/*
 * Copyright 2004-2008 H2 Group. Licensed under the H2 License, Version 1.0
 * (http://h2database.com/html/license.html).
 * Initial Developer: H2 Group
 */
package org.h2.expression;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.sql.Connection;
import java.sql.Date;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Time;
import java.sql.Timestamp;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.HashMap;
import java.util.Locale;
import java.util.TimeZone;
import java.util.regex.PatternSyntaxException;

import org.h2.command.Command;
import org.h2.constant.ErrorCode;
import org.h2.engine.Database;
import org.h2.engine.Mode;
import org.h2.engine.Session;
import org.h2.message.Message;
import org.h2.schema.Sequence;
import org.h2.security.BlockCipher;
import org.h2.security.CipherFactory;
import org.h2.security.SHA256;
import org.h2.table.Column;
import org.h2.table.ColumnResolver;
import org.h2.table.LinkSchema;
import org.h2.table.TableFilter;
import org.h2.tools.CompressTool;
import org.h2.tools.Csv;
import org.h2.util.AutoCloseInputStream;
import org.h2.util.FileUtils;
import org.h2.util.MathUtils;
import org.h2.util.MemoryUtils;
import org.h2.util.ObjectArray;
import org.h2.util.ObjectUtils;
import org.h2.util.RandomUtils;
import org.h2.util.StringUtils;
import org.h2.value.Value;
import org.h2.value.ValueArray;
import org.h2.value.ValueBoolean;
import org.h2.value.ValueBytes;
import org.h2.value.ValueDate;
import org.h2.value.ValueDouble;
import org.h2.value.ValueInt;
import org.h2.value.ValueLob;
import org.h2.value.ValueLong;
import org.h2.value.ValueNull;
import org.h2.value.ValueResultSet;
import org.h2.value.ValueString;
import org.h2.value.ValueTime;
import org.h2.value.ValueTimestamp;
import org.h2.value.ValueUuid;

/**
 * This class implements most built-in functions of this database.
 */
public class Function extends Expression implements FunctionCall {
    // TODO functions: add function hashcode(value)

    public static final int ABS = 0, ACOS = 1, ASIN = 2, ATAN = 3, ATAN2 = 4, BITAND = 5, BITOR = 6, BITXOR = 7,
            CEILING = 8, COS = 9, COT = 10, DEGREES = 11, EXP = 12, FLOOR = 13, LOG = 14, LOG10 = 15, MOD = 16,
            PI = 17, POWER = 18, RADIANS = 19, RAND = 20, ROUND = 21, ROUNDMAGIC = 22, SIGN = 23, SIN = 24, SQRT = 25,
            TAN = 26, TRUNCATE = 27, SECURE_RAND = 28, HASH = 29, ENCRYPT = 30, DECRYPT = 31, COMPRESS = 32,
            EXPAND = 33, ZERO = 34, RANDOM_UUID = 35;

    public static final int ASCII = 50, BIT_LENGTH = 51, CHAR = 52, CHAR_LENGTH = 53, CONCAT = 54, DIFFERENCE = 55,
            HEXTORAW = 56, INSERT = 57, INSTR = 58, LCASE = 59, LEFT = 60, LENGTH = 61, LOCATE = 62, LTRIM = 63,
            OCTET_LENGTH = 64, RAWTOHEX = 65, REPEAT = 66, REPLACE = 67, RIGHT = 68, RTRIM = 69, SOUNDEX = 70,
            SPACE = 71, SUBSTR = 72, SUBSTRING = 73, UCASE = 74, LOWER = 75, UPPER = 76, POSITION = 77, TRIM = 78,
            STRINGENCODE = 79, STRINGDECODE = 80, STRINGTOUTF8 = 81, UTF8TOSTRING = 82, XMLATTR = 83, XMLNODE = 84,
            XMLCOMMENT = 85, XMLCDATA = 86, XMLSTARTDOC = 87, XMLTEXT = 88, REGEXP_REPLACE = 89, RPAD = 90, LPAD = 91;

    public static final int CURDATE = 100, CURTIME = 101, DATEADD = 102, DATEDIFF = 103, DAYNAME = 104,
            DAYOFMONTH = 105, DAYOFWEEK = 106, DAYOFYEAR = 107, HOUR = 108, MINUTE = 109, MONTH = 110, MONTHNAME = 111,
            NOW = 112, QUARTER = 113, SECOND = 114, WEEK = 115, YEAR = 116, CURRENT_DATE = 117, CURRENT_TIME = 118,
            CURRENT_TIMESTAMP = 119, EXTRACT = 120, FORMATDATETIME = 121, PARSEDATETIME = 122;

    public static final int DATABASE = 150, USER = 151, CURRENT_USER = 152, IDENTITY = 153, AUTOCOMMIT = 154,
            READONLY = 155, DATABASE_PATH = 156, LOCK_TIMEOUT = 157;

    public static final int IFNULL = 200, CASEWHEN = 201, CONVERT = 202, CAST = 203, COALESCE = 204, NULLIF = 205,
            CASE = 206, NEXTVAL = 207, CURRVAL = 208, ARRAY_GET = 209, CSVREAD = 210, CSVWRITE = 211,
            MEMORY_FREE = 212, MEMORY_USED = 213, LOCK_MODE = 214, SCHEMA = 215, SESSION_ID = 216, ARRAY_LENGTH = 217,
            LINK_SCHEMA = 218, GREATEST = 219, LEAST = 220, CANCEL_SESSION = 221, SET = 222, TABLE = 223, TABLE_DISTINCT = 224,
            FILE_READ = 225;

    private static final int VAR_ARGS = -1;

    private static final HashMap FUNCTIONS = new HashMap();
    private static final HashMap DATE_PART = new HashMap();
    private static final SimpleDateFormat FORMAT_DAYNAME = new SimpleDateFormat("EEEE", Locale.ENGLISH);
    private static final SimpleDateFormat FORMAT_MONTHNAME = new SimpleDateFormat("MMMM", Locale.ENGLISH);
    private static final char[] SOUNDEX_INDEX = new char[128];

    private FunctionInfo info;
    protected Expression[] args;
    private ObjectArray varArgs;
    private int dataType, scale;
    private long precision;
    private int displaySize;
    private Database database;

    static {
        // DATE_PART
        DATE_PART.put("YY", ObjectUtils.getInteger(Calendar.YEAR));
        DATE_PART.put("YEAR", ObjectUtils.getInteger(Calendar.YEAR));
        DATE_PART.put("MM", ObjectUtils.getInteger(Calendar.MONTH));
        DATE_PART.put("MONTH", ObjectUtils.getInteger(Calendar.MONTH));
        DATE_PART.put("DD", ObjectUtils.getInteger(Calendar.DATE));
        DATE_PART.put("DAY", ObjectUtils.getInteger(Calendar.DATE));
        DATE_PART.put("HH", ObjectUtils.getInteger(Calendar.HOUR_OF_DAY));
        DATE_PART.put("HOUR", ObjectUtils.getInteger(Calendar.HOUR_OF_DAY));
        DATE_PART.put("MI", ObjectUtils.getInteger(Calendar.MINUTE));
        DATE_PART.put("MINUTE", ObjectUtils.getInteger(Calendar.MINUTE));
        DATE_PART.put("SS", ObjectUtils.getInteger(Calendar.SECOND));
        DATE_PART.put("SECOND", ObjectUtils.getInteger(Calendar.SECOND));
        DATE_PART.put("MS", ObjectUtils.getInteger(Calendar.MILLISECOND));
        DATE_PART.put("MILLISECOND", ObjectUtils.getInteger(Calendar.MILLISECOND));

        // SOUNDEX_INDEX
        String index = "7AEIOUY8HW1BFPV2CGJKQSXZ3DT4L5MN6R";
        char number = 0;
        for (int i = 0; i < index.length(); i++) {
            char c = index.charAt(i);
            if (c < '9') {
                number = c;
            } else {
                SOUNDEX_INDEX[c] = number;
                SOUNDEX_INDEX[Character.toLowerCase(c)] = number;
            }
        }

        // FUNCTIONS
        addFunction("ABS", ABS, 1, Value.NULL);
        addFunction("ACOS", ACOS, 1, Value.DOUBLE);
        addFunction("ASIN", ASIN, 1, Value.DOUBLE);
        addFunction("ATAN", ATAN, 1, Value.DOUBLE);
        addFunction("ATAN2", ATAN2, 2, Value.DOUBLE);
        addFunction("BITAND", BITAND, 2, Value.INT);
        addFunction("BITOR", BITOR, 2, Value.INT);
        addFunction("BITXOR", BITXOR, 2, Value.INT);
        addFunction("CEILING", CEILING, 1, Value.DOUBLE);
        addFunction("COS", COS, 1, Value.DOUBLE);
        addFunction("COT", COT, 1, Value.DOUBLE);
        addFunction("DEGREES", DEGREES, 1, Value.DOUBLE);
        addFunction("EXP", EXP, 1, Value.DOUBLE);
        addFunction("FLOOR", FLOOR, 1, Value.DOUBLE);
        addFunction("LOG", LOG, 1, Value.DOUBLE);
        addFunction("LOG10", LOG10, 1, Value.DOUBLE);
        addFunction("MOD", MOD, 2, Value.INT);
        addFunction("PI", PI, 0, Value.DOUBLE);
        addFunction("POWER", POWER, 2, Value.DOUBLE);
        addFunction("RADIANS", RADIANS, 1, Value.DOUBLE);
        // RAND without argument: get the next value
        // RAND with one argument: seed the random generator
        addFunctionNotConst("RAND", RAND, VAR_ARGS, Value.DOUBLE);
        addFunction("ROUND", ROUND, 2, Value.DOUBLE);
        addFunction("ROUNDMAGIC", ROUNDMAGIC, 1, Value.DOUBLE);
        addFunction("SIGN", SIGN, 1, Value.INT);
        addFunction("SIN", SIN, 1, Value.DOUBLE);
        addFunction("SQRT", SQRT, 1, Value.DOUBLE);
        addFunction("TAN", TAN, 1, Value.DOUBLE);
        addFunction("TRUNCATE", TRUNCATE, 2, Value.DOUBLE);
        addFunction("HASH", HASH, 3, Value.BYTES);
        addFunction("ENCRYPT", ENCRYPT, 3, Value.BYTES);
        addFunction("DECRYPT", DECRYPT, 3, Value.BYTES);
        addFunctionNotConst("SECURE_RAND", SECURE_RAND, 1, Value.BYTES);
        addFunction("COMPRESS", COMPRESS, VAR_ARGS, Value.BYTES);
        addFunction("EXPAND", EXPAND, 1, Value.BYTES);
        addFunction("ZERO", ZERO, 0, Value.INT);
        addFunctionNotConst("RANDOM_UUID", RANDOM_UUID, 0, Value.UUID);
        addFunctionNotConst("SYS_GUID", RANDOM_UUID, 0, Value.UUID);
        // string
        addFunction("ASCII", ASCII, 1, Value.INT);
        addFunction("BIT_LENGTH", BIT_LENGTH, 1, Value.INT);
        addFunction("CHAR", CHAR, 1, Value.STRING);
        addFunction("CHR", CHAR, 1, Value.STRING);
        addFunction("CHAR_LENGTH", CHAR_LENGTH, 1, Value.INT);
        addFunction("CHARACTER_LENGTH", CHAR_LENGTH, 1, Value.INT); // same as
                                                                    // CHAR_LENGTH
        addFunctionWithNull("CONCAT", CONCAT, VAR_ARGS, Value.STRING);
        addFunction("DIFFERENCE", DIFFERENCE, 2, Value.INT);
        addFunction("HEXTORAW", HEXTORAW, 1, Value.STRING);
        addFunctionWithNull("INSERT", INSERT, 4, Value.STRING);
        addFunction("LCASE", LCASE, 1, Value.STRING);
        addFunction("LEFT", LEFT, 2, Value.STRING);
        addFunction("LENGTH", LENGTH, 1, Value.INT);
        addFunction("LOCATE", LOCATE, VAR_ARGS, Value.INT); // 2 or 3 arguments
        addFunction("POSITION", LOCATE, 2, Value.INT); // same as LOCATE with 2
                                                        // arguments
        addFunction("INSTR", INSTR, VAR_ARGS, Value.INT);
        addFunction("LTRIM", LTRIM, VAR_ARGS, Value.STRING);
        addFunction("OCTET_LENGTH", OCTET_LENGTH, 1, Value.INT);
        addFunction("RAWTOHEX", RAWTOHEX, 1, Value.STRING);
        addFunction("REPEAT", REPEAT, 2, Value.STRING);
        addFunctionWithNull("REPLACE", REPLACE, VAR_ARGS, Value.STRING);
        addFunction("RIGHT", RIGHT, 2, Value.STRING);
        addFunction("RTRIM", RTRIM, VAR_ARGS, Value.STRING);
        addFunction("SOUNDEX", SOUNDEX, 1, Value.STRING);
        addFunction("SPACE", SPACE, 1, Value.STRING);
        addFunction("SUBSTR", SUBSTR, VAR_ARGS, Value.STRING);
        addFunction("SUBSTRING", SUBSTRING, VAR_ARGS, Value.STRING);
        addFunction("UCASE", UCASE, 1, Value.STRING);
        addFunction("LOWER", LOWER, 1, Value.STRING);
        addFunction("UPPER", UPPER, 1, Value.STRING);
        addFunction("POSITION", POSITION, 2, Value.INT);
        addFunction("TRIM", TRIM, VAR_ARGS, Value.STRING);
        addFunction("STRINGENCODE", STRINGENCODE, 1, Value.STRING);
        addFunction("STRINGDECODE", STRINGDECODE, 1, Value.STRING);
        addFunction("STRINGTOUTF8", STRINGTOUTF8, 1, Value.BYTES);
        addFunction("UTF8TOSTRING", UTF8TOSTRING, 1, Value.STRING);
        addFunction("XMLATTR", XMLATTR, 2, Value.STRING);
        addFunctionWithNull("XMLNODE", XMLNODE, VAR_ARGS, Value.STRING);
        addFunction("XMLCOMMENT", XMLCOMMENT, 1, Value.STRING);
        addFunction("XMLCDATA", XMLCDATA, 1, Value.STRING);
        addFunction("XMLSTARTDOC", XMLSTARTDOC, 0, Value.STRING);
        addFunction("XMLTEXT", XMLTEXT, 1, Value.STRING);
        addFunction("REGEXP_REPLACE", REGEXP_REPLACE, 3, Value.STRING);
        addFunction("RPAD", RPAD, VAR_ARGS, Value.STRING);
        addFunction("LPAD", LPAD, VAR_ARGS, Value.STRING);

        // date
        addFunctionNotConst("CURRENT_DATE", CURRENT_DATE, 0, Value.DATE);
        addFunctionNotConst("CURDATE", CURDATE, 0, Value.DATE);
        addFunctionNotConst("CURRENT_TIME", CURRENT_TIME, 0, Value.TIME);
        addFunctionNotConst("CURTIME", CURTIME, 0, Value.TIME);
        addFunctionNotConst("CURRENT_TIMESTAMP", CURRENT_TIMESTAMP, VAR_ARGS, Value.TIMESTAMP);
        addFunctionNotConst("NOW", NOW, VAR_ARGS, Value.TIMESTAMP);
        addFunction("DATEADD", DATEADD, 3, Value.TIMESTAMP);
        addFunction("DATEDIFF", DATEDIFF, 3, Value.LONG);
        addFunction("DAYNAME", DAYNAME, 1, Value.STRING);
        addFunction("DAY", DAYOFMONTH, 1, Value.INT);
        addFunction("DAYOFMONTH", DAYOFMONTH, 1, Value.INT);
        addFunction("DAYOFWEEK", DAYOFWEEK, 1, Value.INT);
        addFunction("DAYOFYEAR", DAYOFYEAR, 1, Value.INT);
        addFunction("HOUR", HOUR, 1, Value.INT);
        addFunction("MINUTE", MINUTE, 1, Value.INT);
        addFunction("MONTH", MONTH, 1, Value.INT);
        addFunction("MONTHNAME", MONTHNAME, 1, Value.STRING);
        addFunction("QUARTER", QUARTER, 1, Value.INT);
        addFunction("SECOND", SECOND, 1, Value.INT);
        addFunction("WEEK", WEEK, 1, Value.INT);
        addFunction("YEAR", YEAR, 1, Value.INT);
        addFunction("EXTRACT", EXTRACT, 2, Value.INT);
        addFunctionWithNull("FORMATDATETIME", FORMATDATETIME, VAR_ARGS, Value.STRING);
        addFunctionWithNull("PARSEDATETIME", PARSEDATETIME, VAR_ARGS, Value.TIMESTAMP);
        // system
        addFunctionNotConst("DATABASE", DATABASE, 0, Value.STRING);
        addFunctionNotConst("USER", USER, 0, Value.STRING);
        addFunctionNotConst("CURRENT_USER", CURRENT_USER, 0, Value.STRING);
        addFunctionNotConst("IDENTITY", IDENTITY, 0, Value.LONG);
        addFunctionNotConst("IDENTITY_VAL_LOCAL", IDENTITY, 0, Value.LONG);
        addFunctionNotConst("LAST_INSERT_ID", IDENTITY, 0, Value.LONG);
        addFunctionNotConst("AUTOCOMMIT", AUTOCOMMIT, 0, Value.BOOLEAN);
        addFunctionNotConst("READONLY", READONLY, 0, Value.BOOLEAN);
        addFunction("DATABASE_PATH", DATABASE_PATH, 0, Value.STRING);
        addFunction("LOCK_TIMEOUT", LOCK_TIMEOUT, 0, Value.INT);
        addFunctionWithNull("IFNULL", IFNULL, 2, Value.NULL);
        addFunctionWithNull("CASEWHEN", CASEWHEN, 3, Value.NULL);
        addFunctionWithNull("CONVERT", CONVERT, 1, Value.NULL);
        addFunctionWithNull("CAST", CAST, 1, Value.NULL);
        addFunctionWithNull("COALESCE", COALESCE, VAR_ARGS, Value.NULL);
        addFunctionWithNull("NVL", COALESCE, VAR_ARGS, Value.NULL);
        addFunctionWithNull("NULLIF", NULLIF, 2, Value.NULL);
        addFunctionWithNull("CASE", CASE, VAR_ARGS, Value.NULL);
        addFunctionNotConst("NEXTVAL", NEXTVAL, VAR_ARGS, Value.LONG);
        addFunctionNotConst("CURRVAL", CURRVAL, VAR_ARGS, Value.LONG);
        addFunction("ARRAY_GET", ARRAY_GET, 2, Value.NULL);
        addFunction("CSVREAD", CSVREAD, VAR_ARGS, Value.RESULT_SET, false, false);
        addFunction("CSVWRITE", CSVWRITE, VAR_ARGS, Value.INT, false, false);
        addFunctionNotConst("MEMORY_FREE", MEMORY_FREE, 0, Value.INT);
        addFunctionNotConst("MEMORY_USED", MEMORY_USED, 0, Value.INT);
        addFunctionNotConst("LOCK_MODE", LOCK_MODE, 0, Value.INT);
        addFunctionNotConst("SCHEMA", SCHEMA, 0, Value.STRING);
        addFunctionNotConst("SESSION_ID", SESSION_ID, 0, Value.INT);
        addFunction("ARRAY_LENGTH", ARRAY_LENGTH, 1, Value.INT);
        addFunction("LINK_SCHEMA", LINK_SCHEMA, 6, Value.RESULT_SET);
        addFunctionWithNull("LEAST", LEAST, VAR_ARGS, Value.NULL);
        addFunctionWithNull("GREATEST", GREATEST, VAR_ARGS, Value.NULL);
        addFunction("CANCEL_SESSION", CANCEL_SESSION, 1, Value.BOOLEAN);
        addFunction("SET", SET, 2, Value.NULL, false, false);
        addFunction("FILE_READ", FILE_READ, VAR_ARGS, Value.NULL, false, true);

        // TableFunction
        addFunctionWithNull("TABLE", TABLE, VAR_ARGS, Value.RESULT_SET);
        addFunctionWithNull("TABLE_DISTINCT", TABLE_DISTINCT, VAR_ARGS, Value.RESULT_SET);
    }

    private static void addFunction(String name, int type, int parameterCount, int dataType,
            boolean nullIfParameterIsNull, boolean isDeterm) {
        FunctionInfo info = new FunctionInfo();
        info.name = name;
        info.type = type;
        info.parameterCount = parameterCount;
        info.dataType = dataType;
        info.nullIfParameterIsNull = nullIfParameterIsNull;
        info.isDeterministic = isDeterm;
        FUNCTIONS.put(name, info);
    }

    private static void addFunctionNotConst(String name, int type, int parameterCount, int dataType) {
        addFunction(name, type, parameterCount, dataType, true, false);
    }

    private static void addFunction(String name, int type, int parameterCount, int dataType) {
        addFunction(name, type, parameterCount, dataType, true, true);
    }

    private static void addFunctionWithNull(String name, int type, int parameterCount, int dataType) {
        addFunction(name, type, parameterCount, dataType, false, true);
    }

    public static FunctionInfo getFunctionInfo(String name) {
        return (FunctionInfo) FUNCTIONS.get(name);