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folkugat-web/folkugat_web/services/temes/search.py
2025-03-23 21:46:04 +01:00

100 lines
4.1 KiB
Python

import time
from collections.abc import Iterable, Iterator
from sqlite3 import Connection
from typing import Callable
import Levenshtein
from folkugat_web.config import search as config
from folkugat_web.dal.sql import get_connection
from folkugat_web.dal.sql.temes import query as temes_q
from folkugat_web.log import logger
from folkugat_web.model import search as search_model
from folkugat_web.model import temes as model
from folkugat_web.utils import FnChain
def get_query_word_similarity(query_word: str, text_ngrams: search_model.NGrams) -> search_model.SearchMatch:
n = len(query_word)
if n < config.MIN_NGRAM_LENGTH:
return search_model.SearchMatch(distance=0.0, ngram='')
ns = filter(lambda i: i >= config.MIN_NGRAM_LENGTH, range(
n - config.QUERY_NGRAM_RANGE, n + config.QUERY_NGRAM_RANGE + 1))
candidate_ngrams = ((m, ngram)
for m, ngrams in map(lambda i: (i, text_ngrams.get(i, [])), ns)
for ngram in ngrams)
return min((search_model.SearchMatch(distance=Levenshtein.distance(query_word, ngram)/m,
ngram=ngram)
for m, ngram in candidate_ngrams),
default=search_model.SearchMatch(distance=float("inf"), ngram=""))
def get_query_similarity(query: str, ngrams: search_model.NGrams) -> search_model.SearchMatch:
query_words = query.lower().split()
word_matches = map(lambda query_word: get_query_word_similarity(query_word, ngrams), query_words)
return search_model.SearchMatch.combine_matches(word_matches)
def _build_results_fn(query: str) -> Callable[[Iterable[tuple[int, search_model.NGrams]]],
Iterator[search_model.QueryResult]]:
def build_result(entry: tuple[int, search_model.NGrams]) -> search_model.QueryResult:
if len(query) == 0:
return search_model.QueryResult(
id=entry[0],
distance=0,
ngram="",
)
match = get_query_similarity(query, entry[1])
return search_model.QueryResult(
id=entry[0],
distance=match.distance,
ngram=match.ngram,
)
def build_results(entries: Iterable[tuple[int, search_model.NGrams]]) -> Iterator[search_model.QueryResult]:
return map(build_result, entries)
return build_results
def _filter_distance(qrs: Iterable[search_model.QueryResult]) -> Iterator[search_model.QueryResult]:
return filter(lambda qr: qr.distance <= config.SEARCH_DISTANCE_THRESHOLD, qrs)
def _sort_by_distance(qrs: Iterable[search_model.QueryResult]) -> list[search_model.QueryResult]:
return sorted(qrs, key=lambda qr: qr.distance)
def _query_results_to_temes(con: Connection) -> Callable[[Iterable[search_model.QueryResult]], Iterator[model.Tema]]:
def fetch_temes(qrs: Iterable[search_model.QueryResult]) -> Iterator[model.Tema]:
return filter(None, map(lambda qr: temes_q.get_tema_by_id(tema_id=qr.id, con=con), qrs))
return fetch_temes
def _filter_hidden(hidden: bool) -> Callable[[Iterable[model.Tema]], Iterator[model.Tema]]:
def filter_hidden(temes: Iterable[model.Tema]) -> Iterator[model.Tema]:
return filter(lambda t: hidden or not t.hidden, temes)
return filter_hidden
def _apply_limit_offset(limit: int, offset: int) -> Callable[[Iterable[model.Tema]], list[model.Tema]]:
def apply_limit_offset(temes: Iterable[model.Tema]) -> list[model.Tema]:
return list(temes)[offset:offset + limit]
return apply_limit_offset
def busca_temes(query: str, hidden: bool = False, limit: int = 10, offset: int = 0) -> list[model.Tema]:
t0 = time.time()
with get_connection() as con:
result = (
FnChain.transform(temes_q.get_tema_id_to_ngrams(con).items()) |
_build_results_fn(query) |
_filter_distance |
_sort_by_distance |
_query_results_to_temes(con) |
_filter_hidden(hidden) |
_apply_limit_offset(limit=limit, offset=offset)
).result()
logger.info(f"Search time: { int((time.time() - t0) * 1000) } ms")
return result