/*
 * Copyright (c) 2005-2011 Grameen Foundation USA
 * All rights reserved.
 *
 * 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.
 *
 * See also http://www.apache.org/licenses/LICENSE-2.0.html for an
 * explanation of the license and how it is applied.
 */

package org.mifos.core;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.util.ResourceUtils;

/**
 * Load resources from the classpath.
 */
public final class MifosResourceUtil {
    private MifosResourceUtil() {
    }

    private static final ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();

    public static File getFile(String fileNameWithLocation) {
        File file;
        try {
            file = ResourceUtils.getFile(fileNameWithLocation);
        } catch (FileNotFoundException e) {
            throw new MifosRuntimeException("file not found :" + fileNameWithLocation, e);
        }
        return file;
    }

    private static File getFile(String location, String fileName) {
        return getFile(location + fileName);
    }

    public static Reader getSQLFileAsReader(String fileName) throws FileNotFoundException {
        return new FileReader(getFile("/sql/", fileName));
    }

    public static InputStream getSQLFileAsStream(String fileName) throws FileNotFoundException {
        return new FileInputStream(getFile("/sql/" + fileName));
    }
    
    public static InputStream[] getSQLFilesAsStreams(String[] fileNames) throws IOException {
        InputStream[] streams = new InputStream[fileNames.length];
        int index = 0;
        for(String fileName : fileNames) {
            streams[index++] = getClassPathResourceAsResource(fileName).getInputStream();
        }
        return streams;
    }

    /**
     * Should be avoided, because an InputStream needs to be closed by somebody, more clear if caller creates the IS from a Resource.
     * Use {@link #getClassPathResourceAsResource(String)} instead.
     */
    public static InputStream getClassPathResourceAsStream(String fileName) {
        return Thread.currentThread().getContextClassLoader().getResourceAsStream(fileName);
    }

    public static Resource getClassPathResourceAsResource(String fileName) throws IOException {
        return new ClassPathResource(fileName);
    }

    /**
     * Find a Resource on the Classpath and return it's URI (as a String).
     *
     * Intended for calling code which accepts URI, such as the javax.xml APIs. Better than File-based API, which should
     * never be used. Better than InputStream, because an InputStream needs to be closed by somebody - and that's
     * usually forgotten.
     *
     * If calling code can deal directly with a org.springframework.core.io.Resource, that's always preferable over a
     * raw URI; simply use new ClassPathResource(path) in that case.
     *
     * @param path Path on the classpath, e.g. "org/mifos/something.xml"
     * @return a Stringified Classpath URI
     */
    public static String getClassPathResourceAsURIString(String path) throws IOException {
        return new ClassPathResource(path).getURI().toString();
    }

    /**
     * Returns all classpath resources matching a certain pattern.
     *
     * @param pattern an Ant-style "/"-based (not "."-based) resource path pattern, WITHOUT any prefix
     * (like "classpath:" or "classpath*:"); so e.g. "org/mifos/package/**/*.xml".
     * @return an array of {@link Resource}. These may not actually be ClassPathResource instance, but any Resource (e.g. FileSystemResource)
     * @throws IOException in case of I/O errors
     */
    public static Resource[] getClassPathResourcesAsResources(String pattern) throws IOException {
        return resourcePatternResolver.getResources(ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX + "/" + pattern);
    }
}