package org.gcube.portlets.user.geoportaldataentry.server;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;

import org.gcube.application.geoportalcommon.shared.geoportal.config.GcubeProfileDV;
import org.gcube.portlets.user.geoportaldataentry.shared.GeoNaFormDataObject;
import org.gcube.portlets.user.geoportaldataentry.shared.Tree_Node;
import org.gcube.portlets.widgets.mpformbuilder.shared.GenericDatasetBean;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.jayway.jsonpath.Configuration;
import com.jayway.jsonpath.JsonPath;
import com.jayway.jsonpath.spi.json.JsonOrgJsonProvider;

/**
 * The Class FormDataObjectToJSON.
 *
 * @author Francesco Mangiacrapa at ISTI-CNR francesco.mangiacrapa@isti.cnr.it
 * 
 *         Mar 10, 2022
 */
public class FormDataObjectToJSON {

	public static final String JSON_$_POINTER = "$";
	private static final Logger LOG = LoggerFactory.getLogger(FormDataObjectToJSON.class);

	/**
	 * Convert.
	 *
	 * @param tree_Node       the tree node
	 * @param theRootDocument the the root document
	 * @return the JSON object
	 * @throws JSONException the JSON exception
	 */
	public JSONObject convert(Tree_Node<GeoNaFormDataObject> tree_Node, JSONObject theRootDocument)
			throws JSONException {

		if (tree_Node == null)
			return theRootDocument;

		// the root, instancing new json document
		if (tree_Node.isRoot()) {
			theRootDocument = JSONObjecOrdered.instance();
		}

		Configuration configuration = Configuration.builder().jsonProvider(new JsonOrgJsonProvider()).build();

		for (Tree_Node<GeoNaFormDataObject> treeNodeChild : tree_Node.getChildren()) {

			GeoNaFormDataObject gnaFO = treeNodeChild.getData();
			
			// Reading data and profile
			List<GenericDatasetBean> listGDB = gnaFO.getListGDB();
			GcubeProfileDV profile = gnaFO.getGcubeProfileDV();
			LOG.debug("The profile is: " + profile);

			// Building JSON/section full PATH and section name
			String sectionJSONPath = "";
			String parentPathFromProfile = profile.getParentName() == null ? "" : profile.getParentName();
			String theSectionName = profile.getSectionName();

			if (theSectionName.compareTo(JSON_$_POINTER) == 0 || theSectionName.compareTo(JSON_$_POINTER + ".") == 0) {
				sectionJSONPath = JSON_$_POINTER;
				theSectionName = "";
			} else {
				sectionJSONPath = String.format("%s%s",
						parentPathFromProfile.endsWith(".") ? parentPathFromProfile : parentPathFromProfile + ".", theSectionName);
			}
			LOG.debug("The sectionJSONPath is: " + sectionJSONPath);
			LOG.info("Current document is: " + theRootDocument);

			// Building Parent PATH
			String parentPath = sectionJSONPath.compareTo(JSON_$_POINTER) == 0 ? JSON_$_POINTER
					: sectionJSONPath.substring(0, sectionJSONPath.lastIndexOf("."));
			JsonPath parentJSONPath = JsonPath.compile(parentPath);
			LOG.info("Putting into parentJSONPath: " + parentJSONPath);

			List<JSONObject> listJSONObject = toListJonObject(listGDB);
			JSONObject jsonObject = listJSONObject.get(0);

			// If the maxOccurs is not 1
			if (profile.getMaxOccurs() == 0 || profile.getMaxOccurs() > 1) {
				LOG.debug("maxOccurs is NOT 1");
				// Must be an array
				boolean pathExists = pathExists(theRootDocument, sectionJSONPath + "[*]");
				LOG.debug(sectionJSONPath+ "exists? "+pathExists);
				if (pathExists) {
					theRootDocument = JsonPath.parse(theRootDocument, configuration).add(sectionJSONPath, jsonObject)
							.json();
				} else {
					// Adding as array of object
					JSONArray targetArray = JSONArrayOrdered.instance();
					targetArray.put(jsonObject);
					LOG.debug("JSON array created: " + targetArray);
					theRootDocument = JsonPath.parse(theRootDocument, configuration)
							.put(parentJSONPath, theSectionName, targetArray).json();
				}

				LOG.debug("theRootDocument as array is: " + theRootDocument);

			} else {
				LOG.debug("maxOccurs is 1");
				// Merging as direct properties of the JSON root document
				if (theSectionName == null || theSectionName.isEmpty()) {
					deepMerge(jsonObject, theRootDocument);
				} else {
					// Putting as child of the JSON document
					// theRootDocument.put(profile.getSectionName(), jsonObject);
					theRootDocument = JsonPath.parse(theRootDocument, configuration)
							.put(parentJSONPath, theSectionName, jsonObject).json();
				}

				LOG.debug("theRootDocument as single object is: " + theRootDocument);
			}
			// recursive call...
			theRootDocument = convert(treeNodeChild, theRootDocument);
		}

		LOG.debug("Partial Root Document is: " + theRootDocument);
		return theRootDocument;

	}

	/**
	 * Path exists.
	 *
	 * @param document the document
	 * @param pathExp  the path exp
	 * @return true, if successful
	 */
	public static boolean pathExists(JSONObject document, String pathExp) {
		LOG.debug("pathExists called");

		try {
			LOG.debug("pathExists finding: " + pathExp + " into node: " + document);
			Object object = JsonPath.read(document.toString(), pathExp);
			if (object != null) {
				LOG.debug("pathExists returning true");
				return true;
			}
		} catch (Exception e) {
			LOG.error("pathExists error", e);
			return false;
		}

		LOG.debug("pathExists returning false");
		return false;
	}

	/**
	 * Generic dataset bean to JSON.
	 *
	 * @param gdb the gdb
	 * @return the JSON object
	 * @throws JSONException the JSON exception
	 */
	protected JSONObject genericDatasetBeanToJSON(GenericDatasetBean gdb) throws JSONException {

		JSONObject sectJSONObject = JSONObjecOrdered.instance();

		LinkedHashMap<String, List<String>> mapFields = gdb.getFormDataEntryFields();
		LOG.debug("Map ordered: " + mapFields);
		for (String key : mapFields.keySet()) {
			List<String> listValues = mapFields.get(key);
			if (listValues == null || listValues.isEmpty()) {
				continue;
			}
			// key/value as string
			if (listValues.size() == 1) {
				sectJSONObject.put(key, listValues.get(0));
				continue;
			}
			// value is a list
			JSONArray array = new JSONArray();
			for (String value : listValues) {
				array.put(value);
			}

			sectJSONObject.put(key, array);
		}

		return sectJSONObject;
	}

	/**
	 * To list jon object.
	 *
	 * @param listGDB the list GDB
	 * @return the list
	 * @throws JSONException the JSON exception
	 */
	private List<JSONObject> toListJonObject(List<GenericDatasetBean> listGDB) throws JSONException {

		List<JSONObject> listJSONObject = new ArrayList<JSONObject>();

		for (GenericDatasetBean gdb : listGDB) {
			JSONObject jsonObject = genericDatasetBeanToJSON(gdb);
			listJSONObject.add(jsonObject);
		}

		LOG.info("returning : " + listJSONObject);
		return listJSONObject;

	}

	/**
	 * Merge "source" into "target". If fields have equal name, merge them
	 * recursively.
	 *
	 * @param source the source
	 * @param target the target
	 * @return the merged object (target).
	 * @throws JSONException the JSON exception
	 */
	public static JSONObject deepMerge(JSONObject source, JSONObject target) throws JSONException {
		for (String key : JSONObject.getNames(source)) {
			Object value = source.get(key);
			if (!target.has(key)) {
				// new value for "key":
				target.put(key, value);
			} else {
				// existing value for "key" - recursively deep merge:
				if (value instanceof JSONObject) {
					JSONObject valueJson = (JSONObject) value;
					deepMerge(valueJson, target.getJSONObject(key));
				} else {
					target.put(key, value);
				}
			}
		}
		return target;
	}
	

	/**
	 * The Class JSONObjecOrdered.
	 *
	 * @author Francesco Mangiacrapa at ISTI-CNR francesco.mangiacrapa@isti.cnr.it
	 * 
	 *         Mar 10, 2022
	 */
	public static class JSONObjecOrdered {

		/**
		 * Instance.
		 *
		 * @return the JSON object
		 */
		public static JSONObject instance() {
			JSONObject jsonObject = new JSONObject();
			try {
				Field changeMap = jsonObject.getClass().getDeclaredField("map");
				changeMap.setAccessible(true);
				changeMap.set(jsonObject, new LinkedHashMap<>());
				changeMap.setAccessible(false);
			} catch (IllegalAccessException | NoSuchFieldException e) {
			}
			return jsonObject;
		}
	}

	/**
	 * The Class JSONObjecOrdered.
	 *
	 * @author Francesco Mangiacrapa at ISTI-CNR francesco.mangiacrapa@isti.cnr.it
	 * 
	 *         Mar 10, 2022
	 */
	public static class JSONArrayOrdered {

		/**
		 * Instance.
		 *
		 * @return the JSON object
		 */
		public static JSONArray instance() {
			JSONArray jsonArray = new JSONArray();
			try {
				Field changeMap = jsonArray.getClass().getDeclaredField("map");
				changeMap.setAccessible(true);
				changeMap.set(jsonArray, new LinkedHashMap<>());
				changeMap.setAccessible(false);
			} catch (IllegalAccessException | NoSuchFieldException e) {
			}
			return jsonArray;
		}
	}

}