/*
 * Copyright (c) 2005, PostgreSQL Global Development Group
 * See the LICENSE file in the project root for more information.
 */

package org.postgresql.jdbc;

import org.postgresql.core.BaseConnection;
import org.postgresql.core.BaseStatement;
import org.postgresql.core.Oid;
import org.postgresql.core.QueryExecutor;
import org.postgresql.core.ServerVersion;
import org.postgresql.core.TypeInfo;
import org.postgresql.util.GT;
import org.postgresql.util.PGobject;
import org.postgresql.util.PSQLException;
import org.postgresql.util.PSQLState;

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

public class TypeInfoCache implements TypeInfo {

  // pgname (String) -> java.sql.Types (Integer)
  private Map<String, Integer> pgNameToSQLType;

  // pgname (String) -> java class name (String)
  // ie "text" -> "java.lang.String"
  private Map<String, String> pgNameToJavaClass;

  // oid (Integer) -> pgname (String)
  private Map<Integer, String> oidToPgName;
  // pgname (String) -> oid (Integer)
  private Map<String, Integer> pgNameToOid;

  // pgname (String) -> extension pgobject (Class)
  private Map<String, Class<? extends PGobject>> pgNameToPgObject;

  // type array oid -> base type's oid
  private Map<Integer, Integer> pgArrayToPgType;

  // array type oid -> base type array element delimiter
  private Map<Integer, Character> arrayOidToDelimiter;

  private BaseConnection conn;
  private final int unknownLength;
  private PreparedStatement getOidStatementSimple;
  private PreparedStatement getOidStatementComplexNonArray;
  private PreparedStatement getOidStatementComplexArray;
  private PreparedStatement getNameStatement;
  private PreparedStatement getArrayElementOidStatement;
  private PreparedStatement getArrayDelimiterStatement;
  private PreparedStatement getTypeInfoStatement;

  // basic pg types info:
  // 0 - type name
  // 1 - type oid
  // 2 - sql type
  // 3 - java class
  // 4 - array type oid
  private static final Object[][] types = {
      {"int2", Oid.INT2, Types.SMALLINT, "java.lang.Integer", Oid.INT2_ARRAY},
      {"int4", Oid.INT4, Types.INTEGER, "java.lang.Integer", Oid.INT4_ARRAY},
      {"oid", Oid.OID, Types.BIGINT, "java.lang.Long", Oid.OID_ARRAY},
      {"int8", Oid.INT8, Types.BIGINT, "java.lang.Long", Oid.INT8_ARRAY},
      {"money", Oid.MONEY, Types.DOUBLE, "java.lang.Double", Oid.MONEY_ARRAY},
      {"numeric", Oid.NUMERIC, Types.NUMERIC, "java.math.BigDecimal", Oid.NUMERIC_ARRAY},
      {"float4", Oid.FLOAT4, Types.REAL, "java.lang.Float", Oid.FLOAT4_ARRAY},
      {"float8", Oid.FLOAT8, Types.DOUBLE, "java.lang.Double", Oid.FLOAT8_ARRAY},
      {"char", Oid.CHAR, Types.CHAR, "java.lang.String", Oid.CHAR_ARRAY},
      {"bpchar", Oid.BPCHAR, Types.CHAR, "java.lang.String", Oid.BPCHAR_ARRAY},
      {"varchar", Oid.VARCHAR, Types.VARCHAR, "java.lang.String", Oid.VARCHAR_ARRAY},
      {"text", Oid.TEXT, Types.VARCHAR, "java.lang.String", Oid.TEXT_ARRAY},
      {"name", Oid.NAME, Types.VARCHAR, "java.lang.String", Oid.NAME_ARRAY},
      {"bytea", Oid.BYTEA, Types.BINARY, "[B", Oid.BYTEA_ARRAY},
      {"bool", Oid.BOOL, Types.BIT, "java.lang.Boolean", Oid.BOOL_ARRAY},
      {"bit", Oid.BIT, Types.BIT, "java.lang.Boolean", Oid.BIT_ARRAY},
      {"date", Oid.DATE, Types.DATE, "java.sql.Date", Oid.DATE_ARRAY},
      {"time", Oid.TIME, Types.TIME, "java.sql.Time", Oid.TIME_ARRAY},
      {"timetz", Oid.TIMETZ, Types.TIME, "java.sql.Time", Oid.TIMETZ_ARRAY},
      {"timestamp", Oid.TIMESTAMP, Types.TIMESTAMP, "java.sql.Timestamp", Oid.TIMESTAMP_ARRAY},
      {"timestamptz", Oid.TIMESTAMPTZ, Types.TIMESTAMP, "java.sql.Timestamp",
          Oid.TIMESTAMPTZ_ARRAY},
      //JCP! if mvn.project.property.postgresql.jdbc.spec >= "JDBC4.2"
      {"refcursor", Oid.REF_CURSOR, Types.REF_CURSOR, "java.sql.ResultSet", Oid.REF_CURSOR_ARRAY},
      //JCP! endif
      {"json", Oid.JSON, Types.OTHER, "org.postgresql.util.PGobject", Oid.JSON_ARRAY},
      {"point", Oid.POINT, Types.OTHER, "org.postgresql.geometric.PGpoint", Oid.POINT_ARRAY}
  };

  
PG maps several alias to real type names. When we do queries against pg_catalog, we must use
the real type, not an alias, so use this mapping.
/**
   * PG maps several alias to real type names. When we do queries against pg_catalog, we must use
   * the real type, not an alias, so use this mapping.
   */
  private static final HashMap<String, String> typeAliases;

  static {
    typeAliases = new HashMap<String, String>();
    typeAliases.put("smallint", "int2");
    typeAliases.put("integer", "int4");
    typeAliases.put("int", "int4");
    typeAliases.put("bigint", "int8");
    typeAliases.put("float", "float8");
    typeAliases.put("boolean", "bool");
    typeAliases.put("decimal", "numeric");
  }

  public TypeInfoCache(BaseConnection conn, int unknownLength) {
    this.conn = conn;
    this.unknownLength = unknownLength;
    oidToPgName = new HashMap<Integer, String>((int) Math.round(types.length * 1.5));
    pgNameToOid = new HashMap<String, Integer>((int) Math.round(types.length * 1.5));
    pgNameToJavaClass = new HashMap<String, String>((int) Math.round(types.length * 1.5));
    pgNameToPgObject = new HashMap<String, Class<? extends PGobject>>((int) Math.round(types.length * 1.5));
    pgArrayToPgType = new HashMap<Integer, Integer>((int) Math.round(types.length * 1.5));
    arrayOidToDelimiter = new HashMap<Integer, Character>((int) Math.round(types.length * 2.5));

    // needs to be synchronized because the iterator is returned
    // from getPGTypeNamesWithSQLTypes()
    pgNameToSQLType = Collections.synchronizedMap(new HashMap<String, Integer>((int) Math.round(types.length * 1.5)));

    for (Object[] type : types) {
      String pgTypeName = (String) type[0];
      Integer oid = (Integer) type[1];
      Integer sqlType = (Integer) type[2];
      String javaClass = (String) type[3];
      Integer arrayOid = (Integer) type[4];

      addCoreType(pgTypeName, oid, sqlType, javaClass, arrayOid);
    }

    pgNameToJavaClass.put("hstore", Map.class.getName());
  }

  public synchronized void addCoreType(String pgTypeName, Integer oid, Integer sqlType,
      String javaClass, Integer arrayOid) {
    pgNameToJavaClass.put(pgTypeName, javaClass);
    pgNameToOid.put(pgTypeName, oid);
    oidToPgName.put(oid, pgTypeName);
    pgArrayToPgType.put(arrayOid, oid);
    pgNameToSQLType.put(pgTypeName, sqlType);

    // Currently we hardcode all core types array delimiter
    // to a comma. In a stock install the only exception is
    // the box datatype and it's not a JDBC core type.
    //
    Character delim = ',';
    arrayOidToDelimiter.put(oid, delim);
    arrayOidToDelimiter.put(arrayOid, delim);

    String pgArrayTypeName = pgTypeName + "[]";
    pgNameToJavaClass.put(pgArrayTypeName, "java.sql.Array");
    pgNameToSQLType.put(pgArrayTypeName, Types.ARRAY);
    pgNameToOid.put(pgArrayTypeName, arrayOid);
    pgArrayTypeName = "_" + pgTypeName;
    if (!pgNameToJavaClass.containsKey(pgArrayTypeName)) {
      pgNameToJavaClass.put(pgArrayTypeName, "java.sql.Array");
      pgNameToSQLType.put(pgArrayTypeName, Types.ARRAY);
      pgNameToOid.put(pgArrayTypeName, arrayOid);
      oidToPgName.put(arrayOid, pgArrayTypeName);
    }
  }

  public synchronized void addDataType(String type, Class<? extends PGobject> klass)
      throws SQLException {
    pgNameToPgObject.put(type, klass);
    pgNameToJavaClass.put(type, klass.getName());
  }

  public Iterator<String> getPGTypeNamesWithSQLTypes() {
    return pgNameToSQLType.keySet().iterator();
  }

  public int getSQLType(int oid) throws SQLException {
    return getSQLType(getPGType(oid));
  }

  public synchronized int getSQLType(String pgTypeName) throws SQLException {
    if (pgTypeName.endsWith("[]")) {
      return Types.ARRAY;
    }
    Integer i = pgNameToSQLType.get(pgTypeName);
    if (i != null) {
      return i;
    }

    if (getTypeInfoStatement == null) {
      // There's no great way of telling what's an array type.
      // People can name their own types starting with _.
      // Other types use typelem that aren't actually arrays, like box.
      //
      String sql;
      // in case of multiple records (in different schemas) choose the one from the current
      // schema,
      // otherwise take the last version of a type that is at least more deterministic then before
      // (keeping old behaviour of finding types, that should not be found without correct search
      // path)
      sql = "SELECT typinput='array_in'::regproc, typtype "
            + "  FROM pg_catalog.pg_type "
            + "  LEFT "
            + "  JOIN (select ns.oid as nspoid, ns.nspname, r.r "
            + "          from pg_namespace as ns "
            // -- go with older way of unnesting array to be compatible with 8.0
            + "          join ( select s.r, (current_schemas(false))[s.r] as nspname "
            + "                   from generate_series(1, array_upper(current_schemas(false), 1)) as s(r) ) as r "
            + "         using ( nspname ) "
            + "       ) as sp "
            + "    ON sp.nspoid = typnamespace "
            + " WHERE typname = ? "
            + " ORDER BY sp.r, pg_type.oid DESC LIMIT 1;";

      getTypeInfoStatement = conn.prepareStatement(sql);
    }

    getTypeInfoStatement.setString(1, pgTypeName);

    // Go through BaseStatement to avoid transaction start.
    if (!((BaseStatement) getTypeInfoStatement)
        .executeWithFlags(QueryExecutor.QUERY_SUPPRESS_BEGIN)) {
      throw new PSQLException(GT.tr("No results were returned by the query."), PSQLState.NO_DATA);
    }

    ResultSet rs = getTypeInfoStatement.getResultSet();

    Integer type = null;
    if (rs.next()) {
      boolean isArray = rs.getBoolean(1);
      String typtype = rs.getString(2);
      if (isArray) {
        type = Types.ARRAY;
      } else if ("c".equals(typtype)) {
        type = Types.STRUCT;
      } else if ("d".equals(typtype)) {
        type = Types.DISTINCT;
      } else if ("e".equals(typtype)) {
        type = Types.VARCHAR;
      }
    }

    if (type == null) {
      type = Types.OTHER;
    }
    rs.close();

    pgNameToSQLType.put(pgTypeName, type);
    return type;
  }

  private PreparedStatement getOidStatement(String pgTypeName) throws SQLException {
    boolean isArray = pgTypeName.endsWith("[]");
    boolean hasQuote = pgTypeName.contains("\"");
    int dotIndex = pgTypeName.indexOf('.');

    if (dotIndex == -1 && !hasQuote && !isArray) {
      if (getOidStatementSimple == null) {
        String sql;
        // see comments in @getSQLType()
        // -- go with older way of unnesting array to be compatible with 8.0
        sql = "SELECT pg_type.oid, typname "
              + "  FROM pg_catalog.pg_type "
              + "  LEFT "
              + "  JOIN (select ns.oid as nspoid, ns.nspname, r.r "
              + "          from pg_namespace as ns "
              + "          join ( select s.r, (current_schemas(false))[s.r] as nspname "
              + "                   from generate_series(1, array_upper(current_schemas(false), 1)) as s(r) ) as r "
              + "         using ( nspname ) "
              + "       ) as sp "
              + "    ON sp.nspoid = typnamespace "
              + " WHERE typname = ? "
              + " ORDER BY sp.r, pg_type.oid DESC LIMIT 1;";
        getOidStatementSimple = conn.prepareStatement(sql);
      }
      // coerce to lower case to handle upper case type names
      String lcName = pgTypeName.toLowerCase();
      // default arrays are represented with _ as prefix ... this dont even work for public schema
      // fully
      getOidStatementSimple.setString(1, lcName);
      return getOidStatementSimple;
    }
    PreparedStatement oidStatementComplex;
    if (isArray) {
      if (getOidStatementComplexArray == null) {
        String sql;
        if (conn.haveMinimumServerVersion(ServerVersion.v8_3)) {
          sql = "SELECT t.typarray, arr.typname "
              + "  FROM pg_catalog.pg_type t"
              + "  JOIN pg_catalog.pg_namespace n ON t.typnamespace = n.oid"
              + "  JOIN pg_catalog.pg_type arr ON arr.oid = t.typarray"
              + " WHERE t.typname = ? AND (n.nspname = ? OR ? AND n.nspname = ANY (current_schemas(true)))"
              + " ORDER BY t.oid DESC LIMIT 1";
        } else {
          sql = "SELECT t.oid, t.typname "
              + "  FROM pg_catalog.pg_type t"
              + "  JOIN pg_catalog.pg_namespace n ON t.typnamespace = n.oid"
              + " WHERE t.typelem = (SELECT oid FROM pg_catalog.pg_type WHERE typname = ?)"
              + " AND substring(t.typname, 1, 1) = '_' AND t.typlen = -1"
              + " AND (n.nspname = ? OR ? AND n.nspname = ANY (current_schemas(true)))"
              + " ORDER BY t.typelem DESC LIMIT 1";
        }
        getOidStatementComplexArray = conn.prepareStatement(sql);
      }
      oidStatementComplex = getOidStatementComplexArray;
    } else {
      if (getOidStatementComplexNonArray == null) {
        String sql = "SELECT t.oid, t.typname "
            + "  FROM pg_catalog.pg_type t"
            + "  JOIN pg_catalog.pg_namespace n ON t.typnamespace = n.oid"
            + " WHERE t.typname = ? AND (n.nspname = ? OR ? AND n.nspname = ANY (current_schemas(true)))"
            + " ORDER BY t.oid DESC LIMIT 1";
        getOidStatementComplexNonArray = conn.prepareStatement(sql);
      }
      oidStatementComplex = getOidStatementComplexNonArray;
    }
    //type name requested may be schema specific, of the form "{schema}"."typeName",
    //or may check across all schemas where a schema is not specified.
    String fullName = isArray ? pgTypeName.substring(0, pgTypeName.length() - 2) : pgTypeName;
    String schema;
    String name;
    // simple use case
    if (dotIndex == -1) {
      schema = null;
      name = fullName;
    } else {
      if (fullName.startsWith("\"")) {
        if (fullName.endsWith("\"")) {
          String[] parts = fullName.split("\"\\.\"");
          schema = parts.length == 2 ? parts[0] + "\"" : null;
          name = parts.length == 2 ? "\"" + parts[1] : parts[0];
        } else {
          int lastDotIndex = fullName.lastIndexOf('.');
          name = fullName.substring(lastDotIndex + 1);
          schema = fullName.substring(0, lastDotIndex);
        }
      } else {
        schema = fullName.substring(0, dotIndex);
        name = fullName.substring(dotIndex + 1);
      }
    }
    if (schema != null && schema.startsWith("\"") && schema.endsWith("\"")) {
      schema = schema.substring(1, schema.length() - 1);
    } else if (schema != null) {
      schema = schema.toLowerCase();
    }
    if (name.startsWith("\"") && name.endsWith("\"")) {
      name = name.substring(1, name.length() - 1);
    } else {
      name = name.toLowerCase();
    }
    oidStatementComplex.setString(1, name);
    oidStatementComplex.setString(2, schema);
    oidStatementComplex.setBoolean(3, schema == null);
    return oidStatementComplex;
  }

  public synchronized int getPGType(String pgTypeName) throws SQLException {
    Integer oid = pgNameToOid.get(pgTypeName);
    if (oid != null) {
      return oid;
    }

    PreparedStatement oidStatement = getOidStatement(pgTypeName);

    // Go through BaseStatement to avoid transaction start.
    if (!((BaseStatement) oidStatement).executeWithFlags(QueryExecutor.QUERY_SUPPRESS_BEGIN)) {
      throw new PSQLException(GT.tr("No results were returned by the query."), PSQLState.NO_DATA);
    }

    oid = Oid.UNSPECIFIED;
    ResultSet rs = oidStatement.getResultSet();
    if (rs.next()) {
      oid = (int) rs.getLong(1);
      String internalName = rs.getString(2);
      oidToPgName.put(oid, internalName);
      pgNameToOid.put(internalName, oid);
    }
    pgNameToOid.put(pgTypeName, oid);
    rs.close();

    return oid;
  }

  public synchronized String getPGType(int oid) throws SQLException {
    if (oid == Oid.UNSPECIFIED) {
      return null;
    }

    String pgTypeName = oidToPgName.get(oid);
    if (pgTypeName != null) {
      return pgTypeName;
    }

    if (getNameStatement == null) {
      String sql;
      sql = "SELECT n.nspname = ANY(current_schemas(true)), n.nspname, t.typname "
            + "FROM pg_catalog.pg_type t "
            + "JOIN pg_catalog.pg_namespace n ON t.typnamespace = n.oid WHERE t.oid = ?";

      getNameStatement = conn.prepareStatement(sql);
    }

    getNameStatement.setInt(1, oid);

    // Go through BaseStatement to avoid transaction start.
    if (!((BaseStatement) getNameStatement).executeWithFlags(QueryExecutor.QUERY_SUPPRESS_BEGIN)) {
      throw new PSQLException(GT.tr("No results were returned by the query."), PSQLState.NO_DATA);
    }

    ResultSet rs = getNameStatement.getResultSet();
    if (rs.next()) {
      boolean onPath = rs.getBoolean(1);
      String schema = rs.getString(2);
      String name = rs.getString(3);
      if (onPath) {
        pgTypeName = name;
        pgNameToOid.put(schema + "." + name, oid);
      } else {
        // TODO: escaping !?
        pgTypeName = "\"" + schema + "\".\"" + name + "\"";
        // if all is lowercase add special type info
        // TODO: should probably check for all special chars
        if (schema.equals(schema.toLowerCase()) && schema.indexOf('.') == -1
            && name.equals(name.toLowerCase()) && name.indexOf('.') == -1) {
          pgNameToOid.put(schema + "." + name, oid);
        }
      }
      pgNameToOid.put(pgTypeName, oid);
      oidToPgName.put(oid, pgTypeName);
    }
    rs.close();

    return pgTypeName;
  }

  public int getPGArrayType(String elementTypeName) throws SQLException {
    elementTypeName = getTypeForAlias(elementTypeName);
    return getPGType(elementTypeName + "[]");
  }

  
Return the oid of the array's base element if it's an array, if not return the provided oid.
This doesn't do any database lookups, so it's only useful for the originally provided type
mappings. This is fine for it's intended uses where we only have intimate knowledge of types
that are already known to the driver.
Params:
oid – input oid
Returns:
oid of the array's base element or the provided oid (if not array)/**
   * Return the oid of the array's base element if it's an array, if not return the provided oid.
   * This doesn't do any database lookups, so it's only useful for the originally provided type
   * mappings. This is fine for it's intended uses where we only have intimate knowledge of types
   * that are already known to the driver.
   *
   * @param oid input oid
   * @return oid of the array's base element or the provided oid (if not array)
   */
  protected synchronized int convertArrayToBaseOid(int oid) {
    Integer i = pgArrayToPgType.get(oid);
    if (i == null) {
      return oid;
    }
    return i;
  }

  public synchronized char getArrayDelimiter(int oid) throws SQLException {
    if (oid == Oid.UNSPECIFIED) {
      return ',';
    }

    Character delim = arrayOidToDelimiter.get(oid);
    if (delim != null) {
      return delim;
    }

    if (getArrayDelimiterStatement == null) {
      String sql;
      sql = "SELECT e.typdelim FROM pg_catalog.pg_type t, pg_catalog.pg_type e "
            + "WHERE t.oid = ? and t.typelem = e.oid";
      getArrayDelimiterStatement = conn.prepareStatement(sql);
    }

    getArrayDelimiterStatement.setInt(1, oid);

    // Go through BaseStatement to avoid transaction start.
    if (!((BaseStatement) getArrayDelimiterStatement)
        .executeWithFlags(QueryExecutor.QUERY_SUPPRESS_BEGIN)) {
      throw new PSQLException(GT.tr("No results were returned by the query."), PSQLState.NO_DATA);
    }

    ResultSet rs = getArrayDelimiterStatement.getResultSet();
    if (!rs.next()) {
      throw new PSQLException(GT.tr("No results were returned by the query."), PSQLState.NO_DATA);
    }

    String s = rs.getString(1);
    delim = s.charAt(0);

    arrayOidToDelimiter.put(oid, delim);

    rs.close();

    return delim;
  }

  public synchronized int getPGArrayElement(int oid) throws SQLException {
    if (oid == Oid.UNSPECIFIED) {
      return Oid.UNSPECIFIED;
    }

    Integer pgType = pgArrayToPgType.get(oid);

    if (pgType != null) {
      return pgType;
    }

    if (getArrayElementOidStatement == null) {
      String sql;
      sql = "SELECT e.oid, n.nspname = ANY(current_schemas(true)), n.nspname, e.typname "
            + "FROM pg_catalog.pg_type t JOIN pg_catalog.pg_type e ON t.typelem = e.oid "
            + "JOIN pg_catalog.pg_namespace n ON t.typnamespace = n.oid WHERE t.oid = ?";
      getArrayElementOidStatement = conn.prepareStatement(sql);
    }

    getArrayElementOidStatement.setInt(1, oid);

    // Go through BaseStatement to avoid transaction start.
    if (!((BaseStatement) getArrayElementOidStatement)
        .executeWithFlags(QueryExecutor.QUERY_SUPPRESS_BEGIN)) {
      throw new PSQLException(GT.tr("No results were returned by the query."), PSQLState.NO_DATA);
    }

    ResultSet rs = getArrayElementOidStatement.getResultSet();
    if (!rs.next()) {
      throw new PSQLException(GT.tr("No results were returned by the query."), PSQLState.NO_DATA);
    }

    pgType = (int) rs.getLong(1);
    boolean onPath = rs.getBoolean(2);
    String schema = rs.getString(3);
    String name = rs.getString(4);
    pgArrayToPgType.put(oid, pgType);
    pgNameToOid.put(schema + "." + name, pgType);
    String fullName = "\"" + schema + "\".\"" + name + "\"";
    pgNameToOid.put(fullName, pgType);
    if (onPath && name.equals(name.toLowerCase())) {
      oidToPgName.put(pgType, name);
      pgNameToOid.put(name, pgType);
    } else {
      oidToPgName.put(pgType, fullName);
    }

    rs.close();

    return pgType;
  }

  public synchronized Class<? extends PGobject> getPGobject(String type) {
    return pgNameToPgObject.get(type);
  }

  public synchronized String getJavaClass(int oid) throws SQLException {
    String pgTypeName = getPGType(oid);

    String result = pgNameToJavaClass.get(pgTypeName);
    if (result != null) {
      return result;
    }

    if (getSQLType(pgTypeName) == Types.ARRAY) {
      result = "java.sql.Array";
      pgNameToJavaClass.put(pgTypeName, result);
    }

    return result;
  }

  public String getTypeForAlias(String alias) {
    String type = typeAliases.get(alias);
    if (type != null) {
      return type;
    }
    if (alias.indexOf('"') == -1) {
      type = typeAliases.get(alias.toLowerCase());
      if (type != null) {
        return type;
      }
    }
    return alias;
  }

  public int getPrecision(int oid, int typmod) {
    oid = convertArrayToBaseOid(oid);
    switch (oid) {
      case Oid.INT2:
        return 5;

      case Oid.OID:
      case Oid.INT4:
        return 10;

      case Oid.INT8:
        return 19;

      case Oid.FLOAT4:
        // For float4 and float8, we can normally only get 6 and 15
        // significant digits out, but extra_float_digits may raise
        // that number by up to two digits.
        return 8;

      case Oid.FLOAT8:
        return 17;

      case Oid.NUMERIC:
        if (typmod == -1) {
          return 0;
        }
        return ((typmod - 4) & 0xFFFF0000) >> 16;

      case Oid.CHAR:
      case Oid.BOOL:
        return 1;

      case Oid.BPCHAR:
      case Oid.VARCHAR:
        if (typmod == -1) {
          return unknownLength;
        }
        return typmod - 4;

      // datetime types get the
      // "length in characters of the String representation"
      case Oid.DATE:
      case Oid.TIME:
      case Oid.TIMETZ:
      case Oid.INTERVAL:
      case Oid.TIMESTAMP:
      case Oid.TIMESTAMPTZ:
        return getDisplaySize(oid, typmod);

      case Oid.BIT:
        return typmod;

      case Oid.VARBIT:
        if (typmod == -1) {
          return unknownLength;
        }
        return typmod;

      case Oid.TEXT:
      case Oid.BYTEA:
      default:
        return unknownLength;
    }
  }

  public int getScale(int oid, int typmod) {
    oid = convertArrayToBaseOid(oid);
    switch (oid) {
      case Oid.FLOAT4:
        return 8;
      case Oid.FLOAT8:
        return 17;
      case Oid.NUMERIC:
        if (typmod == -1) {
          return 0;
        }
        return (typmod - 4) & 0xFFFF;
      case Oid.TIME:
      case Oid.TIMETZ:
      case Oid.TIMESTAMP:
      case Oid.TIMESTAMPTZ:
        if (typmod == -1) {
          return 6;
        }
        return typmod;
      case Oid.INTERVAL:
        if (typmod == -1) {
          return 6;
        }
        return typmod & 0xFFFF;
      default:
        return 0;
    }
  }

  public boolean isCaseSensitive(int oid) {
    oid = convertArrayToBaseOid(oid);
    switch (oid) {
      case Oid.OID:
      case Oid.INT2:
      case Oid.INT4:
      case Oid.INT8:
      case Oid.FLOAT4:
      case Oid.FLOAT8:
      case Oid.NUMERIC:
      case Oid.BOOL:
      case Oid.BIT:
      case Oid.VARBIT:
      case Oid.DATE:
      case Oid.TIME:
      case Oid.TIMETZ:
      case Oid.TIMESTAMP:
      case Oid.TIMESTAMPTZ:
      case Oid.INTERVAL:
        return false;
      default:
        return true;
    }
  }

  public boolean isSigned(int oid) {
    oid = convertArrayToBaseOid(oid);
    switch (oid) {
      case Oid.INT2:
      case Oid.INT4:
      case Oid.INT8:
      case Oid.FLOAT4:
      case Oid.FLOAT8:
      case Oid.NUMERIC:
        return true;
      default:
        return false;
    }
  }

  public int getDisplaySize(int oid, int typmod) {
    oid = convertArrayToBaseOid(oid);
    switch (oid) {
      case Oid.INT2:
        return 6; // -32768 to +32767
      case Oid.INT4:
        return 11; // -2147483648 to +2147483647
      case Oid.OID:
        return 10; // 0 to 4294967295
      case Oid.INT8:
        return 20; // -9223372036854775808 to +9223372036854775807
      case Oid.FLOAT4:
        // varies based upon the extra_float_digits GUC.
        // These values are for the longest possible length.
        return 15; // sign + 9 digits + decimal point + e + sign + 2 digits
      case Oid.FLOAT8:
        return 25; // sign + 18 digits + decimal point + e + sign + 3 digits
      case Oid.CHAR:
        return 1;
      case Oid.BOOL:
        return 1;
      case Oid.DATE:
        return 13; // "4713-01-01 BC" to "01/01/4713 BC" - "31/12/32767"
      case Oid.TIME:
      case Oid.TIMETZ:
      case Oid.TIMESTAMP:
      case Oid.TIMESTAMPTZ:
        // Calculate the number of decimal digits + the decimal point.
        int secondSize;
        switch (typmod) {
          case -1:
            secondSize = 6 + 1;
            break;
          case 0:
            secondSize = 0;
            break;
          case 1:
            // Bizarrely SELECT '0:0:0.1'::time(1); returns 2 digits.
            secondSize = 2 + 1;
            break;
          default:
            secondSize = typmod + 1;
            break;
        }

        // We assume the worst case scenario for all of these.
        // time = '00:00:00' = 8
        // date = '5874897-12-31' = 13 (although at large values second precision is lost)
        // date = '294276-11-20' = 12 --enable-integer-datetimes
        // zone = '+11:30' = 6;

        switch (oid) {
          case Oid.TIME:
            return 8 + secondSize;
          case Oid.TIMETZ:
            return 8 + secondSize + 6;
          case Oid.TIMESTAMP:
            return 13 + 1 + 8 + secondSize;
          case Oid.TIMESTAMPTZ:
            return 13 + 1 + 8 + secondSize + 6;
        }
      case Oid.INTERVAL:
        // SELECT LENGTH('-123456789 years 11 months 33 days 23 hours 10.123456 seconds'::interval);
        return 49;
      case Oid.VARCHAR:
      case Oid.BPCHAR:
        if (typmod == -1) {
          return unknownLength;
        }
        return typmod - 4;
      case Oid.NUMERIC:
        if (typmod == -1) {
          return 131089; // SELECT LENGTH(pow(10::numeric,131071)); 131071 = 2^17-1
        }
        int precision = (typmod - 4 >> 16) & 0xffff;
        int scale = (typmod - 4) & 0xffff;
        // sign + digits + decimal point (only if we have nonzero scale)
        return 1 + precision + (scale != 0 ? 1 : 0);
      case Oid.BIT:
        return typmod;
      case Oid.VARBIT:
        if (typmod == -1) {
          return unknownLength;
        }
        return typmod;
      case Oid.TEXT:
      case Oid.BYTEA:
        return unknownLength;
      default:
        return unknownLength;
    }
  }

  public int getMaximumPrecision(int oid) {
    oid = convertArrayToBaseOid(oid);
    switch (oid) {
      case Oid.NUMERIC:
        return 1000;
      case Oid.TIME:
      case Oid.TIMETZ:
        // Technically this depends on the --enable-integer-datetimes
        // configure setting. It is 6 with integer and 10 with float.
        return 6;
      case Oid.TIMESTAMP:
      case Oid.TIMESTAMPTZ:
      case Oid.INTERVAL:
        return 6;
      case Oid.BPCHAR:
      case Oid.VARCHAR:
        return 10485760;
      case Oid.BIT:
      case Oid.VARBIT:
        return 83886080;
      default:
        return 0;
    }
  }

  public boolean requiresQuoting(int oid) throws SQLException {
    int sqlType = getSQLType(oid);
    return requiresQuotingSqlType(sqlType);
  }

  
Returns true if particular sqlType requires quoting.
This method is used internally by the driver, so it might disappear without notice.
Params:
sqlType – sql type as in java.sql.Types
Throws:
SQLException – if something goes wrong
Returns:
true if the type requires quoting/**
   * Returns true if particular sqlType requires quoting.
   * This method is used internally by the driver, so it might disappear without notice.
   *
   * @param sqlType sql type as in java.sql.Types
   * @return true if the type requires quoting
   * @throws SQLException if something goes wrong
   */
  public boolean requiresQuotingSqlType(int sqlType) throws SQLException {
    switch (sqlType) {
      case Types.BIGINT:
      case Types.DOUBLE:
      case Types.FLOAT:
      case Types.INTEGER:
      case Types.REAL:
      case Types.SMALLINT:
      case Types.TINYINT:
      case Types.NUMERIC:
      case Types.DECIMAL:
        return false;
    }
    return true;
  }
}