/**
 *
 */
package org.gcube.portlets.user.geoportaldataviewer.server.gis;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.apache.commons.io.IOUtils;
import org.gcube.application.geoportalcommon.shared.gis.BoundsMap;
import org.gcube.application.geoportalcommon.util.URLParserUtil;
import org.gcube.portlets.user.geoportaldataviewer.client.GeoportalDataViewerConstants;
import org.gcube.portlets.user.geoportaldataviewer.shared.gis.LayerItem;
import org.gcube.portlets.user.geoportaldataviewer.shared.gis.wfs.FeatureGeometry;
import org.gcube.portlets.user.geoportaldataviewer.shared.gis.wfs.FeatureRow;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The Class FeatureParser.
 *
 * @author Francesco Mangiacrapa at ISTI-CNR (francesco.mangiacrapa@isti.cnr.it)
 * 
 *         Nov 13, 2020
 */
public class FeatureParser {

	private static Logger LOG = LoggerFactory.getLogger(FeatureParser.class);

	/**
	 * Gets the WFS features.
	 *
	 * @param layerItem     the layer item
	 * @param mapSrsName    the map srs name
	 * @param selectBBOX    the select BBOX
	 * @param maxWFSFeature the max WFS feature
	 * @return the WFS features
	 */
	public static List<FeatureRow> getWFSFeatures(LayerItem layerItem, String mapSrsName, BoundsMap selectBBOX,
			int maxWFSFeature) {

		if (maxWFSFeature < 0) {
			maxWFSFeature = GeoportalDataViewerConstants.MAX_WFS_FEATURES;
		}
		return getWFSFeatureProperties(layerItem, mapSrsName, selectBBOX, maxWFSFeature);
	}

	/**
	 * Gets the WFS feature properties.
	 *
	 * @param layerItem     the layer item
	 * @param mapSrsName    the map srs name
	 * @param selectBBOX    the select BBOX
	 * @param maxWFSFeature the max WFS feature
	 * @return the WFS feature properties
	 */
	@SuppressWarnings("unchecked")
	private static List<FeatureRow> getWFSFeatureProperties(LayerItem layerItem, String mapSrsName,
			BoundsMap selectBBOX, int maxWFSFeature) {

		LOG.info("getWFSFeatureProperties for layerItem:  " + layerItem.getName() + " in the " + selectBBOX
				+ " and maxWFSFeature: " + maxWFSFeature);
		InputStream is = null;
		List<FeatureRow> listFeaturesRow = new ArrayList<FeatureRow>();
		try {
			String url = GisMakers.buildWFSFeatureQuery(layerItem, mapSrsName, selectBBOX, maxWFSFeature,
					GisMakers.JSON);
			String cqlFilterValue = URLParserUtil.extractValueOfParameterFromURL(GisMakers.CQL_FILTER_PARAMETER, url);
			LOG.info("Found CQL filter value into query string: " + cqlFilterValue);

			if (cqlFilterValue != null) {
				String notEncodedCQLFilter = String.format("%s=%s", GisMakers.CQL_FILTER_PARAMETER, cqlFilterValue);
				// log.info("Found CQL filter: "+notEncodedCQLFilter);
				String toEncodeCQLFilter = String.format("%s=%s", GisMakers.CQL_FILTER_PARAMETER,
						URLEncoder.encode(cqlFilterValue, "UTF-8"));
				LOG.debug("Encoded CQL filter: " + toEncodeCQLFilter);
				url = url.replace(notEncodedCQLFilter, toEncodeCQLFilter);
			}

			LOG.info("Built WFS URL:  " + url);
			is = new URL(url).openStream();
			String jsonTxt = IOUtils.toString(is);

			if (jsonTxt == null || jsonTxt.isEmpty()) {
				jsonTxt = "{\"type\":\"FeatureCollection\",\"features\":[]}";
			}

			// get json object
			JSONObject json = new JSONObject(jsonTxt);
			// iterate features
			JSONArray features = json.getJSONArray("features");
			if (features.length() == 0) {
				LOG.info("No features detected in the response, returning empty list");
				return listFeaturesRow;
			}

			String featureCRSName = "";
			try {
				JSONObject crs = json.getJSONObject("crs");
				JSONObject crsProp = crs.getJSONObject("properties");
				featureCRSName = crsProp.getString("name");
				LOG.info("Crs name found:  " + featureCRSName);
			} catch (Exception e) {
				LOG.warn("Unable to read the field 'crs'");
			}

			LOG.info("Features are:  " + features.length());

			for (int i = 0; i < features.length(); i++) {
				final FeatureRow row = new FeatureRow();
				row.setCrsName(featureCRSName);
				JSONObject theFeature = ((JSONObject) features.get(i));
				LOG.debug("Building at index: " + i);

				try {
					String fetaureId = theFeature.getString("id");
					row.setId(fetaureId);
					JSONObject geometry = theFeature.getJSONObject("geometry");
					String typeValue = geometry.getString("type");
					FeatureGeometry fg = new FeatureGeometry();
					fg.setType(typeValue);
					
					try {
						JSONArray coordinates = geometry.getJSONArray("coordinates");
						String coordinateJSONString = coordinates.toString();
						LOG.debug("coordinates are: " + coordinateJSONString);
						fg.setCoordinatesJSON(coordinates.toString());
					} catch (Exception e) {
						LOG.warn("Not able to parse the 'coordinates' field: ", e);
					}

					row.setGeometry(fg);
				} catch (Exception e) {
					LOG.debug("Unable to parse geometry at index: " + i);
				}

//				// iterate properties
				JSONObject properties = theFeature.getJSONObject("properties");
				Map<String, List<String>> mapProperties = new HashMap<String, List<String>>();
				@SuppressWarnings("unchecked")
				Iterator<String> ii = properties.keys();
				while (ii.hasNext()) {
					String key = ii.next();
					String value = properties.optString(key, "");

					List<String> theValues = mapProperties.get(key);
					if (theValues == null)
						mapProperties.put(key, Arrays.asList(value));
					else {
						theValues.add(value);
						mapProperties.put(key, theValues);
					}
				}
				row.setMapProperties(mapProperties);
				listFeaturesRow.add(row);
				LOG.info("Added row " + row + " to exported properties");
			}

		} catch (IOException e) {
			LOG.error("Error for layerItem name: " + layerItem.getName(), e);
		} catch (JSONException e) {
			LOG.error("Error for layerItem name: " + layerItem.getName(), e);
		} finally {
			IOUtils.closeQuietly(is);
		}

		LOG.info("Returning  " + listFeaturesRow.size() + " features");
		return listFeaturesRow;
	}
}