/**
 * Copyright 2015 ArcBees 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.arcbees.gaestudio.server.api.visualizer;

import javax.inject.Inject;
import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.ResponseBuilder;
import javax.ws.rs.core.Response.Status;

import com.arcbees.gaestudio.server.dto.mapper.EntityMapper;
import com.arcbees.gaestudio.server.guice.GaeStudioResource;
import com.arcbees.gaestudio.server.service.visualizer.EntityService;
import com.arcbees.gaestudio.server.util.AppEngineHelper;
import com.arcbees.gaestudio.shared.dto.entity.EntityDto;
import com.arcbees.gaestudio.shared.rest.EndPoints;
import com.arcbees.gaestudio.shared.rest.UrlParameters;
import com.google.api.client.repackaged.com.google.common.base.Strings;
import com.google.appengine.api.datastore.Entity;
import com.google.appengine.api.datastore.EntityNotFoundException;
import com.google.appengine.api.datastore.Key;
import com.google.appengine.api.datastore.KeyFactory;

@Path(EndPoints.ENTITY)
@Produces(MediaType.APPLICATION_JSON)
@GaeStudioResource
public class EntityResource {
    private final EntityMapper entityMapper;
    private final EntityService entityService;

    @Inject
    EntityResource(
            EntityService entityService,
            EntityMapper entityMapper) {
        this.entityMapper = entityMapper;
        this.entityService = entityService;
    }

    @GET
    public Response getEntity(@QueryParam(UrlParameters.KEY) String encodedKey) throws EntityNotFoundException {
        ResponseBuilder responseBuilder;

        if (isBadRequest(encodedKey)) {
            responseBuilder = Response.status(Status.BAD_REQUEST);
        } else {
            Entity entity = entityService.getEntity(encodedKey);

            responseBuilder = buildResponseFromEntity(entity);
        }

        return responseBuilder.build();
    }

    @PUT
    public Response updateEntity(EntityDto newEntityDto) throws EntityNotFoundException {
        ResponseBuilder responseBuilder;
        Entity newEntity = entityMapper.mapDtoToEntity(newEntityDto);
        Entity updatedEntity = entityService.updateEntity(newEntity);

        if (updatedEntity == null) {
            responseBuilder = Response.status(Status.NOT_FOUND);
        } else {
            EntityDto updatedEntityDto = entityMapper.mapEntityToDto(updatedEntity);
            responseBuilder = Response.ok(updatedEntityDto);
        }

        return responseBuilder.build();
    }

    @DELETE
    public Response deleteEntity(@QueryParam(UrlParameters.KEY) String encodedKey) {
        AppEngineHelper.disableApiHooks();
        ResponseBuilder responseBuilder = Response.noContent();
        Key key;

        if (isBadRequest(encodedKey)) {
            responseBuilder = Response.status(Status.BAD_REQUEST);
        } else {
            key = KeyFactory.stringToKey(encodedKey);

            entityService.deleteEntity(key);
        }

        return responseBuilder.build();
    }

    private ResponseBuilder buildResponseFromEntity(Entity entity) {
        ResponseBuilder responseBuilder;

        if (entity == null) {
            responseBuilder = Response.status(Status.NOT_FOUND);
        } else {
            EntityDto entityDto = entityMapper.mapEntityToDto(entity);
            responseBuilder = Response.ok(entityDto);
        }

        return responseBuilder;
    }

    private boolean isBadRequest(String encodedKey) {
        return Strings.isNullOrEmpty(encodedKey);
    }
}