPath.length - 2) {
                sb.append("/");
            }
        }

        return sb.toString();
    }

    private String getProperty(Node node, String uri) {
        for (Property property : node.getProperties()) {
            if (uri.equals(property.getUri())) {
                return property.getValue();
            }
        }
        return null;
    }

    private Array fromPropertyToArray(PreparedStatement ps, String myProperty) throws SQLException {
        if (myProperty == null || myProperty.isBlank()) {
            return null;
        } else {
            return ps.getConnection().createArrayOf("varchar", myProperty.split(" "));
        }
    }

    private Array fromViewsToArray(PreparedStatement ps, Node node, Function<DataNode, List<View>> viewsExtractor) throws SQLException {
        if (node instanceof DataNode) {
            DataNode dataNode = (DataNode) node;
            List<View> views = viewsExtractor.apply(dataNode);
            if (views != null && !views.isEmpty()) {
                Object[] array = views.stream().map(v -> v.getUri()).toArray();
                return ps.getConnection().createArrayOf("varchar", array);
            }
        }
        return null;
    }

    private List<View> getViews(Array array) throws SQLException {
        if (array == null) {
            return null;
        }
        return Arrays.stream((String[]) array.getArray())
                .map(uri -> {
                    View view = new View();
                    view.setUri(uri);
                    return view;
                })
                .collect(Collectors.toList());
    }

    private String getDbNodeType(Node node) {
        if (node instanceof ContainerNode) {
            return "container";
        } else if (node instanceof DataNode) {
            return "data";
        }
        throw new UnsupportedOperationException("Unable to retrieve database node type for class " + node.getClass().getCanonicalName());
    }

    private class NodePaths {

        private final String path;
        private final String relativePath;

        public NodePaths(String myPath, String myRelativePath) {

            this.path = myPath;
            this.relativePath = myRelativePath;
        }

        @Override
        public String toString() {
            return relativePath + " " + path;
        }
    }
}