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package m.timeseries.aggregate;

import com.mongodb.MongoClient;
import com.mongodb.MongoClientURI;
import com.mongodb.client.AggregateIterable;
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import static com.mongodb.client.model.Aggregates.group;
import static com.mongodb.client.model.Aggregates.match;
import static com.mongodb.client.model.Aggregates.project;
import static com.mongodb.client.model.Aggregates.sort;
import static com.mongodb.client.model.Aggregates.unwind;
import com.mongodb.client.model.Filters;
import javax.ws.rs.Path;
import csip.ModelDataService;
import csip.ServiceException;
import csip.annotations.*;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import static java.util.Arrays.asList;
import java.util.Date;
import java.util.List;
import java.util.TimeZone;
import org.bson.Document;
import org.bson.types.ObjectId;
import org.bson.conversions.Bson;
import org.codehaus.jettison.json.JSONArray;
import org.codehaus.jettison.json.JSONException;
import org.codehaus.jettison.json.JSONObject;

/**
 * Mongodb timeseries data aggregation
 *
 * @author Dave Patterson
 */
@Name("Timeseries aggregation")
@Description("Aggregate timeseries data in mongo.")
@Author(org = "CSU")
@License(License.MIT)
@Path("m/aggregate/1.0")
public class V1_0 extends ModelDataService {

  MongoClient mongo;
  MongoDatabase db;

  JSONArray results = new JSONArray();

  protected void open(String mongoclienturi) {
    MongoClientURI u = new MongoClientURI(mongoclienturi);
    mongo = new MongoClient(u);
    if (u.getDatabase() == null) {
      throw new RuntimeException("Missing database in mongo uri: " + mongoclienturi);
    }
    db = mongo.getDatabase(u.getDatabase());
  }

  protected void close() {
    mongo.close();
  }

  @Override
  public void doProcess() throws Exception {
    String mongoUri = getStringParam("mongo_uri");
    String mongoCollection = getStringParam("mongo_collection");
    String startDate = getStringParam("start_date", null);
    String endDate = getStringParam("end_date", null);
    String searchId = getStringParam("search_id", null);
    JSONObject searchFeature = getJSONParam("search_feature", null);
    String aggregationLevel = getStringParam("aggregation_level", "monthly");

    run(mongoUri, mongoCollection, searchFeature, searchId, startDate, endDate, aggregationLevel);
  }

  @Override
  protected void postProcess() throws Exception {
    putResult("result", results);
  }

  /**
   * 
   * @param mongoUri
   * @param mongoCollection
   * @param searchFeature
   * @param searchId
   * @param startDateStr
   * @param endDateStr
   * @param aggregationLevel
   * @throws JSONException
   * @throws ServiceException 
   */
  void run(String mongoUri, String mongoCollection, JSONObject searchFeature, String searchId,
          String startDateStr, String endDateStr, String aggregationLevel)
          throws JSONException, ServiceException {

    open(mongoUri);
    MongoCollection<Document> collection = db.getCollection(mongoCollection);

    SimpleDateFormat ft = new SimpleDateFormat("yyyy-MM-dd");
    ft.setTimeZone(TimeZone.getTimeZone("UTC"));
    Date startDate = null;
    Date endDate = null;
    if (startDateStr != null) {
      try {
        startDate = ft.parse(startDateStr);
        endDate = ft.parse(endDateStr);
      } catch (ParseException ex) {
        throw new ServiceException(ex);
      }
    }

    // This will find all location (top-level) documents by checking that the
    //   foreign-key location_id does not exist.
    Document locationsOnly = new Document().append("location_id", new Document().append("$exists", false));
    if (searchFeature == null) {
      FindIterable<Document> c;
      if (searchId == null) {
        // No search and no location filter, so get all docs in collection
        c = collection.find(locationsOnly);
      } else {
        // Search by document ID.
        // Check for object ID (will be a hexidecimal string)
        boolean idTest = searchId.matches("\\p{XDigit}+");
        if (idTest) {
          ObjectId search_objid = new ObjectId(searchId);
          c = collection.find(Filters.eq("_id", search_objid));
        } else {
          // Simple search using string
          c = collection.find(Filters.eq("_id", searchId));
        }
      }
      for (Document locationDoc : c) {
        JSONObject res = getResult(collection, locationDoc, startDate, endDate, aggregationLevel);
        results.put(res);
      }
    } else {
      JSONArray features = searchFeature.getJSONArray("features");
      for (int i = 0; i < features.length(); i++) {
        JSONObject feat = features.getJSONObject(i);
        List<Bson> aggMatch = null;
        try {
          aggMatch = getMatch(feat, searchId);
        } catch (IOException ex) {
          throw new ServiceException(ex);
        }
        AggregateIterable<Document> c = collection.aggregate(aggMatch);
        for (Document locationDoc : c) {
          JSONObject res = getResult(collection, locationDoc, startDate, endDate, aggregationLevel);
          results.put(res);
        }
      }
    }
    close();
  }

  private JSONObject getResult(MongoCollection<Document> c, Document locationDoc, Date startDate, Date endDate,
          String aggregationLevel) throws JSONException {
    /*
    db.getCollection("bigdata test series").aggregate([
    { "$match": { "location_id": "big_yearlychunks" } },
    { "$unwind": "$data" },
    { "$project": {
        "tmin": { "$arrayElemAt": ["$data", 1] },
        "month": { $month: { "$arrayElemAt": ["$data", 0] } },
        "year": { $year: { "$arrayElemAt": ["$data", 0] } },
    } },
    { "$group": {
        "_id": { month: "$month", year: "$year" },
        "tmin_avg": { "$avg": "$tmin" },
        "tmin_min": { "$min": "$tmin" },
        "tmin_max": { "$max": "$tmin" },
        "month": { "$first": "$month" },
        "year": { "$first": "$year" },
    } },
    { "$sort": { "year": 1, "month": 1 } },
    ])
    */
    List<String> header = (ArrayList) locationDoc.get("header");
    List<List<Object>> filtered = new ArrayList();

    List<Bson> aggList = asList(
            match(new Document("location_id", locationDoc.getString("_id"))),
            unwind("$data"),
            match(new Document("data.0", filterData(startDate, endDate))),
            project(projectData(header)),
            // I can't use Aggregates.group because $first in the _id field causes an error.
            new Document("$group", groupData(header)),
            sort(new Document("year", 1).append("month", 1))
    );
            
    AggregateIterable<Document> iter = c.aggregate(aggList).allowDiskUse(true);
    for (Document d : iter) {
        List<Object> row = new ArrayList<>();
        // Fix date formatting
        row.add(d.get("year") + "-" + d.get("month") + "-01");
        for (int i = 1; i < header.size(); i++) {
          String p = header.get(i);
          row.add(d.get(p + "_avg"));
        }
        filtered.add(row);
    }

    JSONObject res = new JSONObject(locationDoc.toJson());
    res.put("header", header);
    res.put("data", filtered);

    return res;
  }
  
  private Document filterData(Date startDate, Date endDate) {
    Document datesQuery = new Document();
    if ((startDate != null || endDate != null)) {
      if (startDate != null) {
        datesQuery.append("$gte", startDate);
      }
      if (endDate != null) {
        datesQuery.append("$lte", endDate);
      }
    }
    return datesQuery;
  }
  
  private Document projectData(List<String> header) {
    Document project = new Document();
    for (int i = 1; i < header.size(); i++) {
      project.append(header.get(i), new Document("$arrayElemAt", asList("$data", i)));
    }
    project.append("month", new Document("$month", new Document("$arrayElemAt", asList("$data", 0))));
    project.append("year", new Document("$year", new Document("$arrayElemAt", asList("$data", 0))));
    return project;
  }
  
  private Document groupData(List<String> header) {
    Document group = new Document("_id", new Document("month", "$month").append("year", "$year"));
    for (int i = 1; i < header.size(); i++) {
      group.append(header.get(i) + "_avg", new Document("$avg", "$" + header.get(i)));
    }
    group.append("month", new Document("$first", "$month"));
    group.append("year", new Document("$first", "$year"));
    return group;
  }

  public List<Bson> getMatch(JSONObject feat, String search_id) throws JSONException, IOException {
    String geom = feat.getJSONObject("geometry").toString();
    Document match_arg = new Document("location",
            new Document("$geoWithin",
                    new Document("$geometry", Document.parse(geom))
            )
    );
    if (search_id != null) {
      // Check for object ID (will be a hexidecimal string)
      boolean id_test = search_id.matches("\\p{XDigit}+");
      if (id_test) {
        ObjectId search_objid = new ObjectId(search_id);
        match_arg.put("_id", search_objid);
      } else {
        match_arg.put("_id", search_id);
      }
    }
    Document new_match = new Document("$match", match_arg);
    List<Bson> agg_match = new ArrayList<>();
    agg_match.add(new_match);
    return agg_match;
  }

  public static void main(String[] args) throws FileNotFoundException, IOException, JSONException, ParseException, ServiceException {
    V1_0 timeseries = new V1_0();
    JSONObject searchFeature = new JSONObject("{\n"
            + "                \"type\": \"FeatureCollection\",\n"
            + "                \"features\": [\n"
            + "                  {\n"
            + "                    \"geometry\": {\n"
            + "                      \"type\": \"MultiPolygon\",\n"
            + "                      \"coordinates\": [\n"
            + "                        [\n"
            + "                          [\n"
            + "                            [\n"
            + "                              -105.09928580027,\n"
            + "                              40.701406829918\n"
            + "                            ],\n"
            + "                            [\n"
            + "                              -105.09447928172,\n"
            + "                              40.365324016903\n"
            + "                            ],\n"
            + "                            [\n"
            + "                              -104.72849722611,\n"
            + "                              40.358522384503\n"
            + "                            ],\n"
            + "                            [\n"
            + "                              -104.72437735306,\n"
            + "                              40.701927386425\n"
            + "                            ],\n"
            + "                            [\n"
            + "                              -105.09928580027,\n"
            + "                              40.701406829918\n"
            + "                            ]\n"
            + "                          ]\n"
            + "                        ]\n"
            + "                      ]\n"
            + "                    },\n"
            + "                    \"type\": \"Feature\",\n"
            + "                    \"properties\": {\n"
            + "                      \"gid\": 1,\n"
            + "                      \"name\": \"gid 1\"\n"
            + "                    }\n"
            + "                  }\n"
            + "                ]\n"
            + "            }");
    String search_id = null;
    timeseries.run("mongodb://eds0.engr.colostate.edu:27017/csip_timeseries", "test_coll", searchFeature, search_id, "2014-04-04", "2014-05-08", "monthly");
  }
}