/*
 * Janino - An embedded Java[TM] compiler
 *
 * Copyright (c) 2001-2010, Arno Unkrig
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
 * following conditions are met:
 *
 *    1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
 *       following disclaimer.
 *    2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
 *       following disclaimer in the documentation and/or other materials provided with the distribution.
 *    3. The name of the author may not be used to endorse or promote products derived from this software without
 *       specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

package org.codehaus.janino.util.resource;

import java.io.File;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

/**
 * A {@link org.codehaus.janino.util.resource.FileResourceFinder} that finds file resources in
 * a directory. The name of the file is constructed by concatenating a dirctory name
 * with the resource name such that slashes in the resource name map to file
 * separators.
 */
@SuppressWarnings({ "rawtypes", "unchecked" }) public
class DirectoryResourceFinder extends FileResourceFinder {
    private final File                                     directory;
    private final Map<String /*directoryName*/, Set<File>> subdirectoryNameToFiles = new HashMap();

    /** @param directory the directory to use as the search base */
    public
    DirectoryResourceFinder(File directory) { this.directory = directory; }

    @Override public final String toString() { return "dir:" + this.directory; }

    // Implement FileResourceFinder.
    @Override protected final File
    findResourceAsFile(String resourceName) {

        // Determine the subdirectory name (null for no subdirectory).
        int    idx              = resourceName.lastIndexOf('/');
        String subdirectoryName = (
            idx == -1 ? null :
            resourceName.substring(0, idx).replace('/', File.separatorChar)
        );

        // Determine files existing in this subdirectory.
        Set<File> files = (Set) this.subdirectoryNameToFiles.get(subdirectoryName);
        if (files == null) {
            File subDirectory = (
                subdirectoryName == null
                ? this.directory
                : new File(this.directory, subdirectoryName)
            );
            File[] fa = subDirectory.listFiles();
            files = (fa == null) ? Collections.EMPTY_SET : new HashSet(Arrays.asList(fa));
            this.subdirectoryNameToFiles.put(subdirectoryName, files);
        }

        // Notice that "File.equals()" performs all the file-system dependent
        // magic like case conversion.
        File file = new File(this.directory, resourceName.replace('/', File.separatorChar));
        if (!files.contains(file)) return null;

        return file;
    }
}