/*
 * 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.
 */

/* $Id$ */

package org.apache.fop.apps.io;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URI;
import java.net.URISyntaxException;

import javax.xml.transform.Source;
import javax.xml.transform.TransformerException;
import javax.xml.transform.stream.StreamSource;

import org.apache.xmlgraphics.io.Resource;
import org.apache.xmlgraphics.io.ResourceResolver;
import org.apache.xmlgraphics.util.uri.DataURIResolver;

This object holds the base URI from which to resolve URIs against as well as the resolver for resource acquisition. It also does some URI sanitization of common URI syntactical errors. This class takes in a ResourceResolver and delegates all relevant URIs to it. /**
 * This object holds the base URI from which to resolve URIs against as well as the resolver for
 * resource acquisition. It also does some URI sanitization of common URI syntactical errors. This
 * class takes in a {@link org.apache.xmlgraphics.io.ResourceResolver} and delegates all relevant
 * URIs to it.
 */
public class InternalResourceResolver {
    private final URI baseUri;
    private final ResourceResolver resourceResolver;
    private final DataURIResolver dataSchemeResolver = new DataURIResolver();

    
Params:
baseUri – the base URI from which to resolve relative URIs
resourceResolver – the resolver to delegate to/**
     * @param baseUri the base URI from which to resolve relative URIs
     * @param resourceResolver the resolver to delegate to
     */
    InternalResourceResolver(URI baseUri, ResourceResolver resourceResolver) {
        this.baseUri = baseUri;
        this.resourceResolver = resourceResolver;
    }

    
Returns the base URI from which to resolve all URIs against.
Returns:
the base URI/**
     * Returns the base URI from which to resolve all URIs against.
     *
     * @return the base URI
     */
    public URI getBaseURI() {
        return baseUri;
    }

    
Retrieve a resource given a URI in String form. This also does some syntactical sanitaion on
the URI.
Params:
stringUri – the URI in String form
Throws:
IOException – if an I/O error occurred
URISyntaxException – if the URI syntax was invalid
Returns:
the resource/**
     * Retrieve a resource given a URI in String form. This also does some syntactical sanitaion on
     * the URI.
     *
     * @param stringUri the URI in String form
     * @return the resource
     * @throws IOException if an I/O error occurred
     * @throws URISyntaxException if the URI syntax was invalid
     */
    public Resource getResource(String stringUri) throws IOException, URISyntaxException {
        if (stringUri.startsWith("data:")) {
            return new Resource(resolveDataURI(stringUri));
        }
        return getResource(cleanURI(stringUri));
    }

    
Retrieve a resource given a URI in String form.
Params:
uri – the resource URI
Throws:
IOException – if an I/O error occurred
Returns:
the resource/**
     * Retrieve a resource given a URI in String form.
     *
     * @param uri the resource URI
     * @return the resource
     * @throws IOException if an I/O error occurred
     */
    public Resource getResource(URI uri) throws IOException {
        if (uri.getScheme() != null && uri.getScheme().startsWith("data")) {
            return new Resource(resolveDataURI(uri.toASCIIString()));
        }
        return resourceResolver.getResource(resolveFromBase(uri));
    }

    
Returns the OutputStream for a given URI.
Params:
uri – the URI for the inteded stream
Throws:
IOException – if an I/O error occurrred
Returns:
the output stream/**
     * Returns the OutputStream for a given URI.
     *
     * @param uri the URI for the inteded stream
     * @return the output stream
     * @throws IOException if an I/O error occurrred
     */
    public OutputStream getOutputStream(URI uri) throws IOException {
        return resourceResolver.getOutputStream(resolveFromBase(uri));
    }

    
Resolves a URI against the base URI.
Params:
uri – the URI that requires resolution
Returns:
the resolved URI/**
     * Resolves a URI against the base URI.
     *
     * @param uri the URI that requires resolution
     * @return the resolved URI
     */
    public URI resolveFromBase(URI uri) {
        return baseUri.resolve(uri);
    }

    
Performs some sanitation for some of the most common URI syntax mistakes.
Params:
uriStr – the URI in String form
Throws:
URISyntaxException – if the given String was too erroneous to validate
Returns:
a valid URI/**
     * Performs some sanitation for some of the most common URI syntax mistakes.
     *
     * @param uriStr the URI in String form
     * @return a valid URI
     * @throws URISyntaxException if the given String was too erroneous to validate
     */
    public static URI cleanURI(String uriStr) throws URISyntaxException {
        // replace back slash with forward slash to ensure windows file:/// URLS are supported
        if (uriStr == null) {
            return null;
        }
        String fixedUri = uriStr.replace('\\', '/');
        fixedUri = fixedUri.replace(" ", "%20");
        URI baseURI = new URI(fixedUri);
        return baseURI;
    }

    
Performs some sanitation for some of the most common URI syntax mistakes but returns a
directory URI rather than a file URI.
Params:
base – the directory URI in String form
Throws:
URISyntaxException – if the given String was too erroneous to validate
Returns:
the directory URI/**
     * Performs some sanitation for some of the most common URI syntax mistakes but returns a
     * directory URI rather than a file URI.
     *
     * @param base the directory URI in String form
     * @return the directory URI
     * @throws URISyntaxException if the given String was too erroneous to validate
     */
    public static URI getBaseURI(String base) throws URISyntaxException {
        String path = base + (base.endsWith("/") ? "" : "/");
        return cleanURI(path);
    }

    private InputStream resolveDataURI(String dataURI) {
        try {
            Source src = dataSchemeResolver.resolve(dataURI, "");
            return src == null ? null : ((StreamSource) src).getInputStream();
        } catch (TransformerException e) {
            throw new RuntimeException(e);
        }
    }
}