#!/usr/bin/env python3
"""Модуль для работы с базой данных"""
import psycopg2
import psycopg2.extras
import os

DB_CONN = os.environ.get(
    'DB_CONN',
    'dbname=books user=postgres password=Karabas@Barabas host=172.20.0.4'
)


def get_db():
    """Возвращает соединение с БД"""
    return psycopg2.connect(DB_CONN)


def get_cursor():
    """Возвращает соединение и курсор с RealDictCursor"""
    conn = get_db()
    cur = conn.cursor(cursor_factory=psycopg2.extras.RealDictCursor)
    return conn, cur


def get_stats():
    """Возвращает статистику библиотеки"""
    conn, cur = get_cursor()

    cur.execute("SELECT COUNT(*) as cnt FROM books")
    books_count = cur.fetchone()['cnt']

    cur.execute("SELECT COUNT(*) as cnt FROM authors")
    authors_count = cur.fetchone()['cnt']

    cur.execute("SELECT COUNT(*) as cnt FROM series")
    series_count = cur.fetchone()['cnt']

    cur.execute("SELECT COUNT(*) as cnt FROM genres")
    genres_count = cur.fetchone()['cnt']

    conn.close()

    return {
        'books': books_count,
        'authors': authors_count,
        'series': series_count,
        'genres': genres_count
    }