/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with this
 * work for additional information regarding copyright ownership. The ASF
 * 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.apache.sling.maven.bundlesupport.deploy.method;

import java.net.URI;
import java.util.ArrayList;
import java.util.List;

/**
 * Helper which extracts intermediate URIs from an URI 
 */
final class IntermediateUrisExtractor {

    private IntermediateUrisExtractor() {
        // static methods only
    }

    /**
     * Extracts a list of intermediate paths from an URL.
     * 
     * <p>For instance, <tt>http://localhost:8080/apps/slingshot/install</tt> would have the following intermediate
     * URIs:
     * <ol>
     *   <li>http://localhost:8080/apps</li>
     *   <li>http://localhost:8080/apps/slingshot</li>
     *   <li>http://localhost:8080/apps/slingshot/install</li>
     * </ol>
     * </p>
     * 
     * @param url the url to extract paths from
     * @return the intermediate paths, possibly empty
     */
    public static List<URI> extractIntermediateUris(URI uri) {
        
        List<URI> paths = new ArrayList<>();
        
        String path = uri.getPath();
        StringBuilder accu = new StringBuilder();
        for ( String segment : path.split("/") ) {

            // ensure we have a trailing slash to join with the next segment
            if ( accu.length() == 0 || accu.charAt(accu.length() - 1) != '/') {
                accu.append('/');
            }
            
            accu.append(segment);
            
            // don't add the root segment ( / ) 
            if ( segment.length() != 0 ) {
                paths.add(0, uri.resolve(accu.toString()));
            }
            
        }
        
        return paths;
    }
    
}