/**
 * Copyright (C) 2010-2017 Structr GmbH
 *
 * This file is part of Structr <http://structr.org>.
 *
 * Structr is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * Structr is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with Structr.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.structr.web.function;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.reflect.TypeToken;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import org.apache.commons.lang3.StringUtils;
import org.structr.core.GraphObjectMap;
import org.structr.schema.action.ActionContext;

/**
 *
 */
public class FromJsonFunction extends UiFunction {

	public static final String ERROR_MESSAGE_FROM_JSON    = "Usage: ${from_json(src)}. Example: ${from_json('{name:test}')}";
	public static final String ERROR_MESSAGE_FROM_JSON_JS = "Usage: ${{Structr.from_json(src)}}. Example: ${{Structr.from_json('{name:test}')}}";

	@Override
	public String getName() {
		return "from_json()";
	}

	@Override
	public Object apply(final ActionContext ctx, final Object caller, final Object[] sources) {

		if (sources != null && sources.length > 0) {

			if (sources[0] == null) {
				return "";
			}

			try {

				final String source = sources[0].toString();
				final Gson gson = new GsonBuilder().create();
				List<Map<String, Object>> objects = new LinkedList<>();

				if (StringUtils.startsWith(source, "[")) {

					final List<Map<String, Object>> list = gson.fromJson(source, new TypeToken<List<Map<String, Object>>>() {
					}.getType());
					final List<GraphObjectMap> elements = new LinkedList<>();

					if (list != null) {

						objects.addAll(list);
					}

					for (final Map<String, Object> src : objects) {

						final GraphObjectMap destination = new GraphObjectMap();
						elements.add(destination);

						recursivelyConvertMapToGraphObjectMap(destination, src, 0);
					}

					return elements;

				} else if (StringUtils.startsWith(source, "{")) {

					final Map<String, Object> value = gson.fromJson(source, new TypeToken<Map<String, Object>>() {
					}.getType());
					final GraphObjectMap destination = new GraphObjectMap();

					if (value != null) {

						recursivelyConvertMapToGraphObjectMap(destination, value, 0);
					}

					return destination;
				}

			} catch (Throwable t) {

				logException(caller, t, sources);

			}

			return "";

		} else {

			logParameterError(caller, sources, ctx.isJavaScriptContext());

		}

		return usage(ctx.isJavaScriptContext());
	}

	@Override
	public String usage(boolean inJavaScriptContext) {
		return (inJavaScriptContext ? ERROR_MESSAGE_FROM_JSON_JS : ERROR_MESSAGE_FROM_JSON);
	}

	@Override
	public String shortDescription() {
		return "Parses the given JSON string and returns an object";
	}

}