/**

 * 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.hadoop.hive.ql.udf.generic;



import java.util.HashSet;

import java.util.Set;



import org.apache.hadoop.hive.ql.exec.UDFArgumentException;

import org.apache.hadoop.hive.ql.exec.UDFArgumentLengthException;

import org.apache.hadoop.hive.ql.exec.UDFArgumentTypeException;

import org.apache.hadoop.hive.ql.metadata.HiveException;

import org.apache.hadoop.hive.serde.Constants;

import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;

import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;

import org.apache.hadoop.hive.serde2.objectinspector.primitive.StringObjectInspector;

import org.apache.hadoop.io.Text;



/**

 * Mimics oracle's function translate(str1, str2, str3).

 */

public class GenericUDFTestTranslate extends GenericUDF {

  ObjectInspector[] argumentOIs;



  /**

   * Return a corresponding ordinal from an integer.

   */

  static String getOrdinal(int i) {

    int unit = i % 10;

    return (i <= 0) ? "" : (i != 11 && unit == 1) ? i + "st"

        : (i != 12 && unit == 2) ? i + "nd" : (i != 13 && unit == 3) ? i + "rd"

        : i + "th";

  }



  @Override

  public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentException {

    if (arguments.length != 3) {

      throw new UDFArgumentLengthException(

          "The function TRANSLATE(expr,from_string,to_string) accepts exactly 3 arguments, but "

          + arguments.length + " arguments is found.");

    }



    for (int i = 0; i < 3; i++) {

      if (arguments[i].getTypeName() != Constants.STRING_TYPE_NAME

          && arguments[i].getTypeName() != Constants.VOID_TYPE_NAME) {

        throw new UDFArgumentTypeException(i, "The " + getOrdinal(i + 1)

            + " argument of function TRANSLATE is expected to \""

            + Constants.STRING_TYPE_NAME + "\", but \""

            + arguments[i].getTypeName() + "\" is found");

      }

    }



    argumentOIs = arguments;

    return PrimitiveObjectInspectorFactory.writableStringObjectInspector;

  }



  private final Text resultText = new Text();



  @Override

  public Object evaluate(DeferredObject[] arguments) throws HiveException {

    if (arguments[0].get() == null || arguments[1].get() == null

        || arguments[2].get() == null) {

      return null;

    }

    String exprString = ((StringObjectInspector) argumentOIs[0])

        .getPrimitiveJavaObject(arguments[0].get());

    String fromString = ((StringObjectInspector) argumentOIs[1])

        .getPrimitiveJavaObject(arguments[1].get());

    String toString = ((StringObjectInspector) argumentOIs[2])

        .getPrimitiveJavaObject(arguments[2].get());



    char[] expr = exprString.toCharArray();

    char[] from = fromString.toCharArray();

    char[] to = toString.toCharArray();

    char[] result = new char[expr.length];

    System.arraycopy(expr, 0, result, 0, expr.length);

    Set<Character> seen = new HashSet<Character>();



    for (int i = 0; i < from.length; i++) {

      if (seen.contains(from[i])) {

        continue;

      }

      seen.add(from[i]);

      for (int j = 0; j < expr.length; j++) {

        if (expr[j] == from[i]) {

          result[j] = (i < to.length) ? to[i] : 0;

        }

      }

    }



    int pos = 0;

    for (int i = 0; i < result.length; i++) {

      if (result[i] != 0) {

        result[pos++] = result[i];

      }

    }

    resultText.set(new String(result, 0, pos));

    return resultText;

  }



  @Override

  public String getDisplayString(String[] children) {

    assert (children.length == 3);

    return "translate(" + children[0] + "," + children[1] + "," + children[2]

        + ")";

  }

}