/**
 * 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.hcatalog.utils;

import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

public class Util {

    static Map<String, Class<?>> typeMap = new HashMap<String, Class<?>>();

    static {
        typeMap.put("tinyint", Byte.class);
        typeMap.put("smallint", Short.class);
        typeMap.put("int", Integer.class);
        typeMap.put("bigint", Long.class);
        typeMap.put("float", Float.class);
        typeMap.put("double", Double.class);
        typeMap.put("string", String.class);
        typeMap.put("boolean", Boolean.class);
        typeMap.put("struct<num:int,str:string,dbl:double>", List.class);
        typeMap.put("map<string,string>", Map.class);
        typeMap.put("array<map<string,string>>", List.class);
    }

    public static void die(String expectedType, Object o) throws IOException {
        throw new IOException("Expected " + expectedType + ", got " +
            o.getClass().getName());
    }


    public static String check(String type, Object o) throws IOException {
        if (o == null) {
            return "null";
        }
        if (check(typeMap.get(type), o)) {
            if (type.equals("map<string,string>")) {
                Map<String, String> m = (Map<String, String>) o;
                check(m);
            } else if (type.equals("array<map<string,string>>")) {
                List<Map<String, String>> listOfMaps = (List<Map<String, String>>) o;
                for (Map<String, String> m : listOfMaps) {
                    check(m);
                }
            } else if (type.equals("struct<num:int,str:string,dbl:double>")) {
                List<Object> l = (List<Object>) o;
                if (!check(Integer.class, l.get(0)) ||
                    !check(String.class, l.get(1)) ||
                    !check(Double.class, l.get(2))) {
                    die("struct<num:int,str:string,dbl:double>", l);
                }
            }
        } else {
            die(typeMap.get(type).getName(), o);
        }
        return o.toString();
    }

    /**
     * @param m
     * @throws IOException
     */
    public static void check(Map<String, String> m) throws IOException {
        if (m == null) {
            return;
        }
        for (Entry<String, String> e : m.entrySet()) {
            // just access key and value to ensure they are correct
            if (!check(String.class, e.getKey())) {
                die("String", e.getKey());
            }
            if (!check(String.class, e.getValue())) {
                die("String", e.getValue());
            }
        }

    }

    public static boolean check(Class<?> expected, Object actual) {
        if (actual == null) {
            return true;
        }
        return expected.isAssignableFrom(actual.getClass());
    }

}