michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: package org.mozilla.gecko.sync.setup.activities;
michael@0: 
michael@0: import java.net.URI;
michael@0: import java.net.URISyntaxException;
michael@0: import java.util.ArrayList;
michael@0: import java.util.Collection;
michael@0: import java.util.LinkedList;
michael@0: import java.util.List;
michael@0: import java.util.regex.Matcher;
michael@0: 
michael@0: import android.util.Patterns;
michael@0: 
michael@0: public class WebURLFinder {
michael@0:   public final List<String> candidates;
michael@0: 
michael@0:   public WebURLFinder(String string) {
michael@0:     if (string == null) {
michael@0:       throw new IllegalArgumentException("string must not be null");
michael@0:     }
michael@0: 
michael@0:     this.candidates = candidateWebURLs(string);
michael@0:   }
michael@0: 
michael@0:   public WebURLFinder(List<String> strings) {
michael@0:     if (strings == null) {
michael@0:       throw new IllegalArgumentException("strings must not be null");
michael@0:     }
michael@0: 
michael@0:     this.candidates = candidateWebURLs(strings);
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Check if string is a Web URL.
michael@0:    * <p>
michael@0:    * A Web URL is a URI that is not a <code>file:</code> or
michael@0:    * <code>javascript:</code> scheme.
michael@0:    *
michael@0:    * @param string
michael@0:    *          to check.
michael@0:    * @return <code>true</code> if <code>string</code> is a Web URL.
michael@0:    */
michael@0:   public static boolean isWebURL(String string) {
michael@0:     try {
michael@0:       new URI(string);
michael@0:     } catch (Exception e) {
michael@0:       return false;
michael@0:     }
michael@0: 
michael@0:     if (android.webkit.URLUtil.isFileUrl(string) ||
michael@0:         android.webkit.URLUtil.isJavaScriptUrl(string)) {
michael@0:       return false;
michael@0:     }
michael@0: 
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Return best Web URL.
michael@0:    * <p>
michael@0:    * "Best" means a Web URL with a scheme, and failing that, a Web URL without a
michael@0:    * scheme.
michael@0:    *
michael@0:    * @return a Web URL or <code>null</code>.
michael@0:    */
michael@0:   public String bestWebURL() {
michael@0:     String firstWebURLWithScheme = firstWebURLWithScheme();
michael@0:     if (firstWebURLWithScheme != null) {
michael@0:       return firstWebURLWithScheme;
michael@0:     }
michael@0: 
michael@0:     return firstWebURLWithoutScheme();
michael@0:   }
michael@0: 
michael@0:   protected static List<String> candidateWebURLs(Collection<String> strings) {
michael@0:     List<String> candidates = new ArrayList<String>();
michael@0: 
michael@0:     for (String string : strings) {
michael@0:       if (string == null) {
michael@0:         continue;
michael@0:       }
michael@0: 
michael@0:       candidates.addAll(candidateWebURLs(string));
michael@0:     }
michael@0: 
michael@0:     return candidates;
michael@0:   }
michael@0: 
michael@0:   protected static List<String> candidateWebURLs(String string) {
michael@0:     Matcher matcher = Patterns.WEB_URL.matcher(string);
michael@0:     List<String> matches = new LinkedList<String>();
michael@0: 
michael@0:     while (matcher.find()) {
michael@0:       // Remove URLs with bad schemes.
michael@0:       if (!isWebURL(matcher.group())) {
michael@0:         continue;
michael@0:       }
michael@0: 
michael@0:       // Remove parts of email addresses.
michael@0:       if (matcher.start() > 0 && (string.charAt(matcher.start() - 1) == '@')) {
michael@0:         continue;
michael@0:       }
michael@0: 
michael@0:       matches.add(matcher.group());
michael@0:     }
michael@0: 
michael@0:     return matches;
michael@0:   }
michael@0: 
michael@0:   protected String firstWebURLWithScheme() {
michael@0:     for (String match : candidates) {
michael@0:       try {
michael@0:         if (new URI(match).getScheme() != null) {
michael@0:           return match;
michael@0:         }
michael@0:       } catch (URISyntaxException e) {
michael@0:         // Ignore: on to the next.
michael@0:         continue;
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     return null;
michael@0:   }
michael@0: 
michael@0:   protected String firstWebURLWithoutScheme() {
michael@0:     if (!candidates.isEmpty()) {
michael@0:       return candidates.get(0);
michael@0:     }
michael@0: 
michael@0:     return null;
michael@0:   }
michael@0: }