/*
* Copyright (C) 2009 The Android Open Source Project
*
* 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.
*/
package com.example.android.wiktionary;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.net.Uri;
import android.text.TextUtils;
import android.webkit.WebView;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Extended version of {@link SimpleWikiHelper}. This version adds methods to
* pick a random word, and to format generic wiki-style text into HTML.
*/
public class ExtendedWikiHelper extends SimpleWikiHelper {
/**
* HTML style sheet to include with any {@link #formatWikiText(String)} HTML
* results. It formats nicely for a mobile screen, and hides some content
* boxes to keep things tidy.
*/
private static final String STYLE_SHEET = "<style>h2 {font-size:1.2em;font-weight:normal;} " +
"a {color:#6688cc;} ol {padding-left:1.5em;} blockquote {margin-left:0em;} " +
".interProject, .noprint {display:none;} " +
"li, blockquote {margin-top:0.5em;margin-bottom:0.5em;}</style>";
/**
* Pattern of section titles we're interested in showing. This trims out
* extra sections that can clutter things up on a mobile screen.
*/
private static final Pattern sValidSections =
Pattern.compile("(verb|noun|adjective|pronoun|interjection)", Pattern.CASE_INSENSITIVE);
/**
* Pattern that can be used to split a returned wiki page into its various
* sections. Doesn't treat children sections differently.
*/
private static final Pattern sSectionSplit =
Pattern.compile("^=+(.+?)=+.+?(?=^=)", Pattern.MULTILINE | Pattern.DOTALL);
/**
* When picking random words in {@link #getRandomWord()}, we sometimes
* encounter special articles or templates. This pattern ignores any words
* like those, usually because they have ":" or other punctuation.
*/
private static final Pattern sInvalidWord = Pattern.compile("[^A-Za-z0-9 ]");
/**
* {@link Uri} authority to use when creating internal links.
*/
public static final String WIKI_AUTHORITY = "wiktionary";
/**
* {@link Uri} host to use when creating internal links.
*/
public static final String WIKI_LOOKUP_HOST = "lookup";
/**
* Mime-type to use when showing parsed results in a {@link WebView}.
*/
public static final String MIME_TYPE = "text/html";
/**
* Encoding to use when showing parsed results in a {@link WebView}.
*/
public static final String ENCODING = "utf-8";
/**
* {@link Uri} to use when requesting a random page.
*/
private static final String WIKTIONARY_RANDOM =
"http://en.wiktionary.org/w/api.php?action=query&list=random&format=json";
/**
* Fake section to insert at the bottom of a wiki response before parsing.
* This ensures that {@link #sSectionSplit} will always catch the last
* section, as it uses section headers in its searching.
*/
private static final String STUB_SECTION = "\n=Stub section=";
/**
* Number of times to try finding a random word in {@link #getRandomWord()}.
* These failures are usually when the found word fails the
* {@link #sInvalidWord} test, or when a network error happens.
*/
private static final int RANDOM_TRIES = 3;
/**
* Internal class to hold a wiki formatting rule. It's mostly a wrapper to
* simplify {@link Matcher#replaceAll(String)}.
*/
private static class FormatRule {
private Pattern mPattern;
private String mReplaceWith;
/**
* Create a wiki formatting rule.
*
* @param pattern Search string to be compiled into a {@link Pattern}.
* @param replaceWith String to replace any found occurances with. This
* string can also include back-references into the given
* pattern.
* @param flags Any flags to compile the {@link Pattern} with.
*/
public FormatRule(String pattern, String replaceWith, int flags) {
mPattern = Pattern.compile(pattern, flags);
mReplaceWith = replaceWith;
}
/**
* Create a wiki formatting rule.
*
* @param pattern Search string to be compiled into a {@link Pattern}.
* @param replaceWith String to replace any found occurances with. This
* string can also include back-references into the given
* pattern.
*/
public FormatRule(String pattern, String replaceWith) {
this(pattern, replaceWith, 0);
}
/**
* Apply this formatting rule to the given input string, and return the
* resulting new string.
*/
public String apply(String input) {
Matcher m = mPattern.matcher(input);
return m.replaceAll(mReplaceWith);
}
}
/**
* List of internal formatting rules to apply when parsing wiki text. These
* include indenting various bullets, apply italic and bold styles, and
* adding internal linking.
*/
private static final List<FormatRule> sFormatRules = new ArrayList<FormatRule>();
static {
// Format header blocks and wrap outside content in ordered list
sFormatRules.add(new FormatRule("^=+(.+?)=+", "</ol><h2>$1</h2><ol>",
Pattern.MULTILINE));
// Indent quoted blocks, handle ordered and bullet lists
sFormatRules.add(new FormatRule("^#+\\*?:(.+?)$", "<blockquote>$1</blockquote>",
Pattern.MULTILINE));
sFormatRules.add(new FormatRule("^#+:?\\*(.+?)$", "<ul><li>$1</li></ul>",
Pattern.MULTILINE));
sFormatRules.add(new FormatRule("^#+(.+?)$", "<li>$1</li>",
Pattern.MULTILINE));
// Add internal links
sFormatRules.add(new FormatRule("\\[\\[([^:\\|\\]]+)\\]\\]",
String.format("<a href=\"%s://%s/$1\">$1</a>", WIKI_AUTHORITY, WIKI_LOOKUP_HOST)));
sFormatRules.add(new FormatRule("\\[\\[([^:\\|\\]]+)\\|([^\\]]+)\\]\\]",
String.format("<a href=\"%s://%s/$1\">$2</a>", WIKI_AUTHORITY, WIKI_LOOKUP_HOST)));
// Add bold and italic formatting
sFormatRules.add(new FormatRule("'''(.+?)'''", "<b>$1</b>"));
sFormatRules.add(new FormatRule("([^'])''([^'].*?[^'])''([^'])", "$1<i>$2</i>$3"));
// Remove odd category links and convert remaining links into flat text
sFormatRules.add(new FormatRule("(\\{+.+?\\}+|\\[\\[[^:]+:[^\\\\|\\]]+\\]\\]|" +
"\\[http.+?\\]|\\[\\[Category:.+?\\]\\])", "", Pattern.MULTILINE | Pattern.DOTALL));
sFormatRules.add(new FormatRule("\\[\\[([^\\|\\]]+\\|)?(.+?)\\]\\]", "$2",
Pattern.MULTILINE));
}
/**
* Query the Wiktionary API to pick a random dictionary word. Will try
* multiple times to find a valid word before giving up.
*
* @return Random dictionary word, or null if no valid word was found.
* @throws ApiException If any connection or server error occurs.
* @throws ParseException If there are problems parsing the response.
*/
public static String getRandomWord() throws ApiException, ParseException {
// Keep trying a few times until we find a valid word
int tries = 0;
while (tries++ < RANDOM_TRIES) {
// Query the API for a random word
String content = getUrlContent(WIKTIONARY_RANDOM);
try {
// Drill into the JSON response to find the returned word
JSONObject response = new JSONObject(content);
JSONObject query = response.getJSONObject("query");
JSONArray random = query.getJSONArray("random");
JSONObject word = random.getJSONObject(0);
String foundWord = word.getString("title");
// If we found an actual word, and it wasn't rejected by our invalid
// filter, then accept and return it.
if (foundWord != null &&
!sInvalidWord.matcher(foundWord).find()) {
return foundWord;
}
} catch (JSONException e) {
throw new ParseException("Problem parsing API response", e);
}
}
// No valid word found in number of tries, so return null
return null;
}
/**
* Format the given wiki-style text into formatted HTML content. This will
* create headers, lists, internal links, and style formatting for any wiki
* markup found.
*
* @param wikiText The raw text to format, with wiki-markup included.
* @return HTML formatted content, ready for display in {@link WebView}.
*/
public static String formatWikiText(String wikiText) {
if (wikiText == null) {
return null;
}
// Insert a fake last section into the document so our section splitter
// can correctly catch the last section.
wikiText = wikiText.concat(STUB_SECTION);
// Read through all sections, keeping only those matching our filter,
// and only including the first entry for each title.
HashSet<String> foundSections = new HashSet<String>();
StringBuilder builder = new StringBuilder();
Matcher sectionMatcher = sSectionSplit.matcher(wikiText);
while (sectionMatcher.find()) {
String title = sectionMatcher.group(1);
if (!foundSections.contains(title) &&
sValidSections.matcher(title).matches()) {
String sectionContent = sectionMatcher.group();
foundSections.add(title);
builder.append(sectionContent);
}
}
// Our new wiki text is the selected sections only
wikiText = builder.toString();
// Apply all formatting rules, in order, to the wiki text
for (FormatRule rule : sFormatRules) {
wikiText = rule.apply(wikiText);
}
// Return the resulting HTML with style sheet, if we have content left
if (!TextUtils.isEmpty(wikiText)) {
return STYLE_SHEET + wikiText;
} else {
return null;
}
}
}