/* 
 * _____________________________________________________________________________
 * 
 * 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 it.inaf.ia2.tsm.datalayer.DBBrokerFactory;
import it.inaf.ia2.tsm.datalayer.DBWrapper;
import it.inaf.ia2.tsm.xmlmodel.TableModel;
import it.inaf.ia2.tsm.xmlmodel.TapSchemaModel;
import it.inaf.ia2.tsm.xmlmodel.TapSchemaModels;
import java.io.Serializable;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

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

    // Mandatory tables constants
    public static final String TABLES_TABLE = "tables";
    public static final String SCHEMAS_TABLE = "schemas";
    public static final String COLUMNS_TABLE = "columns";
    public static final String KEYS_TABLE = "keys";
    public static final String KEY_COLUMNS_TABLE = "key_columns";

    private static final long serialVersionUID = 1678083091602571256L;

    private static final Logger LOG = LoggerFactory.getLogger(TapSchema.class);

    private final Map<String, Schema> schemas;
    private final List<KeyMetadata> keysMetadata;
    private final Set<Key> allKeys;
    private final ConsistencyChecks consistencyChecks;

    private boolean loading;
    private String version;
    private DBWrapper dbWrapper;
    private String tapSchemaName;
    private boolean exists;

    private transient DBBroker sourceDBBroker;
    private transient DBBroker tapSchemaDBBroker;

    public final DBBroker getSourceDBBroker() {
        if (sourceDBBroker == null) {
            sourceDBBroker = DBBrokerFactory.getDBBroker(dbWrapper.getSourceDataSourceWrapper());
        }
        return sourceDBBroker;
    }

    public final DBBroker getTapSchemaDBBroker() {
        if (tapSchemaDBBroker == null) {
            tapSchemaDBBroker = DBBrokerFactory.getDBBroker(dbWrapper.getTapSchemaDataSourceWrapper());
        }
        return tapSchemaDBBroker;
    }

    private TapSchema() {
        // for serialization
        schemas = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
        allKeys = new HashSet<>();
        keysMetadata = new ArrayList<>();
        consistencyChecks = new ConsistencyChecks();
    }

    public TapSchema(String version, DBWrapper dbWrapper, String tapSchemaName, boolean exists) throws SQLException {
        this();

        loading = true;
        this.version = version;
        this.dbWrapper = dbWrapper;
        this.tapSchemaName = tapSchemaName;
        this.exists = exists;

        // Initializing schemas map
        for (String schemaName : getSourceDBBroker().getAllSchemaNames()) {
            schemas.put(schemaName, null);
        }
        schemas.put(tapSchemaName, null); // the TAP_SCHEMA contains itself

//        if (exists) {
//            DaoSchema.fillSavedSchemas(dbWrapper, (this));
//            DaoTable.fillSavedTables(dbWrapper, (this));
//            DaoColumn.fillSavedColumns(dbWrapper, (this));
//            DaoKey.fillSavedKeys(dbWrapper, (this));
//        }
        loading = false;
        checkKeys();
    }

    public DBBroker getDBBroker(String schemaName) {
        if (schemaName.equals(tapSchemaName)) {
            return getTapSchemaDBBroker();
        } else {
            return getSourceDBBroker();
        }
    }

    /**
     * The name of the TAP_SCHEMA schema.
     */
    public String getName() {
        return tapSchemaName;
    }

    /**
     * The version selected for this TAP_SCHEMA.
     */
    public String getVersion() {
        return version;
    }

    private void loadSchemaKeysMetadata(String schemaName) throws SQLException {
        keysMetadata.addAll(getDBBroker(schemaName).getKeysMetadata(schemaName));
    }

    protected Set<Key> getAllKeys() {
        return allKeys;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public Schema addChild(String schemaName) throws SQLException {
        LOG.debug("Adding schema {}", schemaName);

        Schema schema;

        if (!schemas.containsKey(schemaName)) {

            consistencyChecks.addUnexistingSchema(schemaName);
            schema = null;
        } else {

            schema = schemas.get(schemaName);

            if (schema == null) {
                schema = new Schema(this, schemaName);
                schema.setStatus(Status.ADDED_NOT_PERSISTED);
                schemas.put(schemaName, schema);
                loadSchemaKeysMetadata(schemaName);
            } else {
                switch (schema.getStatus()) {
                    case TO_REMOVE:
                        schema.setStatus(Status.ADDED_PERSISTED);
                        break;
                    case REMOVED_NOT_PERSISTED:
                        schema.setStatus(Status.ADDED_NOT_PERSISTED);
                        break;
                    default:
                        throw new IllegalArgumentException("Cannot add the schema " + schemaName + ". Invalid status. Schema status is " + schema.getStatus());
                }
            }
        }

        checkKeys();

        return schema;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void removeChild(String schemaName) {
        LOG.debug("Removing schema {}", schemaName);

        if (!schemas.containsKey(schemaName)) {
            throw new IllegalArgumentException("The database doesn't contains a schema named " + schemaName);
        }

        Schema schema = schemas.get(schemaName);
        if (schema == null || schema.getStatus() == Status.LOADED) {
            throw new IllegalArgumentException("Cannot remove the schema " + schemaName + ". It has never been added.");
        }

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

        checkKeys();
    }

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

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

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

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

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

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

    /**
     * Save or update the TAP_SCHEMA changes into the database.
     */
    public void save() throws SQLException {

        fillKeyIds();

        DBBroker broker = getTapSchemaDBBroker();

        broker.save(this);

        if (!exists) {
            // Adding TAP_SCHEMA into TAP_SCHEMA
            Schema tapSchemaSchema = addChild(tapSchemaName);
            for (String tableName : tapSchemaSchema.getAddableChildrenNames()) {
                Table table = tapSchemaSchema.addChild(tableName);
                for (String columnName : table.getAddableChildrenNames()) {
                    table.addChild(columnName);
                }
            }
            LOG.debug(this.toString());
            TSMUtil.putInfoIntoTapSchemaSchema(tapSchemaSchema);

            exists = true; // important!

            //broker.save(this); // save again
        }

        exists = true;

        consistencyChecks.getInconsistencies().clear();
    }

    /**
     * Retrieve the maximum key id from all the schemas that are added into the
     * TAP_SCHEMA.
     *
     * @return the maximum key, if it exists, zero otherwise.
     */
    private int getMaxKeyId() {
        int maxKeyId = 0;
        for (Key key : allKeys) {
            if (key.getId() != null && !KeyMetadata.NEW_KEY.equals(key.getId())) {
                int keyId = Integer.parseInt(key.getId());
                if (keyId > maxKeyId) {
                    maxKeyId = keyId;
                }
            }
        }
        return maxKeyId;
    }

    private void fillKeyIds() {

        List<Key> newKeys = new ArrayList<>();
        for (Key key : allKeys) {
            if (key.isVisible() && KeyMetadata.NEW_KEY.equals(key.getId())) {
                newKeys.add(key);
            }
        }

        int maxKeyId = getMaxKeyId();
        for (Key newKey : newKeys) {
            maxKeyId++;
            newKey.setId(maxKeyId + "");
        }
    }

//    /**
//     * Set keys visibility based on other entities visibility (a key is visible
//     * if all schemas, tables and columns involved have
//     * {@link Status} {@code ADDED_PERSISTED} or {@code ADDED_NOT_PERSISTED}).
//     */
//    protected void checkKeys() {
//
//        int currentKey = getMaxKeyId() + 1;
//
//        for (Key key : allKeys) {
//
//            ((Key) key).setVisible(false);
//
//            Schema fromSchema = getChild(key.getFromSchemaName(), Status.ADDED_PERSISTED, Status.ADDED_NOT_PERSISTED);
//            Schema targetSchema = getChild(key.getTargetSchemaName(), Status.ADDED_PERSISTED, Status.ADDED_NOT_PERSISTED);
//            if (fromSchema != null && targetSchema != null) {
//
//                Table fromTable = fromSchema.getChild(key.getFromTableSimpleName(), Status.ADDED_PERSISTED, Status.ADDED_NOT_PERSISTED);
//                Table targetTable = targetSchema.getChild(key.getTargetTableSimpleName(), Status.ADDED_PERSISTED, Status.ADDED_NOT_PERSISTED);
//
//                if (fromTable != null && targetTable != null) {
//
//                    boolean allColumnsVisible = true;
//
//                    for (KeyColumn keyColumn : key.getKeyColumns()) {
//
//                        Column fromColumn = fromTable.getChild(keyColumn.getFromColumn(), Status.ADDED_PERSISTED, Status.ADDED_NOT_PERSISTED);
//                        Column targetColumn = targetTable.getChild(keyColumn.getTargetColumn(), Status.ADDED_PERSISTED, Status.ADDED_NOT_PERSISTED);
//
//                        if (fromColumn == null || targetColumn == null) {
//                            allColumnsVisible = false;
//                            break;
//                        }
//                    }
//
//                    if (allColumnsVisible) {
//                        ((Key) key).setVisible(true);
//                        if (key.getId() == null) {
//                            key.setId(currentKey + "");
//                            currentKey++;
//                        }
//                    }
//                }
//            }
//        }
//        for (Key key : allKeys) {
//            log.debug("{} [{}]", key, key.getStatus());
//        }
//    }
//
//    public void addFictitiousKey(Table fromTable, String[] fromColumns, Table targetTable, String[] targetColumns) {
//        Key key = new Key(dbWrapper, this, fromTable.getCompleteName(), targetTable.getCompleteName());
//        key.setId((getMaxKeyId() + 1) + "");
//
//        for (int i = 0; i < fromColumns.length; i++) {
//            key.addKeyColumn(fromColumns[i], targetColumns[i]);
//        }
//
//        fromTable.addFromKey(key);
//        targetTable.addTargetKey(key);
//
//        allKeys.add(key);
//        checkKeys();
//    }
    /**
     * Automatically add and remove keys that should be visible.
     */
    public final void checkKeys() {
        if (!loading) {

            for (KeyMetadata keyMetadata : keysMetadata) {

                // Check if key should be exposed in TAP_SCHEMA
                boolean keyVisible = true;

                for (String fromColumn : keyMetadata.getFromColumns()) {
                    if (!isColumnVisible(keyMetadata.getFromSchema(), keyMetadata.getFromTable(), fromColumn)) {
                        keyVisible = false;
                        break;
                    }
                }
                if (keyVisible) {
                    for (String targetColumn : keyMetadata.getTargetColumns()) {
                        if (!isColumnVisible(keyMetadata.getTargetSchema(), keyMetadata.getTargetTable(), targetColumn)) {
                            keyVisible = false;
                            break;
                        }
                    }
                }

                Key key = null;
                for (Key k : allKeys) {
                    if (k.getKeyMetadata().equals(keyMetadata)) {
                        key = k;
                        break;
                    }
                }

                // TODO: use status instead of set visibile [?]
                if (keyVisible) {
                    if (key == null) {
                        key = new Key(this, keyMetadata);
                        allKeys.add(key);
                    }
                    key.setVisible(true);
                } else if (key != null) {
                    key.setVisible(false);
                }
            }
        }
    }

    /**
     * Print all TAP_SCHEMA tree (useful for debugging).
     */
    @Override
    public String toString() {

        StringBuilder sb = new StringBuilder("\n");

        sb.append(String.format(">> TAP_SCHEMA %s <<\n", tapSchemaName));

//        for (Schema schema : getChildren()) {
//            sb.append("--");
//            sb.append(schema.getName());
//            sb.append(String.format(" [%s]", schema.getStatus()));
//            sb.append("\n");
//            List<Table> tables = schema.getChildren();
//            for (int i = 0; i < tables.size(); i++) {
//                Table table = tables.get(i);
//                sb.append("   |--");
//                sb.append(table.getName());
//                sb.append(String.format(" [%s]", table.getStatus()));
//                sb.append("\n");
//
//                String padder = i < tables.size() - 1 ? "   |   " : "       ";
//
//                for (Column column : table.getChildren()) {
//                    sb.append(padder);
//                    sb.append("|--");
//                    sb.append(column.getName());
//                    sb.append(String.format(" [%s]", column.getStatus()));
//                    sb.append("\n");
//                }
//
//                if (table.getAllFromKeys().size() > 0) {
//                    sb.append(padder);
//                    sb.append("** From keys **\n");
//                    for (Key fromKey : table.getAllFromKeys()) {
//                        sb.append(padder);
//                        sb.append("* ");
//                        sb.append(fromKey.toString());
//                        sb.append(String.format(" [visible=%s]", fromKey.isVisible()));
//                        sb.append("\n");
//                    }
//                }
//                if (table.getAllTargetKeys().size() > 0) {
//                    sb.append(padder);
//                    sb.append("** Target keys **\n");
//                    for (Key targetKey : table.getAllTargetKeys()) {
//                        sb.append(padder);
//                        sb.append("* ");
//                        sb.append(targetKey.toString());
//                        sb.append(String.format(" [visible=%s]", targetKey.isVisible()));
//                        sb.append("\n");
//                    }
//                }
//
//                sb.append("\n");
//            }
//        }
        return sb.toString();
    }

    public boolean isSchemaVisible(String schemaName) {
        Schema schema = schemas.get(schemaName);
        if (schema == null) {
            return false;
        }
        return schema.getStatus() == Status.ADDED_PERSISTED
                || schema.getStatus() == Status.ADDED_NOT_PERSISTED;
    }

    public boolean isTableVisible(String schemaName, String tableName) {
        if (!isSchemaVisible(schemaName)) {
            return false;
        }

        Table table = schemas.get(schemaName).getChild(tableName);
        if (table == null) {
            return false;
        }

        if (table.getStatus() == Status.ADDED_PERSISTED
                || table.getStatus() == Status.ADDED_NOT_PERSISTED) {
            return isSchemaVisible(schemaName);
        }

        return false;
    }

    public boolean isColumnVisible(String schemaName, String tableName, String columnName) {
        if (!isTableVisible(schemaName, tableName)) {
            return false;
        }

        Column column = schemas.get(schemaName).getChild(tableName).getChild(columnName);
        if (column == null) {
            return false;
        }

        if (column.getStatus() == Status.ADDED_PERSISTED
                || column.getStatus() == Status.ADDED_NOT_PERSISTED) {
            return isTableVisible(schemaName, tableName);
        }

        return false;
    }

    /**
     * Define if the TAP_SCHEMA schema was already written into the database.
     */
    public boolean exists() {
        return exists;
    }

    public ConsistencyChecks getConsistencyChecks() {
        return consistencyChecks;
    }

    public TapSchemaModel getTapSchemaModel() {
        return TapSchemaModels.getTapSchemaModel(version);
    }

    public TableModel getTableModel(String tableName) {
        return getTapSchemaModel().getTables().get(tableName);
    }

    public KeyMetadata searchKeyMetadata(String fromSchemaName, String fromTableName, String fromColumnName) {
        for (KeyMetadata km : keysMetadata) {
            if (km.getFromSchema().equals(fromSchemaName) && km.getFromTable().equals(fromTableName)
                    && km.getFromColumns().contains(fromColumnName)) {
                return km;
            }
        }
        return null;
    }

    public Map<String, Object> getSchemaMetadata(String schemaName) {
        Map<String, Object> metadata = new HashMap<>();
        metadata.put(Schema.SCHEMA_NAME_KEY, schemaName);
        return metadata;
    }

    public List<Key> getVisibileKeys() {
        List<Key> visibleKeys = new ArrayList<>();
        for (Key key : allKeys) {
            if (key.isVisible()) {
                visibleKeys.add(key);
            }
        }
        return visibleKeys;
    }
}