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/*
 * Copyright 2013-2015 the original author or authors.
 *
 * Licensed 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.glowroot.container.common;

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

import javax.annotation.Nullable;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.BeanDescription;
import com.fasterxml.jackson.databind.DeserializationConfig;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.deser.Deserializers;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import org.checkerframework.checker.nullness.qual.EnsuresNonNull;
import org.checkerframework.checker.nullness.qual.PolyNull;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

// unfortunately this is mostly a duplicate of a class from the glowroot module test-container
// cannot use the class from the glowroot module since sometimes that class exposes unshaded jackson
// types (in IDE) and sometimes it exposes shaded jackson types (in maven build)
public class ObjectMappers {

    private static final Logger logger = LoggerFactory.getLogger(ObjectMappers.class);

    private ObjectMappers() {}

    public static ObjectMapper create() {
        return new ObjectMapper().registerModule(EnumModule.create());
    }

    public static  T readRequiredValue(ObjectMapper mapper, String content, Class valueType)
            throws IOException {
        T value = mapper.readValue(content, valueType);
        if (value == null) {
            throw new JsonMappingException("Content is json null");
        }
        return value;
    }

    public static JsonNode getRequiredChildNode(JsonNode parentNode, String fieldName)
            throws IOException {
        JsonNode node = parentNode.get(fieldName);
        if (node == null) {
            throw new JsonMappingException("Missing required field: " + fieldName);
        }
        if (node.isNull()) {
            throw new JsonMappingException("Required field is json null: " + fieldName);
        }
        return node;
    }

    @EnsuresNonNull("#1")
    public static  void checkRequiredProperty(final T reference, String fieldName)
            throws JsonMappingException {
        if (reference == null) {
            throw new JsonMappingException("Null value not allowed for field: " + fieldName);
        }
    }

    @SuppressWarnings("return.type.incompatible")
    public static  List orEmpty(@Nullable List list, String fieldName)
            throws JsonMappingException {
        if (list == null) {
            return ImmutableList.of();
        }
        for (T item : list) {
            if (item == null) {
                throw new JsonMappingException(
                        "Null items are not allowed in array field: " + fieldName);
            }
        }
        return list;
    }

    @PolyNull
    @SuppressWarnings("return.type.incompatible")
    public static  List checkNotNullItems(@PolyNull List list,
            String fieldName) throws JsonMappingException {
        if (list == null) {
            return null;
        }
        for (T item : list) {
            if (item == null) {
                throw new JsonMappingException(
                        "Null items are not allowed in array field: " + fieldName);
            }
        }
        return list;
    }

    @PolyNull
    @SuppressWarnings("return.type.incompatible")
    public static  Map checkNotNullValuesForProperty(
            @PolyNull Map map, String fieldName) throws JsonMappingException {
        if (map == null) {
            return null;
        }
        for (Entry entry : map.entrySet()) {
            if (entry.getValue() == null) {
                throw new JsonMappingException(
                        "Null values are not allowed in object: " + fieldName);
            }
        }
        return map;
    }

    // named after guava Strings.nullToEmpty
    public static  List nullToEmpty(@Nullable List list) {
        if (list == null) {
            return Lists.newArrayList();
        } else {
            return list;
        }
    }

    // named after guava Strings.nullToEmpty
    public static  Map nullToEmpty(@Nullable Map map) {
        if (map == null) {
            return Maps.newHashMap();
        } else {
            return map;
        }
    }

    // named after guava Strings.nullToEmpty
    public static boolean nullToFalse(@Nullable Boolean value) {
        return value == null ? false : value;
    }

    @SuppressWarnings("serial")
    private static class EnumModule extends SimpleModule {
        private static EnumModule create() {
            EnumModule module = new EnumModule();
            module.addSerializer(Enum.class, new EnumSerializer());
            return module;
        }
        @Override
        public void setupModule(SetupContext context) {
            super.setupModule(context);
            context.addDeserializers(new Deserializers.Base() {
                @Override
                public EnumDeserializer findEnumDeserializer(Class enumClass,
                        DeserializationConfig config, BeanDescription beanDesc)
                                throws JsonMappingException {
                    return new EnumDeserializer(enumClass);
                }
            });
        }
    }

    private static class EnumSerializer extends JsonSerializer