/*
 * 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.infrastructure.persistence.vertica;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.inject.Inject;
import javax.inject.Named;

import org.skife.jdbi.v2.DBI;
import org.skife.jdbi.v2.Handle;
import org.skife.jdbi.v2.Query;

import monasca.common.model.metric.MetricDefinition;
import monasca.api.domain.model.metric.MetricDefinitionRepo;
import monasca.api.infrastructure.persistence.DimensionQueries;

/**
 * Vertica metric definition repository implementation.
 */
public class MetricDefinitionVerticaRepoImpl implements MetricDefinitionRepo {
  private static final String FIND_BY_METRIC_DEF_SQL =
      "select dd.id, def.name, d.name as dname, d.value as dvalue "
          + "from MonMetrics.Definitions def, MonMetrics.DefinitionDimensions dd "
          + "left outer join MonMetrics.Dimensions d on d.dimension_set_id = dd.dimension_set_id%s "
          + "where def.id = dd.definition_id and def.tenant_id = :tenantId%s order by dd.id";

  private final DBI db;

  @Inject
  public MetricDefinitionVerticaRepoImpl(@Named("vertica") DBI db) {
    this.db = db;
  }

  @Override
  public List<MetricDefinition> find(String tenantId, String name, Map<String, String> dimensions,
                                     String offset) {
    // Todo. Use offset for pagination.

    try (Handle h = db.open()) {
      // Build sql
      StringBuilder sbWhere = new StringBuilder();
      if (name != null)
        sbWhere.append(" and def.name = :name");
      String sql =
          String.format(FIND_BY_METRIC_DEF_SQL, MetricQueries.buildJoinClauseFor(dimensions),
              sbWhere);

      // Build query
      Query<Map<String, Object>> query = h.createQuery(sql).bind("tenantId", tenantId);
      if (name != null)
        query.bind("name", name);
      DimensionQueries.bindDimensionsToQuery(query, dimensions);

      // Execute query
      List<Map<String, Object>> rows = query.list();

      // Build results
      List<MetricDefinition> metricDefs = new ArrayList<>(rows.size());
      byte[] currentId = null;
      Map<String, String> dims = null;
      for (Map<String, Object> row : rows) {
        byte[] defId = (byte[]) row.get("id");
        String metricName = (String) row.get("name");
        String dName = (String) row.get("dname");
        String dValue = (String) row.get("dvalue");

        if (defId == null || !Arrays.equals(currentId, defId)) {
          currentId = defId;
          dims = new HashMap<>();
          if (dName != null && dValue != null)
            dims.put(dName, dValue);
          metricDefs.add(new MetricDefinition(metricName, dims));
        } else
          dims.put(dName, dValue);
      }

      return metricDefs;
    }
  }
}