Работающий функционал

app/genre_utils.py

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+#!/usr/bin/env python3
+"""Модуль для работы с жанрами"""
+from db_utils import get_cursor
+
+
+def get_root_genres():
+    """Возвращает корневые жанры с количеством книг"""
+    conn, cur = get_cursor()
+
+    cur.execute("""
+        SELECT g.id, g.code, g.title_ru, g.title_en,
+               COUNT(DISTINCT bg.book_id) as books_count
+        FROM genres g
+        LEFT JOIN book_genres bg ON bg.genre_id = g.id
+        WHERE g.is_root = TRUE
+        GROUP BY g.id, g.code, g.title_ru, g.title_en
+        ORDER BY books_count DESC
+    """)
+
+    genres = cur.fetchall()
+    conn.close()
+    return genres
+
+
+def get_subgenres(root_code):
+    """Возвращает поджанры для корневого жанра"""
+    conn, cur = get_cursor()
+
+    cur.execute("""
+        SELECT g.id, g.code, g.title_ru, g.title_en,
+               COUNT(DISTINCT bg.book_id) as books_count
+        FROM genres g
+        LEFT JOIN book_genres bg ON bg.genre_id = g.id
+        WHERE g.root_code = %s AND g.is_root = FALSE
+        GROUP BY g.id, g.code, g.title_ru, g.title_en
+        ORDER BY books_count DESC
+    """, (root_code,))
+
+    genres = cur.fetchall()
+    conn.close()
+    return genres
+
+
+def get_genre_books(genre_id, limit=100, offset=0):
+    """Возвращает книги жанра"""
+    conn, cur = get_cursor()
+
+    cur.execute("""
+        SELECT b.id, b.title, b.language, b.added_date,
+               string_agg(DISTINCT a.full_name, ', ' ORDER BY ba.position) as authors
+        FROM books b
+        JOIN book_genres bg ON bg.book_id = b.id
+        JOIN book_authors ba ON ba.book_id = b.id
+        JOIN authors a ON a.id = ba.author_id
+        WHERE bg.genre_id = %s
+        GROUP BY b.id, b.title, b.language, b.added_date
+        ORDER BY b.added_date DESC NULLS LAST
+        LIMIT %s OFFSET %s
+    """, (genre_id, limit, offset))
+
+    books = cur.fetchall()
+    conn.close()
+    return books
+
+
+def get_custom_genres():
+    """Возвращает кастомные жанры (не из genres.xml)"""
+    conn, cur = get_cursor()
+
+    cur.execute("""
+        SELECT g.code, g.parent_code, g.root_code,
+               COUNT(DISTINCT bg.book_id) as books_count
+        FROM genres g
+        LEFT JOIN book_genres bg ON bg.genre_id = g.id
+        WHERE g.is_custom = TRUE
+        GROUP BY g.code, g.parent_code, g.root_code
+        ORDER BY books_count DESC
+    """)
+
+    genres = cur.fetchall()
+    conn.close()
+    return genres