/*
* Sone - SoneTextParser.java - Copyright © 2010–2016 David Roden
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package net.pterodactylus.sone.text;
import static java.util.logging.Logger.getLogger;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.net.MalformedURLException;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import net.pterodactylus.sone.data.Post;
import net.pterodactylus.sone.data.Sone;
import net.pterodactylus.sone.data.impl.IdOnlySone;
import net.pterodactylus.sone.database.PostProvider;
import net.pterodactylus.sone.database.SoneProvider;
import com.google.common.base.Optional;
import freenet.keys.FreenetURI;
/**
* {@link Parser} implementation that can recognize Freenet URIs.
*
* @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
*/
public class SoneTextParser implements Parser<SoneTextParserContext> {
/** The logger. */
private static final Logger logger = getLogger(SoneTextParser.class.getName());
/** Pattern to detect whitespace. */
private static final Pattern whitespacePattern = Pattern.compile("[\\u000a\u0020\u00a0\u1680\u180e\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u200b\u200c\u200d\u202f\u205f\u2060\u2800\u3000]");
/**
* Enumeration for all recognized link types.
*
* @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
*/
private enum LinkType {
KSK("KSK@", true),
CHK("CHK@", true),
SSK("SSK@", true),
USK("USK@", true),
HTTP("http://", false),
HTTPS("https://", false),
SONE("sone://", false),
POST("post://", false);
private final String scheme;
private final boolean freenetLink;
LinkType(String scheme, boolean freenetLink) {
this.scheme = scheme;
this.freenetLink = freenetLink;
}
/**
* Returns the scheme of this link type.
*
* @return The scheme of this link type
*/
public String getScheme() {
return scheme;
}
public boolean isFreenetLink() {
return freenetLink;
}
}
/** The Sone provider. */
private final SoneProvider soneProvider;
/** The post provider. */
private final PostProvider postProvider;
/**
* Creates a new freenet link parser.
*
* @param soneProvider
* The Sone provider
* @param postProvider
* The post provider
*/
public SoneTextParser(SoneProvider soneProvider, PostProvider postProvider) {
this.soneProvider = soneProvider;
this.postProvider = postProvider;
}
//
// PART METHODS
//
/**
* {@inheritDoc}
*/
@Nonnull
@Override
public Iterable<Part> parse(@Nonnull String source, @Nullable SoneTextParserContext context) {
PartContainer parts = new PartContainer();
try (Reader sourceReader = new StringReader(source);
BufferedReader bufferedReader = new BufferedReader(sourceReader)) {
String line;
boolean lastLineEmpty = true;
int emptyLines = 0;
while ((line = bufferedReader.readLine()) != null) {
if (line.trim().length() == 0) {
if (lastLineEmpty) {
continue;
}
parts.add(new PlainTextPart("\n"));
++emptyLines;
lastLineEmpty = emptyLines == 2;
continue;
}
emptyLines = 0;
/*
* lineComplete tracks whether the block you are parsing is the
* first block of the line. this is important because sometimes
* you have to add an additional line break.
*/
boolean lineComplete = true;
while (line.length() > 0) {
Optional<NextLink> nextLink = NextLink.findNextLink(line);
if (!nextLink.isPresent()) {
if (lineComplete && !lastLineEmpty) {
parts.add(new PlainTextPart("\n" + line));
} else {
parts.add(new PlainTextPart(line));
}
break;
}
LinkType linkType = nextLink.get().getLinkType();
int next = nextLink.get().getPosition();
/* cut off “freenet:” from before keys. */
if (linkType.isFreenetLink() && (next >= 8) && (line.substring(next - 8, next).equals("freenet:"))) {
next -= 8;
line = line.substring(0, next) + line.substring(next + 8);
}
/* if there is text before the next item, write it out. */
if (lineComplete && !lastLineEmpty) {
parts.add(new PlainTextPart("\n"));
}
if (next > 0) {
parts.add(new PlainTextPart(line.substring(0, next)));
line = line.substring(next);
}
lineComplete = false;
int endOfLink = findEndOfLink(line);
String link = line.substring(0, endOfLink);
logger.log(Level.FINER, String.format("Found link: %s", link));
/* if there is no text after the scheme, it’s not a link! */
if (link.equals(linkType.getScheme())) {
parts.add(new PlainTextPart(linkType.getScheme()));
line = line.substring(linkType.getScheme().length());
continue;
}
switch (linkType) {
case SONE:
renderSoneLink(parts, link);
break;
case POST:
renderPostLink(parts, link);
break;
case KSK:
case CHK:
case SSK:
case USK:
renderFreenetLink(parts, link, linkType, context);
break;
case HTTP:
case HTTPS:
renderHttpLink(parts, link, linkType);
break;
}
line = line.substring(endOfLink);
}
lastLineEmpty = false;
}
} catch (IOException ioe1) {
// a buffered reader around a string reader should never throw.
throw new RuntimeException(ioe1);
}
for (int partIndex = parts.size() - 1; partIndex >= 0; --partIndex) {
Part part = parts.getPart(partIndex);
if (!(part instanceof PlainTextPart) || !"\n".equals(part.getText())) {
break;
}
parts.removePart(partIndex);
}
return parts;
}
private void renderSoneLink(PartContainer parts, String line) {
if (line.length() >= (7 + 43)) {
String soneId = line.substring(7, 50);
Optional<Sone> sone = soneProvider.getSone(soneId);
parts.add(new SonePart(sone.or(new IdOnlySone(soneId))));
} else {
parts.add(new PlainTextPart(line));
}
}
private void renderPostLink(PartContainer parts, String line) {
if (line.length() >= (7 + 36)) {
String postId = line.substring(7, 43);
Optional<Post> post = postProvider.getPost(postId);
if (post.isPresent()) {
parts.add(new PostPart(post.get()));
} else {
parts.add(new PlainTextPart(line.substring(0, 43)));
}
} else {
parts.add(new PlainTextPart(line));
}
}
private void renderFreenetLink(PartContainer parts, String link, LinkType linkType, @Nullable SoneTextParserContext context) {
String name = link;
if (name.indexOf('?') > -1) {
name = name.substring(0, name.indexOf('?'));
}
if (name.endsWith("/")) {
name = name.substring(0, name.length() - 1);
}
try {
FreenetURI uri = new FreenetURI(name);
name = uri.lastMetaString();
if (name == null) {
name = uri.getDocName();
}
if (name == null) {
name = link.substring(0, Math.min(9, link.length()));
}
boolean fromPostingSone = ((linkType == LinkType.SSK) || (linkType == LinkType.USK)) && (context != null) && (context.getPostingSone() != null) && link.substring(4, Math.min(link.length(), 47)).equals(context.getPostingSone().getId());
parts.add(new FreenetLinkPart(link, name, fromPostingSone));
} catch (MalformedURLException mue1) {
/* not a valid link, insert as plain text. */
parts.add(new PlainTextPart(link));
} catch (NullPointerException npe1) {
/* FreenetURI sometimes throws these, too. */
parts.add(new PlainTextPart(link));
} catch (ArrayIndexOutOfBoundsException aioobe1) {
/* oh, and these, too. */
parts.add(new PlainTextPart(link));
}
}
private void renderHttpLink(PartContainer parts, String link, LinkType linkType) {
String name;
name = link.substring(linkType == LinkType.HTTP ? 7 : 8);
int firstSlash = name.indexOf('/');
int lastSlash = name.lastIndexOf('/');
if ((lastSlash - firstSlash) > 3) {
name = name.substring(0, firstSlash + 1) + "…" + name.substring(lastSlash);
}
if (name.endsWith("/")) {
name = name.substring(0, name.length() - 1);
}
if (((name.indexOf('/') > -1) && (name.indexOf('.') < name.lastIndexOf('.', name.indexOf('/'))) || ((name.indexOf('/') == -1) && (name.indexOf('.') < name.lastIndexOf('.')))) && name.startsWith("www.")) {
name = name.substring(4);
}
if (name.indexOf('?') > -1) {
name = name.substring(0, name.indexOf('?'));
}
parts.add(new LinkPart(link, name));
}
private int findEndOfLink(String line) {
Matcher matcher = whitespacePattern.matcher(line);
int endOfLink = matcher.find() ? matcher.start() : line.length();
while ((endOfLink > 0) && isPunctuation(line.charAt(endOfLink - 1))) {
endOfLink--;
}
int openParens = 0;
for (int i = 0; i < endOfLink; i++) {
switch (line.charAt(i)) {
case '(':
openParens++;
break;
case ')':
openParens--;
if (openParens < 0) {
return i;
}
default:
}
}
return endOfLink;
}
private static boolean isPunctuation(char character) {
return (character == '.') || (character == ',');
}
private static class NextLink {
private final int position;
private final LinkType linkType;
private NextLink(int position, LinkType linkType) {
this.position = position;
this.linkType = linkType;
}
public int getPosition() {
return position;
}
public LinkType getLinkType() {
return linkType;
}
public static Optional<NextLink> findNextLink(String line) {
int earliestLinkPosition = Integer.MAX_VALUE;
LinkType linkType = null;
for (LinkType possibleLinkType : LinkType.values()) {
int nextLinkPosition = line.indexOf(possibleLinkType.getScheme());
if (nextLinkPosition > -1) {
if (nextLinkPosition < earliestLinkPosition) {
earliestLinkPosition = nextLinkPosition;
linkType = possibleLinkType;
}
}
}
return earliestLinkPosition < Integer.MAX_VALUE ?
Optional.of(new NextLink(earliestLinkPosition, linkType)) : Optional.<NextLink>absent();
}
}
}