001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.data.validation.tests;
003
004import static java.util.regex.Pattern.CASE_INSENSITIVE;
005import static java.util.regex.Pattern.UNICODE_CASE;
006import static org.openstreetmap.josm.tools.I18n.tr;
007
008import java.awt.geom.Point2D;
009import java.text.Normalizer;
010import java.util.ArrayList;
011import java.util.Arrays;
012import java.util.HashMap;
013import java.util.List;
014import java.util.Locale;
015import java.util.Map;
016import java.util.regex.Matcher;
017import java.util.regex.Pattern;
018
019import org.openstreetmap.josm.data.osm.OsmPrimitive;
020import org.openstreetmap.josm.data.osm.Way;
021import org.openstreetmap.josm.data.validation.Severity;
022import org.openstreetmap.josm.data.validation.Test;
023import org.openstreetmap.josm.data.validation.TestError;
024import org.openstreetmap.josm.data.validation.util.ValUtil;
025import org.openstreetmap.josm.gui.progress.ProgressMonitor;
026import org.openstreetmap.josm.tools.MultiMap;
027
028/**
029 * Checks for similar named ways, symptom of a possible typo. It uses the
030 * Levenshtein distance to check for similarity
031 *
032 * @author frsantos
033 */
034public class SimilarNamedWays extends Test {
035
036    protected static final int SIMILAR_NAMED = 701;
037
038    private static final Pattern REMOVE_DIACRITICS = Pattern.compile("\\p{InCombiningDiacriticalMarks}+");
039
040    /** All ways, grouped by cells */
041    private Map<Point2D, List<Way>> cellWays;
042    /** The already detected errors */
043    private MultiMap<Way, Way> errorWays;
044
045    private final List<NormalizeRule> rules = new ArrayList<>();
046
047    /**
048     * Constructor
049     */
050    public SimilarNamedWays() {
051        super(tr("Similarly named ways"),
052                tr("This test checks for ways with similar names that may have been misspelled."));
053
054        // FIXME: hardcode these rules for now. Replace them with preferences later
055        // See https://josm.openstreetmap.de/ticket/3733#comment:19
056        addRegExprRule("\\pN+", "0"); // Unicode numbers: matches "Highway 66" but also persian numbers
057        addRegExprRule("\\d+(st|nd|rd|th)", "0st"); // 3rd Ave
058        addRegExprRule("^[A-Z] ", "X"); // E Street
059        addSynonyms("east", "west", "north", "south");
060        addSynonyms("first", "second", "third");
061    }
062
063    @Override
064    public void startTest(ProgressMonitor monitor) {
065        super.startTest(monitor);
066        cellWays = new HashMap<>(1000);
067        errorWays = new MultiMap<>();
068    }
069
070    @Override
071    public void endTest() {
072        cellWays = null;
073        errorWays = null;
074        super.endTest();
075    }
076
077    @Override
078    public void visit(Way w) {
079        if (!w.isUsable())
080            return;
081
082        String name = w.get("name");
083        if (name == null || name.length() < 6)
084            return;
085
086        List<List<Way>> theCellWays = ValUtil.getWaysInCell(w, cellWays);
087        for (List<Way> ways : theCellWays) {
088            for (Way w2 : ways) {
089                if (errorWays.contains(w, w2) || errorWays.contains(w2, w)) {
090                    continue;
091                }
092
093                String name2 = w2.get("name");
094                if (name2 == null || name2.length() < 6) {
095                    continue;
096                }
097
098                if (similaryName(name, name2)) {
099                    List<OsmPrimitive> primitives = new ArrayList<>(2);
100                    primitives.add(w);
101                    primitives.add(w2);
102                    errors.add(TestError.builder(this, Severity.WARNING, SIMILAR_NAMED)
103                            .message(tr("Similarly named ways"))
104                            .primitives(primitives)
105                            .build());
106                    errorWays.put(w, w2);
107                }
108            }
109            ways.add(w);
110        }
111    }
112
113    /**
114     * Compute Levenshtein distance
115     *
116     * @param s First word
117     * @param t Second word
118     * @return The distance between words
119     */
120    public static int getLevenshteinDistance(String s, String t) {
121        int[][] d; // matrix
122        int n; // length of s
123        int m; // length of t
124        int i; // iterates through s
125        int j; // iterates through t
126        char si; // ith character of s
127        char tj; // jth character of t
128        int cost; // cost
129
130        // Step 1
131        n = s.length();
132        m = t.length();
133        if (n == 0)
134            return m;
135        if (m == 0)
136            return n;
137        d = new int[n+1][m+1];
138
139        // Step 2
140        for (i = 0; i <= n; i++) {
141            d[i][0] = i;
142        }
143        for (j = 0; j <= m; j++) {
144            d[0][j] = j;
145        }
146
147        // Step 3
148        for (i = 1; i <= n; i++) {
149
150            si = s.charAt(i - 1);
151
152            // Step 4
153            for (j = 1; j <= m; j++) {
154
155                tj = t.charAt(j - 1);
156
157                // Step 5
158                if (si == tj) {
159                    cost = 0;
160                } else {
161                    cost = 1;
162                }
163
164                // Step 6
165                d[i][j] = Math.min(Math.min(d[i - 1][j] + 1, d[i][j - 1] + 1), d[i - 1][j - 1] + cost);
166            }
167        }
168
169        // Step 7
170        return d[n][m];
171    }
172
173    /**
174     * Add a regular expression rule.
175     * @param regExpr the regular expression to search for
176     * @param replacement a string to replace with, which should match the expression.
177     */
178    public void addRegExprRule(String regExpr, String replacement) {
179        rules.add(new RegExprRule(regExpr, replacement));
180    }
181
182    /**
183     * Add a rule with synonym words.
184     * @param words words which are synonyms
185     */
186    public void addSynonyms(String... words) {
187        for (String word : words) {
188            rules.add(new SynonymRule(word, words));
189        }
190    }
191
192    /**
193     * Check if two names are similar, but not identical. First both names will be "normalized".
194     * Afterwards the Levenshtein distance will be calculated.<br>
195     * Examples for normalization rules:<br>
196     * <code>replaceAll("\\d+", "0")</code><br>
197     * would cause similaryName("track 1", "track 2") = false, but similaryName("Track 1", "track 2") = true
198     * @param name first name to compare
199     * @param name2 second name to compare
200     * @return true if the normalized names are different but only a "little bit"
201     */
202    public boolean similaryName(String name, String name2) {
203        // check plain strings
204        int distance = getLevenshteinDistance(name, name2);
205        boolean similar = distance > 0 && distance <= 2;
206
207        // check if only the case differs, so we don't consider large distance as different strings
208        if (distance > 2 && name.length() == name2.length()) {
209            similar = deAccent(name).equalsIgnoreCase(deAccent(name2));
210        }
211
212        // try all rules
213        for (NormalizeRule rule : rules) {
214            int levenshteinDistance = getLevenshteinDistance(rule.normalize(name), rule.normalize(name2));
215            if (levenshteinDistance == 0)
216                // one rule results in identical names: identical
217                return false;
218            else if (levenshteinDistance <= 2) {
219                // 0 < distance <= 2
220                similar = true;
221            }
222        }
223        return similar;
224    }
225
226    /**
227     * Removes diacritics (accents) from string.
228     * @param str string
229     * @return {@code str} without any diacritic (accent)
230     * @since 12283
231     */
232    public static String deAccent(String str) {
233        // https://stackoverflow.com/a/1215117/2257172
234        return REMOVE_DIACRITICS.matcher(Normalizer.normalize(str, Normalizer.Form.NFD)).replaceAll("");
235    }
236
237    /**
238     * A normalization that is applied to names before testing them
239     */
240    @FunctionalInterface
241    public interface NormalizeRule {
242
243        /**
244         * Normalize the string by replacing parts.
245         * @param name name to normalize
246         * @return normalized string
247         */
248        String normalize(String name);
249    }
250
251    /**
252     * A rule to replace by regular expression,
253     * so that all strings matching the regular expression are handled as if they were {@link RegExprRule#replacement}
254     */
255    public static class RegExprRule implements NormalizeRule {
256        private final Pattern regExpr;
257        private final String replacement;
258
259        /**
260         * Create a new rule to replace by regular expression
261         * @param expression The regular expression
262         * @param replacement The replacement
263         */
264        public RegExprRule(String expression, String replacement) {
265            this.regExpr = Pattern.compile(expression);
266            this.replacement = replacement;
267        }
268
269        @Override
270        public String normalize(String name) {
271            return regExpr.matcher(name).replaceAll(replacement);
272        }
273
274        @Override
275        public String toString() {
276            return "replaceAll(" + regExpr + ", " + replacement + ')';
277        }
278    }
279
280    /**
281     * A rule that registers synonyms to a given word
282     */
283    public static class SynonymRule implements NormalizeRule {
284
285        private final String[] words;
286        private final Pattern regExpr;
287        private final String replacement;
288
289        /**
290         * Create a new {@link SynonymRule}
291         * @param replacement The word to use instead
292         * @param words The synonyms for that word
293         */
294        public SynonymRule(String replacement, String... words) {
295            this.replacement = replacement.toLowerCase(Locale.ENGLISH);
296            this.words = words;
297
298            // build regular expression for other words (for fast match)
299            StringBuilder expression = new StringBuilder();
300            int maxLength = 0;
301            for (int i = 0; i < words.length; i++) {
302                if (words[i].length() > maxLength) {
303                    maxLength = words[i].length();
304                }
305                if (expression.length() > 0) {
306                    expression.append('|');
307                }
308                expression.append(Pattern.quote(words[i]));
309            }
310            this.regExpr = Pattern.compile(expression.toString(), CASE_INSENSITIVE + UNICODE_CASE);
311        }
312
313        @Override
314        public String normalize(String name) {
315            // find first match
316            Matcher matcher = regExpr.matcher(name);
317            if (!matcher.find())
318                return name;
319
320            int start = matcher.start();
321
322            // which word matches?
323            String part = "";
324            for (int i = 0; i < words.length; i++) {
325                String word = words[i];
326                part = name.substring(start, start + word.length());
327                if (word.equalsIgnoreCase(part)) {
328                    break;
329                }
330            }
331
332            // replace the word
333            char[] newName = matcher.replaceFirst(replacement).toCharArray();
334
335            // adjust case (replacement is not shorter than matching word!)
336            int minLength = Math.min(replacement.length(), part.length());
337            for (int i = 0; i < minLength; i++) {
338                if (Character.isUpperCase(part.charAt(i))) {
339                    newName[start + i] = Character.toUpperCase(newName[start + i]);
340                }
341            }
342
343            return new String(newName);
344        }
345
346        @Override
347        public String toString() {
348            return "synonyms(" + replacement + ", " + Arrays.toString(words) + ')';
349        }
350    }
351}