book_library_server/fastapi_book_server/app/services/sequence.py

from typing import TypedDict

from app.models import Sequence
from app.services.common import TRGMSearchService, MeiliSearchService, GetRandomService


GET_OBJECT_IDS_QUERY = """
SELECT ARRAY (
    WITH filtered_sequences AS (
        SELECT
            id,
            similarity(name, :query) as sml,
            (
                SELECT count(*) FROM book_sequences
                LEFT JOIN books ON (books.id = book)
                WHERE sequence = sequences.id AND books.is_deleted = 'f'
                    AND books.lang = ANY(:langs ::text[])
            ) as books_count
        FROM sequences
        WHERE name % :query AND
        EXISTS (
            SELECT * FROM book_sequences
            LEFT JOIN books ON (books.id = book)
            WHERE sequence = sequences.id AND books.is_deleted = 'f' AND
                books.lang = ANY(:langs ::text[])
        )
    )
    SELECT fsequences.id FROM filtered_sequences as fsequences
    ORDER BY fsequences.sml DESC, fsequences.books_count DESC
    LIMIT 210
);
"""


class SequenceTGRMSearchService(TRGMSearchService):
    MODEL_CLASS = Sequence
    PREFETCH_RELATED = ["source"]

    GET_OBJECT_IDS_QUERY = GET_OBJECT_IDS_QUERY


GET_OBJECTS_ID_QUERY = """
WITH filtered_sequences AS (
    SELECT id FROM sequences
    WHERE EXISTS (
        SELECT * FROM book_sequences
        LEFT JOIN books
        ON (books.id = book AND
            books.is_deleted = 'f' AND
            books.lang = ANY(:langs ::text[]))
        WHERE sequence = sequences.id
    )
)
SELECT id FROM filtered_sequences
ORDER BY RANDOM() LIMIT 1;
"""


class RandomSequenceServiceQuery(TypedDict):
    allowed_langs: frozenset[str]


class GetRandomSequenceService(GetRandomService[Sequence, RandomSequenceServiceQuery]):
    MODEL_CLASS = Sequence  # type: ignore
    PREFETCH_RELATED = ["source"]

    GET_OBJECTS_ID_QUERY = GET_OBJECTS_ID_QUERY


class SequenceMeiliSearchService(MeiliSearchService):
    MODEL_CLASS = Sequence
    PREFETCH_RELATED = ["source"]

    MS_INDEX_NAME = "sequences"
    MS_INDEX_LANG_KEY = "langs"