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/*
 * Copyright 2014 Proofpoint, Inc.
 *
 * 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 com.proofpoint.http.client;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.dataformat.smile.SmileFactory;
import com.google.common.base.Suppliers;
import com.proofpoint.json.JsonCodec;
import com.proofpoint.json.ObjectMapperProvider;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.lang.reflect.Type;
import java.util.function.Supplier;

public class SmileBodyGenerator
        extends StaticBodyGenerator
{
    private static final Supplier OBJECT_MAPPER_SUPPLIER = Suppliers.memoize(
            () -> new ObjectMapperProvider().get())::get;

    public static  SmileBodyGenerator smileBodyGenerator(JsonCodec jsonCodec, T instance)
    {
        ObjectMapper objectMapper = OBJECT_MAPPER_SUPPLIER.get();
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        JsonGenerator jsonGenerator;
        try {
            jsonGenerator = new SmileFactory().createGenerator(out);
        }
        catch (IOException e) {
            throw new RuntimeException(e);
        }

        Type genericType = jsonCodec.getType();
        // 04-Mar-2010, tatu: How about type we were given? (if any)
        JavaType rootType = null;
        if (genericType != null && instance != null) {
            // 10-Jan-2011, tatu: as per [JACKSON-456], it's not safe to just force root
            // type since it prevents polymorphic type serialization. Since we really
            // just need this for generics, let's only use generic type if it's truly
            // generic.
            if (genericType.getClass() != Class.class) { // generic types are other implementations of 'java.lang.reflect.Type'
                // This is still not exactly right; should root type be further
                // specialized with 'value.getClass()'? Let's see how well this works before
                // trying to come up with more complete solution.
                rootType = objectMapper.getTypeFactory().constructType(genericType);
                // 26-Feb-2011, tatu: To help with [JACKSON-518], we better recognize cases where
                // type degenerates back into "Object.class" (as is the case with plain TypeVariable,
                // for example), and not use that.
                //
                if (rootType.getRawClass() == Object.class) {
                    rootType = null;
                }
            }
        }

        try {
            if (rootType != null) {
                objectMapper.writerFor(rootType).writeValue(jsonGenerator, instance);
            }
            else {
                objectMapper.writeValue(jsonGenerator, instance);
            }
        }
        catch (IOException e) {
            throw new IllegalArgumentException(String.format("%s could not be converted to SMILE", instance == null ? "null" : instance.getClass().getName()), e);
        }

        return new SmileBodyGenerator<>(out.toByteArray());
    }

    private SmileBodyGenerator(byte[] body)
    {
        super(body);
    }
}