Fuzzy lookup results were not respecting type limits.
[zzz-pokedex.git] / pokedex / lookup.py
index 37a50f3..0b09823 100644 (file)
@@ -1,7 +1,9 @@
 # encoding: utf8
 import os, os.path
-import pkg_resources
+import random
 import re
+import shutil
+import unicodedata
 
 from sqlalchemy.sql import func
 import whoosh
@@ -9,188 +11,513 @@ import whoosh.filedb.filestore
 import whoosh.filedb.fileindex
 import whoosh.index
 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
 
-# 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
-indexed_tables = {}
-for cls in [
-        tables.Ability,
-        tables.Item,
-        tables.Move,
-        tables.Pokemon,
-        tables.Type,
-    ]:
-    indexed_tables[cls.__tablename__] = cls
-
-# Dictionary of extra keys to file types of objects under, e.g. Pokémon can
-# also be looked up purely by number
-extra_keys = {
-    tables.Move: [
-        lambda row: u"move %d" % row.id,
-    ],
-    tables.Pokemon: [
-        lambda row: unicode(row.id),
-    ],
-}
-
-def open_index(directory=None, session=None, recreate=False):
-    """Opens the whoosh index stored in the named directory and returns (index,
-    speller).  If the index doesn't already exist, it will be created.
-
-    `directory`
-        Directory containing the index.  Defaults to a location within the
-        `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.
-    """
-
-    # Defaults
-    if not directory:
-        directory = pkg_resources.resource_filename('pokedex',
-                                                    'data/whoosh_index')
-
-    if not session:
-        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!
-        try:
-            index = whoosh.index.open_dir(directory, indexname='pokedex')
-            speller = whoosh.index.open_dir(directory, indexname='spelling')
-            return index, speller
-        except whoosh.index.EmptyIndexError as e:
-            # Apparently not a real index.  Fall out of the if and create it
-            pass
-
-    if not directory_exists:
-        os.mkdir(directory)
-
-
-    # Create index
-    schema = whoosh.fields.Schema(
-        name=whoosh.fields.ID(stored=True),
-        table=whoosh.fields.STORED,
-        row_id=whoosh.fields.STORED,
-        language=whoosh.fields.STORED,
-    )
-
-    index = whoosh.index.create_in(directory, schema=schema,
-                                              indexname='pokedex')
-    writer = index.writer()
-
-    # Index every name in all our tables of interest
-    speller_entries = []
-    for cls in indexed_tables.values():
-        q = session.query(cls)
+__all__ = ['PokedexLookup']
 
-        # Only index base Pokémon formes
-        if hasattr(cls, 'forme_base_pokemon_id'):
-            q = q.filter_by(forme_base_pokemon_id=None)
 
-        for row in q.yield_per(5):
-            row_key = dict(table=cls.__tablename__, row_id=row.id)
+rx_is_number = re.compile('^\d+$')
 
-            # Spelling index only indexes strings of letters, alas, so we
-            # reduce every name to this to make the index work.  However, exact
-            # matches are not returned, so e.g. 'nidoran' would neither match
-            # exactly nor fuzzy-match.  Solution: add the spelling-munged name
-            # as a regular index row too.
-            name = row.name.lower()
-            writer.add_document(name=name, **row_key)
+LookupResult = namedtuple('LookupResult',
+    ['object', 'indexed_name', 'name', 'language', 'iso3166', 'exact'])
 
-            speller_entries.append(name)
+class UninitializedIndex(object):
+    class UninitializedIndexError(Exception):
+        pass
 
-            for extra_key_func in extra_keys.get(cls, []):
-                extra_key = extra_key_func(row)
-                writer.add_document(name=extra_key, **row_key)
+    def __nonzero__(self):
+        """Dummy object should identify itself as False."""
+        return False
 
-    writer.commit()
+    def __bool__(self):
+        """Python 3000 version of the above.  Future-proofing rules!"""
+        return False
 
-    # 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
-    speller = whoosh.spelling.SpellChecker(index.storage, indexname='spelling')
-    speller.add_words(speller_entries)
+    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."
+        )
 
-    return index, speller
-
-
-def lookup(name, session=None, exact_only=False):
-    """Attempts to find some sort of object, given a database session and name.
+class LanguageWeighting(whoosh.scoring.Weighting):
+    """A scoring class that forces otherwise-equal English results to come
+    before foreign results.
+    """
 
-    Returns (objects, exact) where `objects` is a list of database objects, and
-    `exact` is True iff the given name matched the returned objects exactly.
+    def score(self, searcher, fieldnum, text, docnum, weight, QTF=1):
+        doc = searcher.stored_fields(docnum)
+        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
+        else:
+            # Everything else can drop down the totem pole
+            return weight * 0.9
+
+
+class PokedexLookup(object):
+    INTERMEDIATE_LOOKUP_RESULTS = 25
+    MAX_LOOKUP_RESULTS = 10
+
+    # 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
+    indexed_tables = dict(
+        (cls.__tablename__, cls)
+        for cls in (
+            tables.Ability,
+            tables.Item,
+            tables.Location,
+            tables.Move,
+            tables.Nature,
+            tables.Pokemon,
+            tables.Type,
+        )
+    )
 
-    This function ONLY does fuzzy matching if there are no exact matches.
 
-    Formes are not returned; "Shaymin" will return only grass Shaymin.
+    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.
 
-    Currently recognizes:
-    - Pokémon names: "Eevee"
+        `directory`
+            Directory containing the index.  Defaults to a location within the
+            `pokedex` egg directory.
 
-    `name`
-        Name of the thing to look for.
+        `session`
+            Used for creating the index and retrieving objects.  Defaults to an
+            attempt to connect to the default SQLite database installed by
+            `pokedex setup`.
+        """
 
-    `session`
-        A database session to use for retrieving objects.  As with get_index,
-        if this is not provided, a connection to the default database will be
-        attempted.
+        # By the time this returns, self.index, self.speller, and self.session
+        # must be set
 
-    `exact_only`
-        If True, only exact matches are returned.  If set to False (the
-        default), and the provided `name` doesn't match anything exactly,
-        spelling correction will be attempted.
-    """
+        # If a directory was not given, use the default
+        if directory is None:
+            directory = get_default_index_dir()
 
-    if not session:
-        session = connect()
+        self.directory = directory
 
-    index, speller = open_index()
+        if session:
+            self.session = session
+        else:
+            self.session = connect()
 
-    exact = True
+        # Attempt to open or create the 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
 
-    # Look for exact name.  A Term object does an exact match, so we don't have
-    # to worry about a query parser tripping on weird characters in the input
-    searcher = index.searcher()
-    query = whoosh.query.Term('name', name.lower())
-    results = searcher.search(query)
-
-    if not exact_only:
-        # Look for some fuzzy matches
-        if not results:
+        # 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)
+
+
+    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),
+            row_id=whoosh.fields.ID(stored=True),
+            language=whoosh.fields.STORED,
+            iso3166=whoosh.fields.STORED,
+            display_name=whoosh.fields.STORED,  # non-lowercased name
+        )
+
+        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 = []
+        for cls in self.indexed_tables.values():
+            q = self.session.query(cls)
+
+            for row in q.yield_per(5):
+                row_key = dict(table=unicode(cls.__tablename__),
+                               row_id=unicode(row.id))
+
+                def add(name, language, iso3166, score):
+                    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))
+
+
+                # 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)
+
+                # 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
+                        # language; no point and it makes spell results
+                        # confusing
+                        continue
+
+                    add(moonspeak, foreign_name.language.name,
+                                   foreign_name.language.iso3166,
+                                   3)
+
+                    # Add Roomaji too
+                    if foreign_name.language.name == 'Japanese':
+                        roomaji = romanize(foreign_name.name)
+                        add(roomaji, u'Roomaji', u'jp', 8)
+
+        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)
+
+
+    def normalize_name(self, name):
+        """Strips irrelevant formatting junk from name input.
+
+        Specifically: everything is lowercased, and accents are removed.
+        """
+        # http://stackoverflow.com/questions/517923/what-is-the-best-way-to-remove-accents-in-a-python-unicode-string
+        # Makes sense to me.  Decompose by Unicode rules, then remove combining
+        # characters, then recombine.  I'm explicitly doing it this way instead
+        # of testing combining() because Korean characters apparently
+        # decompose!  But the results are considered letters, not combining
+        # characters, so testing for Mn works well, and combining them again
+        # makes them look right.
+        nkfd_form = unicodedata.normalize('NFKD', unicode(name))
+        name = u"".join(c for c in nkfd_form
+                        if unicodedata.category(c) != 'Mn')
+        name = unicodedata.normalize('NFC', name)
+
+        name = name.strip()
+        name = name.lower()
+
+        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__')
+
+        # 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
+        containing database objects.
+        """
+        # XXX this 'exact' thing is getting kinda leaky.  would like a better
+        # way to handle it, since only lookup() cares about fuzzy results
+        seen = {}
+        results = []
+        for record in records:
+            # Skip dupes
+            seen_key = record['table'], record['row_id']
+            if seen_key in seen:
+                continue
+            seen[seen_key] = True
+
+            cls = self.indexed_tables[record['table']]
+            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'],
+                                        exact=exact))
+
+        return results
+
+
+    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.
+
+        This function currently ONLY does fuzzy matching if there are no exact
+        matches.
+
+        Formes are not returned unless requested; "Shaymin" will return only
+        grass Shaymin.
+
+        Extraneous whitespace is removed with extreme prejudice.
+
+        Recognizes:
+        - Names: "Eevee", "Surf", "Run Away", "Payapa Berry", etc.
+        - Foreign names: "Iibui", "Eivui"
+        - Fuzzy names in whatever language: "Evee", "Ibui"
+        - IDs: "133", "192", "250"
+        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.
+        - 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.
+
+        `exact_only`
+            If True, only exact matches are returned.  If set to False (the
+            default), and the provided `name` doesn't match anything exactly,
+            spelling correction will be attempted.
+        """
+
+        name = self.normalize_name(input)
+        exact = True
+        form = None
+
+        # 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=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 name_as_number is not None:
+            # Don't spell-check numbers!
+            exact_only = True
+            query = whoosh.query.Term(u'row_id', unicode(name_as_number))
+        else:
+            # Not an integer
+            query = whoosh.query.Term(u'name', name)
+
+        if type_term:
+            query = query & type_term
+
+
+        ### 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)
+
+        # Look for some fuzzy matches if necessary
+        if not exact_only and not results:
             exact = False
             results = []
 
-            for suggestion in speller.suggest(name, 3):
+            for suggestion in self.speller.suggest(
+                name, self.INTERMEDIATE_LOOKUP_RESULTS):
+
                 query = whoosh.query.Term('name', suggestion)
+                if type_term:
+                    query = query & type_term
                 results.extend(searcher.search(query))
 
-    # Convert results to db objects
-    objects = []
-    seen = {}
-    for result in results:
-        # Skip dupe results
-        seen_key = result['table'], result['row_id']
-        if seen_key in seen:
-            continue
-        seen[seen_key] = True
-
-        cls = indexed_tables[result['table']]
-        obj = session.query(cls).get(result['row_id'])
-        objects.append(obj)
-
-    return objects, exact
+        ### 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]
+
+
+    def random_lookup(self, valid_types=[]):
+        """Returns a random lookup result from one of the provided
+        `valid_types`.
+        """
+
+        tables = []
+        for valid_type in valid_types:
+            table_name = self._parse_table_name(valid_type)
+            if table_name:
+                tables.append(self.indexed_tables[table_name])
+
+        if not tables:
+            # 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] ])
+
+    def prefix_lookup(self, prefix, valid_types=[]):
+        """Returns terms starting with the given exact prefix.
+
+        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)
+
+        return self._whoosh_records_to_results(results)