Significantly improved lookup fuzzy matching.
[zzz-pokedex.git] / pokedex / lookup.py
index 1363c7a..8c3e444 100644 (file)
@@ -1,7 +1,5 @@
 # encoding: utf8
-from collections import namedtuple
 import os, os.path
-import pkg_resources
 import random
 import re
 import shutil
@@ -16,9 +14,12 @@ from whoosh.qparser import QueryParser
 import whoosh.scoring
 import whoosh.spelling
 
+from pokedex.util import namedtuple
+
 from pokedex.db import connect
 import pokedex.db.tables as tables
 from pokedex.roomaji import romanize
+from pokedex.defaults import get_default_index_dir
 
 __all__ = ['PokedexLookup']
 
@@ -26,30 +27,68 @@ __all__ = ['PokedexLookup']
 rx_is_number = re.compile('^\d+$')
 
 LookupResult = namedtuple('LookupResult',
-                          ['object', 'name', 'language', 'iso3166', 'exact'])
+    ['object', 'indexed_name', 'name', 'language', 'iso3166', 'exact'])
+
+class UninitializedIndex(object):
+    class UninitializedIndexError(Exception):
+        pass
+
+    def __nonzero__(self):
+        """Dummy object should identify itself as False."""
+        return False
+
+    def __bool__(self):
+        """Python 3000 version of the above.  Future-proofing rules!"""
+        return False
+
+    def __getattr__(self, *args, **kwargs):
+        raise self.UninitializedIndexError(
+            "The lookup index does not exist.  Please use `pokedex setup` "
+            "or lookup.rebuild_index() to create it."
+        )
 
 class LanguageWeighting(whoosh.scoring.Weighting):
     """A scoring class that forces otherwise-equal English results to come
     before foreign results.
     """
 
+    def __init__(self, extra_weights={}, *args, **kwargs):
+        """`extra_weights` may be a dictionary of weights which will be
+        factored in.
+
+        Intended for use with spelling corrections, which come along with their
+        own weightings.
+        """
+        self.extra_weights = extra_weights
+        super(LanguageWeighting, self).__init__(*args, **kwargs)
+
     def score(self, searcher, fieldnum, text, docnum, weight, QTF=1):
         doc = searcher.stored_fields(docnum)
+
+        # Apply extra weight
+        weight = weight * self.extra_weights.get(text, 1.0)
+
         if doc['language'] == None:
             # English (well, "default"); leave it at 1
             return weight
         elif doc['language'] == u'Roomaji':
             # Give Roomaji a little boost; it's most likely to be searched
-            return weight * 0.95
+            return weight * 0.9
         else:
             # Everything else can drop down the totem pole
-            return weight * 0.9
+            return weight * 0.8
 
 
 class PokedexLookup(object):
     INTERMEDIATE_LOOKUP_RESULTS = 25
     MAX_LOOKUP_RESULTS = 10
 
+    # The speller only checks how much the input matches a word; there can be
+    # all manner of extra unmatched junk, and it won't affect the weighting.
+    # To compensate, greatly boost the weighting of matches at the beginning
+    # and end, so nearly-full-word-matches are much better
+    SPELLER_OPTIONS = dict(booststart=10.0, boostend=9.0)
+
     # Dictionary of table name => table class.
     # Need the table name so we can get the class from the table name after we
     # retrieve something from the index
@@ -58,14 +97,16 @@ class PokedexLookup(object):
         for cls in (
             tables.Ability,
             tables.Item,
+            tables.Location,
             tables.Move,
+            tables.Nature,
             tables.Pokemon,
             tables.Type,
         )
     )
 
 
-    def __init__(self, directory=None, session=None, recreate=False):
+    def __init__(self, directory=None, session=None):
         """Opens the whoosh index stored in the named directory.  If the index
         doesn't already exist, it will be created.
 
@@ -74,22 +115,19 @@ class PokedexLookup(object):
             `pokedex` egg directory.
 
         `session`
-            If the index needs to be created, this database session will be
-            used.  Defaults to an attempt to connect to the default SQLite
-            database installed by `pokedex setup`.
-
-        `recreate`
-            If set to True, the whoosh index will be created even if it already
-            exists.
+            Used for creating the index and retrieving objects.  Defaults to an
+            attempt to connect to the default SQLite database installed by
+            `pokedex setup`.
         """
 
         # By the time this returns, self.index, self.speller, and self.session
         # must be set
 
-        # Defaults
-        if not directory:
-            directory = pkg_resources.resource_filename('pokedex',
-                                                        'data/whoosh-index')
+        # If a directory was not given, use the default
+        if directory is None:
+            directory = get_default_index_dir()
+
+        self.directory = directory
 
         if session:
             self.session = session
@@ -97,31 +135,34 @@ class PokedexLookup(object):
             self.session = connect()
 
         # Attempt to open or create the index
-        directory_exists = os.path.exists(directory)
-        if directory_exists and not recreate:
-            # Already exists; should be an index!  Bam, done.
-            try:
-                self.index = whoosh.index.open_dir(directory, indexname='MAIN')
-                spell_store = whoosh.filedb.filestore.FileStorage(directory)
-                self.speller = whoosh.spelling.SpellChecker(spell_store)
-                return
-            except whoosh.index.EmptyIndexError as e:
-                # Apparently not a real index.  Fall out and create it
-                pass
-
-        # Delete and start over if we're going to bail anyway.
-        if directory_exists and recreate:
-            # Be safe and only delete if it looks like a whoosh index, i.e.,
-            # everything starts with _
-            if all(f[0] == '_' for f in os.listdir(directory)):
-                shutil.rmtree(directory)
-                directory_exists = False
-
-        if not directory_exists:
-            os.mkdir(directory)
-
-
-        ### Create index
+        if not os.path.exists(directory) or not os.listdir(directory):
+            # Directory doesn't exist OR is empty; caller needs to use
+            # rebuild_index before doing anything.  Provide a dummy object that
+            # complains when used
+            self.index = UninitializedIndex()
+            self.speller = UninitializedIndex()
+            return
+
+        # Otherwise, already exists; should be an index!  Bam, done.
+        # Note that this will explode if the directory exists but doesn't
+        # contain an index; that's a feature
+        try:
+            self.index = whoosh.index.open_dir(directory, indexname='MAIN')
+        except whoosh.index.EmptyIndexError:
+            raise IOError(
+                "The index directory already contains files.  "
+                "Please use a dedicated directory for the lookup index."
+            )
+
+        # Create speller, and done
+        spell_store = whoosh.filedb.filestore.FileStorage(directory)
+        self.speller = whoosh.spelling.SpellChecker(spell_store,
+            **self.SPELLER_OPTIONS)
+
+
+    def rebuild_index(self):
+        """Creates the index from scratch."""
+
         schema = whoosh.fields.Schema(
             name=whoosh.fields.ID(stored=True),
             table=whoosh.fields.ID(stored=True),
@@ -129,70 +170,75 @@ class PokedexLookup(object):
             language=whoosh.fields.STORED,
             iso3166=whoosh.fields.STORED,
             display_name=whoosh.fields.STORED,  # non-lowercased name
-            forme_name=whoosh.fields.ID,
         )
 
-        self.index = whoosh.index.create_in(directory, schema=schema,
-                                            indexname='MAIN')
+        if not os.path.exists(self.directory):
+            os.mkdir(self.directory)
+
+        self.index = whoosh.index.create_in(self.directory, schema=schema,
+                                                            indexname='MAIN')
         writer = self.index.writer()
 
         # Index every name in all our tables of interest
-        # speller_entries becomes a list of (word, score) tuples; the score is
-        # 2 for English names, 1.5 for Roomaji, and 1 for everything else.  I
-        # think this biases the results in the direction most people expect,
-        # especially when e.g. German names are very similar to English names
-        speller_entries = []
+        speller_entries = set()
         for cls in self.indexed_tables.values():
-            q = session.query(cls)
+            q = self.session.query(cls)
 
             for row in q.yield_per(5):
-                # Need to give forme_name a dummy value because I can't
-                # search for explicitly empty fields.  Boo.
                 row_key = dict(table=unicode(cls.__tablename__),
-                               row_id=unicode(row.id),
-                               forme_name=u'__empty__')
+                               row_id=unicode(row.id))
 
-                def add(name, language, iso3166, score):
+                def add(name, language, iso3166):
                     normalized_name = self.normalize_name(name)
+
                     writer.add_document(
                         name=normalized_name, display_name=name,
                         language=language, iso3166=iso3166,
                         **row_key
                     )
-                    speller_entries.append((normalized_name, score))
 
-                # If this is a form, mark it as such
-                if getattr(row, 'forme_base_pokemon_id', None):
-                    row_key['forme_name'] = row.forme_name
+                    speller_entries.add(normalized_name)
 
-                name = row.name
-                add(name, None, u'us', 1)
 
-                # Pokemon also get other languages
+                # Add the basic English name to the index
+                if cls == tables.Pokemon:
+                    # Pokémon need their form name added
+                    # XXX kinda kludgy
+                    add(row.full_name, None, u'us')
+
+                    # If this is a default form, ALSO add the unadorned name,
+                    # so 'Deoxys' alone will still do the right thing
+                    if row.forme_name and not row.forme_base_pokemon_id:
+                        add(row.name, None, u'us')
+                else:
+                    add(row.name, None, u'us')
+
+                # Some things also have other languages' names
+                # XXX other language form names..?
                 for foreign_name in getattr(row, 'foreign_names', []):
                     moonspeak = foreign_name.name
-                    if name == moonspeak:
+                    if row.name == moonspeak:
                         # Don't add the English name again as a different
                         # language; no point and it makes spell results
                         # confusing
                         continue
 
                     add(moonspeak, foreign_name.language.name,
-                                   foreign_name.language.iso3166,
-                                   3)
+                                   foreign_name.language.iso3166)
 
                     # Add Roomaji too
                     if foreign_name.language.name == 'Japanese':
                         roomaji = romanize(foreign_name.name)
-                        add(roomaji, u'Roomaji', u'jp', 8)
+                        add(roomaji, u'Roomaji', u'jp')
 
         writer.commit()
 
         # Construct and populate a spell-checker index.  Quicker to do it all
         # at once, as every call to add_* does a commit(), and those seem to be
         # expensive
-        self.speller = whoosh.spelling.SpellChecker(self.index.storage)
-        self.speller.add_scored_words(speller_entries)
+        self.speller = whoosh.spelling.SpellChecker(self.index.storage, mingram=2,
+            **self.SPELLER_OPTIONS)
+        self.speller.add_words(speller_entries)
 
 
     def normalize_name(self, name):
@@ -218,21 +264,81 @@ class PokedexLookup(object):
         return name
 
 
+    def _apply_valid_types(self, name, valid_types):
+        """Combines the enforced `valid_types` with any from the search string
+        itself and updates the query.
+
+        For example, a name of 'a,b:foo' and valid_types of b,c will search for
+        only `b`s named "foo".
+
+        Returns `(name, merged_valid_types, term)`, where `name` has had any type
+        prefix stripped, `merged_valid_types` combines the original
+        `valid_types` with the type prefix, and `term` is a query term for
+        limited to just the allowed types.  If there are no type restrictions
+        at all, `term` will be None.
+        """
+
+        # Remove any type prefix (pokemon:133) first
+        user_valid_types = []
+        if ':' in name:
+            prefix_chunk, name = name.split(':', 1)
+            name = name.strip()
+
+            prefixes = prefix_chunk.split(',')
+            user_valid_types = [_.strip() for _ in prefixes]
+
+        # Merge the valid types together.  Only types that appear in BOTH lists
+        # may be used.
+        # As a special case, if the user asked for types that are explicitly
+        # forbidden, completely ignore what the user requested
+        combined_valid_types = []
+        if user_valid_types and valid_types:
+            combined_valid_types = list(
+                set(user_valid_types) & set(combined_valid_types)
+            )
+
+            if not combined_valid_types:
+                # No overlap!  Just use the enforced ones
+                combined_valid_types = valid_types
+        else:
+            # One list or the other was blank, so just use the one that isn't
+            combined_valid_types = valid_types + user_valid_types
+
+        if not combined_valid_types:
+            # No restrictions
+            return name, [], None
+
+        # Construct the term
+        type_terms = []
+        final_valid_types = []
+        for valid_type in combined_valid_types:
+            table_name = self._parse_table_name(valid_type)
+
+            # Quietly ignore bogus valid_types; more likely to DTRT
+            if table_name:
+                final_valid_types.append(valid_type)
+                type_terms.append(whoosh.query.Term(u'table', table_name))
+
+        return name, final_valid_types, whoosh.query.Or(type_terms)
+
+
     def _parse_table_name(self, name):
         """Takes a singular table name, table name, or table object and returns
         the table name.
 
         Returns None for a bogus name.
         """
+        # Table object
         if hasattr(name, '__tablename__'):
             return getattr(name, '__tablename__')
-        elif name in self.indexed_tables:
-            return name
-        elif name + 's' in self.indexed_tables:
-            return name + 's'
-        else:
-            # Bogus.  Be nice and return dummy
-            return None
+
+        # Table name
+        for table in self.indexed_tables.values():
+            if name in (table.__tablename__, table.__singlename__):
+                return table.__tablename__
+
+        # Bogus.  Be nice and return dummy
+        return None
 
     def _whoosh_records_to_results(self, records, exact=True):
         """Converts a list of whoosh's indexed records to LookupResult tuples
@@ -253,6 +359,7 @@ class PokedexLookup(object):
             obj = self.session.query(cls).get(record['row_id'])
 
             results.append(LookupResult(object=obj,
+                                        indexed_name=record['name'],
                                         name=record['display_name'],
                                         language=record['language'],
                                         iso3166=record['iso3166'],
@@ -309,53 +416,37 @@ class PokedexLookup(object):
         exact = True
         form = None
 
-        # Remove any type prefix (pokemon:133) before constructing a query
-        if ':' in name:
-            prefix_chunk, name = name.split(':', 1)
-            name = name.strip()
-
-            if not valid_types:
-                # Only use types from the query string if none were explicitly
-                # provided
-                prefixes = prefix_chunk.split(',')
-                valid_types = [_.strip() for _ in prefixes]
+        # Pop off any type prefix and merge with valid_types
+        name, merged_valid_types, type_term = \
+            self._apply_valid_types(name, valid_types)
 
         # Random lookup
         if name == 'random':
-            return self.random_lookup(valid_types=valid_types)
+            return self.random_lookup(valid_types=merged_valid_types)
 
         # Do different things depending what the query looks like
         # Note: Term objects do an exact match, so we don't have to worry about
         # a query parser tripping on weird characters in the input
+        try:
+            # Let Python try to convert to a number, so 0xff works
+            name_as_number = int(name, base=0)
+        except ValueError:
+            # Oh well
+            name_as_number = None
+
         if '*' in name or '?' in name:
             exact_only = True
             query = whoosh.query.Wildcard(u'name', name)
-        elif rx_is_number.match(name):
+        elif name_as_number is not None:
             # Don't spell-check numbers!
             exact_only = True
-            query = whoosh.query.Term(u'row_id', name)
+            query = whoosh.query.Term(u'row_id', unicode(name_as_number))
         else:
             # Not an integer
-            query = whoosh.query.Term(u'name', name) \
-                  & whoosh.query.Term(u'forme_name', u'__empty__')
+            query = whoosh.query.Term(u'name', name)
 
-            # If there's a space in the input, this might be a form
-            if ' ' in name:
-                form, formless_name = name.split(' ', 1)
-                form_query = whoosh.query.Term(u'name', formless_name) \
-                           & whoosh.query.Term(u'forme_name', form)
-                query = query | form_query
-
-        ### Filter by type of object
-        type_terms = []
-        for valid_type in valid_types:
-            table_name = self._parse_table_name(valid_type)
-            if table_name:
-                # Quietly ignore bogus valid_types; more likely to DTRT
-                type_terms.append(whoosh.query.Term(u'table', table_name))
-
-        if type_terms:
-            query = query & whoosh.query.Or(type_terms)
+        if type_term:
+            query = query & type_term
 
 
         ### Actual searching
@@ -371,11 +462,30 @@ class PokedexLookup(object):
             exact = False
             results = []
 
-            for suggestion in self.speller.suggest(
-                name, self.INTERMEDIATE_LOOKUP_RESULTS):
+            fuzzy_query_parts = []
+            fuzzy_weights = {}
+            min_weight = [None]
+            for suggestion, _, weight in self.speller.suggestions_and_scores(name):
+                # Only allow the top 50% of scores; otherwise there will always
+                # be a lot of trailing junk
+                if min_weight[0] is None:
+                    min_weight[0] = weight * 0.5
+                elif weight < min_weight[0]:
+                    break
+
+                fuzzy_query_parts.append(whoosh.query.Term('name', suggestion))
+                fuzzy_weights[suggestion] = weight
+
+            if not fuzzy_query_parts:
+                # Nothing at all; don't try querying
+                return []
 
-                query = whoosh.query.Term('name', suggestion)
-                results.extend(searcher.search(query))
+            fuzzy_query = whoosh.query.Or(fuzzy_query_parts)
+            if type_term:
+                fuzzy_query = fuzzy_query & type_term
+
+            searcher.weighting = LanguageWeighting(extra_weights=fuzzy_weights)
+            results = searcher.search(fuzzy_query)
 
         ### Convert results to db objects
         objects = self._whoosh_records_to_results(results, exact=exact)
@@ -425,15 +535,21 @@ class PokedexLookup(object):
 
         return self.lookup(unicode(n), valid_types=[ partitions[0][0] ])
 
-    def prefix_lookup(self, prefix):
+    def prefix_lookup(self, prefix, valid_types=[]):
         """Returns terms starting with the given exact prefix.
 
-        No special magic is currently done with the name; type prefixes are not
-        recognized.
+        Type prefixes are recognized, but no other name munging is done.
         """
 
+        # Pop off any type prefix and merge with valid_types
+        prefix, merged_valid_types, type_term = \
+            self._apply_valid_types(prefix, valid_types)
+
         query = whoosh.query.Prefix(u'name', self.normalize_name(prefix))
 
+        if type_term:
+            query = query & type_term
+
         searcher = self.index.searcher()
         searcher.weighting = LanguageWeighting()
         results = searcher.search(query)  # XXX , limit=self.MAX_LOOKUP_RESULTS)