/**
 * 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.oozie.util.db;

import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.collect.Sets;
import org.apache.directory.api.util.Strings;
import org.apache.oozie.util.XLog;

import javax.annotation.Nullable;
import javax.persistence.PersistenceException;
import java.sql.Array;
import java.sql.Blob;
import java.sql.CallableStatement;
import java.sql.Clob;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.NClob;
import java.sql.PreparedStatement;
import java.sql.SQLClientInfoException;
import java.sql.SQLException;
import java.sql.SQLWarning;
import java.sql.SQLXML;
import java.sql.Savepoint;
import java.sql.Statement;
import java.sql.Struct;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import java.util.concurrent.Executor;

public class FailingConnectionWrapper implements Connection {
    private static final XLog LOG = XLog.getLog(FailingConnectionWrapper.class);

    private final Connection delegate;
    private RuntimeExceptionInjector<PersistenceException> injector;
    private Predicate<String> predicate;

    public FailingConnectionWrapper(final Connection delegate, final int failurePercent,
                                    @Nullable final Predicate<String> predicate) {
        this.delegate = delegate;
        injector = new RuntimeExceptionInjector<>(PersistenceException.class, failurePercent);
        if (predicate == null) {
            this.predicate = new OozieDmlStatementPredicate();
        } else {
            this.predicate = predicate;
        }
    }

    @Override
    public Statement createStatement() throws SQLException {
        return delegate.createStatement();
    }

    @Override
    public PreparedStatement prepareStatement(final String sql) throws SQLException {
        return delegate.prepareStatement(sql);
    }

    @Override
    public CallableStatement prepareCall(final String sql) throws SQLException {
        return delegate.prepareCall(sql);
    }

    @Override
    public String nativeSQL(final String sql) throws SQLException {
        return delegate.nativeSQL(sql);
    }

    @Override
    public void setAutoCommit(final boolean autoCommit) throws SQLException {
        delegate.setAutoCommit(autoCommit);
    }

    @Override
    public boolean getAutoCommit() throws SQLException {
        return delegate.getAutoCommit();
    }

    @Override
    public void commit() throws SQLException {
        delegate.commit();
    }

    @Override
    public void rollback() throws SQLException {
        delegate.rollback();
    }

    @Override
    public void close() throws SQLException {
        delegate.close();
    }

    @Override
    public boolean isClosed() throws SQLException {
        return delegate.isClosed();
    }

    @Override
    public DatabaseMetaData getMetaData() throws SQLException {
        return delegate.getMetaData();
    }

    @Override
    public void setReadOnly(final boolean readOnly) throws SQLException {
        delegate.setReadOnly(readOnly);
    }

    @Override
    public boolean isReadOnly() throws SQLException {
        return delegate.isReadOnly();
    }

    @Override
    public void setCatalog(final String catalog) throws SQLException {
        delegate.setCatalog(catalog);
    }

    @Override
    public String getCatalog() throws SQLException {
        return delegate.getCatalog();
    }

    @Override
    public void setTransactionIsolation(final int level) throws SQLException {
        delegate.setTransactionIsolation(level);
    }

    @Override
    public int getTransactionIsolation() throws SQLException {
        return delegate.getTransactionIsolation();
    }

    @Override
    public SQLWarning getWarnings() throws SQLException {
        return delegate.getWarnings();
    }

    @Override
    public void clearWarnings() throws SQLException {
        delegate.clearWarnings();
    }

    @Override
    public Statement createStatement(final int resultSetType, final int resultSetConcurrency) throws SQLException {
        return delegate.createStatement(resultSetType, resultSetConcurrency);
    }

    @Override
    public PreparedStatement prepareStatement(final String sql, final int resultSetType, final int resultSetConcurrency)
            throws SQLException {
        if (predicate.apply(sql)) {
            LOG.trace("Injecting random failure. Preparing this statement might fail.");
            injector.inject(String.format("Deliberately failing to prepare statement. [sql=%s]", sql));
        }

        LOG.trace("Preparing statement. [sql={0}]", sql);
        return delegate.prepareStatement(sql, resultSetType, resultSetConcurrency);
    }

    @Override
    public CallableStatement prepareCall(final String sql, final int resultSetType, final int resultSetConcurrency)
            throws SQLException {
        return delegate.prepareCall(sql, resultSetType, resultSetConcurrency);
    }

    @Override
    public Map<String, Class<?>> getTypeMap() throws SQLException {
        return delegate.getTypeMap();
    }

    @Override
    public void setTypeMap(final Map<String, Class<?>> map) throws SQLException {
        delegate.setTypeMap(map);
    }

    @Override
    public void setHoldability(final int holdability) throws SQLException {
        delegate.setHoldability(holdability);
    }

    @Override
    public int getHoldability() throws SQLException {
        return delegate.getHoldability();
    }

    @Override
    public Savepoint setSavepoint() throws SQLException {
        return delegate.setSavepoint();
    }

    @Override
    public Savepoint setSavepoint(final String name) throws SQLException {
        return delegate.setSavepoint(name);
    }

    @Override
    public void rollback(final Savepoint savepoint) throws SQLException {
        delegate.rollback();
    }

    @Override
    public void releaseSavepoint(final Savepoint savepoint) throws SQLException {
        delegate.releaseSavepoint(savepoint);
    }

    @Override
    public Statement createStatement(final int resultSetType, final int resultSetConcurrency, final int resultSetHoldability)
            throws SQLException {
        return delegate.createStatement(resultSetType, resultSetConcurrency, resultSetHoldability);
    }

    @Override
    public PreparedStatement prepareStatement(final String sql, final int resultSetType, final int resultSetConcurrency,
                                              final int resultSetHoldability) throws SQLException {
        return delegate.prepareStatement(sql, resultSetType, resultSetConcurrency, resultSetHoldability);
    }

    @Override
    public CallableStatement prepareCall(final String sql, final int resultSetType, final int resultSetConcurrency,
                                         final int resultSetHoldability) throws SQLException {
        return delegate.prepareCall(sql, resultSetType, resultSetConcurrency, resultSetHoldability);
    }

    @Override
    public PreparedStatement prepareStatement(final String sql, final int autoGeneratedKeys) throws SQLException {
        return delegate.prepareStatement(sql, autoGeneratedKeys);
    }

    @Override
    public PreparedStatement prepareStatement(final String sql, final int[] columnIndexes) throws SQLException {
        return delegate.prepareStatement(sql, columnIndexes);
    }

    @Override
    public PreparedStatement prepareStatement(final String sql, final String[] columnNames) throws SQLException {
        return delegate.prepareStatement(sql, columnNames);
    }

    @Override
    public Clob createClob() throws SQLException {
        return delegate.createClob();
    }

    @Override
    public Blob createBlob() throws SQLException {
        return delegate.createBlob();
    }

    @Override
    public NClob createNClob() throws SQLException {
        return delegate.createNClob();
    }

    @Override
    public SQLXML createSQLXML() throws SQLException {
        return delegate.createSQLXML();
    }

    @Override
    public boolean isValid(final int timeout) throws SQLException {
        return delegate.isValid(timeout);
    }

    @Override
    public void setClientInfo(final String name, final String value) throws SQLClientInfoException {
        delegate.setClientInfo(name, value);
    }

    @Override
    public void setClientInfo(final Properties properties) throws SQLClientInfoException {
        delegate.setClientInfo(properties);
    }

    @Override
    public String getClientInfo(final String name) throws SQLException {
        return delegate.getClientInfo(name);
    }

    @Override
    public Properties getClientInfo() throws SQLException {
        return delegate.getClientInfo();
    }

    @Override
    public Array createArrayOf(final String typeName, final Object[] elements) throws SQLException {
        return delegate.createArrayOf(typeName, elements);
    }

    @Override
    public Struct createStruct(final String typeName, final Object[] attributes) throws SQLException {
        return delegate.createStruct(typeName, attributes);
    }

    @Override
    public void setSchema(final String schema) throws SQLException {
        delegate.setSchema(schema);
    }

    @Override
    public String getSchema() throws SQLException {
        return delegate.getSchema();
    }

    @Override
    public void abort(final Executor executor) throws SQLException {
        delegate.abort(executor);
    }

    @Override
    public void setNetworkTimeout(final Executor executor, final int milliseconds) throws SQLException {
        delegate.setNetworkTimeout(executor, milliseconds);
    }

    @Override
    public int getNetworkTimeout() throws SQLException {
        return delegate.getNetworkTimeout();
    }

    @Override
    public <T> T unwrap(final Class<T> iface) throws SQLException {
        return delegate.unwrap(iface);
    }

    @Override
    public boolean isWrapperFor(final Class<?> iface) throws SQLException {
        return delegate.isWrapperFor(iface);
    }

    static class OozieDmlStatementPredicate implements Predicate<String> {
        private static final Set<String> DML_PREFIXES = Sets.newHashSet(
                "SELECT ", "INSERT INTO ", "UPDATE ", "DELETE FROM ");
        private static final Set<String> OOZIE_TABLE_NAMES = Sets.newHashSet(
                "BUNDLE_ACTIONS", "BUNDLE_JOBS", "COORD_ACTIONS", "COORD_JOBS", "SLA_REGISTRATION", "SLA_SUMMARY",
                "WF_ACTIONS", "WF_JOBS");

        @Override
        public boolean apply(@Nullable String input) {
            Preconditions.checkArgument(Strings.isNotEmpty(input));

            boolean isDmlStatement = false;
            for (final String dmlPrefix : DML_PREFIXES) {
                if (input.toUpperCase().startsWith(dmlPrefix)) {
                    isDmlStatement = true;
                }
            }

            boolean isOozieTable = false;
            for (final String oozieTableName : OOZIE_TABLE_NAMES) {
                if (input.toUpperCase().contains(oozieTableName)) {
                    isOozieTable = true;
                }
            }

            return isDmlStatement && isOozieTable;
        }
    }
}