/* 
 * _____________________________________________________________________________
 * 
 * INAF - OATS National Institute for Astrophysics - Astronomical Observatory of
 * Trieste INAF - IA2 Italian Center for Astronomical Archives
 * _____________________________________________________________________________
 * 
 * Copyright (C) 2016 Istituto Nazionale di Astrofisica
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License Version 3 as published by the
 * Free Software Foundation.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */
package it.inaf.ia2.tsm;

import it.inaf.ia2.tsm.datalayer.DBBroker;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.TreeMap;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The main implementation of {@link Schema}.
 *
 * @author Sonia Zorba {@literal <zorba at oats.inaf.it>}
 */
public class Schema extends ChildEntity<TapSchema> implements EntitiesContainer<Table> {

    public final static String SCHEMA_NAME_KEY = "schema_name";
    public final static String DBNAME = "dbname";

    private static final long serialVersionUID = 8828583158332877855L;
    private static final Logger LOG = LoggerFactory.getLogger(Schema.class);

    private final Map<String, Table> tables;
    private Map<String, String> tablesTypes;

    private Schema() {
        // for serialization
        super();
        tables = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
    }

    public Schema(TapSchema tapSchema, String name) throws SQLException {
        super(tapSchema, tapSchema.getTableModel(TapSchema.SCHEMAS_TABLE), tapSchema.getSchemaMetadata(name));

        DBBroker broker = tapSchema.getDBBroker(name);

        tables = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
        tablesTypes = broker.getAllTableTypes(getRealSchemaName());

        for (String tableName : broker.getAllTablesNames(getRealSchemaName())) {
            tables.put(tableName, null);
        }
        LOG.debug("Schema {} contains {} tables", name, tables.size());

        setStatus(Status.LOADED);
    }

    public final String getRealSchemaName() {
        if (tapSchema.getDBName() != null && this.getName().equals(tapSchema.getName())) {
            return tapSchema.getDBName();
        }
        if (tapSchema.getIvoaSchemaDBName() != null && this.getName().equals(tapSchema.getIvoaSchemaName())) {
            return tapSchema.getIvoaSchemaDBName();
        }
        return getName();
    }

    /**
     * {@inheritDoc} The value in the {@code schema_name} column.
     */
    @Override
    public String getName() {
        return getValue(SCHEMA_NAME_KEY, String.class);
    }

    /**
     * @param tableSimpleName the name of the table, without the schema name.
     * @return
     */
    @Override
    public Table addChild(String tableSimpleName) throws SQLException {
        String schemaName = getName();

        LOG.debug("Adding table {} into schema {}", tableSimpleName, schemaName);

        if (!tables.containsKey(tableSimpleName)) {
            return null;
        } else {

            Table table = tables.get(tableSimpleName);

            if (table == null) {
                table = new Table(tapSchema, this, tableSimpleName);

                tapSchema.checkKeys();

                tables.put(tableSimpleName, table);
                table.setStatus(Status.ADDED_NOT_PERSISTED);
            } else {
                switch (table.getStatus()) {
                    case TO_REMOVE:
                        table.setStatus(Status.ADDED_PERSISTED);
                        break;
                    case REMOVED_NOT_PERSISTED:
                        table.setStatus(Status.ADDED_NOT_PERSISTED);
                        break;
                    default:
                        throw new IllegalArgumentException("Invalid table status. The status for " + table.getCompleteName() + " is " + table.getStatus());
                }
            }

            tapSchema.checkKeys();

            return table;
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void removeChild(String tableSimpleName) {
        String schemaName = getName();

        LOG.debug("Removing table {} from schema {}", tableSimpleName, schemaName);

        if (!tables.containsKey(tableSimpleName)) {
            throw new IllegalArgumentException("The table " + tableSimpleName + " doesn't exist into the schema " + schemaName + ". Are you sure you are using the simple table name?");
        }

        Table table = tables.get(tableSimpleName);

        if (table == null) {
            throw new IllegalArgumentException("The table " + tableSimpleName + " has never been loaded into the schema " + schemaName + ". Are you sure you are using the simple table name?");
        }

        if (table.getStatus() == Status.LOADED || table.getStatus() == Status.TO_REMOVE) {
            throw new IllegalArgumentException("Invalid table status. The status for " + table.getCompleteName() + " is " + table.getStatus());
        }

        if (table.getStatus() == Status.ADDED_NOT_PERSISTED) {
            table.setStatus(Status.REMOVED_NOT_PERSISTED);
        } else if (table.getStatus() == Status.ADDED_PERSISTED) {
            table.setStatus(Status.TO_REMOVE);
        }

        tapSchema.checkKeys();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public Table getChild(String childName, Status... statuses) {
        return TSMUtil.getChild(tables, childName, statuses);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public List<Table> getChildren(Status... statuses) {
        return TSMUtil.getChildrenByStatus(tables.values(), statuses);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public List<String> getAddableChildrenNames() {
        return TSMUtil.getAddableChildrenNames(tables);
    }

    @Override
    public boolean isAddable(String childName) {
        return tables.containsKey(childName);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public List<Table> getAddedChildren() {
        return getChildren(Status.ADDED_PERSISTED, Status.ADDED_NOT_PERSISTED);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public List<Table> getAddedOrRemovedChildren() {
        return getChildren(Status.ADDED_PERSISTED, Status.ADDED_NOT_PERSISTED, Status.TO_REMOVE, Status.REMOVED_NOT_PERSISTED);
    }

    @Override
    public int hashCode() {
        int hash = 5;
        hash = 53 * hash + Objects.hashCode(this.getName());
        return hash;
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        final Schema other = (Schema) obj;
        return Objects.equals(this.getName(), other.getName());
    }

    /**
     * This method has to be used after TAP_SCHEMA modifications are committed
     * to the database, in order to remove from the memory the tables with
     * status {@code Status.TO_REMOVE} or {@code Status.REMOVED_NOT_PERSISTED}.
     */
    public void cleanTable(String tableSimpleName) {
        if (!tables.containsKey(tableSimpleName)) {
            throw new IllegalArgumentException("Schema " + getName() + "doesn't contain the table " + tableSimpleName);
        }
        tables.put(tableSimpleName, null);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public TapSchema getParent() {
        return tapSchema;
    }

    public Map<String, Object> getTableMetadata(String tableSimpleName) {
        Map<String, Object> metadata = new HashMap<>();
        metadata.put(Table.SCHEMA_NAME_KEY, getName());
        metadata.put(Table.TABLE_NAME_KEY, getName() + "." + tableSimpleName);
        metadata.put(Table.TABLE_TYPE_KEY, tablesTypes.get(tableSimpleName));
        return metadata;
    }
}