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/*
 *  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.hive.hplsql.objects;

import java.util.List;

import org.apache.hive.hplsql.ArityException;
import org.apache.hive.hplsql.File;
import org.apache.hive.hplsql.Row;
import org.apache.hive.hplsql.TypeException;
import org.apache.hive.hplsql.Var;

public class MethodParams {
  private final List actual;

  public MethodParams(String methodName, List actual, Arity arity) {
    this.actual = actual;
    arity.check(methodName, actual);
  }

  public Long longAt(int nth) {
    return at(nth, Long.class);
  }

  public Row rowAt(int nth) {
    return at(nth, Row.class);
  }

  public String stringAt(int nth) {
    return at(nth, String.class);
  }

  public File fileAt(int nth) {
    return at(nth, File.class);
  }

  public  T at(int nth, Class clazz) {
    try {
      return clazz.cast(actual.get(nth).value);
    } catch (ClassCastException e) {
      throw new TypeException(null, clazz, actual.get(nth).type, actual.get(nth).value);
    }
  }

  public interface Arity {
    void check(String methodName, List params);
    Arity NULLARY = Arity.of(0);
    Arity UNARY = Arity.of(1);
    Arity BINARY = Arity.of(2);

    static Arity of(int count) {
      return (methodName, params) -> {
        if (params.size() != count) {
          throw new ArityException(null, methodName, count, params.size());
        }
      };
    }
    static Arity min(int count) {
      return (methodName, params) -> {
        if (params.size() < count) {
          throw new ArityException(null, "wrong number of arguments in call to '" + methodName
                  + "'. Expected at least " + count + " got " + params.size() + ".");
        }
      };
    }
    static Arity max(int count) {
      return (methodName, params) -> {
        if (params.size() > count) {
          throw new ArityException(null, "wrong number of arguments in call to '" + methodName
                  + "'. Expected at most " + count + " got " + params.size() + ".");
        }
      };
    }
  }
}