/*
 * Copyright (c) 2014 Hewlett-Packard Development Company, L.P.
 * 
 * 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 monasca.api.resource;

import com.google.common.base.Strings;

import com.codahale.metrics.annotation.Timed;

import org.joda.time.DateTime;

import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import javax.inject.Inject;
import javax.ws.rs.GET;
import javax.ws.rs.HeaderParam;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.UriInfo;

import monasca.api.app.validation.Validation;
import monasca.api.domain.model.common.Paged;
import monasca.api.domain.model.measurement.MeasurementRepo;
import monasca.api.domain.model.measurement.Measurements;

/**
 * Measurement resource implementation.
 */
@Path("/v2.0/metrics/measurements")
public class MeasurementResource {

  private final MeasurementRepo repo;

  @Inject
  public MeasurementResource(MeasurementRepo repo) {
    this.repo = repo;
  }

  @GET
  @Timed
  @Produces(MediaType.APPLICATION_JSON)
  public Object get(@Context UriInfo uriInfo, @HeaderParam("X-Tenant-Id") String tenantId,
                    @QueryParam("name") String name, @QueryParam("dimensions") String dimensionsStr,
                    @QueryParam("start_time") String startTimeStr,
                    @QueryParam("end_time") String endTimeStr, @QueryParam("offset") String offset)
      throws Exception {

    // Validate query parameters
    DateTime startTime = Validation.parseAndValidateDate(startTimeStr, "start_time", true);
    DateTime endTime = Validation.parseAndValidateDate(endTimeStr, "end_time", false);
    Validation.validateTimes(startTime, endTime);
    Map<String, String>
        dimensions =
        Strings.isNullOrEmpty(dimensionsStr) ? null : Validation
            .parseAndValidateNameAndDimensions(name, dimensionsStr);

    List<Measurements> measurementsList = repo.find(tenantId, name, dimensions, startTime, endTime, offset);
    List<Object> pagedList = new LinkedList();

    for (Measurements measurements : measurementsList) {
      pagedList.add(Links.paginateMeasurements(offset, measurements, uriInfo));
    }

    if (offset != null) {
      Paged paged = new Paged();
      paged.elements = pagedList;
      return paged;
    } else {
      Paged paged = new Paged();
      paged.elements = pagedList;
      return paged;
    }
  }
}