/**
 * Copyright (C) 2012-2017 52°North Initiative for Geospatial Open Source
 * Software GmbH
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 * If the program is linked with libraries which are licensed under one of
 * the following licenses, the combination of the program with the linked
 * library is not considered a "derivative work" of the program:
 *
 *     - Apache License, version 2.0
 *     - Apache Software License, version 1.0
 *     - GNU Lesser General Public License, version 3
 *     - Mozilla Public License, versions 1.0, 1.1 and 2.0
 *     - Common Development and Distribution License (CDDL), version 1.0
 *
 * Therefore the distribution of the program linked with libraries licensed
 * under the aforementioned licenses, is permitted by the copyright holders
 * if the distribution is compliant with both the GNU General Public
 * License version 2 and the aforementioned licenses.
 *
 * This program 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 General
 * Public License for more details.
 */
package org.n52.sos.web.admin;

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.sql.SQLException;
import java.util.Map;
import java.util.ServiceLoader;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.servlet.ModelAndView;

import org.n52.sos.ds.ConnectionProviderException;
import org.n52.sos.ds.GeneralQueryDAO;
import org.n52.sos.ogc.ows.OwsExceptionReport;
import org.n52.sos.util.JSONUtils;
import org.n52.sos.web.ControllerConstants;

import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.google.common.collect.Maps;

/**
 * @since 4.0.0
 *
 */
@Controller
public class AdminDatasourceController extends AbstractDatasourceController {
    private static final Logger LOG = LoggerFactory.getLogger(AdminDatasourceController.class);

    private static final String ROWS = "rows";

    private static final String NAMES = "names";

    private static final String SUPPORTS_CLEAR = "supportsClear";

    private static final String SUPPORTS_DELETE_DELETED = "supportsDeleteDeleted";

    private ServiceLoader<GeneralQueryDAO> daoServiceLoader = ServiceLoader.load(GeneralQueryDAO.class);

    @RequestMapping(value = ControllerConstants.Paths.ADMIN_DATABASE)
    public ModelAndView index() throws SQLException, OwsExceptionReport {
        Map<String, Object> model = Maps.newHashMap();
        model.put(SUPPORTS_CLEAR, getDatasource().supportsClear());
        model.put(SUPPORTS_DELETE_DELETED, daoServiceLoader.iterator().hasNext());

        return new ModelAndView(ControllerConstants.Views.ADMIN_DATASOURCE, model);
    }

    @ResponseBody
    @RequestMapping(value = ControllerConstants.Paths.ADMIN_DATABASE_EXECUTE, method = RequestMethod.POST)
    public String processQuery(@RequestBody String querySQL) {
        try {
            String q = URLDecoder.decode(querySQL, "UTF-8");
            LOG.info("Query: {}", q);
            GeneralQueryDAO dao = daoServiceLoader.iterator().next();
            GeneralQueryDAO.QueryResult rs = dao.query(q);
            ObjectNode j = JSONUtils.nodeFactory().objectNode();
            if (rs.getMessage() != null) {
                j.put(rs.isError() ? "error" : "message", rs.getMessage());
                return JSONUtils.print(j);
            }
            j.putArray(ROWS).addAll(JSONUtils.toJSON(rs.getColumnNames()));
            ArrayNode names = j.putArray(NAMES);
            for (GeneralQueryDAO.Row row : rs.getRows()) {
                names.addArray().addAll(JSONUtils.toJSON(row.getValues()));
            }
            return JSONUtils.print(j);
        } catch (UnsupportedEncodingException ex) {
            LOG.error("Could not decode String", ex);
            return "Could not decode String: " + ex.getMessage();
        } catch (Exception ex) {
            LOG.error("Query unsuccesfull.", ex);
            return "Query unsuccesful. Cause: " + ex.getMessage();
        }
    }

    @ResponseBody
    @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
    @ExceptionHandler(UnsupportedOperationException.class)
    public String onError(UnsupportedOperationException e) {
        return "The operation is not supported.";
    }

    @ResponseStatus(HttpStatus.NO_CONTENT)
    @RequestMapping(value = ControllerConstants.Paths.ADMIN_DATABASE_CLEAR, method = RequestMethod.POST)
    public void clearDatasource() throws OwsExceptionReport, ConnectionProviderException {
        if (getDatasource().supportsClear()) {
            LOG.info("Clearing database contents.");
            getDatasource().clear(getSettings());
            updateCache();
        }
    }
}