/***************************************************************************
 * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
 *
 * This program is free software: you can use, redistribute, and/or modify
 * it under the terms of the GNU Affero General Public License, version 3
 * or later ("AGPL"), 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.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 *****************************************************************************/
package com.taosdata.jdbc;

import java.io.InputStream;
import java.io.Reader;
import java.math.BigDecimal;
import java.net.URL;
import java.sql.*;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/*
 * TDengine only supports a subset of the standard SQL, thus this implemetation of the
 * standard JDBC API contains more or less some adjustments customized for certain
 * compatibility needs.
 */
public class TSDBPreparedStatement extends TSDBStatement implements PreparedStatement {
    protected String rawSql;
    protected String sql;
    protected ArrayList<Object> parameters = new ArrayList<Object>();

    //start with insert or import and is case-insensitive
    private static Pattern savePattern = Pattern.compile("(?i)^\\s*(insert|import)");

    // is insert or import
    private boolean isSaved;

    private SavedPreparedStatement savedPreparedStatement;

    TSDBPreparedStatement(TSDBJNIConnector connecter, String sql) {
        super(connecter);
        init(sql);
    }

    private void init(String sql) {
        this.rawSql = sql;
        preprocessSql();

        this.isSaved = isSavedSql(this.rawSql);
        if (this.isSaved) {

            try {
                this.savedPreparedStatement = new SavedPreparedStatement(this.rawSql, this);
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * if the precompiled sql is insert or import
     *
     * @param sql
     * @return
     */
    private boolean isSavedSql(String sql) {
        Matcher matcher = savePattern.matcher(sql);
        return matcher.find();
    }

    @Override
    public int[] executeBatch() throws SQLException {
        if (isSaved) {
            return this.savedPreparedStatement.executeBatch();
        } else {
            return super.executeBatch();
        }
    }

    public ArrayList<Object> getParameters() {
        return parameters;
    }

    public void setParameters(ArrayList<Object> parameters) {
        this.parameters = parameters;
    }

    public String getRawSql() {
        return rawSql;
    }

    /*
     * Some of the SQLs sent by other popular frameworks or tools like Spark, contains syntax that cannot be parsed by
     * the TDengine client. Thus, some simple parsers/filters are intentionally added in this JDBC implementation in
     * order to process those supported SQLs.
     */
    private void preprocessSql() {

        /***** For processing some of Spark SQLs*****/
        // should replace it first
        this.rawSql = this.rawSql.replaceAll("or (.*) is null", "");
        this.rawSql = this.rawSql.replaceAll(" where ", " WHERE ");
        this.rawSql = this.rawSql.replaceAll(" or ", " OR ");
        this.rawSql = this.rawSql.replaceAll(" and ", " AND ");
        this.rawSql = this.rawSql.replaceAll(" is null", " IS NULL");
        this.rawSql = this.rawSql.replaceAll(" is not null", " IS NOT NULL");

        // SELECT * FROM db.tb WHERE 1=0
        this.rawSql = this.rawSql.replaceAll("WHERE 1=0", "WHERE _c0=1");
        this.rawSql = this.rawSql.replaceAll("WHERE 1=2", "WHERE _c0=1");

        // SELECT "ts","val" FROM db.tb
        this.rawSql = this.rawSql.replaceAll("\"", "");

        // SELECT 1 FROM db.tb
        this.rawSql = this.rawSql.replaceAll("SELECT 1 FROM", "SELECT * FROM");

        // SELECT "ts","val" FROM db.tb WHERE ts < 33 or ts is null
        this.rawSql = this.rawSql.replaceAll("OR (.*) IS NULL", "");

        // SELECT "ts","val" FROM db.tb WHERE ts is null or ts < 33
        this.rawSql = this.rawSql.replaceAll("(.*) IS NULL OR", "");

        // SELECT 1 FROM db.tb WHERE (("val" IS NOT NULL) AND ("val" > 50)) AND (ts >= 66)
        this.rawSql = this.rawSql.replaceAll("\\(\\((.*) IS NOT NULL\\) AND", "(");

        // SELECT 1 FROM db.tb WHERE ("val" IS NOT NULL) AND ("val" > 50) AND (ts >= 66)
        this.rawSql = this.rawSql.replaceAll("\\((.*) IS NOT NULL\\) AND", "");

        // SELECT "ts","val" FROM db.tb WHERE (("val" IS NOT NULL)) AND (ts < 33 or ts is null)
        this.rawSql = this.rawSql.replaceAll("\\(\\((.*) IS NOT NULL\\)\\) AND", "");

        /***** For processing inner subqueries *****/
        Pattern pattern = Pattern.compile("FROM\\s+((\\(.+\\))\\s+SUB_QRY)", Pattern.CASE_INSENSITIVE);
        Matcher matcher = pattern.matcher(rawSql);
        String tableFullName = "";
        if (matcher.find() && matcher.groupCount() == 2) {
            String subQry = matcher.group(2);
            Pattern pattern1 = Pattern.compile("FROM\\s+(\\w+\\.\\w+)", Pattern.CASE_INSENSITIVE);
            Matcher matcher1 = pattern1.matcher(subQry);
            if (matcher1.find() && matcher1.groupCount() == 1) {
                tableFullName = matcher1.group(1);
            }
            rawSql = rawSql.replace(matcher.group(1), tableFullName);
        }
        /***** for inner queries *****/

    }

    /**
     * Populate parameters into prepared sql statements
     *
     * @return a string of the native sql statement for TSDB
     */
    private String getNativeSql() {
        this.sql = this.rawSql;
        for (int i = 0; i < parameters.size(); ++i) {
            Object para = parameters.get(i);
            if (para != null) {
                String paraStr = para.toString();
                if (para instanceof Timestamp || para instanceof String) {
                    paraStr = "'" + paraStr + "'";
                }
                this.sql = this.sql.replaceFirst("[?]", paraStr);
            } else {
                this.sql = this.sql.replaceFirst("[?]", "NULL");
            }
        }
        parameters.clear();
        return sql;
    }

    @Override
    public ResultSet executeQuery() throws SQLException {
        if (isSaved) {
            this.savedPreparedStatement.executeBatchInternal();
            return null;
        } else {
            return super.executeQuery(getNativeSql());
        }
    }

    @Override
    public int executeUpdate() throws SQLException {
        if (isSaved) {
            return this.savedPreparedStatement.executeBatchInternal();
        } else {
            return super.executeUpdate(getNativeSql());
        }
    }

    @Override
    public void setNull(int parameterIndex, int sqlType) throws SQLException {
        setObject(parameterIndex, new String("NULL"));
    }

    @Override
    public void setBoolean(int parameterIndex, boolean x) throws SQLException {
        setObject(parameterIndex, x);
    }

    @Override
    public void setByte(int parameterIndex, byte x) throws SQLException {
        setObject(parameterIndex, x);
    }

    @Override
    public void setShort(int parameterIndex, short x) throws SQLException {
        setObject(parameterIndex, x);
    }

    @Override
    public void setInt(int parameterIndex, int x) throws SQLException {
        setObject(parameterIndex, x);
    }

    @Override
    public void setLong(int parameterIndex, long x) throws SQLException {
        setObject(parameterIndex, x);
    }

    @Override
    public void setFloat(int parameterIndex, float x) throws SQLException {
        setObject(parameterIndex, x);
    }

    @Override
    public void setDouble(int parameterIndex, double x) throws SQLException {
        setObject(parameterIndex, x);
    }

    @Override
    public void setBigDecimal(int parameterIndex, BigDecimal x) throws SQLException {
        setObject(parameterIndex, x);
    }

    @Override
    public void setString(int parameterIndex, String x) throws SQLException {
        setObject(parameterIndex, x);
    }

    @Override
    public void setBytes(int parameterIndex, byte[] x) throws SQLException {
        setObject(parameterIndex, x);
    }

    @Override
    public void setDate(int parameterIndex, Date x) throws SQLException {
        setObject(parameterIndex, x);
    }

    @Override
    public void setTime(int parameterIndex, Time x) throws SQLException {
        setObject(parameterIndex, x);
    }

    @Override
    public void setTimestamp(int parameterIndex, Timestamp x) throws SQLException {
        setObject(parameterIndex, x);
    }

    @Override
    public void setAsciiStream(int parameterIndex, InputStream x, int length) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setUnicodeStream(int parameterIndex, InputStream x, int length) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setBinaryStream(int parameterIndex, InputStream x, int length) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void clearParameters() throws SQLException {
        parameters.clear();
    }

    @Override
    public void setObject(int parameterIndex, Object x, int targetSqlType) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setObject(int parameterIndex, Object x) throws SQLException {
        if (isSaved) {
            this.savedPreparedStatement.setParam(parameterIndex, x);
        } else {
            parameters.add(x);
        }
    }

    @Override
    public boolean execute() throws SQLException {
        if (isSaved) {
            int result = this.savedPreparedStatement.executeBatchInternal();
            return result > 0;
        } else {
            return super.execute(getNativeSql());
        }
    }

    @Override
    public void addBatch() throws SQLException {
        if (isSaved) {
            this.savedPreparedStatement.addBatch();
        } else {

            if (this.batchedArgs == null) {
                batchedArgs = new ArrayList<String>();
            }
            super.addBatch(getNativeSql());
        }
    }

    @Override
    public void setCharacterStream(int parameterIndex, Reader reader, int length) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setRef(int parameterIndex, Ref x) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setBlob(int parameterIndex, Blob x) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setClob(int parameterIndex, Clob x) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setArray(int parameterIndex, Array x) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public ResultSetMetaData getMetaData() throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setDate(int parameterIndex, Date x, Calendar cal) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setTime(int parameterIndex, Time x, Calendar cal) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setTimestamp(int parameterIndex, Timestamp x, Calendar cal) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setNull(int parameterIndex, int sqlType, String typeName) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setURL(int parameterIndex, URL x) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public ParameterMetaData getParameterMetaData() throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setRowId(int parameterIndex, RowId x) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setNString(int parameterIndex, String value) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setNCharacterStream(int parameterIndex, Reader value, long length) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setNClob(int parameterIndex, NClob value) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setClob(int parameterIndex, Reader reader, long length) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setBlob(int parameterIndex, InputStream inputStream, long length) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setNClob(int parameterIndex, Reader reader, long length) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setSQLXML(int parameterIndex, SQLXML xmlObject) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setObject(int parameterIndex, Object x, int targetSqlType, int scaleOrLength) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setAsciiStream(int parameterIndex, InputStream x, long length) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setBinaryStream(int parameterIndex, InputStream x, long length) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setCharacterStream(int parameterIndex, Reader reader, long length) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setAsciiStream(int parameterIndex, InputStream x) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setBinaryStream(int parameterIndex, InputStream x) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setCharacterStream(int parameterIndex, Reader reader) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setNCharacterStream(int parameterIndex, Reader value) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setClob(int parameterIndex, Reader reader) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setBlob(int parameterIndex, InputStream inputStream) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }

    @Override
    public void setNClob(int parameterIndex, Reader reader) throws SQLException {
        throw new SQLException(TSDBConstants.UNSUPPORT_METHOD_EXCEPTIONZ_MSG);
    }
}
