
/*
 * Copyright (c) 2017, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
 *
 * WSO2 Inc. licenses this file to you under the Apache License,
 * Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.wso2.carbon.status.dashboard.core.dbhandler;

import org.wso2.carbon.config.ConfigurationException;
import org.wso2.carbon.database.query.manager.QueryProvider;
import org.wso2.carbon.database.query.manager.config.Queries;
import org.wso2.carbon.database.query.manager.exception.QueryMappingNotAvailableException;
import org.wso2.carbon.status.dashboard.core.dbhandler.utils.SQLConstants;
import org.wso2.carbon.status.dashboard.core.internal.MonitoringDataHolder;
import org.yaml.snakeyaml.Yaml;
import org.yaml.snakeyaml.constructor.CustomClassLoaderConstructor;
import org.yaml.snakeyaml.introspector.BeanAccess;

import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Holds the database queries.
 */
public class QueryManager {

    private Map<String, String> queries = new HashMap<>();

    public QueryManager(String databaseType, String databaseVersion) throws
            QueryMappingNotAvailableException, ConfigurationException, IOException {
        queries = readConfigs(databaseType, databaseVersion);
    }

    private Map<String, String> readConfigs(String databaseType, String databaseVersion) throws ConfigurationException,
            QueryMappingNotAvailableException {
        try {
            DeploymentConfigs deploymentConfigurations = MonitoringDataHolder.getInstance()
                    .getConfigProvider()
                    .getConfigurationObject(DeploymentConfigs.class);
            List<Queries> deploymentQueries = deploymentConfigurations.getQueries();
            List<Queries> componentQueries;
            ClassLoader classLoader = getClass().getClassLoader();
            InputStream inputStream = classLoader.getResourceAsStream(SQLConstants.QUERY_CONFIG_FILE);
            if (inputStream != null) {
                DeploymentConfigs componentConfigurations = readYamlContent(inputStream);
                componentQueries = componentConfigurations.getQueries();
            } else {
                throw new RuntimeException("Unable to load queries.yaml file.");
            }
            queries = QueryProvider.mergeMapping(databaseType, databaseVersion, componentQueries,
                    deploymentQueries);
        } catch (ConfigurationException e) {
            throw new ConfigurationException("Unable to read queries.yaml configurations: " + e.getMessage(), e);
        } catch (QueryMappingNotAvailableException e) {
            throw new QueryMappingNotAvailableException("Unable to load queries.", e);
        }
        return queries;
    }

    public String getQuery(String key) {
        if (!queries.containsKey(key)) {
            throw new RuntimeException("Unable to find the configuration entry for the key: " + key);
        }
        return queries.get(key);
    }

    private DeploymentConfigs readYamlContent(InputStream yamlContent) {
        Yaml yaml = new Yaml(new CustomClassLoaderConstructor
                (DeploymentConfigs.class, DeploymentConfigs.class.getClassLoader()));
        yaml.setBeanAccess(BeanAccess.FIELD);
        return yaml.loadAs(yamlContent, DeploymentConfigs.class);
    }
}
