Random lookup algorithm is now more naive, but less broken.
[zzz-pokedex.git] / pokedex / lookup.py
index b00f5a7..8488f21 100644 (file)
@@ -1,5 +1,4 @@
 # encoding: utf8
-from collections import namedtuple
 import os, os.path
 import random
 import re
@@ -15,6 +14,8 @@ 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
@@ -25,8 +26,9 @@ __all__ = ['PokedexLookup']
 
 rx_is_number = re.compile('^\d+$')
 
-LookupResult = namedtuple('LookupResult',
-    ['object', 'indexed_name', 'name', 'language', 'iso3166', 'exact'])
+LookupResult = namedtuple('LookupResult', [
+    'object', 'indexed_name', 'name', 'language', 'iso639', 'iso3166', 'exact',
+])
 
 class UninitializedIndex(object):
     class UninitializedIndexError(Exception):
@@ -51,22 +53,44 @@ class LanguageWeighting(whoosh.scoring.Weighting):
     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)
-        if doc['language'] == None:
+
+        # Apply extra weight
+        weight = weight * self.extra_weights.get(text, 1.0)
+
+        language = doc.get('language')
+        if language is None:
             # English (well, "default"); leave it at 1
             return weight
-        elif doc['language'] == u'Roomaji':
+        elif 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
+    MAX_FUZZY_RESULTS = 10
+    MAX_EXACT_RESULTS = 43
+    INTERMEDIATE_FACTOR = 2
+
+    # 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
@@ -80,6 +104,7 @@ class PokedexLookup(object):
             tables.Move,
             tables.Nature,
             tables.Pokemon,
+            tables.PokemonForm,
             tables.Type,
         )
     )
@@ -135,7 +160,8 @@ class PokedexLookup(object):
 
         # Create speller, and done
         spell_store = whoosh.filedb.filestore.FileStorage(directory)
-        self.speller = whoosh.spelling.SpellChecker(spell_store)
+        self.speller = whoosh.spelling.SpellChecker(spell_store,
+            **self.SPELLER_OPTIONS)
 
 
     def rebuild_index(self):
@@ -146,11 +172,18 @@ class PokedexLookup(object):
             table=whoosh.fields.ID(stored=True),
             row_id=whoosh.fields.ID(stored=True),
             language=whoosh.fields.STORED,
-            iso3166=whoosh.fields.STORED,
+            iso639=whoosh.fields.ID(stored=True),
+            iso3166=whoosh.fields.ID(stored=True),
             display_name=whoosh.fields.STORED,  # non-lowercased name
         )
 
-        if not os.path.exists(self.directory):
+        if os.path.exists(self.directory):
+            # create_in() isn't totally reliable, so just nuke whatever's there
+            # manually.  Try to be careful about this...
+            for f in os.listdir(self.directory):
+                if re.match('^_?(MAIN|SPELL)_', f):
+                    os.remove(os.path.join(self.directory, f))
+        else:
             os.mkdir(self.directory)
 
         self.index = whoosh.index.create_in(self.directory, schema=schema,
@@ -158,11 +191,7 @@ class PokedexLookup(object):
         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 = self.session.query(cls)
 
@@ -170,57 +199,57 @@ class PokedexLookup(object):
                 row_key = dict(table=unicode(cls.__tablename__),
                                row_id=unicode(row.id))
 
-                def add(name, language, iso3166, score):
+                def add(name, language, iso639, iso3166):
                     normalized_name = self.normalize_name(name)
 
                     writer.add_document(
                         name=normalized_name, display_name=name,
-                        language=language, iso3166=iso3166,
+                        language=language, iso639=iso639, iso3166=iso3166,
                         **row_key
                     )
 
-                    speller_entries.append((normalized_name, score))
+                    speller_entries.add(normalized_name)
 
 
                 # 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', 1)
-
-                    # 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', 1)
-                else:
-                    add(row.name, None, u'us', 1)
+                    # Don't re-add alternate forms of the same Pokémon; they'll
+                    # be added as Pokémon forms instead
+                    if not row.is_base_form:
+                        continue
+                elif cls == tables.PokemonForm:
+                    if row.name:
+                        add(row.pokemon_name, None, u'en', u'us')
+                    continue
 
                 # 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 row.name == moonspeak:
-                        # Don't add the English name again as a different
+                seen = set()
+                for language, name in getattr(row, 'name_map', {}).items():
+                    if name in seen:
+                        # Don't add the name again as a different
                         # language; no point and it makes spell results
                         # confusing
                         continue
+                    seen.add(name)
 
-                    add(moonspeak, foreign_name.language.name,
-                                   foreign_name.language.iso3166,
-                                   3)
+                    add(name, language.name,
+                              language.iso639,
+                              language.iso3166)
 
                     # Add Roomaji too
-                    if foreign_name.language.name == 'Japanese':
-                        roomaji = romanize(foreign_name.name)
-                        add(roomaji, u'Roomaji', u'jp', 8)
+                    if language.identifier == 'ja':
+                        roomaji = romanize(name)
+                        add(roomaji, u'Roomaji', u'ja', 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):
@@ -267,41 +296,62 @@ class PokedexLookup(object):
             name = name.strip()
 
             prefixes = prefix_chunk.split(',')
-            user_valid_types = [_.strip() for _ in prefixes]
+            user_valid_types = []
+            for prefix in prefixes:
+                prefix = prefix.strip()
+                if prefix:
+                    user_valid_types.append(prefix)
 
         # 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
+        # forbidden, completely ignore what the user requested.
+        # And, just to complicate matters: "type" and language need to be
+        # considered separately.
+        def merge_requirements(func):
+            user = filter(func, user_valid_types)
+            system = filter(func, valid_types)
+
+            if user and system:
+                merged = list(set(user) & set(system))
+                if merged:
+                    return merged
+                else:
+                    # No overlap; use the system restrictions
+                    return system
+            else:
+                # One or the other is blank; use the one that's not
+                return user or system
 
-        if not combined_valid_types:
-            # No restrictions
-            return name, [], None
+        # @foo means language must be foo; otherwise it's a table name
+        lang_requirements = merge_requirements(lambda req: req[0] == u'@')
+        type_requirements = merge_requirements(lambda req: req[0] != u'@')
+        all_requirements = lang_requirements + type_requirements
 
         # Construct the term
+        lang_terms = []
+        for lang in lang_requirements:
+            # Allow for either country or language codes
+            lang_code = lang[1:]
+            lang_terms.append(whoosh.query.Term(u'iso639', lang_code))
+            lang_terms.append(whoosh.query.Term(u'iso3166', lang_code))
+
         type_terms = []
-        final_valid_types = []
-        for valid_type in combined_valid_types:
-            table_name = self._parse_table_name(valid_type)
+        for type in type_requirements:
+            table_name = self._parse_table_name(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)
+        # Combine both kinds of restriction
+        all_terms = []
+        if type_terms:
+            all_terms.append(whoosh.query.Or(type_terms))
+        if lang_terms:
+            all_terms.append(whoosh.query.Or(lang_terms))
+
+        return name, all_requirements, whoosh.query.And(all_terms)
 
 
     def _parse_table_name(self, name):
@@ -343,7 +393,8 @@ class PokedexLookup(object):
             results.append(LookupResult(object=obj,
                                         indexed_name=record['name'],
                                         name=record['display_name'],
-                                        language=record['language'],
+                                        language=record.get('language'),
+                                        iso639=record['iso639'],
                                         iso3166=record['iso3166'],
                                         exact=exact))
 
@@ -353,12 +404,11 @@ class PokedexLookup(object):
     def lookup(self, input, valid_types=[], exact_only=False):
         """Attempts to find some sort of object, given a name.
 
-        Returns a list of named (object, name, language, iso3166, exact)
-        tuples.  `object` is a database object, `name` is the name under which
-        the object was found, `language` and `iso3166` are the name and country
-        code of the language in which the name was found, and `exact` is True
-        iff this was an
-        exact match.
+        Returns a list of named (object, name, language, iso639, iso3166,
+        exact) tuples.  `object` is a database object, `name` is the name under
+        which the object was found, `language` and the two isos are the name
+        and country codes of the language in which the name was found, and
+        `exact` is True iff this was an exact match.
 
         This function currently ONLY does fuzzy matching if there are no exact
         matches.
@@ -376,17 +426,19 @@ class PokedexLookup(object):
         Also:
         - Type restrictions.  "type:psychic" will only return the type.  This
           is how to make ID lookup useful.  Multiple type specs can be entered
-          with commas, as "move,item:1".  If `valid_types` are provided, any
-          type prefix will be ignored.
+          with commas, as "move,item:1".
+        - Language restrictions.  "@fr:charge" will only return Tackle, which
+          is called "Charge" in French.  These can be combined with type
+          restrictions, e.g., "@fr,move:charge".
         - Alternate formes can be specified merely like "wash rotom".
 
         `input`
             Name of the thing to look for.
 
         `valid_types`
-            A list of table objects or names, e.g., `['pokemon', 'moves']`.  If
-            this is provided, only results in one of the given tables will be
-            returned.
+            A list of type or language restrictions, e.g., `['pokemon',
+            '@ja']`.  If this is provided, only results in one of the given
+            tables will be returned.
 
         `exact_only`
             If True, only exact matches are returned.  If set to False (the
@@ -432,33 +484,62 @@ class PokedexLookup(object):
 
 
         ### Actual searching
-        searcher = self.index.searcher()
-        # XXX is this kosher?  docs say search() takes a weighting arg, but it
-        # certainly does not
-        searcher.weighting = LanguageWeighting()
-        results = searcher.search(query,
-                                  limit=self.INTERMEDIATE_LOOKUP_RESULTS)
+        # Limits; result limits are constants, and intermediate results (before
+        # duplicate items are stripped out) are capped at the result limit
+        # times another constant.
+        # Fuzzy are capped at 10, beyond which something is probably very
+        # wrong.  Exact matches -- that is, wildcards and ids -- are far less
+        # constrained.
+        # Also, exact matches are sorted by name, since weight doesn't matter.
+        sort_by = dict()
+        if exact_only:
+            max_results = self.MAX_EXACT_RESULTS
+            sort_by['sortedby'] = (u'table', u'name')
+        else:
+            max_results = self.MAX_FUZZY_RESULTS
+
+        searcher = self.index.searcher(weighting=LanguageWeighting())
+        results = searcher.search(
+            query,
+            limit=int(max_results * self.INTERMEDIATE_FACTOR),
+            **sort_by
+        )
 
         # Look for some fuzzy matches if necessary
         if not exact_only and not results:
             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
 
-                query = whoosh.query.Term('name', suggestion)
-                results.extend(searcher.search(query))
+            if not fuzzy_query_parts:
+                # Nothing at all; don't try querying
+                return []
+
+            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)
 
-        # Only return up to 10 matches; beyond that, something is wrong.  We
-        # strip out duplicate entries above, so it's remotely possible that we
-        # should have more than 10 here and lost a few.  The speller returns 25
-        # to give us some padding, and should avoid that problem.  Not a big
-        # deal if we lose the 25th-most-likely match anyway.
-        return objects[:self.MAX_LOOKUP_RESULTS]
+        # Truncate and return
+        return objects[:max_results]
 
 
     def random_lookup(self, valid_types=[]):
@@ -466,37 +547,34 @@ class PokedexLookup(object):
         `valid_types`.
         """
 
-        tables = []
+        table_names = []
         for valid_type in valid_types:
             table_name = self._parse_table_name(valid_type)
-            if table_name:
-                tables.append(self.indexed_tables[table_name])
+            # Skip anything not recognized.  Could be, say, a language code.
+            # XXX The vast majority of Pokémon forms are unnamed and unindexed,
+            #     which can produce blank results.  So skip them too for now.
+            if table_name and table_name != 'pokemon_forms':
+                table_names.append(table_name)
 
-        if not tables:
+        if not table_names:
             # n.b.: It's possible we got a list of valid_types and none of them
             # were valid, but this function is guaranteed to return
-            # *something*, so it politely selects from the entire index isntead
-            tables = self.indexed_tables.values()
-
-        # Rather than create an array of many hundred items and pick randomly
-        # from it, just pick a number up to the total number of potential
-        # items, then pick randomly from that, and partition the whole range
-        # into chunks.  This also avoids the slight problem that the index
-        # contains more rows (for languages) for some items than others.
-        # XXX ought to cache this (in the index?) if possible
-        total = 0
-        partitions = []
-        for table in tables:
-            count = self.session.query(table).count()
-            total += count
-            partitions.append((table, count))
-
-        n = random.randint(1, total)
-        while n > partitions[0][1]:
-            n -= partitions[0][1]
-            partitions.pop(0)
-
-        return self.lookup(unicode(n), valid_types=[ partitions[0][0] ])
+            # *something*, so it politely selects from the entire index instead
+            table_names = self.indexed_tables.keys()
+            table_names.remove('pokemon_forms')
+
+        # Pick a random table, then pick a random item from it.  Small tables
+        # like Type will have an unnatural bias.  The alternative is that a
+        # simple search for "random" will do some eight queries, counting the
+        # rows in every single indexed table, and that's awful.
+        # XXX Can we improve on this, reasonably?
+        table_name = random.choice(table_names)
+        count = self.session.query(self.indexed_tables[table_name]).count()
+        id, = self.session.query(self.indexed_tables[table_name].id) \
+            .offset(random.randint(0, count - 1)) \
+            .first()
+
+        return self.lookup(unicode(id), valid_types=[table_name])
 
     def prefix_lookup(self, prefix, valid_types=[]):
         """Returns terms starting with the given exact prefix.