/*
 * Copyright 2014 James Moger.
 *
 * Licensed 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 com.iciql;

import com.iciql.Iciql.Mode;

import java.io.InputStream;
import java.util.Properties;

/**
 * Loads DAO statements from Properties resource files the classpath.
 *
 * @author James Moger
 */
public class DaoClasspathStatementProvider implements DaoStatementProvider {

    private final Properties externalStatements;

    public DaoClasspathStatementProvider() {
        externalStatements = load();
    }

    /**
     * Returns the list of statement resources to try locating.
     *
     * @return
     */
    protected String[] getStatementResources() {
        return new String[]{"/iciql.properties", "/iciql.xml", "/conf/iciql.properties", "/conf/iciql.xml"};
    }

    /**
     * Loads the first statement resource found on the classpath.
     *
     * @return the loaded statements
     */
    private Properties load() {

        Properties props = new Properties();
        for (String resource : getStatementResources()) {

            InputStream is = null;

            try {
                is = DaoProxy.class.getResourceAsStream(resource);

                if (is != null) {

                    if (resource.toLowerCase().endsWith(".xml")) {
                        // load an .XML statements file
                        props.loadFromXML(is);
                    } else {
                        // load a .Properties statements file
                        props.load(is);
                    }

                    break;
                }

            } catch (Exception e) {
                throw new IciqlException(e, "Failed to parse {0}", resource);
            } finally {
                try {
                    is.close();
                } catch (Exception e) {
                }
            }

        }
        return props;
    }

    @Override
    public String getStatement(String idOrStatement, Mode mode) {
        final String modePrefix = "%" + mode.name().toLowerCase() + ".";
        String value = externalStatements.getProperty(idOrStatement, idOrStatement);
        value = externalStatements.getProperty(modePrefix + idOrStatement, value);
        return value;
    }

}