/*
 * Copyright (c) 2015 OpenSilk Productions LLC
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 */

package syncthing.api;

import com.google.gson.FieldNamingPolicy;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.JsonPrimitive;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;

import org.joda.time.DateTime;

import java.lang.reflect.Type;
import java.util.Date;

import javax.inject.Singleton;

import dagger.Module;
import dagger.Provides;
import syncthing.api.model.Versioning;
import syncthing.api.model.VersioningTypeConverter;
import syncthing.api.model.event.Event;
import syncthing.api.model.event.EventDeserializer;

/**
 * Created by drew on 3/8/15.
 */
@Module
public class GsonModule {

    @Provides @Singleton
    public Gson provideGson() {
        return new GsonBuilder()
                .setFieldNamingPolicy(FieldNamingPolicy.IDENTITY)
                .registerTypeAdapter(DateTime.class, new DateTimeTypeConverter())
                .registerTypeAdapter(Event.class, new EventDeserializer())
                .registerTypeAdapter(Versioning.class, new VersioningTypeConverter())
                .create();
    }

    private static class DateTimeTypeConverter implements JsonSerializer<DateTime>, JsonDeserializer<DateTime> {
        @Override
        public JsonElement serialize(DateTime src, Type srcType, JsonSerializationContext context) {
            return new JsonPrimitive(src.toString());
        }

        @Override
        public DateTime deserialize(JsonElement json, Type type, JsonDeserializationContext context) throws JsonParseException {
            try {
                return new DateTime(json.getAsString());
            } catch (IllegalArgumentException e) {
                // May be it came in formatted as a java.util.Date, so try that
                Date date = context.deserialize(json, Date.class);
                return new DateTime(date);
            }
        }
    }
}