package com.temp.shared.utils;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Utility methods around Collections / Arrays to reduce the code in other
 * places (e.g. the Activities).
 *
 * @author georgs
 */
public class CollectionsUtils {
    public static <T> List<T> deNull(List<T> list) {
        if (list != null) { // can not "in line" as compiler gets confused!
            return list;
        }
        return Collections.emptyList();
    }

    public static <T> List<T> noEmpty(List<T> list) {
        return isEmpty(list) ? null : list;
    }

    public static boolean isEmpty(Collection<?> collection) {
        return (collection == null) || collection.isEmpty();
    }

    public static boolean isEmpty(Map<?, ?> collection) {
        return (collection == null) || collection.isEmpty();
    }

    public static boolean isEmpty(Object[] array) {
        return (array == null) || (array.length == 0);
    }

    /**
     * Use type inference to create a map - from Guava
     */
    public static <V> List<V> newArrayList() {
        return new ArrayList<V>();
    }

    /**
     * Use type inference to create a map - from Guava
     */
    public static <K, V> Map<K, V> newHashMap() {
        return new HashMap<K, V>();
    }

    public static Map<String, String> newMap(String... keyValuePairs) {
        Map<String, String> map = newHashMap();
        if (!isEmpty(keyValuePairs)) {
            if ((keyValuePairs.length & 1) == 1) { // Odd == Not Paired!
                throw new IllegalArgumentException("To construct a String String Map, must provide Strings in pairs (key, value)");
            }
            for (int i = 0; i < keyValuePairs.length;) {
                String key = keyValuePairs[i++];
                String value = keyValuePairs[i++];
                addNonEmptiesTo(map, key, value);
            }
        }
        return map;
    }

    public static Map<String, String> addNonEmptiesTo(Map<String, String> map, String key, String value) {
        map.put(Assert.notNullOrEmpty("key", key), Assert.notNullOrEmpty("value", value));
        return map;
    }

    public static <K, V> Map<K, V> addNonNullsTo(Map<K, V> map, K key, V value) {
        Assert.notNull("key", key);
        Assert.notNull("value", value);
        map.put(key, value);
        return map;
    }
}